eMedicine Specialties > Emergency Medicine > Gastrointestinal

Obstruction, Small Bowel

Brian A Nobie FACEP, MD, Director of Recruitment, Consulting Staff, Florida Emergency Physicians, Florida Hospital, Celebration Health

Updated: Nov 12, 2009

Introduction

Background

A small-bowel obstruction (SBO) is caused by a variety of pathologic processes. The leading cause of SBO in developed countries is postoperative adhesions (60%) followed by malignancy, Crohn's disease, and hernias, although some studies have reported Crohn disease as a greater etiologic factor than neoplasia. Surgeries most closely associated with SBO are appendectomy, colorectal surgery, and gynecologic and upper gastrointestinal (GI) procedures. One study from Canada reported a higher frequency of SBO after colorectal surgery, followed by gynecologic surgery, hernia repair, and appendectomy. Lower abdominal and pelvic surgeries lead to obstruction more often than upper GI surgeries.

SBOs can be partial or complete, simple (ie, nonstrangulated) or strangulated. Strangulated obstructions are surgical emergencies. If not diagnosed and properly treated, vascular compromise leads to bowel ischemia and further morbidity and mortality. Because as many as 40% of patients have strangulated obstructions, differentiating the characteristics and etiologies of obstruction is critical to proper patient treatment.

Small bowel obstruction.

Pathophysiology

Obstruction of the small bowel leads to proximal dilatation of the intestine due to accumulation of GI secretions and swallowed air. This bowel dilatation stimulates cell secretory activity resulting in more fluid accumulation. This leads to increased peristalsis both above and below the obstruction with frequent loose stools and flatus early in its course.

Vomiting occurs if the level of obstruction is proximal. Increasing small-bowel distention leads to increased intraluminal pressures. This can cause compression of mucosal lymphatics leading to bowel wall lymphedema. With even higher intraluminal hydrostatic pressures, increased hydrostatic pressure in the capillary beds results in massive third spacing of fluid, electrolytes, and proteins into the intestinal lumen. The fluid loss and dehydration that ensue may be severe and contribute to increased morbidity and mortality.

Strangulated SBOs are most commonly associated with adhesions and occur when a loop of distended bowel twists on its mesenteric pedicle. The arterial occlusion leads to bowel ischemia and necrosis. If left untreated, this progresses to perforation, peritonitis, and death.

Bacteria in the gut proliferate proximal to the obstruction. Microvascular changes in the bowel wall allow translocation to the mesenteric lymph nodes. This is associated with an increase in incidence of bacteremia due to Escherichia coli, but the clinical significance is unclear.

Frequency

United States

SBO accounts for 20% of all acute surgical admissions.

Mortality/Morbidity

Mortality and morbidity are dependent on the early recognition and correct diagnosis of obstruction. If untreated, strangulated obstructions cause death in 100% of patients. If surgery is performed within 36 hours, the mortality rate decreases to 8%. The mortality rate is 25% if the surgery is postponed beyond 36 hours in these patients.

Clinical

History

Obstruction can be characterized as either partial or complete versus simple or strangulated.

• Abdominal pain (characteristic with most patients)
  • Pain, often described as crampy and intermittent, is more prevalent in simple obstruction.
  • Often, the presentation may provide clues to the approximate location and nature of the obstruction. Usually, pain that occurs for a shorter duration of time and is colicky and accompanied by bilious vomiting may be more proximal. Pain lasting as many as several days, which is progressive in nature and with abdominal distention, may be typical of a more distal obstruction.
  • Changes in the character of the pain may indicate the development of a more serious complication (ie, constant pain of strangulated or ischemic bowel).
• Nausea
• Vomiting, which is associated more with proximal obstructions
• Diarrhea (an early finding)
• Constipation (a late finding) as evidenced by the absence of flatus or bowel movements
• Fever and tachycardia - Occur late and may be associated with strangulation
• Previous abdominal or pelvic surgery,  previous radiation therapy, or both (may be part of patient's medical history)
• History of malignancy (particularly ovarian and colonic)

