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Diarrhea
Khalil G. Ghanem, M.D.
02-08-2008
- Diarrhea is common in HIV+ pts in Zambia and is typically managed empirically.
- Etiology for acute diarrhea in Zambia predominantly bacterial.
- Etiology of persistent diarrhea appears to be predominantly protozoal (microsporidia, Isospora, and Cryptosporidium).
- Use of cotrimoxazole for prophylaxis in HIV+ pts leads to decrease in diarrhea incidence and may lead to shift in causative agents as well.
- Acute diarrhea (<14 days): Typically managed symptomatically unless there is blood in stools, severe dehydration, and/or suspicion for cholera.
- Persistent diarrhea (>14 days) WHO/IMAI Recommendations: If no blood in stool, treat with cotrimoxazole + metronidazole. If no response, refer. If not able to refer, treat with albendazole or mebendazole. If pt responds to antimicrobial, treat for 2 weeks total.
- Bloody diarrhea: Should be empirically treated with a quinolone for 5 days given presumption of Shigella-related disease. Metronidazole also recommended if concern for amebic colitis. Severe acute, non-bloody diarrhea may also be empirically treated in this manner.
- Dehydration: All pts with diarrhea should be evaluated for dehydration. Depending on level of dehydration, management options include encouraging usual fluid and food intake, oral rehydration solution (ORS), or IV hydration for severe cases.
- Suspected cholera: If cholera suspected based on clinical presentation and consistent recent local epidemiology, initiate treatment based on known susceptibilities if possible. If not possible, empiric treatment with erythromycin (500 mg QID x 3-5 days) is reasonable. Azithromycin (1000 mg x 1) and quinolone therapy (ciprofloxacin 1000mg x 1) are also likely to be efficacious.
- ARV side effect: Diarrhea can be a side effect from many ARVs, especially PIs. Typically, but not always, diarrhea related to medications will improve over time. If pt does not have significant dehydration, can usually be managed symptomatically.
- Prevention of diarrhea is critical and can be achieved through use of water safety precautions such as hand hygiene, household-based water treatment methods, appropriate water storage devices, and proper disposal of feces.
- Stool microscopy/diagnostics should be pursued if possible in cases of dysentery, persistent or refractory diarrhea, significant illness, or diagnostic uncertainty.
Zambia Information Author: Larry William Chang, MD, MPH
- Acute: Salmonella, Shigella, Campylobacter, Clostridium difficile, C. jejuni, norovirus, E. coli (enteroaggregative EAEC), S. aureus, & other viruses (calicivirus, astrovirus, adenovirus).
- Chronic: Cryptosporidium, microsporidium, MAC, CMV, Cyclospora, Giardia, Isospora, Entamoeba histolytica, HIV enteropathy, & causes of acute diarrhea (especially Salmonella).
- CD4 <50: Cryptosporidium, microsporidium, CMV, MAC
- Rule out medication-induced, especially PIs (NFV & LPV/r)
- Alteration in a normal bowel movement characterized by increase in water content, volume, or frequency of stools.
- Small bowel diarrhea: watery large volume; colitis: fever, inflammation, tenesmus, cramping, small volume.
- Definitions: acute <14d in duration; persistent >14d; chronic >30d
- DDx depends on duration, CD4 count, Sx (fever, tenesmus, blood), Hx of travel, Hx of food ingestion (seafood), Hx of ABx use (including OI prophylaxis).
- 2 major causes of vomiting: viral pathogens & preformed toxins of S. aureus and B. cereus. Bloody diarrhea: Shigella, Salmonella, hemorrhagic E. coli, C. jejuni, amoebic, CMV, KS
- Fever common: Shigella, Salmonella, invasive E. coli, C. jejuni, Vibrio parahemolyticus (seafood consumption), CMV.
- Fever less common: S. aureus, B. cereus, C. perfringens, enterotoxigenic E. coli, & E. coli 0157:H7, microsporidium, Cryptosporidium (if present, usually low-grade)
- Stool: Cx; ova & parasites (AFB & trichrome stain for Cyclospora, Isospora, Cryptosporidium & microsporidium). Stool toxin assay: C. difficile
- Consider stool Cx in all HIV-infected pts w/ diarrhea. In those with CD4 counts <100, consider additional AFB & trichrome stains.
- Blood cultures: MAC & Salmonella
- Colonoscopy: CMV (blood antigenemia not good indicator in pts. w/ AIDS); also helps to R/O KS and lymphoma.
- Radiology: usually not helpful; CT scan may be useful to localize affected bowel, directing Bx for CMV.
- Empiric Rx for severe acute diarrhea: consider ciprofloxacin 500 mg PO bid +/- metronidazole 500 mg PO tid. Avoid empiric therapy if E. coli O157:H7 suspected, as it may increase risk of HUS.
- See below for pathogen-specific therapy.
- If non-bloody & not C. difficile, antiperistaltic agents can be used:loperamide (Imodium) 4 mg PO x1 then 2mg prn, max 16mg/d OR atropine/diphenoxylate (Lomotil)1-2 PO tid-qid prn.
- Severe chronic diarrhea: codeine 30mg po q4-6h prn; deodorized tincture of opium (DTO) 0.6 ml PO tid-qid prn.
- Diet: frequent small feedings; low-fat; avoid caffeine and milk products.
- Medication-related: often PIs; calcium 500 mg po qid; fiber (oat bran 1500mg PO bid or fiber supplements). Use antiperistaltics if calcium and fiber ineffective.
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C. difficile: stop offending antimicrobial.
- Acute diarrhea incubation period: <2h-chemical agents; 2-7hrs- preformed toxin (S. aureus, B. cereus); 8-14hrs- C. perfringens; >14hrs- most bacterial and viral pathogens.
- Causes of chronic diarrhea may present as acute diarrhea.
- Pathogen-negative, chronic, large volume diarrhea: suspect KS or lymphoma.
- Published guidelines for diarrhea: IDSA- Clin Infect Dis 2001: 32;331; American College of Gastroenterology- Am J Gastroenterol 1997;92:1962.
- No etiology found in 30% of pts. w/ AIDS and chronic diarrhea. Diarrhea usually responds to antiperistaltics.
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