Small Intestinal Diverticulosis

Small intestinal diverticulosis refers to the clinical entity characterized by the presence of multiple saclike mucosal herniations through weak points in the intestinal wall.[1, 2, 3] Small intestinal diverticula are far less common than colonic diverticula. The singular form is diverticulum, and the plural form is diverticula.

The cause of this condition is not known. It is believed to develop as the result of abnormalities in peristalsis, intestinal dyskinesis, and high segmental intraluminal pressures.

The resulting diverticula emerge on the mesenteric border (ie, sites where mesenteric vessels penetrate the small bowel). Diverticula are classified as true and false. True diverticula are composed of all layers of the intestinal wall, whereas false diverticula are formed from the herniation of the mucosal and submucosal layers. Meckel diverticulum is a true diverticulum.

Diverticula can be classified as intraluminal or extraluminal. Intraluminal diverticula and Meckel diverticulum are congenital. Extraluminal diverticula may be found in various anatomic locations and are referred to as duodenal, jejunal, ileal, or jejunoileal diverticula.

The following risk factors apply to acquired pseudodiverticula:

• Low-fiber diet

• High-fat diet

• Advancing age

• Heredity: No evidence indicates that heredity plays a role in the development of small bowel diverticula.

• Systemic sclerosis

• Visceral myopathy

• Visceral neuropathy

United States

Duodenal diverticula are approximately five times more common than jejunoileal diverticula. The actual incidence of both types of diverticula is not known because these lesions are usually asymptomatic. The incidence at autopsy of duodenal diverticula is 6-22%. Jejunal diverticula are less common, with a reported incidence of less than 0.5% on upper gastrointestinal radiographs and a 0.3-1.3% autopsy incidence.

The international incidence parallels that of the United States.

Race-, sex-, and age-related demographics

No known racial predilection exists.

Duodenal diverticula occur in equal numbers of men and women, while a slight male preponderance exists in jejunoileal diverticula.

Most cases of duodenal diverticula are observed in patients older than 50 years, while jejunoileal diverticula are commonly observed in patients aged 60-70 years. Reports of this condition in young adults exist as well.

The prognosis is good even with complications.

Complications

Complications include the following:

• Chronic abdominal pain

• Diverticulitis

• Intestinal obstruction

• Intestinal hemorrhage

• Malabsorption

Small bowel diverticula are generally asymptomatic, with the exception of Meckel diverticulum.

Major complications include diverticulitis, gastrointestinal hemorrhage, intestinal obstruction, acute perforation, and pancreatic and/or biliary disease in duodenal diverticula. Mortality is influenced by patients' age, nature of complications, and timeliness of intervention.

Unusual complications associated with Meckel diverticulum that have been reported include intussusception within its own lumen,[4] formation of a hernia sac with its mesentery and band,[5] and axial torsion and gangrene.[6]

Patients should understand the benign nature of the disease and that no definitive cure for this entity exists. In addition, they should know where to seek help if complications develop.

For patient education resources, see the Digestive Disorders Center, as well as Diverticulosis and Diverticulitis.

Most patients with small bowel diverticula are asymptomatic. Patients who develop symptoms generally report symptoms that reflect associated complications. The most common symptom is nonspecific epigastric pain or a bloating sensation. Complication rates as high as 10-12% for duodenal diverticulosis and 46% for jejunal diverticulosis have been reported. These complications include the following:

• Diverticular pain - Abdominal pain in the absence of other complications (can be the only manifestation of small bowel diverticulosis)

• Bleeding - Hematochezia, melena, or obscure bleeding that leads to iron deficiency

• Diverticulitis - Fever and localized tenderness associated with inflammation

• Intestinal obstruction - Colicky abdominal pain, constipation, nausea, vomiting

• Perforation and localized abscess - Fever, abdominal pain with or without signs of peritonitis

• Malabsorption - Diarrhea, flatulence, weight loss

• Anemia - Obscure, occult gastrointestinal bleed, fatigue, leg swelling

• Biliary tract disease - Biliary colic

• Volvulus - Intestinal obstruction

• Enteroliths - Intestinal obstruction

• Bacterial overgrowth - Flatulence

Physical findings are also related to the complications mentioned above. These findings include abdominal fullness, localized or vague tenderness, rectal bleeding, and melena. Note the following:

• No set of symptoms or signs is pathognomonic for small bowel diverticulosis. In the absence of complications, history and physical examination findings are often negative.