Physical

• Abdominal distention
  • Duodenal or proximal small bowel has less distention when obstructed than the distal bowel has when obstructed.
  • Hyperactive bowel sounds occur early as GI contents attempt to overcome the obstruction.
  • Hypoactive bowel sounds occur late.
  • Exclude incarcerated hernias of the groin, femoral triangle, and obturator foramina.
  • Proper genitourinary and pelvic examinations are essential.
  • Look for the following during rectal examination:
    • Gross or occult blood, which suggests late strangulation or malignancy
    • Masses, which suggest obturator hernia
  • Check for symptoms commonly believed to be more diagnostic of intestinal ischemia, including the following:
    • Fever (temperature >100°F)
    • Tachycardia (>100 beats/min)
    • Peritoneal signs
  • No reliable way exists to differentiate simple from early strangulated obstruction on physical examination. Serial abdominal examinations are important and may detect changes early.

Causes

• The most common cause of SBO is postsurgical adhesions.
  • Postoperative adhesions can be the cause of acute obstruction within 4 weeks of surgery or of chronic obstruction decades later.
  • The incidence of SBO parallels the increasing number of laparotomies performed in developing countries.
  • The second most common identified cause of SBO is an incarcerated groin hernia.
• Other etiologies of SBO include malignant tumor (20%), hernia (10%), inflammatory bowel disease (5%), volvulus (3%), and miscellaneous causes (2%).
• The causes of SBO in pediatric patients include congenital atresia, pyloric stenosis, and intussusception.

Differential Diagnoses

Workup

Laboratory Studies

• Essential laboratory tests
  • Serum chemistries: Results are usually normal or mildly elevated.
  • BUN level: If the BUN level is increased, this may indicate decreased volume state (eg, dehydration).
  • Creatinine level: Creatinine level elevations may indicate dehydration.
  • CBC: WBC count may be elevated with a left shift in simple or strangulated obstructions. Increased hematocrit is an indicator of volume state (ie, dehydration).
  • Lactate dehydrogenase tests
  • Urinalysis
  • Type and crossmatch: The patient may require surgical intervention.
• Laboratory tests to exclude biliary or hepatic disease
  • Phosphate level
  • Creatine kinase level
  • Liver panels

