Constipation 

Updated: Jul 05, 2019
Author: Marc D Basson, MD, PhD, MBA, FACS; Chief Editor: BS Anand, MD 

Overview

Practice Essentials

Constipation is a symptom rather than a disease, generally defined as when bowel movements occur three or fewer times a week and are difficult to pass.[1] It is the one of the most common digestive complaints in the United States.[2] Despite its frequency, it often remains unrecognized until the patient develops sequelae, such as anorectal disorders. (See the image below.)

Constipation. Note the large amount of stool throu Constipation. Note the large amount of stool throughout the colon on this radiograph.

Signs and symptoms

According to the Rome IV criteria for constipation, a patient must have experienced at least two of the following symptoms over the preceding 6 months:

  • Fewer than three spontaneous bowel movements per week

  • Straining for more than 25% of defecation attempts

  • Lumpy or hard stools for at least 25% of defecation attempts

  • Sensation of anorectal obstruction or blockage for at least 25% of defecation attempts

  • Sensation of incomplete defecation for at least 25% of defecation attempts

  • Manual maneuvering required to defecate for at least 25% of defecation attempts

In addition, the patient must rarely have loose stools present without use of a laxative and must not meet Rome IV criteria for irritable bowel syndrome (IBS).

A constipated patient may be otherwise totally asymptomatic or may complain of one or more of the following:

  • Abdominal bloating

  • Pain on defecation

  • Rectal bleeding

  • Spurious diarrhea

  • Low back pain

The following also suggest that the patient may have difficult rectal evacuation:

  • Feeling of incomplete evacuation

  • Digital extraction

  • Tenesmus

  • Enema retention

The following signs and symptoms, if present, are grounds for particular concern:

  • Rectal bleeding

  • Abdominal pain (suggestive of possible IBS with constipation [IBS-C])

  • Inability to pass flatus

  • Vomiting

See Presentation for more detail.

Diagnosis

An extensive workup of the constipated patient is performed on an outpatient basis and usually occurs after approximately 3-6 months of failed medical management. Features of the workup are as follows:

  • Rectal and perineal examination should already have been performed but should be repeated

  • Laboratory evaluation does not play a large role in the initial assessment of the patient

  • Imaging studies are used to rule out acute processes that may be causing colonic ileus or to evaluate causes of chronic constipation

  • In patients with acute abdominal pain, fever, leukocytosis, or other symptoms suggesting possible systemic or intra-abdominal processes, imaging studies are used to rule out sources of sepsis or intra-abdominal problems

  • Lower gastrointestinal (GI) endoscopy, colonic transit study, defecography, anorectal manometry, surface anal electromyography (EMG), and balloon expulsion testing may be used in the evaluation of constipation

See Workup for more detail.

Management

Initial treatment measures for constipation include manual disimpaction and transrectal enemas. A well-lubricated gloved finger might be required in patients with lower anorectal impactions. These initial measures are then followed by elective evaluation of the causes of constipation.

Medical care should focus on dietary changes and exercise rather than laxatives, enemas, and suppositories, none of which really address the underlying problem.

The key to treating most patients with constipation is correction of dietary deficiencies, which generally involves increasing intake of fiber and fluid and decreasing the use of constipating agents (eg, milk products, coffee, tea, alcohol).

Medications to treat constipation include the following:

  • Bulk-forming agents (fibers; eg, psyllium): arguably the best and least expensive medication for long-term treatment

  • Emollient stool softeners (eg, docusate): Best used for short-term prophylaxis (eg, postoperative)

  • Rapidly acting lubricants (eg, mineral oil): Used for acute or subacute management of constipation

  • Prokinetics (eg, tegaserod): Proposed for use with severe constipation-predominant symptoms

  • Stimulant laxatives (eg, senna): Over-the-counter agents commonly but inappropriately used for long-term treatment of constipation

Newer therapies for constipation include the following:

  • Prucalopride is a prokinetic selective 5-hydroxytryptamine-4 (5-HT4) receptor antagonist that stimulates colonic motility and decreases the transit time

  • The osmotic agent lubiprostone is FDA approved for constipation caused by IBS[3] and opioid-induced constipation[4] in adults with chronic, noncancer pain

  • Linaclotide[5] and plecanatide[6, 7] are guanylate cyclase C (GC-C) agonists; they are indicated for chronic idiopathic constipation. Additionally, linaclotide is indicated for constipation caused by IBS in adults

  • Several peripherally-acting mu-opioid receptor antagonists (PAMORA) have been approved by the FDA for opioid-induced constipation in adults with chronic noncancer pain and/or for palliative care (eg, naloxegol, methylnaltrexone, naldemedine)

See Treatment and Medication for more detail.

Background

Constipation is one of the most common digestive complaints in the United States.[2]  It is a symptom rather than a disease and, despite its frequency, often remains unrecognized until the patient develops sequelae, such as anorectal disorders.

No widely accepted clinically useful definition of constipation exists. Healthcare providers usually use the frequency of bowel movements (ie, less than three bowel movements per week) to define constipation.[1] However, the Rome criteria, initially introduced in 1988 and subsequently modified three times to yield the Rome IV criteria, have become the research-standard definition of constipation.[8]

According to the Rome IV criteria for constipation, a patient must have experienced at least two of the following symptoms over the preceding 3 months:

  • Fewer than three spontaneous bowel movements per week

  • Straining for more than 25% of defecation attempts

  • Lumpy or hard stools for at least 25% of defecation attempts

  • Sensation of anorectal obstruction or blockage for at least 25% of defecation attempts

  • Sensation of incomplete defecation for at least 25% of defecation attempts

  • Manual maneuvering required to defecate for at least 25% of defecation attempts

The Rome IV criteria also stipulate that a patient should not meet the suggested criteria for irritable bowel syndrome (IBS) and that loose stools are rarely present without the use of laxatives.

For surgical purposes, the most useful definition of constipation is simply a change in bowel habit or defecatory behavior that results in acute or chronic symptoms or diseases that would be resolved with relief of the constipation.

Acute or subacute constipation in middle-aged or elderly patients should prompt a search for an obstructing colonic lesion. Acute constipation must be carefully distinguished from ileus secondary to intra-abdominal emergencies, including infections.

Constipation is frequently chronic, can significantly affect an individual’s quality of life, and may be associated with significant health care costs. It is considered chronic if it is present for at least 12 weeks (in total, not necessarily consecutively) during the previous year. Chronic constipation may be associated with psychological disturbances, and the reverse is true as well. However, these issues are beyond the scope of this article.

Laboratory evaluation does not play a large role in the initial assessment of the patient. Imaging studies are used to rule out acute processes that may be causing colonic ileus, to evaluate causes of chronic constipation, or to rule out sources of sepsis or intra-abdominal problems. Lower gastrointestinal (GI) endoscopy, anorectal manometry, electromyography (EMG), and balloon expulsion study may be used in the evaluation of constipation.

Medical care should focus on dietary changes and exercise rather than laxatives, enemas, and suppositories, none of which really addresses the underlying problem. Surgical care is generally restricted to the evaluation of underlying causes; it may also be indicated for the management of acute complications of constipation. Once acute constipation has resolved and the associated medical or surgical conditions have been ruled out, additional inpatient care is rarely indicated.

Pathophysiology

Constipation is divided, with considerable overlap, into issues of stool consistency (hard, painful stools) and issues of defecatory behavior (infrequency, difficulty in evacuation, straining during defecation). Although hard stools frequently result in defecatory difficulties, soft bulky stools may also be associated with constipation, particularly in elderly patients with anatomic abnormalities and in patients with impaired colorectal motility.

Constipation may originate primarily from within the colon and rectum or may originate externally. Processes involved in constipation originating from the colon or rectum include the following:

  • Colon obstruction (neoplasm, volvulus, stricture)

  • Slow colonic motility, particularly in patients with a history of chronic laxative abuse

  • Outlet obstruction (anatomic or functional) - Anatomic outlet obstruction may derive from intussusception of the anterior wall of the rectum on straining, rectal prolapse, and rectocele; functional outlet obstruction may derive from puborectalis or external sphincter spasm when bearing down, short-segment Hirschsprung disease, and damage to the pudendal nerve, typically related to chronic straining or vaginal delivery

  • Hirschsprung disease in children

  • Chagas disease

Factors involved in constipation originating outside the colon include poor dietary habit (the most common factor, generally involving inadequate fiber or fluid intake and/or overuse of caffeine or alcohol), medications, systemic endocrine or neurologic diseases, and psychological issues.

Constipation results in various degrees of subjective symptoms and is associated with abnormalities (eg, colonic diverticular disease, hemorrhoidal disease, anal fissures) that occur secondary to an increase in the colonic luminal pressure and intravascular pressure in the hemorrhoidal venous cushions.

Nearly 50% of patients with diverticular or anorectal disease, when asked, deny experiencing constipation. On careful questioning, however, nearly all of these patients report having symptoms suggestive of defecatory straining or infrequency, mostly constipation related, although occasionally diarrhea related in patients with irritable bowel or other chronic diarrheal disorders.

Etiology

The etiology of constipation is usually multifactorial, but it can be broadly divided into two main groups: primary constipation and secondary constipation.

Primary constipation

Primary (idiopathic, functional) constipation can generally be subdivided into the following three types:

  • Normal-transit constipation (NTC)

  • Slow-transit constipation (STC)

  • Pelvic floor dysfunction (ie, pelvic floor dyssynergia)

NTC is the most common subtype of primary constipation. Although the stool passes through the colon at a normal rate, patients find it difficult to evacuate their bowels. Patients in this category sometimes meet the criteria for IBS with constipation (IBS-C). The primary difference between chronic constipation and IBS-C is the prominence of abdominal pain or discomfort in IBS. Patients with NTC usually have a normal physical examination.

STC is characterized by infrequent bowel movements, decreased urgency, or straining to defecate. It occurs more commonly in female patients. Patients with STC have impaired phasic colonic motor activity. They may demonstrate mild abdominal distention or palpable stool in the sigmoid colon.

Pelvic floor dysfunction is characterized by dysfunction of the pelvic floor or anal sphincter. Patients often report prolonged or excessive straining, a feeling of incomplete evacuation, or the use of perineal or vaginal pressure during defecation to allow the passage of stool, or they may report digital evacuation of stool.

