Internal Medicine

0521779407-10 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 18:40

826 Infectious Diarrheas

detect opportunistic infections such as CMV in immunocompro-

mised pts, and rarely to diagnose C. difficile with pseudomembranes

while toxin assays are pending)

differential diagnosis

■nausea, vomiting, watery diarrhea: viral gastroenteritis (e.g., noro-

viruses in families and outbreaks; rotaviruses in young children) or

preformed toxin (e.g.,S. aureus, B. cereus)

■dehydration: cholera, ETEC (in very young & very old), EPEC

(infants), rotavirus, rarely Salmonella

■large volume diarrhea, upper abdominal pain/cramps: small intesti-

nal pathogen±colonic involvement

■many small frequent stools, urgency, tenesmus, dysentery:

➣colitis – Campylobacter most common; IBD

➣proctitis – N. gonorrhoeae

■persistent diarrhea (≥14 days): parasites (e.g.,Giardia, Cryptosporid-

ium, Cyclospora, Microsporidium, Isospora), bacterial infection or

overgrowth, malabsorption

■recent travel to: developing countries (bacteria); mountainous

areas/recreational waters with wildlife (Giardia); Russia (Cryp-

tosporidium, Giardia)

■recent antibiotic treatment (≤2 mo) or recent hospitalization: C. dif-

ficile

■day care center contact: any agent spread by fecal-oral route

■food- or water-borne outbreak: Norwalk virus,S. aureus, B. cereus,

V. parahaemolyticus, V. cholerae, Aeromonas, Plesiomonas, L. mono-

cytogenes, Cyclospora, Giardia

management

What To Do First

■assess hydration

■prompt fluid and electrolyte therapy

General Measures

■nondehydrated, otherwise healthy: sport drinks, diluted fruit juices,

soft drinks and saltine crackers/broths/soups, avoidance of milk

products, use of “BRAT” diet (bananas, rice, applesauce, and toast)

■elderly and/or immunosuppressed: Pedialyte or Rehydrolyte solu-

tions (containing 45–75 mEq Na per liter)

■dehydrating, cholera-like: WHO oral rehydration solution or home-

made recipe (1/2 tsp table salt, 1/2 tsp baking soda, 4 tbsp sugar,

1 liter clean water)

■severe dehydration, hypovolemic shock: IV hydration