Imaging Studies

• Plain radiography
  • Obtain plain radiographs first for patients in whom SBO is suspected.
  • At least 2 views, supine or flat and upright, are required.
  • Plain radiographs are diagnostically more accurate in cases of simple obstruction; however, diagnostic failure rates of as much as 30% have been reported. In one small study, the sensitivity of plain radiographs was reported as 75%, and specificity was reported to be 53%. Similar findings were reported in a second study.
  • In one study, plain films were more accurate in the detection of an acute SBO and the accuracy was higher if interpreted by more experienced radiologists.
  • Plain radiography is of little assistance in differentiating strangulation from simple obstruction. Some have used abdominal radiography to distinguish between complete obstruction and partial or no SBO. A study by Lappas et al proposed that 2 findings were more predictive of a higher grade or complete SBO: presence of air-fluid differential height in the same small-bowel loop and presence of a mean level width greater than 25 mm.^{[1 ]}The study found that when the 2 findings are present, the obstruction is most likely high grade or complete. When both are absent, the authors proposed that a low-grade (partial) SBO is likely or nonexistent.
  • Dilated small-bowel loops with air fluid levels indicate SBO.
  • Absent or minimal colonic gas indicates SBO.
• Enteroclysis
  • Enteroclysis is valuable in detecting the presence of obstruction and in differentiating partial from complete blockages.
  • This study is useful when plain radiographic findings are normal in the presence of clinical signs of SBO or if plain radiographic findings are nonspecific.
  • It distinguishes adhesions from metastases, tumor recurrence, and radiation damage.
  • Enteroclysis offers a high negative predictive value and can be performed with 2 types of contrast.
  • Barium is the classic contrast agent used in this study. It is safe and useful when diagnosing obstructions provided no evidence of bowel ischemia or perforation exists. Barium has been associated with peritonitis and should be avoided if perforation is suspected.
• CT scanning
  • CT scanning is useful in making an early diagnosis of strangulated obstruction and in delineating the myriad other causes of acute abdominal pain, particularly when clinical and radiographic findings are inconclusive. It also has proved useful in distinguishing the etiologies of SBO, that is, extrinsic causes such as adhesions and hernia from intrinsic causes such as neoplasms or Crohn disease. It also differentiates the above from intraluminal causes such as bezoars.
  • CT scanning is about 90% sensitive and specific in detecting SBO.
  • CT scanning is the study of choice if the patient has fever, tachycardia, localized abdominal pain, and/or leukocytosis.
  • It is capable of revealing abscess, inflammatory process, extraluminal pathology resulting in obstruction, and mesenteric ischemia.
  • CT scanning enables the clinician to distinguish between ileus and mechanical small bowel in postoperative patients.
  • CT scanning does not require oral contrast for the diagnosis of SBO because the retained intraluminal fluid serves as a natural contrast agent.
  • Obstruction is present if the small-bowel loop is greater than 2.5 cm in diameter dilated proximal to a distinct transition zone of collapsed bowel less than 1 cm in diameter.
  • A smooth beak indicates simple obstruction without vascular compromise; a serrated beak may indicate strangulation.
  • Bowel wall thickening indicates early strangulation.
  • Portal venous gas indicates early strangulation.
  • Pneumatosis indicates early strangulation.
  • CT scanning is useful in identifying abscesses, hernias, and tumors.
  • CT may be less useful in the evaluation of small bowel ischemia associated with obstruction.
  • One small series reported a sensitivity of 93%, specificity of 100%, and accuracy of 94% in detecting obstruction. Another reported a sensitivity of 92% and specificity of 71% in correct identification of partial or complete SBO.
• CT enterography (CT enteroclysis) 
  • This modality is replacing enteroclysis in clinical practice.^{[2,3,4 ]}
  • This is also the examination of choice for intermittent SBO or in patients with complicated surgical history (eg, prior surgery, tumors).^{[5 ]}
  • It displays the entire thickness of the bowel wall and allows evaluation of surrounding mesentery and perinephric fat.^{[2 ]}
  • Newer imaging technique that uses CT technology to perform thin slices of bowel along while simultaneously using large volume enteric contrast material for imagery.^{[2 ]}
  • More accurate than conventional CT at finding cause of SBO (89% vs 50%), as well as locating site (100% vs 94%).^{[6 ]}
  • Helpful in patients being managed conservatively (ie, nonoperatively).^{[6 ]}  
• MRI
  • The accuracy of MRI almost approaches that of CT scanning for detection of obstruction.^{[2 ]}
  • MRI is also effective in defining location and etiology of obstruction.^{[7 ]}
  • MRI has several limitations, such as lack of availability (transporting sicker patients is difficult) and poor visualization of masses or inflammation.^{[8,9 ]}
       
• Ultrasonography
  • Ultrasonography is less costly and less invasive than CT scanning.
  • It may reliably exclude SBO in as many as 89% of patients.
  • Specificity is reportedly 100%.

Other Tests

• Studies have been performed to evaluate the use of water-soluble oral contrast as a tool in the management of small-bowel obstruction and as a predictive tool for nonoperative resolution of adhesive SBO. It does not cause resolution of the SBO, but it may reduce the hospital stay in patients not requiring surgery.

Procedures

• Nasogastric tube placement and suction should be performed for patients with severe nausea and vomiting.

Treatment

Emergency Department Care

Initial ED treatment consists of aggressive fluid resuscitation, bowel decompression, administration of analgesia and antiemetic as indicated clinically, antibiotics, and early surgical consultation.

