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% of patients have symptomatic involvement of the upper intestinal tract

• Smokers are at increased risk

• Treatment is directed both toward improving the symptoms 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 can occur

  • Between the small intestine and the colon and commonly are asymptomatic but can cause

    • Diarrhea

    • Weight loss

    • Bacterial overgrowth

    • Malnutrition

  • Between the small intestine and the bladder or vagina and can cause

    • Recurrent urinary tract infections

    • Recurrent vaginal infections

  • Between the small intestine and the skin and can cause

    • Cutaneous fistulas

    • Perianal abscesses

    • Anal fissures

    • Skin tags

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

Diagnosis

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 ...