Cholera

Background

  • Endemic to Asia, Africa, and Central and South America [1]
  • Occasionally seen on the Gulf Coast of US, due to inadequately cooked seafood.

Pathophysiology

  • Usually Vibrio cholera (gram negative), which produces an enterotoxin which causes a secretory diarrhea[2]
    • Toxin causes increase in cell cAMP leading to secretion of water and electrolytes into the gut lumen

Natural History

  • Transmission via ingestion of contaminated food or water, usually undercooked seafood
  • Incubation period between hours to 5 days, depending on size of inoculum (usually 1-2 days)[3]
  • Most people are asymptomatic, and simply have bacteria in their feces for 7-14 days
  • Diarrhea is most severe in days 1-2, usually resolves in 7 days

Risk Factors

  • Persons with blood group O are more likely to have severe disease

Vibrio species

Clinical Features

  • Classic “rice water” diarrhea with fishy odor; usually painless
  • Fluid losses can be significant, up to 1L/hr, leading to severe fluid and electrolyte depletion. However, most cases are mild.
  • Occasionally seen: sudden watery vomiting, borborygmi, abdominal cramping.

Later manifestations:

  • Fluid loss may lead to → sunken eyes, dry mouth, cold clammy skin, decreased skin turgor, or wrinkled hands and feet (also known as “washer woman’s hands”)
  • Acidosis from loss of bicarbonate
  • Muscle cramps from loss of K, Ca

Differential Diagnosis

Acute diarrhea

Infectious

Noninfectious

Watery Diarrhea

  • Enterotoxigenic E. coli (most common cause of watery diarrhea)[4]
  • Norovirus (often has prominent vomiting)
  • Campylobacter
  • Non-typhoidal Salmonella
  • Enteroaggregative E. coli (EAEC)
  • Enterotoxigenic Bacteroides fragilis

Traveler's Diarrhea

Evaluation

Work-up

  • Fecal smears will NOT show leukocytes or erythrocytes.
  • Diagnosis can be confirmed by stool cultures on TCBS medium (must inform lab cholera is suspected so appropriate medium is used)

Evaluation

  • Diagnosis largely based on clinical presentation + epidemiological risk factors

Labs

  • Non-specific abnormalities: hyponatremia, hypokalemia, hypoglycemia, increased hematocrit & plasma protein concentration (from water depletion)

Management

  • Aggressive volume repletion (primary treatment)[5]
    • Mild/moderate dehydration: oral rehydration solution
    • Severe dehydration: IV fluids - bolus lactated ringers 100ml/kg over 3 hrs
    • May require more than 350ml/kg in first 24 hours
  • Antibiotics (decreases severity and duration of disease)[6]
  • Give children Zinc and Vitamin A supplementation
^Pregnant
@Children

Disposition

Complications

See Also

References

  1. http://www.who.int/cholera/en/
  2. LaRocque R and Pietroni M. “Approach to the Adult with Acute Diarrhea in Developing Countries”. UpToDate.com
  3. Mobula LM. Community health facility preparedness for a cholera surge in Haiti. Am J Disaster Med. 2013 Autumn;8(4):235-41
  4. Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.
  5. Sack DA, et al. Cholera. Lancet 2004; 363:223.
  6. Neilson AA, Mayer CA. Cholera - recommendations for prevention in travelers. Aust Fam Physician. 2010 Apr;39(4):220-6
  7. 7.0 7.1 7.2 Stanford Guide to Antimicrobial Therapy 2014.