– A nonspecific chronic inflammatory disease of the gastrointestinal system most commonly affecting the distal ileum and the colon.
Causes and Incidence
The etiology is unknown, and research examining the causal role of immune factors, infectious agents, and dietary factors has proved fruitless. There are an estimated 30 to 50 cases per 100,000 population, and the incidence is rising in underdeveloped countries, among blacks and Hispanics, and in Western and Northern European and Anglo-Saxon populations. The disease is equally distributed across gender lines, is most common among Jews, and occurs primarily between 15 and 30 years of age.
Crohn’s disease begins with lymphedema in the GI submucosa and microscopic focal ulcerations of the mucosa. The inflammation spreads slowly and progressively, involving all layers of the intestinal wall, which thicken with extensive fibrosis and granulomas as patchy ulcerations form on the mucosa. This process creates a characteristic cobblestone appearance of the mucosa. As the disease progresses, the mesentery becomes edematous and thickens, and mesenteric fat extends onto the serosal surface of the bowel, causing serositis with adhesion of bowel loops to one another. Mesenteric lymph nodes enlarge, and abscess and deep sinus tracts and fissures are formed. Eventually the lumen of the intestine severely narrows or becomes obstructed. This process very often affects one segment of the intestine, skips over normal tissue, then repeats the obstructive process in another segment (iskip lesionsi).
Symptoms may be abrupt or insidious in onset and are characterized by exacerbations and remissions. The most common presenting features are chronic diarrhea with urgency and incontinence; abdominal pain and cramping, often in the lower right quadrant; fever; anorexia; and weight loss. However, some individuals have acute abdominal pain resembling that caused by appendicitis.
Complications of Crohn’s disease can be either intestinal or systemic. An anal fistula or perianal abscess caused by chronic diarrhea is the most common complication. Other fistulas may form to the bladder, vagina, or skin. Malabsorption, obstruction, perforation, and cancer of the colon are other intestinal complications. Systemic complications include arthritis, episcleritis, stomatitis, erythema nodosum, pyoderma gangrenosum, ankylosing spondylitis, sacroiliitis, uveitis, and sclerosing cholangitis.
Linear ulcerations, skip lesions, thickening of wall, narrowing of lumen
To aid in differentiation of disease
Nonspecific; may include decreased hemoglobin and hematocrit, serum albumin, and folic acid; elevated erythrocyte sedimentation rate
Bowel resection with failure to respond to conservative therapy; colectomy with ileostomy when disease is limited to colon; strictureplasty to open obstructions.
Sulfasalazine, corticosteroids, and metronidazole to treat inflammation and ulceration; anticholinergics for diarrhea; fat-soluble vitamins, folic acid, iron, calcium magnesium, and zinc for replacement; immunosuppressive agents for retractive disease.
Adequate rest; nutrition: NPO in acute phase to rest bowel, followed by total parenteral nutrition or restricted diet low in fiber; emotional support for anxiety and depression; referral to source of information and support group.