• Initial decompression can be performed by placement of a nasogastric (NG) tube for suctioning GI contents and preventing aspiration.
• Antibiotics are used to cover against gram-negative and anaerobic organisms.
• Monitor airway, breathing, and circulation (ABCs).
  • Blood pressure monitoring
  • Cardiac monitoring in selected patients (especially elderly patients or those with comorbid conditions)

Consultations

• General surgeon (early and without delay): Laparoscopy is being used in addition to laparotomy and has been shown to reduce hospital stay, speed recovery, and decrease morbidity.

Medication

Fluid replacement with aggressive intravenous resuscitation using isotonic saline or lactated Ringer solution is indicated. Oxygen and appropriate monitoring are also required. Antibiotics are used to cover gram-negative and anaerobic organisms.

Antibiotics

These agents are for prophylaxis in surgical intervention, if needed.

Cefazolin (Ancef, Kefzol, Zolicef)

First-generation semisynthetic cephalosporin that arrests bacterial cell wall synthesis, inhibiting bacterial growth.

Dosing

Adult

1-2 g IV 1 h before surgery

Pediatric

20 mg/kg IV 1 h before surgery

Interactions

Probenecid prolongs effect of cefazolin; coadministration with aminoglycosides may increase renal toxicity; may yield false-positive urine-dip test results for glucose

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Adjust dose in severe renal insufficiency (high doses may cause CNS toxicity); superinfections and promotion of nonsusceptible organisms may occur with prolonged use or repeated therapy

Cefoxitin (Mefoxin)

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

Dosing

Adult

2 g IV 1 h before surgery

Pediatric

20 mg/kg IV 1 h before surgery

Interactions

Probenecid may increase effects of cefoxitin; coadministration with aminoglycosides or furosemide may increase nephrotoxicity (closely monitor renal function)

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Adjust dose in severe renal insufficiency (high doses may cause CNS toxicity); superinfections and promotion of nonsusceptible organisms may occur with prolonged use or repeated therapy

Cefotetan (Cefotan)

Second-generation cephalosporin indicated for infections caused by susceptible gram-positive cocci and gram-negative rods.
Dosage and route of administration depend on condition of patient, severity of infection, and susceptibility of causative organism.

Dosing

Adult

1-2 g IV 1 h before surgery

Pediatric

Not established

Interactions

Consumption of alcohol within 72 h of cefotetan may produce disulfiramlike reactions; may increase hypoprothrombinemic effects of anticoagulants; coadministration with potent diuretics (eg, loop diuretics) or aminoglycosides may increase nephrotoxicity

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Reduce dosage by one half if CrCl is 10-30 mL/min and by one fourth if <10 mL/min (high doses may cause CNS toxicity); bacterial or fungal overgrowth of nonsusceptible organisms may occur with prolonged or repeated therapy

Cefuroxime (Ceftin, Kefurox, Zinacef)

Second-generation cephalosporin maintains gram-positive activity of first-generation cephalosporins; adds activity against Proteus mirabilis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, and Moraxella catarrhalis.
Condition of patient, severity of infection, and susceptibility of microorganism determine proper dose and route of administration.

Dosing

Adult

1.5 g IV 1 h before surgery

Pediatric

50 mg/kg IV 1 h before surgery

Interactions

Disulfiramlike reactions may occur when alcohol is consumed within 72 h after taking cefuroxime; may increase hypoprothrombinemic effects of anticoagulants; may increase nephrotoxicity in patients receiving potent diuretics such as loop diuretics; coadministration with aminoglycosides increases nephrotoxic potential

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Reduce dosage by one half if CrCl is 10-30 mL/min and by three fourths if <10 mL/min (high doses may cause CNS toxicity); bacterial or fungal overgrowth of nonsusceptible organisms may occur with prolonged or repeated therapy

Meropenem (Merrem)

Bactericidal broad-spectrum carbapenem antibiotic that inhibits cell-wall synthesis. Effective against most gram-positive and gram-negative bacteria.

