Differential Diagnosis in Ulcerative Colitis: Other Forms of Colitis
A host of disorders that cause intestinal inflammation present with symptoms that mimic ulcerative colitis (UC). In this section, a sample of forms of colitis other than UC will be discussed. As a general rule, these are included in the differential diagnosis for the initial evaluation of individuals suspected of having inflammatory bowel disease.
Infectious Colitis
Diarrhea, bleeding, and abdominal pain may result from infection with an enteric pathogen, either bacterial, viral, or parasitic. The most common bacterial organisms that cause symptoms mimicking ulcerative colitis (UC) are Shigella, Salmonella, and Campylobacter. These organisms can be detected through the use of routine stool cultures. Other bacterial organisms that cause symptoms mimicking inflammatory bowel disease (IBD) may require a specific type of culture or the need to alert the laboratory to perform special tests for their detection. These include Escherichia coli (enterohemorrhagic E coli and enteroinvasive E coli), Yersinia, and Clostridium difficile. Entamoeba histolytica is a parasite that can cause colitis. Cytomegalovirus (CMV) can lead to a presentation that mimics IBD in the immunosuppressed host. Diagnosis of CMV usually requires a mucosal biopsy. Stool tests for suspected infection are useful in the initial evaluation of persons with symptoms suggestive of IBD. Risk factors, such as foreign travel, recent antibiotic use, recent hospitalization (because of the risk of nosocomially acquired C difficile), ingestion of food suspected of contamination, and contact with ill household members all increase the suspicion of an infectious cause for the presenting symptoms.2584
Lymphocytic Colitis and Collagenous Colitis
Lymphocytic colitis and collagenous colitis are 2 forms of microscopic colitis, often presenting with protracted non-bloody, typically watery diarrhea. Inflammation is generally not seen on endoscopic examination of the mucosa but is evident on histologic examination of tissue. Biopsy specimens of patients with lymphocytic colitis show an infiltration of lymphocytes into the colonic epithelium. Collagenous colitis also demonstrates lymphocytic infiltration but is also associated with thickening of the subepithelial collagen layer.2718 In an effort to identify the association of chronic drug therapy with microscopic colitis, Fernandez-Banares and colleagues conducted a case-controlled study of 39 patients with collagenous colitis, 39 patients with lymphocytic colitis, 52 patients with functional diarrhea, and 103 normal controls. The use of selective serotonin reuptake inhibitors (SSRIs), beta blockers, statins, and bisphosphonates were found to be significantly associated with risk of lymphocytic colitis, while use of nonsteroidal anti-inflammatory drugs (NSAIDs) and SSRIs was related to the risk of collagenous colitis.2719
Diversion Colitis
In patients who have had surgical procedures that divert the fecal stream (colostomy, ileostomy), diversion colitis may occur. Inflammation in the lower part of the remaining colon results in symptoms of pain, bloody diarrhea, and passage of mucus from the rectum. This presentation should raise suspicion for diversion colitis in a patient with a history of a surgical procedure that resulted in diversion of the fecal stream. Short-chain fatty acid enemas have been shown to be effective in the treatment of this condition.2720
Drug and Chemical-Induced Colitis
Numerous drugs and chemical agents have the ability to cause gastrointestinal (GI) irritation and inflammation. The ability of nonsteroidal anti-inflammatory drugs (NSAIDs) to cause mucosal damage throughout the GI tract in healthy individuals has been well-documented. A variety of mechanisms for this phenomenon have been proposed, including topical irritation, inhibition of prostaglandin synthesis, reduced mucosal blood flow, neutrophil adherence, alterations in intestinal permeability, and upregulation of nitrous oxide synthase.2635 Cancer chemotherapy has also been implicated in intestinal inflammation, and immunosuppression from cancer chemotherapy predisposes the patient to development of enteric infections. Chemotherapy and the associated potential for infection should be considered in patients with a relevant medical history. Other agents, such as cathartics, enemas, oral contraceptives, and potassium supplements have the potential to cause inflammation and a broad spectrum of drugs can cause an inflammatory response in the GI tract. A thorough history should be taken, and both prescription and nonprescription therapies should be investigated for their potential role in causing the patient’s symptoms. The diagnosis of drug-induced diarrhea relies on the exclusion of other diagnoses and removal of the suspected drug. Resolution of symptoms following removal of the drug along with recurrence with reintroduction of the drug helps to confirm the diagnosis of drug-induced symptoms.
