Irritable bowel syndrome

Last reviewed: March 2019

Last updated: January 2019

Summary

Irritable bowel syndrome symptoms include recurrent abdominal pain or discomfort that is associated with a change in stool frequency or form. The pain or discomfort may be relieved by defecation.

It is important to determine whether there are any dietary associations such as lactose-containing foods or fructose-containing foods.

Exam of the abdomen is usually unremarkable. There may be mild and poorly localized tenderness in the right lower quadrant and/or left lower quadrant.

The diagnosis is based on the patient's history, and there are no specific diagnostic tests. If the patient has worrying symptoms or findings such as anemia, weight loss, or fever, then these require more thorough investigation.

Treatment should be individualized and is dependent on the patient's predominant symptoms.

Definition

Irritable bowel syndrome (IBS) is a chronic condition characterized by abdominal pain associated with bowel dysfunction. The pain is often relieved by defecation and is sometimes accompanied by abdominal bloating. There are no structural abnormalities to explain the pain. IBS occurs in about 15% of the adult population. The etiology is probably multifactorial and evidence suggests motility, inflammatory, genetic, immune, psychological, and dietary components. [1]

History and exam

Key diagnostic factors

abdominal discomfort
alteration of bowel habits associated with pain
abdominal bloating or distention
normal exam of abdomen

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Other diagnostic factors

passage of mucus with stool

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Risk factors

physical and sexual abuse
age <50 years
female sex
previous enteric infection
family and job stress

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Diagnostic investigations

1st investigations to order

CBC
stool studies
antiendomysial antibodies
anti-tTG antibodies
plain abdominal radiograph
flexible sigmoidoscopy
colonoscopy

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Investigations to consider

hydrogen breath test
fecal calprotectin
serum CRP

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Treatment algorithm

ONGOING

Contributors

Authors VIEW ALL 

Ned Snyder, MD, MACP, AGAF

Chief of Gastroenterology and Hepatology

Kelsey-Seybold Clinic

Clinical Professor of Medicine

Baylor College of Medicine

Houston

Adjunct Professor of Medicine

University of Texas Medical Branch

Galveston

Disclosures

NS declares that he has no competing interests.

Peer reviewers VIEW ALL 

Douglas Drossman, MD

Professor of Medicine and Psychiatry

School of Medicine

Co-Director

UNC Center for Functional GI and Motility Disorders

Chapel Hill

Disclosures

DD declares that he has no competing interests.

Simon McLaughlin, MBBS

Research Fellow

Department of Gastroenterology

St Mark's Hospital

Northwick Park

Harrow

Disclosures

SM declares that he has no competing interests.

Horace Williams, MBBS

Clinical Research Fellow

Division of Medicine

Imperial College

London

Disclosures

HW declares that he has no competing interests.

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Irritable bowel syndrome

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

constipation-predominant

diarrhea-predominant

alternating constipation and diarrhea

Contributors

Authors VIEW ALL 

Ned Snyder, MD, MACP, AGAF

Disclosures

Peer reviewers VIEW ALL 

Douglas Drossman, MD

Disclosures

Simon McLaughlin, MBBS

Disclosures

Horace Williams, MBBS

Disclosures

Differentials

Guidelines

Patient leaflets

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