Dosing

Adult

1 g IV q8h

Pediatric

40 mg/kg IV q8h

Interactions

Probenecid may inhibit renal excretion of meropenem, increasing meropenem levels

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Pseudomembranous colitis and thrombocytopenia may occur, requiring immediate discontinuation of medication

Antiemetic

These agents should be administered for symptomatic relief, usually in conjunction with GI decompression via placement of an NG tube to suction.

Promethazine (Phenergan)

For symptomatic treatment of nausea and vomiting. Antidopaminergic agent effective in treating emesis. Blocks postsynaptic mesolimbic dopaminergic receptors in brain and reduces stimuli to brainstem reticular system.

Dosing

Adult

12.5-25 mg PO/IV/IM/PR q4h prn

Pediatric

<2 years: Contraindicated
>2 years: 0.25-1 mg/kg PO/IV/IM/PR 4-6 times/d prn

Interactions

May have additive effects when used concurrently with other CNS depressants or anticonvulsants; elderly persons may be particularly susceptible to experience decreased mental status; coadministration with epinephrine may cause hypotension

Contraindications

Documented hypersensitivity; children <2 y (incidences of death due to respiratory depression)

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in cardiovascular disease, impaired liver function, seizures, sleep apnea, and asthma; start with lower dose in elderly patients

Ondansetron (Zofran)

Selective 5-HT3-receptor antagonist that blocks serotonin both peripherally and centrally, used in the prevention of nausea and vomiting. Metabolized in the liver through the P-450 pathway.

Dosing

Adult

4-8 mg PO q8h; alternatively, 4 mg IV q8h

Pediatric

4 mg PO q8h; alternatively, 0.1-0.15 mg/kg IV q8h

Interactions

Although potential exists for cytochrome P-450 inducers (barbiturates, rifampin, carbamazepine, and phenytoin) to change half-life and clearance of ondansetron, dosage adjustment is not usually required

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

May cause headache

Analgesics

Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties, which are beneficial for patients who experience pain.

Morphine sulfate (Astramorph, MS Contin, MSIR, Oramorph)

DOC for analgesia due to reliable and predictable effects, safety profile, and ease of reversibility with naloxone.
Various IV doses are used; commonly titrated until desired effect obtained.

Dosing

Adult

Starting dose: 0.1 mg/kg IV/IM/SC
Maintenance dose: 5-20 mg/70 kg IV/IM/SC q2-4h
Relatively hypovolemic patients: Start with 2 mg IV/IM/SC and reassess hemodynamic effects of dose

Pediatric

Neonates: 0.05-0.2 mg/kg dose IV/IM/SC prn
Children: 0.1-0.2 mg/kg dose IV/IM/SC q2-4h prn

Interactions

Phenothiazines may antagonize analgesic effects of opiate agonists; tricyclic antidepressants, MAO inhibitors, and other CNS depressants may potentiate adverse effects of morphine

Contraindications

Documented hypersensitivity; hypotension; potentially compromised airway where establishing rapid airway control would be difficult

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in hypotension, respiratory depression, nausea, emesis, constipation, urinary retention, atrial flutter, and other supraventricular tachycardias; has vagolytic action and may increase ventricular response rate