Secondary constipation

Dietary issues that may cause constipation include inadequate water intake; inadequate fiber intake; overuse of coffee, tea, or alcohol; a recent change in bowel habit paralleled by changes in the diet; and ignoring the urge to defecate. Reduced levels of exercise may play a role as well.

Structural causes of secondary constipation include anal fissures, thrombosed hemorrhoids, colonic strictures, obstructing tumors, volvulus, and idiopathic megarectum.

Systemic diseases that may cause constipation include the following:

  • Endocrinologic and metabolic disorders - Hypercalcemia, hyperparathyroidism, hypokalemia, hypothyroidism, pregnancy, and diabetes mellitus (constipation is the most common gastrointestinal problem affecting the diabetic population)

  • Neurologic disorders - Stroke, Hirschsprung disease, Parkinson disease, multiple sclerosis, diabetic autonomic neuropathy, spinal cord lesion, head injury, cerebrovascular accident, Chagas disease, and familial dysautonomia

  • Connective-tissue disorders - Scleroderma, amyloidosis, and mixed connective-tissue disease

Often, what appears to be an acute or subacute constipation may represent a colonic or small bowel ileus from systemic or intra-abdominal infection or other intra-abdominal emergencies. In appropriate settings, this should be addressed and not missed, lest the patient’s condition deteriorate acutely.

Medications that may contribute to constipation include the following:

  • Antidepressants (eg, cyclic antidepressants and monoamine oxidase inhibitors [MAOIs])

  • Metals (eg, iron and bismuth)

  • Anticholinergics (eg, benztropine and trihexyphenidyl)

  • Opioids (eg, codeine and morphine)

  • Antacids eg, (aluminum and calcium compounds)

  • Calcium channel blockers (eg, verapamil)

  • Nonsteroidal anti-inflammatory drugs (NSAIDs; eg, ibuprofen and diclofenac)

  • Sympathomimetics (eg, pseudoephedrine)

  • Many psychotropic drugs[9]

  • Cholestyramine and stimulant laxatives (long-term use) - Although laxatives are frequently used to treat constipation, chronic laxative use becomes habituating and may lead to the development of a dilated atonic laxative colon, which necessitates increasing laxative use with decreasing efficacy

  • Inadequate thyroid hormone supplementation

Constipation may be of toxicologic origin, as with lead poisoning.

Psychological issues (eg, depression, anxiety, somatization, and eating disorders) may also contribute to the development of constipation.

Epidemiology

United States statistics

Chronic constipation is highly prevalent and affects approximately 15% of persons in the United States.[10] In 2006, the number of constipation-related physician visits reached 5.7 million, and of these, 2.7 million visits had constipation as the primary diagnosis.[11] About 2% of the population describes constant or frequent intermittent episodes of constipation.

International statistics

Prevalence of self-reported constipation varies substantially because of differences among ethnic groups in how constipation is perceived. In North America alone, chronic constipation affects approximately 63 million people. Worldwide, approximately 12% of people suffer from self-defined constipation; people in the Americas and the Asian Pacific suffer twice as much as their European counterparts.

A meta-analysis of patients in Europe and Oceania cited prevalence rates as high as 81%, with a general incidence of approximately 17%. Female sex, age, and educational class were strongly associated with the prevalence of constipation.[12]

Age-related demographics

Constipation can occur in all ages, from newborns to elderly persons. An age-related increase in the incidence of constipation has been observed, with 30%-40% of adults older than 65 years citing constipation as a problem.[13] The increased frequency of constipation in adults older than 65 years may reflect a combination of etiological factors such as dietary alterations, a decrease in muscle tone and exercise, and the use of medications that may result in relative dehydration or colonic dysmotility.[14] Some researchers suggest that cumulative exposure to environmental neurotoxins may play a role.

In some patients, chronic or repeated pelvic injury (eg, from pregnancies) or the development of anatomic abnormalities (eg, rectal prolapse or rectocele [weakness in the posterior vaginal wall that allows the rectum to prolapse into the vagina upon straining]) may lead to functional outlet obstruction.

Sex-related demographics

In the United States, self-reported constipation and admissions to hospital for constipation are more common in women than in men. The overall female-to-male ratio is approximately 3:1. Women are also more likely to receive care for constipation. The condition is seen fairly frequently during pregnancy and is a common problem after childbirth. Surveys of apparently healthy young men and women demonstrate a slightly higher stool frequency among women.

Race-related demographics

In the United States, the prevalence of constipation is 30% higher among nonwhite populations than among white populations.[10] Both self-reported constipation and constipation requiring admission to a hospital are more frequent in black people than in white people.

Whereas constipation is less common in Asians, it is more frequent in those who adopt a Western diet.

In contrast, constipation is less frequent among black Africans than white Africans, further suggesting that diet and other environmental factors play an important role.

Prognosis

Most active patients do well with medical management and appropriate dietary management. Recurrence depends on the patient’s long-term compliance with therapy. A small percentage of patients are quite debilitated as a result of constipation. Some patients with functional (primary or idiopathic) constipation (ie, colonic inertia) require total abdominal colectomy with ileorectal anastomosis.

After a careful preoperative workup that includes physical and psychological assessment, patients with outlet obstruction generally respond well to surgical correction and have a good prognosis.

Dyskinesias of the pelvic floor musculature and of the sphincter mechanism may be managed via biofeedback therapy, but the results are mixed.

Patients who are chronically dependent on increasing doses of self-prescribed laxatives are perhaps the most difficult patients to treat. Most such patients can be treated with a combination of fiber, water, and osmotic agents (eg, polyethylene glycol ,sorbitol). However, the need for increasing the doses of laxatives and the intermittent use of other agents becomes problematic.

In rare situations in which patients have constipation that is virtually refractory to laxatives, total abdominal colectomy may be performed after careful workup. Postoperatively, these patients often experience a greatly improved quality of life. A careful preoperative evaluation and a detailed informed consent discussion are required.

Complications

Difficulty in defecation may cause substantial discomfort, abdominal cramping, and a general feeling of malaise.

Actual or perceived constipation typically results in self-medicating with various laxatives. Although laxatives may correct the acute problem, chronic use of these agents leads to habituation, necessitating ever-increasing doses that result in drug dependency and, ultimately, a hypotonic laxative colon. Melanosis coli from prolonged laxative use is an incidental finding at endoscopy.

Acute or chronic episodes of straining may cause acute or chronic hemorrhoidal disease (characterized by pain, itching, or bleeding) or acute hemorrhoidal thrombosis (characterized by intense pain and acute engorgement of one or more of the hemorrhoidal columns). Generally, hemorrhoids are medically managed; surgical intervention is reserved for when medical management fails.

Whether constipation actually causes hemorrhoidal disease is viewed as controversial by some authors. However, upon careful questioning, these patients frequently provide a history of recent defecatory difficulties, most commonly constipation related, although less commonly diarrhea related (with the exception of patients in the early postpartum period). Furthermore, conservative management of hemorrhoidal disease is more likely successful when future straining is prevented.

The passage of hard stools may result in an acute anal fissure, which is a painful tear in the anoderm that may bleed. The regular passage of hard stools and the painful anal spasms during defecation that impinge the hard stools against the fresh wound prevent the anal fissure from healing. Generally, fissures are managed medically. In addition to local wound care and analgesia, softening of stools is essential for successful management. Surgical intervention is reserved for when medical management fails.

Constipation may be one cause of pelvic floor damage in women. Using structured questionnaires, Amselem et al determined that 61 out of 596 women (10%) attending a gynecologic clinic had pelvic floor damage; constipation was present in 19 of the 61 (31%), rivaling the frequency of obstetric trauma (also 19 women) among these patients.[15]

Amselem et al also determined that of the 535 women without pelvic floor damage, 86 (16%) had constipation and 83 (15.5%) had obstetric trauma.[15] Employing univariate analysis, they reported odds ratios of 2.36 for constipation and 2.46 for obstetric trauma associated with pelvic floor damage. On the basis of their data, the authors suggested that constipation and obstetric trauma are equally important in the development of pelvic floor damage.

The chronic pressure effect of hard stools against the anterior rectal wall when the patient strains during defecation is believed to cause solitary rectal ulcers. This is usually a self-limiting process and responds to treatment of constipation. In adults, surgical or gastroenterologic consultation may be required to differentiate benign solitary rectal ulcers from rectal malignancy.

Other complications of constipation may include the following:

  • Fecal impaction

  • Bowel obstruction

  • Fecal incontinence

  • Stercoral ulceration/perforation

  • Megacolon

  • Volvulus

  • Rectal prolapse

  • Urinary retention

  • Syncope

  • Fistula in ano

Patient Education

Patient education regarding constipation typically involves instructions for improving dietary management. Dietary deficiency requires increased fluid and fiber supplementation for life. For patients who implement recommended dietary changes, the prognosis is excellent.

For patient education resources, see the Digestive Disorders Center, as well as Constipation (Adults) and Constipation in Children (Infants).

 

Presentation

History

Basing the diagnosis of constipation on simply asking the patients whether they are constipated is associated with marked underreporting of the problem in patients who have physical evidence of constipation, such as the presence of hemorrhoidal disease.[16] Accordingly, a careful history must be obtained, including inquiries into current medications (including over-the-counter, herbal agents, and prescription medications), previous colonoscopy, and any other medical problems present.

A constipated patient may be otherwise totally asymptomatic or may complain of one or more of the following:

  • Abdominal bloating

  • Pain on defecation

  • Rectal bleeding

  • Spurious diarrhea

  • Low back pain

The following also suggest that the patient may have difficult rectal evacuation:

  • Feeling of incomplete evacuation

  • Digital extraction

  • Tenesmus

  • Enema retention

The following signs and symptoms, if present, are grounds for particular concern:

  • Rectal bleeding

  • Abdominal pain (suggestive of possible irritable bowel syndrome [IBS] with constipation [IBS-C])

  • Inability to pass flatus

  • Vomiting

  • Unexplained weight loss

The history should begin with a detailed inquiry into the patient’s normal pattern of defecation, the frequency with which the current problem differs from the normal pattern (eg, “missing a day”), the perceived hardness of the stools, whether the patient strains in order to defecate, and any other symptoms the patient may be experiencing.

An inquiry concerning the amount of time spent on the toilet while waiting to defecate may also be illuminating. Patients should be asked to describe in detail what happens when they try to defecate and what maneuvers (pharmacologic or physical) they have used to facilitate this process. The answers to these questions may suggest chronic laxative abuse or less common causes, such as colonic outlet obstruction.

