Chronic Diarrhea

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     1  Chronic Diarrhea Morning Report
     2  Definition >3 weeks duration Average fecal daily weight in normal person is 100-200grams/day >250 grams is considered abnormal, although persons on high fiber diet pass >500grams/day
     3  Approach to Patient Patient should be questioned about the onset, duration, pattern, aggrevants (especially diet), relieving factors, and stool characteristics Presence or absence of fecal incontinence, fever, weight loss, pain, certain exposures-travel, medications, contacts with diarrhea) should be noted
     4  Approach to patient On physical exam, check for thyroid mass, wheezing on lung exam, heart murmurs, edema, hepatomeg, abdominal mass, LAD, perianal fistula, or anal sphincter laxity.
     5  Approach to patient Therapeutic trial of treatment is highly cost effective when a certain diagnosis is suggested on history/physical alone
     6  Chronic Diarrhea If diagnosis is still unclear after initial encounter, further testing is required Further work up should delineate secretory vs. osmotic diarrhea vs. malabsorption vs inflammatory
     9  Malabsorptive diarrhea Malabsorption suspected in patients with weight loss, greasy stools, glossitis, anemia, and hypoalbumenima If malabsorption suspected, a 72 hr stool specimen should be sent for fecal fat determination, if + suspect malabsorption Causes of malabsorption include pancreatic insufficiency (confirmed by CT/pancreatic function tests) and disease of small intestine--Whipple’s disease, tropical sprue, intestinal lymphoma (small bowel biopsies by EGD)
     10  Malabsorptive Diarrhea-Mucosal Malabsorbtion Celiac sprue-hypersensitivity to gluten Tropical sprue-infectious disease of unknown origin, seen in Indian subcontinent, Asia, West Indies, North & South America, central and southern Africa, and Central America -get diarrhea in persons who have resided in these areas for as few as 1-3 months
     11  Mucosal Malabsorptive Tropical Sprue-tx with tetracycline and folic acid Whipple’s->infection form Treponema-whippelii. Diagnosed by + biopsy for PAS macrophages Associated symptoms include hypersomnolescence, arthralgias, fever, hypotension, and LAD
     12  Intraluminal Malabsorbtion Other-Most commonly results from pancreatic exocrine insufficiency when >90% of pancreatic secretory function is lost Most commonly due to ethanol abuse Other causes include cystic fibrosis, pancreatic duct obstruction Also SBO where bacteria deconjugate bile acids, impairing fat digestion SBO one can see low B12, high folate, and megaloblastic anemia
     13  Secretory vs Osmotic Secretory vs Osmotic –check stool osmotic gap 290-2x[NAstool + Kstool] If < 50, diarrhea is diarrhea falls under secretory category
     14  Secretory Diarrhea Characterized by watery, large-volume fecal outputs that are typically painless and persist with fasting—one may do a 24 hr stool quant.-should exceed one liter and not decrease with fasting Usually stool pH is neutral, and fecal fat test is negative
     15  Secretory diarrhea If secretory diarrhea confirmed, recommend checking serum should be sent for: Gastrin (gastrinoma), VIP(VIPOMA), glucagon (glucogonoma), serotonin (carcinoid), calcitonin, histamine, and prostaglandins -if overproduction of one of these mediators is documented, ?abdominal CT scan is recommended
     16  Secretory Diarrhea Carcinod present with watery diarrhea, flushing, skin changes, bronchospasm, and cardiac murmurs which are all symptoms caused by secretion of serotonin, histamine, catecholamines, kinins, and prostaglandins by the tumor masses 1/3 pts with carcinoid present with diarrhea alone
     17  Secretory Diarrhea Medullary carcinomas of thryoid (spontaneous or part of MENIIA) cause secretory diarrhea because of the release of calcitonin
     18  Sectretory Diarrhea Other conditions to consider include: Diseases like Crohn’s ileitis or resection of <100cm of terminal ileum (dihydroxy bile acids may escape absorption and stimulate colonic secretion)
     19  Osmotic Diarrhea Most common cause is lactase deficiency Magnesium ingestion or factitious laxative abuse Intraluminal maldigestion is also seen in cirrhotics and bile duct obstruction-there is impaired delivery of bile salts to small intestine, leads to poor micelle formation with ingested fats