gastrointestinal disorders
Ulcerative Colitis
Diagnosis of Ulcerative Colitis
Stool cultures and microscopy (to exclude infectious causes) Sigmoidoscopy with biopsy Diagnosis of ulcerative colitis is suggested by typical symptoms and signs, particularly when accompanied by extraintestinal manifestations or a history of previous similar attacks. Ulcerative colitis should be distinguished from Crohn Disease (see table In all patients, stool cultures for Etiology should be done, and Sigmoidoscopy should be done; it allows visual confirmation of colitis and permits direct sampling of stool or mucus for culture and microscopic evaluation, as well as biopsy of affected areas. Although visual inspection and biopsies may be nondiagnostic, because there is much overlap in appearance among different types of colitis, acute, self-limited, infectious colitis can usually be distinguished histologically from chronic idiopathic ulcerative colitis or Crohn colitis. Severe perianal disease, rectal sparing, absence of bleeding, and asymmetric or segmental involvement of the colon indicate Crohn disease rather than ulcerative colitis. Colonoscopy is usually unnecessary initially but should be done electively if inflammation has extended proximal to the reach of the sigmoidoscope. Laboratory tests should be done to screen for anemia, hypoalbuminemia, and electrolyte abnormalities. Liver tests should be done; elevated alkaline phosphatase and gamma-glutamyl transpeptidase levels suggest possible primary sclerosing cholangitis. Perinuclear antineutrophil cytoplasmic antibodies are relatively specific (60 to 70%) for ulcerative colitis. Anti–Saccharomyces cerevisiaeantibodies are relatively specific for Crohn disease. However, these tests do not reliably separate the 2 diseases and are not recommended for routine diagnosis. Other possible laboratory abnormalities include leukocytosis, thrombocytosis, and elevated acute-phase reactants (eg, erythrocyte sedimentation rate, C-reactive protein). X-rays are not diagnostic but occasionally show abnormalities. Plain x-rays of the abdomen may show mucosal edema, loss of haustration, and absence of formed stool in the diseased bowel; however, the yield is low and they are not recommended routinely. Barium enema shows similar changes, albeit more clearly, and may also show ulcerations, but the enema should not be done during an acute presentation. A shortened, rigid colon with an atrophic or pseudopolypoid mucosa is often seen after several years of illness. X-ray findings of thumbprinting and segmental distribution are more suggestive of intestinal ischemia or possibly Crohn colitis rather than of ulcerative colitis. Patients with known disease and a recurrence of typical symptoms should be examined, but extensive testing is not always required. Depending on duration and severity of symptoms, sigmoidoscopy or colonoscopy may be done and a complete blood count obtained. Cultures, ova and parasite examination, andC. difficiletoxin assay should be done when there are atypical features to the relapse or when there is an exacerbation after prolonged remission, during a contagious outbreak, after antibiotic exposure, or whenever the clinician is suspicious. Patients require prompt hospitalization during severe flare-ups. Flat and upright abdominal x-rays should be taken; they may show megacolon or intraluminal gas accumulated over a long, continuous, paralyzed segment of colon—a result of lost muscle tone. Barium enema should be avoided because of the risk of perforation, but a careful sigmoidoscopy is typically advisable to assess severity and rule out infection. Complete blood count, platelet count, erythrocyte sedimentation rate, C-reactive protein, electrolytes, andalbuminshould be obtained; prothrombin time, partial thromboplastin time, and blood type and cross-match are also indicated in cases of severe bleeding. The patient must be watched closely for progressive peritonitis or perforation. Percussion over the liver is important because loss of hepatic dullness may be the first clinical sign of free perforation, especially in a patient whose peritoneal signs are suppressed by high-dose corticosteroids. Abdominal x-rays are taken every 1 or 2 days to follow the course of colonic distention and to detect free or intramural air; CT is more sensitive in detecting extraluminal air or pericolic abscess. Avoid barium enemas in severe exacerbations of ulcerative colitis because of risk of perforation. 