The duration of the problem is important. In adolescents and young adults, the duration of the problem may differentiate congenital defects from acquired causes. Neoplastic obstruction is less likely in younger patients or in patients older than 50 years who have had symptoms for at least 2 years and/or have recently had a screening colonoscopy. However, colon cancer certainly occurs in younger adults and even rarely in teenagers, while a previous screening colonoscopy may have missed a neoplasm.

The onset of symptoms is also very important, in that intestinal obstruction can present as acute constipation. In the hospital setting, ileus from another illness or Ogilvie syndrome should also be considered. Questions regarding the onset of constipation may provide useful etiologic information, whether in terms of changes in diet, new medications, or associated psychosocial difficulties at that time.

In addition to defining the nature of the patient’s bowel habit, it is necessary to try to identify the factors likely to be responsible for the abnormal bowel habit. Most patients who are constipated consume either too little fiber or too little water; therefore, assessing the patient’s diet is useful. For acute changes in the bowel habit, a parallel dietary change should be ascertained.

Learning how much fluid and what types of fluids the patient drinks on an average day is important. Epidemiologic studies have clearly established a link between coffee consumption and worsening constipation. The diuretic effects of coffee, tea, and alcohol are likely counterproductive. Milk products may cause constipation in some individuals.

The state of patients’ bowel motility represents a balance between factors that promote motility and factors that inhibit it. The most important influencing factor is exercise, which stimulates bowel motility. Conversely, narcotics, antipsychotic agents, and other constipating medications reduce motility. Diuretics or substantial amounts of coffee, tea, or alcohol decrease available water in the colon. Chronic laxative abuse also causes refractory constipation.

If the patient shows evidence of diseases or symptoms associated with constipation, such as diverticular disease, hemorrhoids, anal fissures, or fistula in ano, delineating these conditions historically and determining the nature of any previous therapy for them is appropriate. For instance, patients with hemorrhoids may neglect to mention that they were previously treated for this problem or that they have been receiving medications for constipation for several years.

Rectal bleeding should be taken seriously and evaluated carefully, particularly in patients who are older than 50 years or have a family history of colorectal disease. Patients with hemorrhoids may also have rectosigmoid cancer. Both cancer and hemorrhoids can produce bright red blood from the rectum. Most patients older than 50 years or with a family history of colorectal disease should be screened for colorectal cancer. A full colonoscopy is preferable, although in some cases flexible sigmoidoscopy or barium enema may be used if colonoscopy cannot be performed. The role of computed tomography (CT) colography in this setting awaits definition, although it offers an attractive alternative in the patient in whom a colonoscopy is attempted and fails.

Finally, the evaluation should include the patient’s description of the act of defecation. Pain during defecation might suggest a fissure or tenesmus from a rectal tumor. Painless inability to pass an otherwise soft stool suggests a rectal outlet obstruction.

Neurologic and endocrine disorders also can cause constipation. Most notably, diabetes may be associated with chronic dysmotility. Patients with hypothyroidism may exhibit decreased motility and slow transit times.[17] Patients with panhypopituitarism, pheochromocytoma, or multiple endocrine neoplasia 2B are also at risk for constipation. When no other cause can be determined, a careful endocrine review is particularly important for patients with a recent onset of constipation and for patients whose constipation is refractory to conservative treatment.

Similarly, central nervous system (CNS) diseases, such as Parkinson disease, multiple sclerosis, stroke, CNS syphilis, and spinal injury or tumors, may cause constipation and should be considered in the patient’s history and evaluation.

Some cases of constipation may have a psychogenic component. On one hand, constipation is a frequent somatic expression of psychological distress; on the other, constipation itself may give rise to psychological disturbances.

A history of sexual abuse is observed with unusual frequency in patients who are chronically constipated, particularly those with anismus (dyssynergic defecation). A history of other psychological abnormalities is often found, particularly among patients whose constipation is refractory to medical treatment and have normal bowel transit times and normal results from anorectal studies.

Such factors should be gently explored in patients in whom first-line conservative treatment has failed. Psychiatric referral may be appropriate in such patients when medical evaluation and therapy have been exhausted or when gentle questioning reveals some unexpected information.

Physical Examination

General physical examination often is of no benefit in determining the etiology or in deciding the treatment. In addition to the general evaluation, the abdomen, pelvis, and rectum, specifically, should be physically examined. Both the cause of constipation and its effects should be sought.[16]

Abdominal distention or masses may indicate the presence of colonic stools or tumors. Large abdominal wall hernias, especially ventral hernias, may interfere with generation of the intra-abdominal pressure required for the initiation of defecation. Rarely, a left-sided sliding inguinal hernia with an incarcerated sigmoid colon may cause difficulties in bowel movements.

It was once widely held that elderly patients with new inguinal hernias should be assumed to have occult constipation due to partially obstructing colonic neoplasms and that these patients therefore required colorectal cancer screening. At present, the requirement for colorectal cancer screening in such patients remains controversial. The pathophysiology underlying a link between colonic neoplasms and hernias is unknown, because the lesions detected on screening are early lesions and are unlikely to have caused constipation.

Pelvic examination in women should specifically address the posterior vaginal wall, with particular attention to any evidence of internal prolapse or rectocele. This region should be palpated while the patient is at rest and then while she is straining to defecate. Many women with rectocele do not experience constipation. Good surgical results are not guaranteed, and a thorough preoperative workup to rule out other potential causes of constipation should always be performed.

During the anorectal examination, the patient should be assessed for the following:

  • Perianal excoriation

  • Skin tags/hemorrhoids

  • Anal fissure

  • Anocutaneous reflex

  • Prolapse during straining

  • Stool amount and consistency - More stool is present within the rectal vault in pelvic outlet dysfunction than in colonic inertia or IBS, in which little or no stool remains in the rectum between defecations; pelvic floor dysfunction is manifested by failure of descent of the examining finger and contraction of the upper segment of the sphincter during straining

Digital rectal examination provides information about the following:

  • Anorectal masses

  • Tone of the internal anal sphincter

  • Strength of the external anal sphincter and puborectalis muscle

  • Presence of a rectocele (an outpouching usually present in the anterior rectal wall)

  • Presence of gross blood or occult bleeding by checking the stool guaiac

  • Presence of fecal impaction

The anorectal examination should attempt to ascertain the cause of the constipation. Causes that may be defined include the following:

  • Anal fissure, particularly in children who retain their feces in order to avoid painful defecation

  • Anal stenosis

  • Partially obstructing rectal masses

  • Rectal prolapse

Rectal prolapse may be either external or internal. The anus should be carefully examined for prolapse at rest and during a Valsalva maneuver. Care should be taken to distinguish a true full-thickness rectal prolapse from a mucosal prolapse, which is unlikely to cause constipation. Asking the patient to perform a Valsalva with the examining finger in the rectum in order to seek evidence of an internal prolapse may be worthwhile, although this is a relatively insensitive way of diagnosing prolapse.

In contrast to inguinal hernias, rectal prolapse is typically related to constipation. At least one retrospective study has demonstrated a strong association between rectal prolapse and rectosigmoid neoplasms in patients older than 50 years. Sigmoidoscopy is probably indicated for these patients, and a full colonoscopy should be performed if they are otherwise due for colorectal cancer screening.

In addition to delineating the cause of the constipation, the anorectal examination should be used to determine the effects of the constipation. The presence of fissures or fistulae, any evidence of scars from previous perirectal abscess drainages or other surgeries, and the nature of the patient’s hemorrhoidal columns should be noted and characterized. Enlarged hemorrhoids do not require treatment unless they cause symptoms.

Although the effectiveness of fecal occult blood testing has been hotly debated, performing such a test after a rectal examination in patients older than 50 years is probably worthwhile. The presence of blood in the stool warrants further evaluation. Never assume that the patient is bleeding from hemorrhoids or fissures until other sources of bleeding have been ruled out.

A complete physical evaluation of the patient should also include a search for the evidence of systemic diseases that may be contributing to constipation. Such systemic diseases include the following:

  • Endocrine dysfunctions (eg, hypothyroidism, hypopituitarism, and diabetes mellitus)

  • Neurologic abnormalities (eg, brain or spinal cord injury, peripheral neuropathy, multiple sclerosis, and Parkinson disease)

 

DDx

Diagnostic Considerations

It is important to be vigilant for colorectal cancer. Anal fissure should be considered in a constipated child. Colonic ileus secondary to sepsis or an intra-abdominal catastrophe may be misdiagnosed as constipation; large bowel obstruction may also be misdiagnosed as constipation.

In addition to the conditions listed in the differential diagnosis, the following problems should be considered:

  • Psychological causes

  • Diabetes mellitus

  • Hyperparathyroidism

  • Hypothyroidism

  • Uremia

  • Lead poisoning

  • Neuropathy

  • Parkinson disease

  • Multiple sclerosis

  • Spinal cord injuries

  • Scleroderma

  • Lupus

  • Amyloidosis

Differential Diagnoses

 

Workup

Approach Considerations

An extensive workup of the constipated patient is performed on an outpatient basis and usually occurs after approximately 3-6 months of failed medical management. Rectal and perineal examination should already have been performed but should be repeated at this point.

Laboratory evaluation does not play a large role in the initial assessment of the patient.

Imaging studies are used to rule out acute processes that may be causing colonic ileus or to evaluate causes of chronic constipation. In patients with acute abdominal pain, fever, leukocytosis, or other symptoms suggesting possible systemic or intra-abdominal processes, imaging studies are used to rule out sources of sepsis or intra-abdominal problems.

Lower gastrointestinal (GI) endoscopy, colonic transit study, defecography, anorectal manometry, surface anal electromyography (EMG), and balloon expulsion study may be used in the evaluation of constipation.

In the acute situation with a patient at low risk who usually is not constipated, no further evaluation is necessary. Consider sigmoidoscopy, colonoscopy, or barium enema for colorectal cancer screening in patients older than 50 years. Colonoscopy represents the current criterion standard. The role of computed tomography (CT) colography awaits further definition.

In children with refractory constipation, colonic and anorectal manometry may help in identifying a disorder of rectal evacuation or colonic motility.[18]  Those with rectal evacuation disorder may potentially benefit from biofeedback therapy or sphincter botulinum toxin.[18]

Regional colonic transit pattern does not conclusively identify evacuation disorders in constipated patients with delayed colonic transit.[19]

Laboratory Studies

A complete blood cell (CBC) count may reveal anemia that might be associated with rectal bleeding (gross or occult). Fecal occult blood should be tested in chronically constipated middle-aged or elderly adults to assess an obstructing neoplasm of the colon.