• Some of these symptoms may be manifestations of other unrelated comorbid conditions. The exact rate of these complications is difficult to estimate but has been reported to be from 10-40%.

• Hemorrhage and pancreaticobiliary disease are the most common complications of duodenal diverticulum, while diverticulitis and perforation are more common with jejunoileal diverticula. Intestinal obstruction is a feature of intraluminal duodenal diverticulum, whereas Meckel diverticulum can be complicated by peptic ulcer infection, and intestinal obstruction. Most patients are diagnosed serendipitously.

Specific features based on anatomic location and type include the following:

• Duodenal diverticula: These vary from a few millimeters to several centimeters and may be multiple. Approximately 75% occur within 2 cm of the ampulla of Vater (juxtapapillary). This anatomic location is of clinical significance. It is associated with increased incidence of biliary stones, pancreatitis, and biliary and pancreatic anomalies. Incidence increases with age. Fifty percent of cases have associated colonic pseudodiverticulosis.

• Jejunoileal diverticula: Duodenal and Meckel diverticulum excluded, small bowel diverticula are most common in the proximal jejunum. They usually are multiple and vary from a few millimeters to 10 cm. They are located on the mesenteric border within the leaves of the mesentery. These lesions are frequently associated with small intestine motility disorders, such as progressive systemic sclerosis, visceral myopathy, and visceral neuropathies.

• Intraluminal diverticula: These are congenital diverticula resulting from defective recanalization of duodenal lumen during fetal development. These structures are believed to start as a fenestrated diaphragm that, over time, transforms into a diverticulum as a result of peristalsis. It occurs singly and has duodenal mucosa on both sides. Intraluminal diverticula are usually located in the second part of the duodenum and can manifest at any age.

• Meckel diverticulum: This congenital diverticulum results from incomplete closure of the vitelline duct during fetal development. It is the most common true diverticulum of the gastrointestinal tract. Incidence at autopsy is approximately 0.3-2%.[7] Meckel diverticulum is generally asymptomatic, causing symptoms in only 2% of adults. The mucosa occasionally contains heterotopic gastric mucosa that is often responsible for peptic ulceration and bleeding.

Laboratory tests have limited value in diagnosing small bowel diverticulosis. The following tests may be indicated:

• CBC count: Elevated white blood cell (WBC) count may occur in diverticulitis. Hematocrit may drop following significant acute or chronic blood loss.

• Chemistry: Liver chemistries, serum amylase and lipase levels are performed only if indicated by clinical presentation to exclude other differential diagnoses.

• Urinalysis: Urinalysis may be indicated to rule out urinary tract infection.

• Blood culture: This is useful in patients presenting with fever, diverticulitis, intestinal perforation, and abscess to exclude septicemia.

Although small bowel diverticulitis is not routinely considered in the differential diagnosis of an acute abdomen, prospective diagnosis by imaging is important. It can result in conservative treatment and eliminate the possibility of unnecessary exploratory laparotomy.[8]

Plain abdominal radiographs and/or chest radiographs demonstrate evidence of perforation, including air under the diaphragm; free peritoneal air; evidence of intestinal obstruction; or evidence of ileus, including multiple air-fluid levels and bowel dilatation.

Abdominal computed tomography (CT) scanning with contrast provides more information in complicated as well as uncomplicated cases. Phlegmon can be identified, especially in the retroperitoneal space, providing the initial clue to the possibility of small intestinal diverticular disease.[9, 10]

In a study of 7 patients with surgically confirmed diagnoses of small bowel diverticulosis/diverticulitis, Mansoori et al found that small bowel diverticulitis demonstrates characteristic magnetic resonance enterography/enteroclysis (MRE) imaging features to distinguish it from more common diseases. The characteristic imaging features included asymmetric, focal mesenteric, and mural inflammation, as well as the presence of multiple diverticula.[11]

A double contrast barium meal and enteroclysis is useful in diagnosis but is contraindicated in acute diverticulitis or perforation.

