What are the difficulties with guaiac testing for fecal occult blood? The sensitivity of three guaiac tests obtained on three consecutive days is moderately high (up to 80%) for detecting colon cancer because colon cancers typically bleed intermittently. Additional weaknesses of guaiac testing for colon cancer include the following: The benign precursor of colon cancer, …
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How is occult GI bleeding usually detected? Occult GI bleeding is typically detected by obtaining a stool sample, smearing the stool sample on a guaiac-impregnated card, and applying a reagent solution to the card. A positive test is indicated by change in the color of the impregnated card from colorless to bright blue because of …
What is occult gastrointestinal (GI) bleeding and how does it differ from overt GI bleeding? Occult GI bleeding is microscopic blood loss from the GI tract that is not overtly or grossly apparent. It is typically detected by a guaiac test or fecal immunologic test (FIT). Overtly apparent GI bleeding includes the following: Hematemesis: bright …
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What are some rare causes of acute abdominal pain? Eosinophilic gastroenteritis Epiploic appendagitis Familial Mediterranean fever Hereditary angioedema Addison’s disease (acute adrenal insufficiency) Diabetic ketoacidosis Porphyria Sickle cell crisis
How common are severe GI manifestations of polyarteritis nodosa (PAN)? PAN is a vasculitis that may have visceral involvement. GI bleeding from intestinal ischemia is seen in 6% of cases, bowel perforation in 5%, and bowel infarction in 1.4%. Acalculous cholecystitis occurs in up to 17% because of direct vasculitic involvement of the cystic artery …
Are patients with systemic lupus erythematosus (SLE) at increased risk for intraabdominal catastrophe? Approximately 2% of patients with SLE develop lupus vasculitis, one of the most devastating complications of SLE. The fatality rate is greater than 50%. Small vessels of the bowel wall are affected, leading to ulceration, hemorrhage, perforation, and infarction.
What conditions can result in an acute abdomen in HIV infected patients? Patients with HIV can have any of the usual causes of an acute abdomen; all non–HIV-specific diagnoses must be considered. Perforation is most often due to cytomegalovirus (CMV) infection in the distal small bowel or colon; this is the most common cause of …