The leukocyte count is useful in patients presenting with abdominal pain or fever or providing an indication that the constipation is secondary to an ileus. This may lead to further, more aggressive evaluation.

Thyroid function tests may be helpful. Check thyroid-stimulating hormone (TSH) levels to rule out hypothyroidism in patients whose constipation is refractory to dietary management.

Serum chemistry may exclude a metabolic cause of constipation, such as hypokalemia and hypercalcemia. Determine the serum electrolyte profile, including measurements of potassium, calcium, glucose, and creatinine, in patients with recent-onset constipation to assess an acute electrolyte imbalance and in chronically constipated patients in whom the initial medical treatment has failed.

Radiography

In patients with acute abdominal pain, fever, leukocytosis, or other symptoms suggesting possible systemic or intra-abdominal processes, imaging studies are used to rule out sources of sepsis or intra-abdominal problems. Order an upright chest roentgenogram and a flat and upright abdominal film. The abdominal film may reveal a colon full of stool (see the images below), confirming the diagnosis of obstipation.

Constipation. Note the large amount of stool throu Constipation. Note the large amount of stool throughout the colon on this radiograph.
Constipation. A large stool mass is visible in the Constipation. A large stool mass is visible in the hepatic flexure of the colon.

Differentiation of fecal impaction (see the images below), bowel obstruction, and fecalith (hard mass of stools) is possible. Diagnosis of fecaliths is important because of the dreaded complication of stercoral ulcers, which can lead to colonic perforation. Stercoral perforation is a rare but life-threatening surgical emergency of perforation due to pressure necrosis that can lead to peritonitis.

Constipation. This radiograph reveals colon disten Constipation. This radiograph reveals colon distention secondary to fecal impaction.
Constipation. Pseudo-obstruction secondary to feca Constipation. Pseudo-obstruction secondary to fecal impaction is shown on this radiograph.

Diabetic gastropathy, as well as fecal impaction, may be seen in patients with diabetic neuropathy. Residual barium (from barium enemas) can be visualized. Scleroderma and other connective-tissue diseases may be complicated by motor disturbances that mimic colonic obstruction on plain films. Myxedema ileus is a consequence of hypothyroidism.

Computed Tomography Scanning

Abdominal computed tomography (CT) may be indicated to further evaluate the possibility of an intra-abdominal abscess. Acute constipation in the setting of an empty rectal vault and a proximal colon that is dilated with air or stool suggests large bowel obstruction, which should be further evaluated via Gastrografin (diatrizoate meglumine–diatrizoate sodium solution) enema or lower GI endoscopy (see below). Gastrografin enema has the advantage of acting as an osmotic laxative, which may aid in the evacuation of the colonic contents.

Barium or Gastrografin Study

An air-contrast barium enema is useful for assessing the possibility of an obstructing colon cancer, intermittent volvulus, or colonic stricture in the setting of chronic constipation. A barium study is preferable to a Gastrografin study for patients who do not present with an acute process. On the other hand, a Gastrografin study is preferable for patients with an acute abdomen because it prevents the risk of extravasation of barium into the peritoneal cavity through a perforated diverticulum or colon cancer.

In patients with suspected colonic obstruction, the author prefers to use colonoscopy rather than barium enema, but either modality may suffice.

Defecography

Defecography should be performed if an obstruction is suspected at the level of the anal canal. Fill the rectosigmoid with barium paste and fluoroscopically observe the act of defecation. This test may demonstrate alterations in the anorectal angle during defecation, presence of pelvic floor weakness,[15] or transient rectal prolapse or intussusception.

Colonic Transit Study

Colonic transit time should be determined in patients suspected of having a colonic motility disorder. Accomplish this by observing the passage of orally administered radiopaque markers via daily abdominal roentgenograms. Record the time taken for the passage of the markers and the site where they appear to be retained. A patient with outlet obstruction tends to retain the markers in the left colon and sigmoid, whereas a patient with colonic dysmotility may retain the markers throughout the colon.

Lower Gastrointestinal Endoscopy

Urgent lower GI endoscopy is useful in patients who are acutely constipated if large bowel obstruction is suspected based on an empty rectal vault and a distended proximal colon. Colonoscopy should not be performed if perforation or acute diverticulitis or other infectious processes are suspected because of the risk of worsening intra-abdominal contamination caused by colonic distension during the procedure.

In the acute setting, either a bowel preparation is not used or, at the most, 1-2 gentle enemas are employed.

Flexible endoscopy is generally preferred to rigid endoscopy because the former is more comfortable for the patient, provides a better view for the endoscopist, and permits access to more of the colon. Rigid endoscopy may be used in an urgent situation when flexible endoscopy is not available.

Advance the flexible endoscope into the rectosigmoid until the site of the obstruction is reached or until the splenic flexure is identified, which suggests the absence of a rectosigmoid obstruction. If the initial sigmoidoscopy reveals no abnormal findings or if the constipation is more chronic, the patient should subsequently undergo a standard oral bowel preparation and either colonoscopy (the author’s preference) or air-contrast barium enema for a fuller evaluation of the remainder of the colon.

Anorectal Manometry

Anorectal manometry documents several parameters, including the following:

  • External anal sphincter and puborectalis function

  • Reflex relaxation of the internal sphincter when the rectum is distended

  • Coordination of these muscles during the bear-down phase of defecation

  • Anorectal pressures during these events

  • The threshold at which rectal distention is perceived

Interpreting the results of anorectal manometry is complex and varies with the center performing the test. Consult a specialist familiar with the local testing facilities.

Other Studies

Controlled pressure-based rectal distention with fluoroscopic rectal imaging to measure the rectal diameter at the minimal distention pressure may be useful in identifying idiopathic megabowel in the absence of an organic cause or other problems.[20]

EMG documents paradoxical external sphincter or puborectalis spasm during defecation, consistent with the diagnosis of anismus. It is useful during subsequent biofeedback training because the patient is taught to relax these muscles.

In balloon expulsion test, a balloon filled with varying amounts of water is inserted rectally. The patient is asked to expel the balloon. Decreased ability to expel a balloon filled with 150 mL of water suggests decreased defecatory ability.

Anoscopy should be routinely performed on all constipated patients to look for anal fissures, ulcers, hemorrhoids, and local anorectal malignancy.

Deep rectal biopsy, sometimes with double or triple bite techniques, may be used to diagnose Hirschsprung disease.

Histologic findings include the histology of any obstructing colonic lesion (eg, neoplasms, strictures from Crohn disease, diverticulitis, or ischemia) and the agangliosis of Hirschsprung disease.

 

Treatment

Approach Considerations

Manual disimpaction and transrectal enemas may be used after any critical illness associated with constipation has been ruled out. A well-lubricated gloved finger might be required in patients with lower anorectal impactions. Warm water enemas usually are unpopular among the nursing staff and probably are not necessary within the emergency department (ED). These initial measures are then followed by elective evaluation of the causes of the constipation.

Medical care should focus on dietary change and exercise rather than laxatives, enemas, and suppositories, none of which really address the underlying problem. The patient is at a high risk for becoming dependent on laxatives and developing a laxative colon. If conservative measures fail and the patient is clearly compliant with the advice, a more detailed evaluation should be performed (see Workup).

In addition, in January 2014, the FDA issued a warning that exceeding one dose of OTC sodium phosphate products for constipation over a course of 24 hours may cause serious harm to the kidneys and heart and, in rare cases, may be fatal.[21, 22] Using more than the recommended dose of these products can cause severe dehydration and changes in serum electrolyte levels. Individuals who may be at a higher risk for potential adverse events include young children; patients older than 55 years; patients who are dehydrated; patients with kidney disease, bowel obstruction, or inflammation of the bowel; and patients who are using medications that may affect kidney function.[21, 22]

The key to treating most patients with constipation is correction of dietary deficiencies. Although some controversy exists about the effectiveness of exercise in constipation treatment, encouraging as much aerobic exercise as possible seems reasonable. Even brisk walking may help stimulate bowel motility and, certainly, is unlikely to hurt most patients.

Counsel the patient regarding the appropriate dietary prophylaxis with follow-up visits on an outpatient basis. If the patient experiences further episodes of constipation, a more detailed evaluation may then become appropriate (see Workup).

Surgical care is generally restricted to the evaluation of underlying causes or the management of acute complications of constipation. For children with constipation, operative management includes the use of antegrade continence enemas, sacral nerve stimulation, and colonic resection.[18] Surgical intervention for constipation should be avoided in a patient with an underlying psychiatric cause.

Once acute constipation has resolved and the associated medical or surgical conditions have been ruled out, additional inpatient care is rarely indicated. Patients requiring surgical intervention for acute conditions require postoperative care; however, that is beyond the scope of this article.

Generally, transfer to another facility is not required unless that there is uncertainty about the diagnosis or the underlying cause and more aggressive medical evaluation is deemed necessary. Such an eventuality might occur in patients institutionalized in nursing homes or in chronic care facilities who require medical consultations to rule out conditions that are more serious. The following factors may warrant a transfer:

  • Uncertain diagnosis

  • Evidence of intra-abdominal catastrophe

  • Acute abdominal pain

  • Fever

  • Lower gastrointestinal (GI) bleeding

  • Chills

  • Instability of vital signs

  • Absence of bowel sounds

  • Acute recent change in bowel habits

  • Unsuccessful or inadequate treatment offered at the local facility

An international expert consensus (Delphi Survey) established five symptoms and their severities to define treatment failure to provide adequate relief in patients with chronic constipation.[23] They indicated that if any one of the following five statements is applicable to a patient, their current therapy has failed to provide adequate relief.[23]

  • The patient reports an inadequate number of bowel movements most of the time in addition to having complete bowel movements occur on fewer than 3 days per week.
  • Straining is required on most occasions or is becoming worse.
  • The stool consistency has not improved on the current therapy in addition to having a Bristol Stool Scale Type 1 or Type 2 (ie, lumpy and hard or small and very hard).
  • The patient reports inadequate improvement of another symptom/sign of chronic constipation while on the current therapy
  • The current therapy is poorly tolerated, such that any relief gained is unacceptable to the patient.