Radiation Colitis
Radiation therapy in the treatment of malignancies in the abdomen (e.g., colon, prostate, or cervical cancer) can damage the colonic mucosa, resulting in diarrhea, bleeding, and painful defecation. Tenesmus may also occur. The most common scenario for radiation proctitis is its development following radiation therapy for prostate cancer. This condition is usually self-limiting and should be suspected in individuals with history of abdominal exposure to therapeutic doses of radiation.
Irritable Bowel Syndrome
Irritable bowel syndrome (IBS), also called spastic colon, is characterized by bloating and abdominal pain, often relieved by defecation. Patients with IBS report stool patterns that range from diarrhea to constipation, classified as diarrhea predominant, constipation predominant, or alternating. Bleeding is not a feature associated with IBS, and the colonic mucosa appears normal during colonoscopy. The diagnosis of IBS is based on patient history and exclusion of other disorders that share similar presenting symptoms. IBS is a common disorder that has been the subject of considerable investigation and drug development.
Gastrointestinal Malignancy
Gastrointestinal malignancies can occasionally mimic inflammatory bowel disease (IBD). Carcinoid tumors are neuroendocrine in nature and secrete hormones (e.g., serotonin) that are responsible for flushing and diarrhea that are classic symptoms of carcinoid syndrome. Lymphoma, adenocarcinoma, and metastatic lesions may also present with symptoms that are also associated with IBD. In the vast majority of these cases, the patient may present with diarrhea that may be severe, but there is no evidence of bleeding or colonic inflammation when endoscopic examination is performed.10119
Ischemic Colitis
Ischemic colitis occurs when disrupted blood flow to the colon results in inflammation and injury. The spectrum of severity of ischemic colitis ranges from transient segmental involvement to fulminant disease. Cardiovascular disease, shock, autoimmune disease, coagulopathy, long-distance running, illicit drug use, and adverse effects of medications have been implicated as causes for ischemic colitis. Scharff and colleagues identified cardiovascular disease and hypertension in 58% and 59% of patients, respectively, as the most prevalent comorbidities seen in a cohort of 129 patients with ischemic colitis.2721
Other Inflammatory Disorders
Based on history and physical examination, other inflammatory disorders of the gastrointestinal tract may be considered. These include but are not limited to sarcoidosis, celiac sprue, diverticular disease, graft-versus-host disease, and eosinophilic gastroenteritis.
Content on this page was last reviewed on October 31, 2009.
Content on this page was last changed on March 19, 2009.
References:| 2584. | Kornbluth A, Sachar DB. Ulcerative colitis practice guidelines in adults (update): American College of Gastroenterology, Practice Parameters Committee. Am J Gastroenterol. 2004; 99(7):1371-1385. |
| 2635. | Wallace JL. Nonsteroidal anti-inflammatory drugs and gastroenteropathy: the second hundred years. Gastroenterology . 1997;112(3):1000-1016. |
| 2718. | Pardi DS, Smyrk TC, Tremaine WJ, et al. Microscopic colitis: a review. Am J Gastroenterol . 2002;97(4):794-802. |
| 2719. | Fernández-Bañares F, Esteve M, Espinós JC, et al. Drug consumption and the risk of microscopic colitis. Am J Gastroenterol. 2007;102(2):324-330. |
| 2720. | Harig JM, Soergel KH, Komorowski RA, Wood CM. Treatment of diversion colitis with short-chain-fatty acid irrigation. N Engl J Med . 1989;320(1):23-28 . |
| 2721. | Scharff JR, Longo WE, Vartanian SM, Jacobs DL, Bahadursingh AN, Kaminski DL. Ischemic colitis: spectrum of disease and outcome. Surgery . 2003;134(4):624-629. |
| 10119. | Eaden JA, Abrams KR, Mayberry JF. The risk of colorectal cancer in ulcerative colitis: a meta-analysis. Gut . 2001;48(4):526-535. |
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