David Musher/Science Source
The differential diagnosis of inflammatory bowel disease (IBD) in older patients is complicated by comorbid conditions such as infectious colitis, segmental colitis associated with diverticular disease, nonsteroidal anti-inflammatory drug-induced intestinal injury, and ischemia, each of which can mimic the intestinal inflammation characteristic of IBD.
Ulcerative colitis is one of the two major types of IBD, along with Crohn disease. Unlike Crohn disease, which can affect any part of the gastrointestinal tract, ulcerative colitis characteristically causes inflammation in the large bowel (see image).
Acute, severe ulcerative colitis (ie, > six bloody bowel movements per day, with one of the following: temperature > 38 °C [100.4 °F], hemoglobin level < 10.5 g/dL, heart rate > 90 beats/min, erythrocyte sedimentation rate > 30 mm/hr, or C-reactive protein level > 30 mg/dL) requires hospitalization and treatment with intravenous high-dose corticosteroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day).
The diagnosis of ulcerative colitis is best made with endoscopy and mucosal biopsy for histopathologic analysis. Characteristic findings are abnormal erythematous mucosa, with or without ulceration, extending from the rectum to a part or all of the colon; and uniform inflammation without intervening areas of normal mucosa (skip lesions tend to be characteristic of Crohn disease). Contact bleeding may also be observed, with mucus identified in the lumen of the bowel.
The bowel wall in a patient with ulcerative colitis is thin or of normal thickness, but edema, the accumulation of fat, and hypertrophy of the muscle layer may give the impression of a thickened bowel wall. The disease is largely confined to the mucosa and, to a lesser extent, the submucosa.
Laboratory studies are helpful to exclude other diagnoses and assess the patient's nutritional status, but serologic markers can help in the differential diagnosis of IBD. Radiographic imaging has an important role in the workup of patients with suspected IBD and in the differentiation of ulcerative colitis from Crohn disease by demonstrating fistulae or the presence of small bowel disease seen only in Crohn disease.
Much work in the past decade has focused on the development of serologic markers for inflammatory bowel disease. pANCA and anti–Saccharomyces cerevisiae antibodies (ASCA) have been the most intensely studied. The World Gastroenterology Organization states that ulcerative colitis is more likely when the test results are positive for pANCA and negative for ASCA antigen; however, the pANCA test result may be positive in patients with Crohn disease, and this may complicate obtaining a diagnosis in an otherwise uncomplicated colitis.
According to the American Gastroenterological Association, drug classes for the long-term management of moderate to severe ulcerative colitis include tumor necrosis factor-alpha antagonists, anti-integrin agent (vedolizumab), Janus kinase inhibitor (tofacitinib), interleukin-12/23 antagonist (ustekinumab), and immunomodulators (thiopurines, methotrexate). In general, most drugs that are initiated for the induction of remission are continued as maintenance therapy if they are effective.
Bhupinder S. Anand, MD, Professor, Department of Medicine, Baylor College of Medicine, Houston, TX
Bhupinder S. Anand, MD, has disclosed no relevant financial relationships.