Cholera mortality – immediate cause of death: In severe cholera due to toxigenic Vibrio cholerae, what ultimately kills the untreated patient?

Introduction / Context:
Cholera is a classic secretory diarrheal disease. While the toxin initiates pathophysiology, fatal outcomes are primarily due to fluid and electrolyte derangements. Recognizing the immediate cause of death is vital for life-saving therapy protocols in outbreaks.

Given Data / Assumptions:

• Cholera toxin increases cAMP in enterocytes, driving chloride and water secretion.
• Patients can lose liters of isotonic fluid rapidly (“rice-water stools”).
• Mortality correlates with hypovolemia, metabolic acidosis, and electrolyte imbalance (especially potassium).

Concept / Approach:
Although the toxin triggers secretion, death results from hypovolemic shock and severe dehydration unless rapid oral rehydration salts (ORS) or intravenous fluids are administered. Hence, the proximate cause of death is fluid and electrolyte loss, not direct tissue destruction by the toxin or lack of water in food.

Step-by-Step Solution:
Connect toxin action (cAMP rise) with massive intestinal secretion.Link secretion to extracellular volume depletion and shock.Identify dehydration and electrolyte loss as the deadly endpoint.Select the corresponding answer.

Verification / Alternative check:
Case fatality drops from >30% to <1% with prompt ORS/IV therapy, confirming that replacing water and electrolytes addresses the true cause of mortality.

Why Other Options Are Wrong:

• Faulty carrier proteins: not the central mechanism.
• Toxin cytotoxicity: cholera toxin is not cytolytic; mucosa remains intact.
• Perforation: not typical of cholera.
• Water in food: irrelevant to pathogenesis.

Common Pitfalls:
Overemphasizing antimicrobial therapy; definitive acute management is aggressive rehydration.

Final Answer:
Dehydration and massive loss of water and electrolytes.