DIARRHEA, CHRONIC

Ask the following questions:

1. Is there a positive drug or alcohol history? It is well known that alcohol can cause diarrhea, as do drugs in common use, such as digitalis, diuretics, beta-blockers, aspirin, colchicine, and other nonsteroidal anti-inflammatory drugs. Perhaps there is overuse of laxatives. Remember, patients may lie about the use of laxatives.
2. Is there blood in the stool? Blood in the stool certainly is significant for ulcerative colitis, carcinoma, and diverticulitis, but it is also found in amebiasis and the Zollinger-Ellison syndrome.
3. Is there a lot of mucus in the stool? Mucus is often found in ulcerative colitis, Crohn's disease, and irritable bowel syndrome.
4. Is there evidence of steatorrhea? Large volumes of stools that are partially formed or formed and float in the commode suggest steatorrhea. Stool analysis can be done, as is discussed later.
5. Is there an abdominal mass? A mass in the right lower quadrant would suggest carcinoma or diverticulitis. Tenderness in the left lower quadrant with or without a significant mass would be suggestive of ulcerative colitis, diverticulitis, and irritable bowel syndrome. A mass in the area of the ascending or descending colon or the transverse colon should be looked for also, as these would suggest carcinoma.
6. Are there signs of systemic disease? Many systemic diseases may cause diarrhea. Among them are thyrotoxicosis, in which case one would be looking for a thyroid tumor and a tremor and tachycardia; carcinoid syndrome, which would cause considerable flushing; Addison's disease, which would cause hyperpigmentation of the skin; and pellagra, which may cause dermatitis and dementia.
7. Does significant diarrhea persist on fasting? Diarrhea that persists after fasting suggests a secretory diarrhea from a polypeptide-secreting tumor, such as villous adenoma, a gastrinoma, or a carcinoid tumor.

DIAGNOSTIC WORKUP

Most patients will be diagnosed by a stool culture, stool for occult blood, and stool for ovum and parasites, along with a sigmoidoscopy and barium enema. Giardiasis may be best diagnosed by the finding of Giardia antigen in the stool. In patients who have been on antibiotics, the stool should be tested for C. difficile toxin B. If a systemic disease is suspected, CBC, sedimentation rate, chemistry panel, and thyroid profile should be done. An HIV antibody test may be indicated depending on the history. A urine test for 5-HIAA will uncover a carcinoid syndrome. A serum gastrin will usually reveal a gastrinoma. If these tests do not provide a diagnosis, the most cost-effective approach at this point is to refer the patient to a gastroenterologist, who will undoubtedly perform a colonoscopy as part of the workup. Small bowel aspiration and biopsy will be useful in diagnosing Giardia infection or celiac sprue; angiography will confirm mesenteric ischemia or infarcts.

If a gastroenterologist is not available, the clinician may proceed with a quantitative 24-hr stool analysis for fat. If there is 10 g or more of fat in the stool in a day, then steatorrhea can be diagnosed and one can proceed with the workup of steatorrhea. If there is less than 7 g of fat per day in the stool, the stool volume after fasting should be done. If it is large and we have ruled out surreptitious laxative abuse, a polypeptide-secreting tumor should be considered. Here again, it would be best to refer the patient to a gastroenterologist. If the volume after a fast is small, the problem is most likely lactose or other food intolerance or an irritable bowel syndrome. Occasionally, the problem is dysfunction of the anal sphincter. Once again, a GI specialist is probably best consulted for workup of a dysfunctional anal sphincter.

Book Source Details

• Book Title: Algorithmic Diagnosis of Symptoms and Signs
• Author(s): R. Douglas Collins
• Year of Publication: 2003
• Copyright Details: Algorithmic Diagnosis of Symptoms and Signs, Copyright © 2003 Lippincott Williams & Wilkins.

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Copyright Details: Algorithmic Diagnosis of Symptoms and Signs, Copyright © 2008 Williams & Wilkins.

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More About This Book: Title: Algorithmic Diagnosis of Symptoms and Signs Authors: R. Douglas Collins Publisher: Lippincott Williams & Wilkins Copyright: 2003 ISBN: 0-7817-3805-9