Comments
INITIAL SYMPTOMS:
Profuse watery diarrhea with vomiting early and then rapid dehydration; Most cases are mild or asymptomatic. [CCDM, p. 102] Rice water stools and severe dehydration in a few hours--only cholera causes this syndrome; [Cecil, p. 1867]
FINDINGS:
Vibrio cholerae bacteria produce a toxin that causes profuse watery diarrhea. Mild cases resemble gastroenteritis caused by rotavirus or ETEC. In severe cases, infection can produce profound dehydration in just a few hours. Diarrhea is painless, but patients may have oliguria and muscle cramps with weakness. Prolonged volume depletion may cause acute renal failure and death. [Merck Manual, p. 1248] If fever, another diagnosis should be considered. [PPID, p. 2473] In children, coma and convulsions are complications of severe hypoglycemia. Cramps in abdominal and skeletal muscles may occur. [Guerrant, p. 153] Leukocytosis is associated with severe cholera. A rare type is cholera "sicca" in which patients have ileus and distention instead of diarrhea. [Cecil, p. 1867] Cases with cholera sicca (abdominal swelling and shock) may be misdiagnosed as "acute abdomen" requiring surgery. [ID, p. 665]
EPIDEMIOLOGY:
A single-dose vaccine is licensed in the U.S. "Direct transmission from person to person, even to health care workers during epidemics, has been reported but is not frequent." [CDC Travel, p. 153-5] The organism appears to persist in coastal salt waters (brackish water or estuaries). Transmission takes place by the fecal-oral route. "Man-made or natural disasters (e.g., floods) resulting in population movements and overcrowded refugee camps are potentially fertile ground for explosive outbreaks with high case fatality rates." Outbreaks have occurred from eating undercooked or raw seafood. [CCDM, p. 104] Death from dehydration can occur within 6 to 12 hours. Cholera is difficult to eradicate because it has an environmental reservoir, but it was eliminated from the US and Northern Europe by safe water and sanitation. Worldwide, two billion people currently lack adequate sanitation. Vaccines play an important role in integrated programs to control and prevent cholera in endemic areas. [PPID, p. 2471-9]
RELATED INFECTION:
The gastroenteritis caused by enterotoxigenic strains of E. coli (ETEC) is similar to cholera. Children in developing countries become immune to ETEC, but travelers to these countries become ill after consuming contaminated food or water. [CCDM, p. 163-5] "ETEC requires special laboratory techniques for identification." [Foodborne Illnesses. MMWR. 4/16/04]
For updated text and symptoms of infectious diseases, see iddx.com.
Diagnostic
Culture; Fecal smear: motile vibrio on darkfield or phase contrast microscopy; Dipsticks for O1 and O139 serotypes are available; [CCDM, p. 103] Stool cx with biochemical ID of isolate; PCR available; Crystal VC dipstick limited usefulness; [ABX Guide]