Crohn Disease

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

Luminal inflammatory disease

• Most common presentation at diagnosis (60–80%)

• Malaise, loss of energy

• Diarrhea, nonbloody, intermittent

• Possible fecal urgency with bloody diarrhea

• Cramping or steady right lower quadrant or periumbilical pain

• Focal right lower quadrant tenderness

• Palpable, tender mass in the lower abdomen

Intestinal stricturing

• Postprandial bloating, cramping pains, and loud borborygmi

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

Penetrating disease and fistulae

• 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 due to fistulas

• Cutaneous fistulas

• Perianal disease

  • Skin tags (large, painful)

  • Anal fissures

  • Perianal abscesses

  • Fistulas

Extraintestinal manifestations

• Arthralgias, arthritis

• Iritis or uveitis

• Pyoderma gangrenosum

• Erythema nodosum

• Oral aphthous lesions

• Gallstones

• Nephrolithiasis

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

DIAGNOSIS

Laboratory Tests

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

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

  • Leukocytosis occurs with abscesses or corticosteroid therapy

  • ESR or CRP elevated (15% have a normal CRP level)

• Fecal calprotectin

  • An excellent noninvasive test

  • Elevated levels are correlated ...