Inflammatory Bowel Disease

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

• 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

Treatment

Nonpharmacologic

• 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 ...