Follow-up

Further Inpatient Care

• Continued NG suction: This provides symptomatic relief, decreases the need for intraoperative decompression, and benefits all patients. No clinical advantage to using a long tube (nasointestinal) instead of a short tube (NG) is observed.
• Nonoperative treatment: A nonoperative trial of as many as 3 days is warranted for partial or simple obstruction. Provide adequate fluid resuscitation and NG suctioning. Resolution of obstruction occurs in virtually all patients with these lesions within 72 hours.
• Good data regarding nonoperative management suggest it to be successful in 65-81% of partial SBO cases without peritonitis.^{[2,10 ]}
• Surgical treatment: A strangulated obstruction is a surgical emergency. In patients with a complete SBO, the risk of strangulation is high and early surgical intervention is warranted. Patients with simple complete obstructions in whom nonoperative trials fail also need surgical treatment but experience no apparent disadvantage to delayed surgery.
• Laparoscopy has been shown to be safe and effective in selected cases of SBO.^{[11 ]}
• Adhesions: Decreasing intraoperative trauma to the peritoneal surfaces can prevent adhesion formation.
• Malignant tumor: Obstruction by tumor is usually caused by metastasis. Initial treatment should be nonoperative; surgical resection is recommended when feasible.
• Inflammatory bowel disease: To reduce the inflammatory process, treatment generally is nonoperative in combination with high-dose steroids. Consider parenteral treatment for prolonged periods of bowel rest. Undertake surgical treatment, bowel resection, and/or stricturoplasty if nonoperative treatment fails.
• Intra-abdominal abscess: CT-guided drainage is usually sufficient to relieve obstruction.
• Radiation enteritis: If obstruction follows radiation therapy acutely, nonoperative treatment accompanied by steroids is usually sufficient. If obstruction is a chronic sequela of radiation therapy, surgical treatment is indicated.
• Acute postoperative obstruction: This is difficult to diagnose because symptoms often are attributed to incisional pain and postoperative ileus. Treatment should be nonoperative.
• Incarcerated hernia: Initially use manual reduction and observation. Advise elective hernia repair as soon as possible after reduction.

Further Outpatient Care

• Treat all patients as inpatients including trial of observation.

Complications

• Sepsis
• Intra-abdominal abscess
• Wound dehiscence
• Aspiration
• Short-bowel syndrome (as a result of multiple surgeries)
• Death (secondary to delayed treatment)

Prognosis

• With proper diagnosis and treatment of the obstruction, prognosis is good. Complete obstructions treated successfully nonoperatively have a higher incidence of recurrence than those treated surgically.

Miscellaneous

Medicolegal Pitfalls

• No accurate clinical picture exists to detect early strangulation of obstruction.
• If the diagnosis is unclear, admission and observation are warranted to detect early obstructions.
• Some factors associated with death and postoperative complications include age, comorbidity, and treatment delay. According to one Norwegian group, morbidity and mortality decreased from 1961 to 1995.

Multimedia

Media file 1: Small bowel obstruction.

Media file 2: Small bowel obstruction.

Media file 3: Small bowel obstruction.

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Keywords

SBO, small bowel obstruction, small bowel obstruction symptoms, small bowel obstruction treatment, small bowel obstruction causes, obstruction of the small bowel, Crohn disease, Crohn's disease, hernia, bowel necrosis, bowel ischemia, peritonitis, inflammatory bowel disease, volvulus, congenital atresia, pyloric stenosis, intussusception

Contributor Information and Disclosures

Author

Brian A Nobie FACEP, MD, Director of Recruitment, Consulting Staff, Florida Emergency Physicians, Florida Hospital, Celebration Health
Brian A Nobie FACEP, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Joseph J Sachter, MD, FACEP, Consulting Staff, Department of Emergency Medicine, Muhlenberg Regional Medical Center
Joseph J Sachter, MD, FACEP is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Physician Executives, American Medical Association, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Eugene Hardin, MD, FAAEM, FACEP, Former Chair and Associate Professor, Department of Emergency Medicine, Charles Drew University of Medicine and Science; Former Chair, Department of Emergency Medicine, Martin Luther King Jr/Drew Medical Center
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Steven C Dronen, MD, FAAEM, Director of Emergency Services, Director of Chest Pain Center, Department of Emergency Medicine, Ft Sanders Sevier Medical Center
Steven C Dronen, MD, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Clinical guidelines

EAST Practice Parameter Workgroup for Management of Small Bowel Obstruction. Practice management guidelines for small bowel obstruction. Chicago (IL): Eastern Association for the Surgery of Trauma (EAST); 2007. 42 p.

Ros PR, Huprich JE, Bree RL, Foley WD, Gay SB, Glick SN, Heiken JP, Levine MS, Rosen MP, Shuman WP, Greene FL, Expert Panel on Gastrointestinal Imaging. Suspected small bowel obstruction. [online publication]. Reston (VA): American College of Radiology (ACR); 2005. 5 p.

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