Double balloon enteroscopy may be useful in diagnosing jejunal diverticulosis; it may also be used preoperatively to diagnose Meckel diverticulum.[12] This modality may reveal an incidental finding or be used for diagnostic purposes. As double balloon enteroscopy has interventional capacity, it may be used to arrest gastrointestinal (GI) bleeding from complicated diverticular disease.

Capsule endoscopy has been used in incidental diagnosis as well as an indication for other GI lesions. This imaging modality involves swallowing a capsule with a battery source, camera, and broadcasting capacity. The signals/images are sent to a device worn on a belt and recorded for further evaluation. The pill passes in the feces and does not need to be retrieved.

Capsule endoscopy should be avoided in acute diverticulitis, perforation, or small bowel obstruction. However, a retrospective review of 31 patients by Yang et al appeared to suggest that this modality may be safe and effective in the visual identification of the etiology of subacute small bowel obstruction, particularly in cases of suspected intestinal tumors or Crohn disease not found with routine studies.[13] Of the 31 cases, the investigators found that capsule endoscopy provided a definitive diagnosis in 12 (38.7%), including 4 Crohn disease, 2 carcinomas, and 1 each of intestinal tuberculosis, ischemic enteritis, abdominal cocoon, intestinal duplication, diverticulum, and ileal polypoid tumor. The procedure did not cause acute small bowel obstruction in any patients, but the capsule was retained in 3 (9.7%) patients either due to Crohn disease (n = 2; retrieved at surgery) or tumor (n = 1; spontaneously passed with medical therapy within 6 mo).[13]

Other studies

Bleeding scan is used to determine the site of bleeding if the patient is hemodynamically stable. It is helpful in localizing bleeding sites, detecting bleeding as slow as 0.5 mL/min.

Mesenteric angiography is used for brisk hemorrhages, at least 1 mL/min, to identify the bleeding site and offers the opportunity for mesenteric occlusion therapy. The catheter may be left in place for ease of identification at surgery.

For more information, see Meckel Diverticulum Imaging.

Esophagogastroduodenoscopy yields 9-20% on all upper gastrointestinal endoscopy. Endoscopic procedures are generally contraindicated in acute diverticulitis. Colonoscopy may be useful in excluding other causes. The jejunoileal diverticulum is not accessible by colonoscopy and esophagogastroduodenoscopy (EGD).

Endoscopic retrograde choledochopancreatography demonstrates periampullary diverticula.

Enteroscopy may be used to evaluate the jejunum and ileum with either the Push or Sonde types of enteroscopy. Experience is of great importance in recognizing these lesions.

Double balloon enteroscopy can help identify the presence of disease and also the cause of any obscure bleeding. This procedure can also therapeutically intervene at the identified site of bleed. In this procedure, the small bowel is pleated proximally on the scope to advance distally through the small bowel.

See Pathophysiology.

Clinicians must maintain a high index of clinical awareness to avoid missing small intestinal diverticulosis. Therefore, any patient with unresolved symptoms, complications, or recurrent symptoms should be evaluated further.

The general recommendation favors a conservative approach to the management of asymptomatic diverticula. These lesions are generally left alone unless they can be related to diseases. In certain locations, diverticula are associated with special complications. For example, periampullary diverticula can be associated with pancreatitis, cholangitis, or recurrent choledocholithiasis after cholecystectomy.

Intraluminal diverticula are observed in the duodenum and can be complicated by intestinal obstruction and biliary and pancreatic diseases. A higher complication rate is associated with jejunoileal diverticulosis and, as such, may justify a less conservative approach to its management. Capsule endoscopy might be of value, if available, to identify the site of the bleeding. Push enteroscopy or double balloon enteroscopy should be used once a lesion amenable to therapeutic intervention has been identified.

