Vibrio cholerae

Snapshot

A 40-year-old man presents to a local emergency room. He is currently on a medical mission in India. He reports sudden-onset nausea, vomiting, and copious amounts of watery diarrhea. His blood pressure is 93/65 mmHg and pulse is 114/min. On physical exam, he has sunken eyes, decreased skin turgor, and dry mucous membranes. He is given intravenous rehydration with the goal of rapid rehydration.

Introduction

Classification
- Vibrio cholerae
  - a comma-shaped, flagellated, and gram(-) rod
  - oxidase + and produces cholera toxin
- transmission
  - fecal-oral via water or uncooked food
Epidemiology
- incidence
  - rare in the United States
- demographics
  - endemic in developing countries
  - most severe in children
- risk factors
  - raw seafood
  - contaminated water
  - travel
Pathogenesis
- acid-labile enterotoxin activates Gs and overactivates adenylate cyclase, causing ↑ cAMP
  - requires large inoculum or decreased acidity in the host’s stomach
  - causes ↑ chloride secretion, resulting in secretory diarrhea and water efflux
  - this results in loss of potassium and bicarbonate
Prevention
- live-attenuated oral cholera vaccine
  - indication
    - adults traveling to endemic areas
    - > 10 days prior to travel
Prognosis
- if untreated, mortality is > 50%
- if treated, mortality is < 1%

Presentation

Symptoms
- may be asymptomatic
- acute onset
  - painless rice-water secretory diarrhea
  - nausea
  - vomiting
Physical exam
- dehydration
  - sunken eyes
  - dry mucous membranes
  - decreased skin turgor

Studies

Differential

Norovirus diarrhea
- distinguishing factors
  - often associated with cruise ships, child care centers, or other crowded condition
  - typically self-limited
  - no association with geographic endemic locations
Campylobacter jejuni-associated diarrhea
- distinguishing factors
  - bloody diarrhea
  - comma-shaped, but does not grow in alkaline media
  - white blood cells in stool

Treatment

Complications