Dietary Measures

The key to treating most patients with constipation is correction of dietary deficiencies. This generally involves increasing intake of fiber and fluid and decreasing the use of constipating agents, such as milk products, coffee, tea, and alcohol.

Increased fiber intake

Dietary fiber is available in diverse natural sources, such as fruits, vegetables, and cereals. Ingestion of natural fiber sources is nutritionally superior to supplementation with purified fiber. However, advising patients to eat more fruits and vegetables is frequently unsuccessful, at least in American patients. American patients do respond reasonably well to prescriptions and often seek them; accordingly, prescribing a fiber supplement, such as wheat, psyllium, or methylcellulose, is often useful.

Many of the available products vary substantially in their potency. For instance, sugar-free Metamucil (psyllium) has twice the potency of standard Metamucil on a volume basis because the latter is half sugar. Pharmaceutical companies may argue that one type of fiber is better tolerated or more effective than another. This may not make much difference in treatment or in fiber tolerance in most patients as long as the fiber supplementation doses start low and are slowly titrated upward.

Theoretical considerations suggest that the use of a fermentable fiber, which increases short-chain fatty acid concentrations in the colonic lumen, may have other health benefits (as opposed to methylcellulose). However, this suggestion remains controversial and awaits further exploration.

Because no convincing reason exists to pick one product over another, a single brand of choice should be prescribed until the patient’s constipation resolves. The patient may then switch to generic or other brands with appropriate dose adjustments.

The author’s experience has been that some patients have preferences based on the taste of the product or other subjective reasons. In particular, those rare patients who cannot tolerate fermentable fiber supplementation because of resulting gas or bloating may do better with methylcellulose, whereas others may find that the quality of the stool, taste preferences, or both favor psyllium supplementation.

To prevent patient noncompliance resulting from the cramping and bloating that may accompany changes in dietary fiber, fiber supplementation should be started at a low subtherapeutic dose and titrated upwards on a weekly basis until the desired effect is achieved. Patients should continue to increase the dose on a weekly basis until they experience daily bowel movements with no straining or until they reach the maximum dose.

Patients should be cautioned that these products are not laxatives, will not induce a bowel movement, and must be taken daily regardless of their perceived need.

Patients may increase or decrease their dose on a week-to-week basis. In particular, the author advises patients who have arrived at what they believe to be an appropriate and successful dose to increase the dose one additional step for at least a week and then back down if they wish. Some patients find that they actually prefer the higher dose. To ensure long-term compliance, the author believes that patients should titrate the doses in case of changes in potency between fiber supplement brands or changes in diet, fluid intake, or exercise.

Patients should be cautioned that, although various stool softeners, such as docusate sodium, appear much more palatable than fiber, they are not suitable for long-term use. Tachyphylaxis to stool softeners develops over time.

Increased fluid intake

Fluid intake is the key to treatment. Patients should be advised to drink at least 8 glasses of water daily. Counseling may be required to achieve this goal.

Milk and milk products should be minimized if these prove constipating.

In some patient populations, coffee, tea, and alcohol account for the majority of the fluid volume consumed. Patients should be made to understand that because of the diuretic effects of these products, this state of affairs is counterproductive. The author usually recommends that patients decrease their consumption of coffee, tea, and alcohol as much as possible and that they make a point of consuming an extra glass of water for every drink of coffee, tea, or alcohol.

Failure of high-fiber, high-water regimen

Failure to control constipation on a regimen of fiber supplementation and increased water intake should prompt an analysis of patient compliance and a search for other physical causes (eg, altered colonic transit time, outlet obstruction, and psychological causes). The author’s experience is that early failures usually reflect inadequate water intake, whereas recidivism months to years later usually reflects a patient’s decision that fiber supplementation is no longer necessary. Counsel patients in advance to encourage them to avoid these inappropriate decisions.

In selected patients who comply with a trial of a high-fiber, high-water diet but find that this approach does not successfully treat their constipation, a trial of a very-low-residue diet, or even a liquid diet, may be appropriate.

Such a regimen is most successful in patients with an outlet obstruction who are not candidates for surgical correction and in patients whose presentation is more characteristic of IBS with a chief complaint of abdominal pain. A low-residue diet may be effective in the latter group of patients if thorough mechanical cleansing of the bowel, such as is done for diagnostic endoscopy or barium enema, temporarily relieves their symptoms.

Pharmacologic Therapy

Medications to treat constipation include bulk-forming agents (fibers), emollient stool softeners, rapidly acting lubricants, prokinetics, laxatives, osmotic agents, and prosecretory drugs.

Use sodium phosphate products with precaution, particularly in young children; patients older than 55 years; patients who are dehydrated; patients with kidney disease, bowel obstruction, or inflammation of the bowel; and patients who are using medications that may affect kidney function.[21, 22] According to an FDA warning, exceeding one dose of OTC sodium phosphate products for constipation over the course of 24 hours may cause serious renal and cardiac damage (and, in rare cases, may be fatal) as a result of severe dehydration and changes in serum electrolyte levels.[21, 22]

Fiber is arguably the best and least expensive medication for long-term treatment, although enthusiasm for the use of polyethylene glycol as first-line therapy in chronic constipation is increasing. It is important to convey to patients that bulk-forming agents generally do not work rapidly and must be used on a long-term basis.

Emollient stool softeners are easier to use, but they lose their effectiveness with long-term administration. These drugs are best reserved for prophylaxis in the short-term setting, as in patients receiving a postoperative narcotic prescription.

Rapidly acting lubricants and laxatives, including over-the-counter products, are often used to treat acute and chronic constipation. A meta-analysis affirmed the efficacy of bisacodyl and sodium picosulfate, which share the same active metabolite, in short- to medium-term use in chronic idiopathic constipation.[24] However, their use for acute episodes should be limited, because of the long-term risk of habituation or toxicity.

Polyethylene glycol is simple to use and is more effective than placebo in the management of chronic constipation; however, the effects of long-term therapy with polyethylene glycol over decades are still not well studied.

Chronic constipation that responds poorly to laxatives may be due to the use of drugs such as opioids or from defecation disorders and advanced colonic dysmotility.[25]

The FDA approved prucalopride, a serotonin-4 receptor agonist indicated for chronic idiopathic constipation (CIC), in December 2018.[26] Approval was based on an integrated analysis of six double-blind, placebo-controlled, randomized, multicenter clinical studies lasting 12 weeks (studies 1-5) or 24 weeks (study 6). An integrated analysis of six main clinical trials (N=2484) found that significantly more patients treated with prucalopride achieved an average of three or more spontaneous, complete bowel movements per week over the 12-week treatment period compared with placebo (27.8% vs 13.2%; P< .001). A rapid response was seen with prucalopride as early as week 1, with improvements maintained throughout 12 weeks of treatment.[27, 28]

Lubiprostone and linaclotide are FDA approved for chronic idiopathic constipation and constipation caused by irritable bowel syndrome (IBS). Lubiprostone is also approved for opioid-induced constipation in patients with chronic, noncancer pain. Plecanatide is only approved for chronic idiopathic constipation in adults.

A 2013 study illustrated the long-term efficacy of lubiprostone for opioid-induced constipation.[29] In a 9-month open-label extension study in 439 patients, lubiprostone treatment (24 μg twice daily) resulted in statistically significant improvements in constipation from baseline determined by monthly assessments. Patients also reported improvements in the average degree of straining, stool consistency, constipation severity, abnormal bloating and discomfort, and bowel habit irregularity (P< .001 at all treatment months). Reliance on rescue medication significantly dropped over the course of the study, from 33% at month 1 to 18.6% at month 9. Treatment-related adverse events were reported by 24.6% of patients, the most common being nausea, diarrhea, and flatulence.[29]

Linaclotide was approved by the US Food and Drug Administration (FDA) in August 2012 to treat chronic idiopathic constipation and for IBS with constipation (IBS-C) in adults. Approval was based on randomized controlled trials that showed significant improvement for each indication compared with placebo.[30, 31, 32]

The FDA approved plecanatide, a GC-C agonist, in January 2017 to treat chronic idiopathic constipation in adults.[6] Approval was based on two randomized controlled trials that demonstrated significant improvements in stool frequency, stool consistency, and time of bowel movement compared with placebo.[6, 7]

These drugs may be useful in chronic constipation when fiber, water, and polyethylene glycol fail, either alone in combination with simpler interventions. When moving a patient to such interventions after failing on fiber, water, and polyethylene glycol, reconsider whether mechanical issues (eg, tumors, pelvic floor problems) have been adequately ruled out.

Other drugs that have been studied include the prokinetic agents, cisapride and tegaserod.[33, 34, 35] Although significant promise had been shown with this new class of drugs, these two agents were withdrawn from the US market.

Since July 27, 2007, use of tegaserod has been permitted only via an emergency treatment investigational new drug (IND) protocol through the FDA. As of July 16, 2014, this treatment IND program is still active.[36] The treatment IND protocol allows tegaserod treatment of IBS-C or chronic idiopathic constipation (CIC) in women younger than 55 years who meet specific guidelines. Its use is further restricted to those in critical need who have no known or preexisting heart disease.

The FDA Gastrointestinal Drugs Advisory Committee reviewed a supplemental new drug application (sNDA) for tegaserod in October 2018 with the proposed indication of treating women with IBS-C who do not have a history of cardiovascular (CV) ischemic disease. Their recommendation was to reintroduce tegaserod to the US market for women with IBS who are at low risk for CV ischemic disease.[37]

Renzapride, a mixed 5-HT4 receptor agonist and 5-HT3 receptor antagonist, has been tested to assess its efficacy and safety in the treatment of chronic constipation.[38]

Neurotrophin-3 stimulates the development, growth, and function of the nervous system and has been used to treat functional constipation. Stem cells have been suggested as a means of repopulating dysfunctional neurons.

Surgical Correction of Causes and Complications

Surgical care is generally restricted to the evaluation of underlying causes, such as large bowel obstruction, volvulus, or intra-abdominal infection or ischemia. Surgical care may also be indicated for the management of acute complications of constipation, such as hemorrhoidal thrombosis.

Surgery may occasionally play a role in the management of rectal outlet obstruction (eg, rectocele, rectal prolapse, internal rectal intussusception) or in patients with a hypomotile (laxative) colon that is refractory to medical treatment.

In the former case, treatment is directed at the cause of the outlet obstruction. In the latter case, total abdominal colectomy may be indicated; the operation may be less morbid if performed laparoscopically.[39, 40] In both cases, thorough preoperative evaluation is essential to rule out other medically treatable causes or potentiating factors.