Inpatient treatment is indicated only in patients presenting with complications. The duration of such admission depends on the nature of the complication and the interventions rendered. Once inflammation/infection has resolved, endoscopic modalities may be employed to further evaluate and treat, if possible.

Prehospital care

Acute abdomen and obvious or occult gastrointestinal (GI) hemorrhage are the clinical scenarios that necessitate prehospital intervention. Vascular access, intravenous fluid, oxygen, and prompt transport to the hospital are all that is required in the field.

Medical management

Abdominal pain without clinical evidence of diverticulitis or intestinal obstruction requires no specific treatment. Patients benefit from the use of bulk-forming agents, such as fiber, bran, and cellulose products. Intractable pain associated with anemia and jejunal loop dilatation on radiograph should heighten concern for jejunal diverticulosis.

When diverticula are secondary to small bowel dysmotility, no specific intervention is warranted, other than surgical if complications arise.

For diverticulitis, patients often require hospitalization because preoperative diagnosis of small bowel diverticulitis is difficult. Initial interventions include the following:

• Bed rest

• Nothing by mouth and/or nasogastric suctioning

• IV fluid

• Broad-spectrum antibiotic coverage

• Surgical consultation: Urgent surgery rarely is indicated unless perforation, abscess, or neoplasm is suspected.

Consultations

Consultation with a general surgeon is indicated for all patients requiring surgical management.

A gastroenterologist assists with diagnosis and follow-up strategy and performs both diagnostic and therapeutic endoscopy

Diet and activity

The role of diet is not clear. A high-fiber diet that improves bowel motility and is used in colonic diverticulosis may be beneficial.

No restriction of activity is indicated.

Management of complications

The approach to management of complicated small bowel diverticula involves initiation of medical and supportive management. Surgical consultation must be performed promptly.

GI bleeding and/or hemorrhage

Note the following:

• Patient is treated with intravenous (IV) fluid and blood products as necessary.

• Diagnostic workup is usually completed in the intensive care setting.

• Most patients stop bleeding, allowing elective surgery.

• Mesenteric angiography with infusion of vasoconstrictors can be used in persistent hemorrhage.

• Laparotomy may be indicated as an emergency therapy for continuing bleeding or as elective treatment if bleeding responds to conservative management. The site of the diverticulum should be identified with angiography and the area should be injected with methylene blue or India ink in order to stain the mesentery involving the bleeding diverticulum.  

Intestinal perforation

Early surgery is the treatment of choice for patients with intestinal perforation. Fluid and electrolyte management as well as antibiotics are essential adjuncts.

Intestinal obstruction

Initial management of intestinal obstruction is similar to uncomplicated diverticulitis. Urgent surgical consultation is mandatory.

Intestinal pseudoobstruction

Cautious conservative management is indicated for intestinal pseudoobstruction while excluding mechanical obstruction.

Fistula formation

Fistula formation is a rare complication.

Malabsorption

Malabsorption is often a complication of bacterial overgrowth resulting from blind loop syndrome. It usually responds to antibiotics.

Diverticula

Preoperative diagnosis of diverticula is seldom made. This can present as intussusception, volvulus, or pseudoobstruction.

Flatulence and bloating

Flatulence and bloating are other complications of bacterial overgrowth, which usually responds to antibiotic therapy.

Complications of small bowel diverticulosis, such as massive bleeding or diverticulitis with perforation, require surgery. Diagnosis is seldom made preoperatively. The aim is to control complications when present and/or to prevent future complications.

Emergency surgery is indicated for severe diverticulitis, intestinal perforation, intestinal obstruction, and hemorrhage that continues after conservative management.

Several operative procedures are available depending on the type of diverticulum, site, and nature of complications.

