Differentials
Other infectious diarrhea
SIGNS / SYMPTOMS
Many causes of infectious diarrhea will be impossible to differentiate from cholera, especially in the early stages of disease, or in mild cases.
Bloody diarrhea is suspicious for Shigella or enterohemorrhagic Escherichia coli.
INVESTIGATIONS
Stool culture is the standard, but some techniques (e.g., for Campylobacter) are difficult and not performed in resource-limited settings.[91]
Polymerase chain reaction for toxins helps distinguish enterohemorrhagic E coli.
For a returning traveler workup, broader testing of stool (and blood) for enteric pathogens through molecular and/or serology may be considered.
Amebic dysentery
SIGNS / SYMPTOMS
Volume of diarrhea rarely exceeds 1 liter/hour for adults.
Bloody diarrhea common.
INVESTIGATIONS
Fresh stool microscopy shows amebae ingesting red blood cells.
Strongyloides and other intestinal helminths
SIGNS / SYMPTOMS
Rare to have large-volume stool loss.
INVESTIGATIONS
Stool microscopy for eggs and live parasites requires training and good equipment to detect Strongyloides stercoralis.
Giardiasis
SIGNS / SYMPTOMS
Giardiasis often causes offensive, yellow, sulfur-scented stools.
Rare to have large-volume stool loss.
INVESTIGATIONS
Stool microscopy for eggs and live parasites requires training and good equipment to detect Giardia.
VIPoma
SIGNS / SYMPTOMS
Volume of diarrhea rarely exceeds 1 liter/hour.
Chronic history.
Much rarer than cholera.
INVESTIGATIONS
Fasting gut hormone analysis confirms diagnosis.
Negative stool culture for cholera.
Tubulovillous adenoma
SIGNS / SYMPTOMS
Volume of diarrhea rarely exceeds 1 liter/hour.
Chronic history of diarrhea.
Much rarer than cholera.
INVESTIGATIONS
Colonoscopy and biopsy of lesions shows adenoma.
Negative stool culture for cholera.
Food poisoning
SIGNS / SYMPTOMS
Volume of diarrhea rarely exceeds 1 liter/hour.
INVESTIGATIONS
Stool WBC count may help differentiate invasive or inflammatory diarrhea.
Stool culture may help isolate specific pathogens.
Other medical causes of diarrhea
SIGNS / SYMPTOMS
Guided by medical history, drug history, presenting illness and medical examination, and laboratory tests.
INVESTIGATIONS
Returning traveler workup, also to include test for malaria (may cause nonspecific symptoms such as diarrhea).
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