Regional Enteritis (Crohn’s Disease) - Inflammatory Bowel Disease

REGIONAL ENTERITIS (CROHN’S DISEASE)

Regional enteritis commonly occurs in adolescents or young adults but can appear at any time of life. It is more common in women, and it occurs frequently in the older population (be-tween the ages of 50 and 80). It can occur anywhere along the GI tract, but the most common areas are the distal ileum and colon. The incidence of Crohn’s disease has risen over the past 30 years. Crohn’s disease is seen two times more often in patients who smoke than in nonsmokers (Rose, 1998).

Pathophysiology

Regional enteritis is a subacute and chronic inflammation that ex-tends through all layers (ie, transmural lesion) of the bowel wall from the intestinal mucosa. It is characterized by periods of re-missions and exacerbations. The disease process begins with edema and thickening of the mucosa. Ulcers begin to appear on the inflamed mucosa. These lesions are not in continuous con-tact with one another and are separated by normal tissue. Fistu-las, fissures, and abscesses form as the inflammation extends into the peritoneum. Granulomas occur in one half of patients. In ad-vanced cases, the intestinal mucosa has a cobblestone appearance. As the disease advances, the bowel wall thickens and becomes fi-brotic, and the intestinal lumen narrows. Diseased bowel loops sometimes adhere to other loops surrounding them

Clinical Manifestations

In regional enteritis, the onset of symptoms is usually insidious, with prominent lower right quadrant abdominal pain and diar-rhea unrelieved by defecation. Scar tissue and the formation of granulomas interfere with the ability of the intestine to transport products of the upper intestinal digestion through the constricted lumen, resulting in crampy abdominal pains. There is abdominal tenderness and spasm. Because eating stimulates intestinal peri-stalsis, the crampy pains occur after meals. To avoid these bouts of crampy pain, the patient tends to limit food intake, reducing the amounts and types of food to such a degree that normal nu-tritional requirements are not met. The result is weight loss, mal-nutrition, and secondary anemia. Ulcers in the membranous lining of the intestine and other inflammatory changes result in a weeping, swollen intestine that continually empties an irritat-ing discharge into the colon. Disrupted absorption causes chronic diarrhea and nutritional deficits. The result is a person who is thin and emaciated from inadequate food intake and constant fluid loss. In some patients, the inflamed intestine may perforate, lead-ing to intra-abdominal and anal abscesses. Fever and leukocyto-sis occur. Chronic symptoms include diarrhea, abdominal pain, steatorrhea, anorexia, weight loss, and nutritional deficiencies.

Abscesses, fistulas, and fissures are common. Symptoms extend beyond the GI tract and commonly include joint involvement (eg, arthritis), skin lesions (eg, erythema nodosum), ocular disorders (eg, conjunctivitis), and oral ulcers. The clinical course and symptoms can vary; in some patients, periods of remission and exacerbation occur, but in others, the disease follows a fulminating course.

Assessment and Diagnostic Findings

A proctosigmoidoscopic examination is usually performed initially to determine whether the rectosigmoid area is inflamed. A stool examination is also performed; the result may be positive for oc-cult blood and steatorrhea (ie, excessive fat in the feces). The most conclusive diagnostic aid for regional enteritis is a barium study of the upper GI tract that shows the classic “string sign” on an x-ray film of the terminal ileum, indicating the constriction of a segment of intestine. Endoscopy and intestinal biopsy may be used for con-firmation of the diagnosis. A barium enema may show ulcerations (the cobblestone appearance described earlier), fissures, and fistu-las. A CT scan may show bowel wall thickening and fistula tracts.

A complete blood cell count is performed to assess hematocrit and hemoglobin levels (usually decreased) and the white blood cell count (may be elevated). The sedimentation rate is usually el-evated. Albumin and protein levels may be decreased, indicating malnutrition.

Complications

Complications of regional enteritis include intestinal obstruction or stricture formation, perianal disease, fluid and electrolyte im-balances, malnutrition from malabsorption, and fistula and ab-scess formation. A fistula is an abnormal communication between two body structures, either internal (ie, between two structures) or external (ie, between an internal structure and the outside sur-face of the body). The most common type of small bowel fistula that results from regional enteritis is the enterocutaneous fistula (ie, between the small bowel and the skin). Abscesses can be the result of an internal fistula tract into an area that results in fluid accumulation and infection. Patients with regional enteritis are also at increased risk for colon cancer.