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Key Features

Essentials of Diagnosis

  • Insidious onset

  • Intermittent bouts of low-grade fever, diarrhea, and right lower quadrant pain

  • Right lower quadrant mass and tenderness

  • Perianal disease with fistulas, fissures, and abscesses

  • Radiographic or endoscopic evidence of ulceration, stricturing, or fistulas of the small intestine or colon

General Considerations

  • Crohn disease is a transmural process

  • Crohn disease may involve

    • Small bowel only, most commonly the terminal ileum (ileitis) in ~33% of cases

    • Small bowel and colon, most often the terminal ileum and adjacent proximal ascending colon (ileocolitis) in ~50%

    • Colon alone in 20%

  • Chronic illness with exacerbations and remissions

  • One-third of patients have associated perianal disease (fistulas, fissures, abscesses)

  • Less than 5% patients have symptomatic involvement of the upper intestinal tract

  • Smokers are at increased risk

  • Treatment is directed both toward symptomatic improvement and controlling the disease process

Clinical Findings

Symptoms and Signs

  • Abdominal pain

  • Liquid bowel movements

  • Abdominal tenderness or abdominal mass

Chronic inflammatory disease

  • Malaise, loss of energy

  • Diarrhea, nonbloody, intermittent

  • Cramping or steady right lower quadrant or periumbilical pain

  • Focal tenderness, right lower quadrant

  • Palpable, tender mass in the lower abdomen

Intestinal obstruction

  • Postprandial bloating, cramping pains, and loud borborygmi

  • Narrowing of the small bowel may occur as a result of inflammation, spasm, or fibrotic stenosis

Fistulization with or without infection

  • Sinus tracts and fistulas can result in intra-abdominal or retroperitoneal abscesses manifested by fevers, chills, tender abdominal mass, and leukocytosis

  • Fistulas between the small intestine and colon commonly are asymptomatic but can result in diarrhea, weight loss, bacterial overgrowth, and malnutrition

  • Bladder or vaginal recurrent infections

  • Cutaneous fistulas

  • Perianal disease

    • Skin tags

    • Anal fissures

    • Perianal abscesses

    • Fistulas

Extraintestinal manifestations

  • Arthralgias, arthritis

  • Iritis or uveitis

  • Pyoderma gangrenosum

  • Erythema nodosum

  • Oral aphthous lesions

  • Gallstones

  • Nephrolithiasis with stones

Differential Diagnosis

  • Ulcerative colitis

  • Irritable bowel syndrome

  • Appendicitis

  • Yersinia enterocolitica enteritis

  • Mesenteric adenitis

  • Intestinal lymphoma

  • Segmental colitis due to ischemic colitis, tuberculosis, amebiasis, chlamydia

  • Diverticulitis or appendicitis with abscess

  • Nonsteroidal anti-inflammatory drug–induced colitis

  • Perianal fistula due to other cause


Laboratory Tests

  • Obtain complete blood count, erythrocyte sedimentation rate or C-reactive protein, serum albumin

    • Anemia may be due to chronic inflammation, blood loss, iron deficiency, or vitamin B12 malabsorption

    • Leukocytosis occurs with abscesses

    • Sedimentation rate or C-reactive protein elevated

  • Fecal calprotectin

    • An excellent noninvasive test

    • Elevated levels are correlated with active inflammation as seen on ileocolonoscopy or radiologic CT or MR enterography

  • Stool specimens are sent for examination for routine pathogens, ova and parasites, and Clostridium difficile toxin by either conventional microscopy and culture or by rapid, polymerase chain reaction (PCR) diagnostic assessment panel

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