These patients may also have an underlying psychological cause for their ailment, and addressing this is important before irreversible surgical interventions are contemplated.

Benign outlet obstruction due to prolapse may be managed by means of stapled transanal rectal resection or anopexy.[41, 42] Laparoscopic ventral rectopexy has also been advocated for this problem, although this may be more invasive.[43]

Sacral Nerve Stimulation

There is increasing interest in the use of sacral nerve stimulation in carefully selected patients with severe refractory constipation. In such patients, temporary percutaneous stimulation is typically used for 2-3 weeks to seek benefit, but such trials may not always predict success with permanently implanted nerve stimulators.[44, 45] This technology seems promising, but further experience will be required to clarify its indications, risks, and benefits.

Management of Constipation in Special Populations

Pregnant women

Pregnant women are frequently constipated because of dietary alterations, anatomic impingement of a large uterus on the rectosigmoid, fluid shifts, decreased exercise levels, and reduced mobility. Typically, these women develop hemorrhoids from passive venous congestion and uterine impingement. Pregnancy-related constipation potentiates the development of symptomatic hemorrhoids, and the resolution of constipation is the only available antihemorrhoidal therapy during pregnancy.

First-line treatment is fiber supplementation, increased water intake, gentle exercise, and occasional laxative use as required. Hemorrhoidal suppositories and sitz baths may offer symptomatic relief.

Attentive management is particularly important to minimize acute and subacute hemorrhoidal complications induced by the straining associated with vaginal delivery.

Elderly persons

Elderly patients appear to be particularly prone to constipation. The rate of self-reported constipation rapidly increases in patients older than 65 years. Careful review of prescribed medications may reveal one or more agents that may potentiate constipation.

Manipulating their diets and encouraging patients to exercise are the cornerstones of treatment. Laxatives may be required, particularly in patients with a history of chronic laxative abuse.

Children

Constipation is frequently diet-related in children, particularly in toddlers who are being switched from formula feeds to milk. Small children are especially liable to experience constipation that is more prolonged. This is associated with painful bowel movements caused by an acute anal fissure, which forces the child to avoid bowel movements.[46]

Painful defecation produces a vicious positive feedback cycle in these children. The child suppresses the urge to defecate, and this results in the formation of a larger and harder stool. When the stools eventually emerge, the pain of defecation is worse, encouraging the child to retain the stools further. Thus, the vicious cycle continues.

Prescribing long-term laxatives for a period of several weeks may be necessary in order to force the child to defecate daily until the cause of the anorectal pain is resolved and the fecal retention behavior is unlearned. Once this pattern has been unlearned, usually within several weeks, laxatives should be gradually tapered off while the use of fiber and fluid supplementation should indefinitely continue. Failure to taper the laxatives without the return of constipation indicates the need for a gastroenterologic consultation to rule out an underlying problem.

The first-line therapy remains dietary manipulation, with increased fluid intake and increased ingestion of fiber, whether via natural sources such as fruits and vegetables or via supplements containing more purified forms of fiber (eg, wheat germ, psyllium, methylcellulose, and malted barley extract). These may be mixed with liquids and administered with the help of a child’s feeding bottle. Stool softeners and local care of any anal fissures may be helpful.

Mentally incapacitated individuals

In mentally incapacitated patients with a pattern of bowel retention, resolution of this pattern requires aggressive short-term use of laxatives, stool softeners, and local care of any anal fissures. As with children, once this pattern is unlearned, laxatives should be gradually tapered off while fiber and fluid supplementation continues indefinitely. If the laxatives cannot be tapered without constipation returning, a gastroenterologic consultation is required to rule out an underlying problem.

Opioid-induced constipation

Opioid-induced constipation (OIC) is a common adverse effect of opioid use. An estimated 40%-80% of patients receiving long-term opioid therapy experience OIC, which can be severe enough to cause discontinuation of opioid therapy. The problem is caused by the binding of opioids to peripheral opioid receptors in the gastrointestinal tract, resulting in absorption of electrolytes, such as chloride, with a subsequent reduction in small intestinal fluid. Activation of enteric opioid receptors also results in abnormal gastrointestinal motility.

Medications to treat OIC and provide analgesia have been approved by the FDA. Lubiprostone (Amitiza) was approved in 2013 and is the first oral treatment for OIC in adults with chronic noncancer pain.[47, 48] The drug is a specific activator of CIC-2 chloride channels in the intestinal epithelium and bypasses the antisecretory action of opiates by activation of apical CIC-2 channels. Approval was based on results from 12-week phase 3 studies in patients taking opioids, including morphine, oxycodone, and fentanyl, for chronic noncancer pain and from a long-term open-label safety study.[47]

Naloxegol (Movantik) is a peripherally-acting mu-opioid receptor antagonist (PAMORA) that was approved by the FDA in September 2014 for OIC in adults with chronic noncancer pain.[49, 50] Approval was based on two randomized, multicenter, placebo-controlled, 12-week studies involving 1352 adult patients.

In the first study, 44% of patients treated with 25 mg of naloxegol and 41% of those treated with 12.5 mg of naloxegol had an increase in the number of bowel movements per week, compared with 29% of patients who received placebo.[49] Results were similar in the second study. Common adverse effects included abdominal pain, diarrhea, headache, and excessive gas. The FDA is requiring a postmarketing study to further examine the potential risk for cardiovascular adverse events with naloxegol treatment.

Data from the KODIAC clinical trial program regarding naloxegol consisted of 4 studies: KODIAC-4, -5, -7, and -8.[51, 52] KODIAC-4 and -5 were placebo controlled, double-blind, 12-week studies assessing safety and efficacy,[51] whereas KODIAC-7 was a 12-week safety extension to KODIAC-4, and KODIAC-8 was a 52-week open-label, long-term safety study.[52]

Methylnaltrexone (Relistor) is a PAMORA indicated for opioid-induced constipation in adults with chronic noncancer pain.[53] It is also indicated for adults with advanced illness who are receiving palliative care when response to laxative therapy has been insufficient. In a randomized, double blind, placebo-controlled trial, patients (n = 312) with chronic noncancer pain were given methylnaltrexone 12 mg SC once daily. A significantly greater portion of patients taking daily methylnaltrexone reported having 3 or more spontaneous bowel movements per week during the 4-week double-blind period compared to those taking placebo (59% vs 38%). Following the first dose, 33% of patients in the treatment group had a spontaneous bowel movement within 4 hours, and approximately half of patients had a spontaneous bowel movement prior to the second dose.[53]

Naldemedine (Symproic), another PAMORA, was approved by the FDA in March 2017 for opioid-induced constipation in adults with noncancer pain.[54]  Approval was based on the COMPOSE clinical trials. COMPOSE III was a 52-week, randomized, double-blind, placebo-controlled, long-term safety study that included approximately 620 adults with opioid-induced constipation and chronic noncancer pain. The treatment group showed significant improvements in weekly bowel movement frequency compared with placebo at all time points measured (P ≤.0001), and no significant opioid withdrawal signs or symptoms were noted.[54, 55]

Consultations

Surgical consultation is indicated when large bowel obstruction or colonic ileus secondary to an acute intra-abdominal process is suspected. It is also indicated for anorectal complications of constipation or for surgical correction of the underlying cause. Symptomatic hemorrhoids and anal fissures represent complications of constipation until proven otherwise. Acute hemorrhoidal thrombosis requires urgent surgical consultation for evacuation of the clot and relief of pain.

For prolonged chronic hemorrhoids, a trial of aggressive medical treatment (fiber supplementation, increased water intake, exercise, decreased coffee and alcohol intake, sitz baths, and local symptomatic treatment) should be carried out before surgical consultation.

Similarly, acute anal fissures should be managed conservatively because most respond well to aggressive programs of sitz baths, stool softeners, and local anesthetic ointment.

Chronic nonhealing fissures may be managed with topical nitroglycerin or botulinum toxin injections with reasonable success. However, the long-term recurrence rate after such therapy has yet to be established. Many of these patients may require surgical sphincterotomy. Uncontrolled anal dilation has become less popular than sphincterotomy because of concerns over an increased risk of sphincter injury. A colorectal surgeon should be consulted for patients with chronic fissures to evaluate the need for surgical intervention and to consider biopsy of the fissure to rule out malignancy.

Perirectal abscess and fistula in ano may be related to chronic constipation. These complications do not respond to medical management and require surgical referral.

A consultation with a gastroenterologist is necessary to rule out other colonic processes and to assist with the long-term program of stool softener and laxative use in patients who do not respond to simple measures.

Either a gastroenterologist or a surgeon may be consulted for lower GI endoscopy, depending on local referral patterns and the availability of expertise, or (in adults) to differentiate benign solitary rectal ulcers from rectal malignancy.

A psychological or psychiatric consultation may be appropriate before surgical intervention to treat patients with potential or identified psychological issues.

Long-Term Monitoring

After constipation resolves in a patient who was acutely constipated, outpatient care requires the following measures:

  • Confirming that the patient is not chronically constipated

  • Ruling out colorectal pathology

For a patient who is chronically constipated, outpatient care may include the following:

  • Colonic imaging or endoscopic visualization

  • Dietary management

  • If these measures fail in a compliant patient, further evaluation

 

Medication

Medication Summary

Medications to treat constipation include bulk-forming agents (fibers), emollient stool softeners, rapidly acting lubricants, prokinetics, laxatives, osmotic agents, and prosecretory drugs. Fiber is arguably the best and least expensive medication for long-term treatment, although enthusiasm for the use of polyethylene glycol as first-line therapy in chronic constipation is increasing.

NOTE: In January 2014, the FDA issued a warning that exceeding one dose of OTC sodium phosphate products for constipation over a course of 24 hours may cause serious harm to the kidneys and heart and, in rare cases, may be fatal.[21, 22] Using more than the recommended dose of these products can cause severe dehydration and changes in serum electrolyte levels. Individuals who may be at higher risk for potential adverse events include young children; patients older than 55 years; patients who are dehydrated; patients with kidney disease, bowel obstruction, or inflammation of the bowel; and patients who are using medications that may affect kidney function.[21, 22]

Emollient stool softeners are easier to use, but they lose their effectiveness with chronic administration. These drugs are best used for prophylaxis in a short-term setting, such as in patients receiving a postoperative narcotic prescription.

