Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android

Key Features

Essentials of Diagnosis

  • Inflammation causes abdominal pain, diarrhea, bloody stools, fever, anorexia, fatigue, and weight loss

  • No single test is diagnostic

  • Low hemoglobin, iron, and serum albumin levels

  • Elevated erythrocyte sedimentation rate and C-reactive protein and fecal calprotectin

  • Genetic association is evident

    • 5–30% of patients identifying a family member with inflammatory bowel disease (IBD)

    • 10–20 relative risk of IBD developing in a sibling

General Considerations

  • IBD is most commonly differentiated into Crohn disease and ulcerative colitis

  • Etiology is multifactorial, involving a complex interaction of environmental and genetic factors leading to maladaptive immune responses to flora in the GI tract

Clinical Findings

Symptoms and Signs

  • Crohn disease

    • May present as a stricturing process with abdominal pain and intestinal obstruction or as a penetrating/fistulizing form with abscess, perianal disease, or symptoms similar to acute appendicitis

    • Can affect any part of the GI tract from the lips to anus

    • Most often affects the terminal ileum and colon in children

  • Ulcerative colitis

    • Usually presents with abdominal pain and bloody diarrhea

    • Limited to the colon; usually involves the entire colon (pancolitis) in children

    • The younger the age at onset, the more severe the disease course

  • Extraintestinal manifestations

    • Common in both forms of IBD

    • May precede the intestinal complaints

    • Include uveitis, recurrent oral aphthous ulcers, arthritis, growth and pubertal delay, liver involvement (typically primary sclerosing cholangitis), rash (erythema nodosa and pyoderma gangrenosum), and iron deficiency anemia

Differential Diagnosis

  • Irritable bowel syndrome

  • Lactose intolerance

  • Rheumatoid arthritis

  • Systemic lupus erythematosus or other vasculitis

  • Celiac disease

  • Hypopituitarism

  • Behçet disease


  • Diagnosis is based on typical presentation, course, radiographic, endoscopic, and histologic findings, and exclusion of other disorders

  • IBD-related serum antibodies are frequently present

    • Antibodies to Saccharomyces cerevisiae (ASCA) in 60% of patients with Crohn disease

    • Perinuclear antineutrophil cytoplasmic antibodies (pANCAs) in 70% of patients with ulcerative colitis

    • Antibodies may be helpful in differentiating Crohn disease from ulcerative colitis, but they are neither sensitive nor specific enough to be diagnostic

  • Abdominal imaging with CT, magnetic resonance enterography, ultrasonography, and barium upper GI radiographs with small bowel follow-through may reveal small bowel disease and exclude other etiologies; findings include

    • Terminal ileal thickening

    • Enteric fistulas

    • Mucosal and mural edema

  • Upper endoscopy and ileocolonoscopy are the most useful diagnostic modalities, revealing severity and extent of upper intestinal, ileal, and colonic involvement



  • A high-protein, high-carbohydrate diet with normal amounts of fat is recommended

  • A diet with decreased fiber may reduce symptoms during active colitis or partial intestinal obstruction

  • However, once the colitis is controlled, increased fiber may benefit mucosal health via bacterial production of fatty acids

  • Low-lactose diet or lactase replacement may be needed temporarily for small ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.