How Does Cholera Cause Dehydration?


Cholera is an infectious disease caused by the bacterium Vibrio cholerae. One of the hallmark features of cholera is profuse watery diarrhea, which can lead to rapid and severe dehydration. Here’s how cholera causes dehydration:

  • Toxin Production: Vibrio cholerae produces a toxin known as cholera toxin. This toxin is responsible for the characteristic symptoms of cholera, including watery diarrhea. The cholera toxin acts on the cells lining the small intestine, specifically the cells in the lining called enterocytes.
  • Activation of Adenylate Cyclase: Cholera toxin activates an enzyme called adenylate cyclase within the enterocytes. Adenylate cyclase, in turn, increases the levels of cyclic AMP (cAMP) in the cells.
  • Increased Ion Secretion: Elevated levels of cAMP in enterocytes lead to an increase in the secretion of chloride ions (Cl-) into the intestinal lumen. This is followed by the passive movement of sodium ions (Na+) and water into the lumen as well.
  • Impaired Water Absorption: The net effect of increased chloride, sodium, and water secretion is a significant loss of fluid from the body into the intestinal lumen. This process overwhelms the normal mechanisms of water absorption in the intestines, leading to a large volume of watery diarrhea.
  • Massive Fluid Loss: The diarrhea associated with cholera can be extremely rapid and voluminous, with patients losing large amounts of water and electrolytes within a short period. This rapid loss of fluid can quickly lead to dehydration.
  • Electrolyte Imbalance: In addition to water, cholera diarrhea results in the loss of essential electrolytes such as sodium, potassium, and bicarbonate. The imbalance of these electrolytes further contributes to the severity of dehydration.
  • Hypovolemic Shock: In severe cases of cholera, the rapid loss of fluid can lead to a state of hypovolemic shock, where the volume of circulating blood is significantly reduced. Hypovolemic shock is a medical emergency that can result in organ failure and death if not promptly treated.

Dehydration is a serious complication of cholera and can lead to a range of symptoms, including extreme thirst, dry mucous membranes, sunken eyes, reduced urine output, and in severe cases, altered mental status and shock. The key to managing cholera is prompt rehydration through oral rehydration therapy (ORT) or intravenous fluids, along with appropriate antibiotic treatment to reduce the duration and severity of the illness.

Prevention of cholera involves ensuring access to clean and safe drinking water, proper sanitation practices, and vaccination in high-risk areas. Vaccination can provide additional protection against severe cholera infections.

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