Crohn Disease, Complications and Surgical Therapy

Clinical Picture

The major presenting symptoms in Crohn disease are abdominal pain, diarrhea or change in bowel habits, and weight loss. Symptoms vary greatly. In ulcerative colitis (UC), diarrhea is the overriding factor. The bowel pattern varies with the area of the intestine involved. When the terminal ileum is involved, the major presenting symptom is usually right lower quadrant pain, which can be confused with appendicitis. At times, the abdominal pain may be diffuse, but it varies with the area of the bowel involved.

Because of the chronicity of the symptoms, most patients lose weight. Depending on the extent of Crohn disease, the symptoms can be accompanied by obstruction, and thus obstipation and abdominal distention; by perianal rectal drainage resulting from fistulization; or in rare cases, by anemia from blood loss and malabsorption. Symptoms vary depending on the site of GI disease.

Physical examination may reveal no findings or a mass in the right lower quadrant. The patient with Crohn disease may have diffuse tenderness or obstruction or may be anemic, pale, and febrile. Once again, physical findings depend on the extent of disease. Atypical presentations from extraintestinal manifestations may be seen.

Diagnosis

Initial laboratory evaluation may reveal anemia, elevated erythrocyte sedimentation rate and C-reactive protein, leukocytosis, and thrombocytosis, again depending on the extent of disease. If the patient is losing weight and has diarrhea, hypoalbuminemia may be present.

The next step in the diagnosis involves examining the GI tract. Symptoms will determine whether to begin with endoscopy. If the patient has diarrhea, colonoscopy will likely reveal the classic aphthous ulcerations of the bowel and “skipped” areas. Histologic examination may confirm the diagnosis. Most colonoscopists can examine the terminal ileum. Biopsy can be performed on that area to confirm or rule out a diagnosis of terminal ileitis.

Barium contrast studies or computed tomography (CT) can be used to image the GI tract. Either technique may make the diagnosis of Crohn disease, or either may be needed to complement the other's findings. Barium studies may reveal a classic stricture or an inflamed loop of bowel. Most often, Crohn disease is in the terminal ileum, but skipped areas may be present. Barium studies may also reveal strictures and enteroenteric fistulae. Because of the symptoms, or possibly a masked presentation, the clinician may prefer CT or may need CT to complement findings of the barium study. CT classically reveals evidence of the increasing fat pad deposition noted in most pathology specimens and the “smudgy” area outside the bowel. The bowel wall shows areas of thickness, depending on the site of involvement.

If the patient has perianal or anal disease, anoscopy should be performed in addition to colonoscopy to determine the sites of fistulization and fissures.

Serologic markers are now available and have been helpful in confirming, and at times making, the diagnosis. About 60% to 70% of patients with Crohn disease have elevated anti– Saccharomyces cerevisiae antibody (ASCA) levels. However, ASCA has specificity greater than 95%. If the perinuclear antineutrophil cytoplasmic antibody (pANCA) is negative, the patient almost certainly has Crohn disease.

Capsule endoscopy is gaining wide acceptance and can demonstrate ulceration and stricture of the small bowel. Because some are subtle, small bowel changes can be missed on barium contrast studies or CT scans. Push enteroscopy, with scopes of distance, often do not cover the entire small bowel. Double-balloon enteroscopy may be helpful in uncertain cases, and biopsy material can be obtained. Positive findings on capsule endoscopy in conjunction with positive serologic markers strongly suggest that the patient has Crohn disease.

Extraintestinal manifestations develop in approximately 25% of the patients. These may complicate Crohn disease, may occur at any time during the disease, or may be a presenting finding, to which the clinician must be alert. Areas involved are the skin, eyes, liver, and musculoskeletal system. In addition, other areas of the gut are reportedly involved, including the mouth, esophagus, stomach, and duodenum. The most dramatic extraintestinal manifestations are pyoderma gangrenosum and perianal tags (skin), uveitis, iritis, and conjunctivitis (eye), and peripheral arthritides, sacroiliitis, and osteoporosis (bones). Primary sclerosing cholangitis may be the presenting symptom if Crohn disease develops later in life.

Diseases that can mimic Crohn disease include bowel lymphomas, other malignancies, tuberculosis of the bowel, and at times, a chronic Yersinia infection. However, laboratory test results and endoscopy can differentiate these diseases readily.