Simple diverticulectomy is most commonly used for a symptomatic diverticulum or a bleeding diverticulum of the duodenum. The diverticulum is simply excised, and the bowel is closed transversely in the Heineke–Mikulicz (H-M) fashion, ensuring minimal luminal stenosis. This procedure requires modification in cases involving a diverticulum that is embedded deep in the head of the pancreas or is associated with the ampulla of Vater, is perforated, or is intraluminal in location. It can be technically difficult in the presence of common duct obstruction. These patients benefit more from choledochoduodenostomy. A bleeding Meckel diverticulum should require resection of a couple inches of small bowel on either end of the Meckel diverticulum, because bleeding is almost always from an adjacent ileal ulceration.

Short segment intestinal resection and end-to-end anastomosis is the preferred approach to jejunoileal diverticulum, which tends to be multiple, irrespective of the type of complication.

Enterotomy can be performed solely to remove enterolith of diverticular origin causing distal obstruction.

Caveats of surgical management

Perforated duodenal diverticulum requires a special approach. Simple excision and closure may be complicated by obstruction; therefore, consider complete diversion of the bowel from the duodenum, then perform vagotomy, antrectomy, closure of the duodenal loop, and Billroth II anastomosis. Dysmotility alone without obstruction is not an indication for bowel resection because resection would not prevent propagation of motility disorder.

Preventive care is not available, although a high-fiber diet may be useful.

No special follow-up care is necessary. However, educate patients concerning the likely complications of small intestinal diverticulosis. Recommend a high-fiber diet posthospitalization. Patients should know that symptoms must be promptly reported to their physician.

Antibiotics are important in the management of diverticulitis and related complications.

Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the clinical setting. Antibiotic combinations are usually recommended for serious gram-negative bacillary infections. This approach ensures coverage for a broad range of organisms and polymicrobial infections. In addition, it prevents resistance from bacterial subpopulations and provides additive or synergistic effects. Once organisms and sensitivities are known, the use of antibiotic monotherapy is then recommended. Antibiotics can be administered PO in mild disease and unambiguous diagnosis, otherwise administer IV.

Rifaximin (Xifaxan)

Broad spectrum non-absorbable antibiotic used for treatment of small bowel bacterial overgrowth and traveler's diarrhea. Inhibits DNA-dependent RNA polymerase(rifamycin)

Metronidazole (Flagyl)

Active against various anaerobic bacteria and protozoa. Appears to be absorbed into the cells and the intermediate metabolized compounds that are formed, act by binding DNA and inhibiting protein synthesis, which causes cell death.

Clindamycin (Cleocin)

Effective against aerobic and anaerobic streptococci but not enterococci. Inhibits bacterial protein synthesis by inhibiting peptide chain initiation at the bacterial ribosome where it preferentially binds to the 50S ribosomal subunit, causing bacterial growth inhibition.

Ampicillin (Marcillin, Omnipen, Polycillin, Principen, Totacillin)

Interferes with bacterial cell wall synthesis during active multiplication, causing bactericidal activity against susceptible organisms.

Amoxicillin (Trimox, Amoxil, Biomox)

Can be used PO when outpatient treatment is indicated. Interferes with the synthesis of cell wall mucopeptide during active multiplication, resulting in a bactericidal activity against susceptible bacteria.

Ciprofloxacin (Cipro)

Fluoroquinolone with activity against pseudomonads, streptococci, MRSA, Staphylococcus epidermidis, and most gram-negative organisms but no activity against anaerobes. Inhibits bacterial DNA synthesis and, consequently, growth.

Imipenem and cilastin (Primaxin)

Used for treatment of multiple organism infections as in peritonitis when other agents are not appropriate.

Cefoxitin (Mefoxin)

Second-generation cephalosporin indicated for gram-positive cocci and gram-negative rod infections. Infections caused by cephalosporin-resistant or penicillin-resistant gram-negative bacteria may respond to cefoxitin.

Ticarcillin and clavulanate potassium (Timentin)

Inhibits biosynthesis of cell wall mucopeptide and is effective during the stage of active growth. Antipseudomonal penicillin plus beta-lactamase inhibitor that provides coverage against most gram-negative bacteria and most anaerobes.

Ampicillin and sulbactam sodium (Unasyn)

Drug combination antimicrobial agents consisting of a beta-lactamase inhibitor and ampicillin. Active against skin, enteric flora, and anaerobes.