Rapidly acting lubricants and laxatives, including over-the-counter products, are often used to treat acute and chronic constipation.

Polyethylene glycol is simple to use and is more effective than placebo in the management of chronic constipation; however, the effects of chronic therapy with polyethylene glycol over decades are still not well studied.

Newer therapies for constipation include the prokinetic agent prucalopride, the osmotic agent lubiprostone, and the guanylate cyclase C (GC-C) agonists, linaclotide and plecanatide.

Laxatives, Bulk-Producing

Class Summary

Bulk-forming agents are used for long-term prophylaxis, treatment of constipation, or both in patients without anatomic outlet obstruction.

Psyllium (Metamucil, Fiberall, Bulk-K, Fibro-XL)

Psyllium dosages vary depending on whether the preparations contain sugar or are sugar-free (the former are 50% sugar). These preparations must be taken with water, or they may cause obstruction.

Methylcellulose (Citrucel)

Theoretically, nonfermentable products such as methylcellulose, which produce less gas, are better tolerated than psyllium. Occasionally, patients who cannot tolerate one preparation may do well with another product.

Laxatives, Stool Softener

Class Summary

Emollient stool softeners are used for prophylaxis against constipation in acute and subacute settings.

Docusate (Colace, Docu-Soft, Dok)

Docusate is indicated for patients who should avoid straining during defecation. It allows incorporation of water and fat into stools, causing stools to soften. Tachyphylaxis develops with long-term use. Docusate is effective acutely. It does not induce defecation.

Laxative, Stimulant; Laxative, Stool Softener

Class Summary

Emollient stool softeners cause stool to soften; stimulants increase the peristaltic activity in the gastrointestinal (GI) system.

Senna concentrate/docusate (Peri-Colace, Dok Plus, Senokot-S)

Docusate sodium allows incorporation of water and fat into stool, causing stool to soften. Sennosides induce defecation by acting directly on the intestinal mucosa or the nerve plexus, which stimulates peristaltic activity, increasing intestinal motility. The combination usually produces action 8-12 hours after administration.

Laxatives, Saline

Class Summary

Saline laxatives are used for acute treatment of constipation in the absence of bowel obstruction.

Magnesium hydroxide (Phillips Milk of Magnesia, Fleet Pedia-Lax Chewable)

Magnesium hydroxide causes osmotic retention of fluid, which distends the colon and increases peristaltic activity; it also promotes emptying of the bowel.

Magnesium citrate (Citroma)

Magnesium citrate causes osmotic retention of fluid, distending the colon and increasing peristaltic activity; it promotes emptying of the bowel. The drug works within 3 hours given orally (PO) or 15 minutes given rectally (PR). It may cause electrolyte imbalance, especially in young children or patients with renal insufficiency.

Magnesium sulfate

Magnesium sulfate causes osmotic retention of fluid, which distends the colon and increases peristaltic activity; it promotes emptying of the bowel.

Laxatives, Lubricant

Class Summary

Lubricant laxatives are used for acute or subacute management of constipation. They lubricate the intestine and facilitate the passage of stool by decreasing water absorption from the intestine.

Mineral oil (Fleet, Kondremul)

Mineral oil is gentler than some other rapidly acting laxatives. It generally works within 8 hours. Long-term use is accompanied by concerns about lipid pneumonia, lymphoid hyperplasia, and foreign body reactions.

Laxatives, Other

Class Summary

These agents elicit various pharmacologic effects resulting in increased intestinal fluid and thereby decrease constipation symptoms.

Lubiprostone (Amitiza)

Lubiprostone is a locally acting chloride channel activator that enhances a chloride-rich intestinal fluid secretion without altering sodium and potassium concentrations in the serum. It specifically activates the C1C-2 chloride channels on the apical membrane of the intestinal epithelial cells. It increases intestinal fluid secretion to assist in GI motility, thereby decreasing the symptoms of constipation (eg, abdominal pain, bloating, straining, hard stools). It is approved to treat chronic idiopathic constipation; opioid-induced constipation in patients with chronic, noncancer pain; and for women with constipation caused by irritable bowel syndrome (IBS-C).

Linaclotide (Linzess)

GC-C agonist. Activation of GC-C receptors in the intestinal neurons leads to increased cyclic guanosine monophosphate (cGMP), anion secretion, fluid secretion, and intestinal transit. It appears to work topically rather than systemically. When administered PO, linaclotide activates chloride channels in intestinal epithelial cells to increase intestinal fluid secretion; it is indicated to treat chronic idiopathic constipation and for IBS-C in adults.

Plecanatide (Trulance)

GC-C agonist; plecanatide and its active metabolite bind to GC-C and act locally on the luminal surface of intestinal epithelial cells; GC-C activation leads to increased cyclic guanosine monophosphate (cGMP) activity, which, in turn, stimulates secretion of chloride and bicarbonate into the intestinal lumen, mainly by activation of the cystic fibrosis transmembrane conductance regulator (CFTR) ion channel, resulting in increased intestinal fluid and accelerated transit; plecanatide is indicated for chronic idiopathic constipation in adults.

Laxatives, Osmotic

Class Summary

Osmotic agents are useful for long-term treatment of constipated patients with slow colonic transit that is refractory to dietary fiber supplementation.

Lactulose (Constulose, Enulose, Generlac, Kristalose)

Lactulose produces an osmotic effect in the colon, resulting in bowel distention and stimulation of peristalsis.

Sorbitol

Sorbitol is a hyperosmotic laxative that has a cathartic action in the GI tract.

Polyethylene glycol solution (Miralax)

Polyethylene glycol is typically used in large volumes for bowel preparation and washout before surgical or endoscopic procedures. It is now being used in smaller volumes as an osmotic (but not hyperosmotic) agent.

In theory, there is a lower risk of dehydration or electrolyte imbalance with isotonic polyethylene glycol than with hypertonic sugar solutions. The laxative effect is generated because polyethylene glycol is not absorbed and continues to hold water by osmotic action throughout the small bowel and the colon, resulting in mechanical cleansing.

Stimulant Laxatives

Class Summary

Stimulant laxatives are commonly employed to treat acute constipation and are the most common class of laxatives used over the long term by individuals taking over-the-counter products. The latter represents an inappropriate choice, at least as first- or second-line therapy, given concerns about the development of tolerance.

Senna (Senokot, Ex-Lax, Senexon)

Sennosides induce defecation by acting directly on the intestinal mucosa or nerve plexus, which stimulates peristaltic activity, by increasing intestinal motility. Senna usually produces its action 8-12 hours after administration.

Bisacodyl (Bisac-Evac, Biscolax, Dulcolax, Dacodyl)

Bisacodyl stimulates peristalsis by possibly stimulating the colonic intramural neuronal plexus. It alters water and electrolyte secretion, resulting in net intestinal fluid accumulation and laxation. It provokes defecation within 24 hours and may cause abdominal cramping.

Castor oil

Castor oil is reduced to ricinoleic acid. It decreases net absorption of fluid and electrolytes and stimulates peristalsis. It acts on the small intestine.

Prokinetic Agents

Class Summary

Prokinetics are promotility agents proposed for use in patients with severe constipation-predominant symptoms.

Prucalopride (Motegrity)

Prucalopride, a selective 5-hydroxytryptamine (serotonin) type 4 receptor (5-HT4) agonist, is a gastrointestinal (GI) prokinetic agent that stimulates colonic peristalsis, thus increasing bowel motility. It is indicated for chronic idiopathic constipation.

Tegaserod (Zelnorm)

Tegaserod is available in the United States only by an emergency treatment investigational new drug (IND) protocol. This can be obtained from the FDA for irritable bowel syndrome (IBS) and IBS with constipation (IBS-C) or chronic idiopathic constipation (CIC) in women younger than 55 years who meet specific guidelines. The FDA Gastrointestinal Drugs Advisory Committee reviewed a supplemental new drug application (sNDA) for tegaserod in October 2018 with the proposed indication of treating women with IBS-C who do not have a history of cardiovascular (CV) ischemic disease. Their recommendation was to reintroduce tegaserod to the US market for women with IBS who are at low risk for CV ischemic disease.

Tegaserod is a serotonin type 4 (5-HT4) receptor partial agonist with no affinity for 5-HT3 receptors. It may trigger peristaltic reflex via 5-HT4 activation, which enhances basal motor activity and normalizes impaired GI motility.

Peripherally-Acting Mu-Opioid Receptor Antagonists

Class Summary

Peripherally acting mu-opioid receptor antagonists (PAMORAs) may provide relief from GI adverse effects such as constipation associated with chronic opioid use.

Methylnaltrexone (Relistor)

Methylnaltrexone is a PAMORA. It selectively displaces opioids from mu-opioid receptors outside the central nervous system (CNS), including those located in the GI tract, thereby decreasing the constipating effects of opioids. It is indicated for opioid-induced constipation in patients with advanced illness receiving palliative care when response to laxatives has not been sufficient. It is also indicated for opioid-induced constipation in patients with chronic noncancer pain who are treated with opioids. It is available as an injectable solution for subcutaneous use.

Naloxegol (Movantik)

Naloxegol is a PAMORA indicated for opioid-induced constipation in adults with chronic noncancer pain. Antagonism of gastrointestinal mu-opioid receptors by naloxegol inhibits the opioid-induced delay of GI transit time.

Alvimopan (Entereg)

Alvimopan is a peripherally acting mu-opioid receptor antagonist. It binds mu-opioid receptors in the gut, thereby selectively inhibiting the negative opioid effects on GI function and motility. It is indicated for postoperative ileus after bowel resection with primary anastomosis.

In 5 clinical studies that enrolled more than 2500 patients, alvimopan demonstrated accelerated recovery time of upper and lower tract GI function compared with placebo. A decrease in the hospital days was also observed in the alvimopan group.

Alvimopan is only available to hospitals after they complete a registration process designed to maintain the benefits associated with short-term use and prevent long-term outpatient use (Entereg Access Support and Education [EASE] program).

Naldemedine (Symproic)

Opioid antagonist with binding affinities for mu-, delta-, and kappa-opioid receptors. Naldemedine is a derivative of naltrexone to which a side chain has been added that increases the molecular weight and the polar surface area, thereby reducing its ability to cross the blood-brain barrier. It is indicated for opioid-induced constipation in adults with noncancer pain.

 

Questions & Answers

Overview

How common is constipation?

What are the criteria for constipation and which complaints are related to constipation?

