Gastroenteritis and Diarrhea:  Diagnosis
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þ Differential Diagnosis
 - Organophosphate Poisoning
 - CO poisoning

þ Clinical Diagnosis
 - Bacterial:  sudden onset of uncomfortable diarrhea
  - with or without fever
  - with or without vomiting
  - with or without blood in stool

 - Protozoal: gradual onset of less severe diarrhea
  - persistent
  - fatigue and weight loss

 - Giardia:
  - "egg burps" NOT pathognomonic for Giardia; ignore sulfuric burps.
  - 2-5 stools/day
  - bloating

 - Amoebiasis:
  - chronic low-grade course
  - alternating symptoms
  - fatigue and weight loss very common
  - longer term travelers
  - some variants are commensals and not diarrea-causing
  - overdiagnosed

 - Amoebic Dysentery
  - very rare in Kathmandu
  - frequent small stools with blood
  - can migrate to liver and cause liver abscess but most with liver abscess
    don't have diarrhea.

   (per David Shlim, M.D., of Kathmandu, world's #2 exit)

þ Fecal leukocytes
 - Clinical status more important than stool WBC's; only found in about 50% of
   those with culture-documented invasive diarrhea.

þ Stool for O+P
 - Only 20-50% effective at detecting parasites.  Expensive.

þ Indications for stool Cx ($$$!):
 - Bloody stool
 - Significant fever
 - Severe Pain
 - Gay male
 - History of recent antibiotic use
 - Exposure to outbreak
 - History of inflammatory bowel disease

þ Giardia
 - New ELISA test for Giardia in stool available.

þ Rotavirus
 - ELISA and PCR tests now available.
 - usually 2-12 days of diarrhea
 - in immunocompromised children may involve intestinal wall,
   kidney, liver.

þ Norwalk agent
 - class Caliciviridae, small round-structured viruses (SRSVs)
 - other Caliciviridae:  Hawii, MArin County, Taunton, and Snow
   Mountain agents
 - Person-person transmission, caused gastroenteritis during
   Desert Storm Gulf war.