Which complaints suggest difficulty with rectal evacuation associated with constipation?

Which signs and symptoms associated with constipation are grounds for particular concern?

Which exams and studies are included in the workup of constipation?

What is the initial treatment of constipation?

What is the focus of medical care in constipation?

Which dietary measures are key to treating constipation?

Which medications and newer therapies are used in the treatment of constipation?

How common is constipation in the US?

What is the clinical definition of constipation?

What are the Rome IV criteria for constipation?

What is the definition of constipation for surgical purposes?

What approach is indicated in acute or subacute constipation in middle-aged or elderly patients which condition must be excluded?

When is constipation defined as chronic?

Which lab studies, imaging studies, and procedures are used in the workup of constipation?

What is the focus of medical management of constipation and when is surgical care indicated?

How are the features of constipation characterized?

Which processes are involved in constipation originating from the colon or rectum?

What are the factors involved in constipation originating outside the colon?

Which symptoms and abnormalities are associated with constipation?

How common is constipation in patients with diverticular or anorectal disease?

How is the etiology of constipation categorized?

What are the subtypes of primary constipation?

What is normal-transit constipation (NTC) and what is the difference between chronic constipation and irritable bowel syndrome with constipation (IBS-C)?

How is slow-transit constipation (STC) characterized?

How is pelvic floor dysfunction/pelvic floor dyssynergia characterized in primary constipation?

Which dietary habits are associated with constipation?

What are structural causes of secondary constipation?

Which systemic diseases may cause constipation and which emergent conditions must be recognized and addressed?

Which medications can cause constipation?

What is the role of toxicologic causes or psychological issues in the development of constipation?

How prevalent is chronic constipation in the US?

What is the worldwide prevalence of constipation?

What are the age-related demographics of constipation and which conditions may lead to functional outlet obstruction?

Is constipation more common in men or women?

What are the race-related demographics of constipation?

What is the prognosis of constipation?

How are dyskinesias of the pelvic floor and sphincter mechanism managed in constipation?

What is the treatment of constipation associated with chronic use of laxatives?

When is a total abdominal colectomy indicated in the treatment of constipation?

Which symptoms may be caused by difficulties in defecation associated with constipation?

What are the potential adverse effects of self-medicating with laxatives in the treatment of constipation?

When is surgical intervention indicated in the treatment of hemorrhoidal disease due to straining associated with constipation?

Does constipation cause hemorrhoidal disease?

What is the role of constipation in anal fissures and how are they managed?

What is the role of constipation in pelvic floor damage?

What causes solitary rectal ulcers associated with constipation?

What are some of the complications of constipation?

What is the role of patient education in the management of constipation?

Presentation

What history is relevant in the workup of constipation?

Which patient complaints suggest constipation or difficult rectal evacuation?

Which signs and symptoms of constipation may indicate a more serious condition?

How is a health history interview conducted in the diagnosis of constipation?

What is the role of onset of symptoms and duration of the problem in the diagnosis of constipation?

What is the role of dietary practices in abnormal bowel habit associated with constipation?

How does fluid intake affect constipation?

Which factors influence bowel motility in constipation?

Which digestive conditions should be assessed in the setting of constipation?

Which patients with constipation should be screened for colorectal cancer?

What should the patient be asked to describe in the evaluation of constipation?

Which disorders and diseases are associated with constipation?

What is the role of psychogenic factors in constipation and how are they approached?

What is included in the physical exam in constipation?

What does abdominal distention, masses, or hernia indicate in the physical exam for constipation?

Should elderly patients with new inguinal hernias have colorectal screening for suspected occult constipation?

What should a pelvic exam in women with constipation address?

Which features of constipation are assessed in an anorectal exam?

What information is provided in a digital rectal exam?

Which causes of constipation can be identified in an anorectal exam?

How is rectal prolapse identified in patients with constipation and when is a sigmoidoscopy indicated?

How are the effects of constipation determined in a physical exam?

When is fecal occult blood testing indicated in the workup of constipation?

Which systems other than the digestive system should be evaluated in the physical evaluation for constipation and what are some systemic diseases associated with constipation?

DDX

What are diagnostic considerations in the differential diagnosis of constipation and which conditions other than gastroenterological should be considered?

What are the differential diagnoses for Constipation?

Workup

When is an extensive workup of constipation indicated and in which setting?

What is the role of lab studies in the initial assessment of constipation?

What is the role of imaging studies in the workup of constipation?

Which procedures are used in the evaluation of constipation?

Which procedures are indicated in the workup of acute constipation?

Which condition may be identified in a CBC and when is fecal occult blood testing indicated in the workup of constipation?

What is the role of a leukocyte count in the workup of constipation?

What is the role of thyroid function testing in the workup of constipation?

What is the role of serum chemistry in the workup of constipation?

When are imaging studies indicated in the workup of constipation?

Which signs of constipation can be distinguished in a radiograph?

Which conditions associated with diabetes may be seen in radiography studies for constipation?

When is abdominal CT scanning or lower GI endoscopy indicated in the workup of constipation?

When is air-contrast barium enema or Gastrografin study indicated in the workup of constipation?

When is defecography indicated in the workup of constipation?

When is an evaluation of colonic transit time indicated in the workup of constipation and how is the study performed?

When is urgent lower GI endoscopy indicated in the workup of constipation and when is colonoscopy contraindicated?

What are the advantages of flexible endoscopy over rigid endoscopy in the workup of constipation?

How is flexible endoscopy performed in the workup of constipation?

Which parameters are assessed in anorectal manometry in the workup of constipation?

How is idiopathic megabowel identified in the workup of constipation?

What is the role of electromyography (EMG) in the workup of constipation?

How is a balloon expulsion test performed in the workup of constipation?

When is anoscopy indicated in the workup of constipation?

How is Hirschsprung disease diagnosed in the setting of constipation?

Which histology studies are indicated in the workup of constipation?

Treatment

What is the emergency department (ED) treatment of constipation after critical illness is excluded?

What is the focus of medical care in constipation and what is the FDA warning regarding OTC sodium phosphate products?

What is the best remedy in the treatment of constipation?

How should patients with constipation be counseled?

When is surgical intervention indicated in constipation?

When is inpatient care indicated in constipation?

Which factors may warrant transfer to another facility in the treatment of constipation?

How is treatment failure to provide adequate relief defined in chronic constipation?

What is the role of dietary changes in the treatment of constipation?

Which sources of dietary fiber and fiber supplements are available in the treatment of constipation?

How is a fiber supplement selected in the treatment of constipation?

How is patient noncompliance with fiber supplement regimens addressed in the treatment of constipation?

What should patients be advised regarding the use of stool softeners in the treatment of constipation?

What is the role of fluid intake in the treatment of constipation and which fluid is recommended?

What action is recommended when a high-fiber, high-water regimen fails in the treatment of constipation?

When is a very-low-residue diet or liquid diet indicated in the treatment of constipation and how effective are they?

Which medications are used to treat constipation?

How are sodium phosphate products used in the treatment of constipation?

What is the most effective approach in the use of fiber or polyethylene glycol in the treatment of constipation?

When are emollient stool softeners indicated in the treatment of constipation?

What is the role of lubricants and laxatives in the treatment of acute or chronic constipation?

Why does chronic constipation respond poorly to laxatives?

What are the novel therapies in the treatment of constipation?

How are lubiprostone and linaclotide used in the treatment of constipation?

How effective is lubiprostone in the treatment of constipation?

How is linaclotide used in the treatment of constipation and what was the FDA approval based on?

How is plecanatide used in the treatment of constipation and what was the FDA approval based on?

When are newer therapeutic drugs indicated in the treatment of constipation?

Which drugs have been investigated in the treatment of constipation?

When is surgical intervention indicated in the evaluation of constipation?

When is surgical treatment indicated in constipation?

How is benign outlet obstruction due to prolapse associated with constipation managed?

What is the role of sacral nerve stimulation in the treatment of constipation and how effective is it?

What causes constipation in pregnancy?

What is the first-line treatment of constipation in pregnancy?

How are acute and subacute hemorrhoidal complications minimized in constipation in the setting of pregnancy?

How common is constipation in elderly patients and what is the treatment?

What causes constipation in children and what are potential complications?

What causes a vicious cycle of constipation in children and what is the treatment?

What is the first-line therapy for constipation in children?

What is the treatment for mentally incapacitated patients with a pattern of bowel retention relative to constipation?

What is opioid-induced constipation (OIC)?

Which medications have been FDA approved to treat opioid-induced constipation (OIC)?

Which medication is used in the treatment of opioid-induced constipation (OIC) in adults with chronic noncancer pain and how effective is it?

When is surgical consultation indicated in constipation?

What is the initial treatment for prolonged chronic hemorrhoids and acute anal fissures associated with constipation?

What is the treatment of chronic nonhealing fissures associated with constipation?

What is the treatment for perirectal abscess and fistula in ano associated with constipation?

When is consultation with a gastroenterologist indicated in constipation?

Who may be consulted for lower GI endoscopy for constipation?

When is a psychological consultation indicated in constipation?

What outpatient care is indicated for acute constipation?

What outpatient care is indicated for chronic constipation?

Medications

Which medications are used in the treatment of constipation?

What is the FDA warning regarding OTC sodium phosphate products for constipation?

What is the role of emollient stool softeners in the treatment of constipation?

What is the role of lubricants and laxatives in the treatment of acute and chronic constipation?

How effective is polyethylene glycol in the management of chronic constipation?

What are the novel therapies for constipation?

Which medications in the drug class Laxatives, Bulk-Producing are used in the treatment of Constipation?

Which medications in the drug class Laxatives, Stool Softener are used in the treatment of Constipation?

Which medications in the drug class Laxative, Stimulant; Laxative, Stool Softener are used in the treatment of Constipation?

Which medications in the drug class Laxatives, Saline are used in the treatment of Constipation?

Which medications in the drug class Laxatives, Lubricant are used in the treatment of Constipation?

Which medications in the drug class Laxatives, Other are used in the treatment of Constipation?

Which medications in the drug class Laxatives, Osmotic are used in the treatment of Constipation?

Which medications in the drug class Stimulant Laxatives are used in the treatment of Constipation?

Which medications in the drug class Prokinetic Agents are used in the treatment of Constipation?

Which medications in the drug class Peripherally-Acting Mu-Opioid Receptor Antagonists are used in the treatment of Constipation?