Patofisiologi Diare Sekretorik : Bakteri Vibrio Cholera

Summary

This video explains the pathophysiology of secretory diarrhea, focusing specifically on cholera. It details how Vibrio cholerae survives the acidic environment of the stomach and attaches to the small intestine’s mucosa. The bacterium then releases toxins, which disrupt fluid and electrolyte transport, leading to diarrhea. The toxins increase cyclic AMP production, which inhibits sodium chloride absorption and stimulates chloride secretion, causing excessive fluid loss. Oral glucose is used as a treatment to help absorb sodium chloride and mitigate the effects of the diarrhea, aiding in recovery.

Takeaways

• 😀 Secretory diarrhea is caused by disturbances in fluid and electrolyte transport in the intestinal mucosa.
• 😀 Cholera is a major cause of secretory diarrhea, caused by the Vibrio cholerae bacterium.
• 😀 After ingestion, Vibrio cholerae survives through the stomach due to its resistance to stomach acid and pepsin, reaching the small intestine.
• 😀 The alkaline environment in the small intestine allows Vibrio cholerae to thrive.
• 😀 Vibrio cholerae attaches to the mucosal surface of the small intestine using specific surface antigens.
• 😀 Upon attachment, Vibrio cholerae releases endotoxins, including the cholera toxin composed of subunits A and B.
• 😀 The cholera toxin binds to receptors on the intestinal epithelial cells, specifically the EM1 receptors.
• 😀 The toxin increases the production of cyclic AMP (cAMP) inside intestinal cells, triggering several effects.
• 😀 Elevated cAMP levels lead to reduced absorption of NaCl and increased secretion of chloride ions (Cl-) and other electrolytes like bicarbonate (HCO3-).
• 😀 This electrolyte imbalance causes water to follow the secreted ions into the lumen of the intestine, contributing to diarrhea.
• 😀 Oral glucose is often administered to cholera patients to aid in the absorption of sodium and chloride, reducing the severity of diarrhea.

Q & A

What is secretory diarrhea?

Secretory diarrhea is a condition where there is an imbalance in the transport of fluids and electrolytes in the intestinal mucosa, leading to excessive secretion of fluids into the intestines.

How does cholera cause secretory diarrhea?

Cholera causes secretory diarrhea by introducing Vibrio cholerae bacteria into the gastrointestinal system. These bacteria release toxins that disrupt the normal function of intestinal cells, leading to increased secretion of chloride ions and water into the intestinal lumen.

What are the key toxins produced by Vibrio cholerae?

The key toxins produced by Vibrio cholerae are the A and B subunits of the cholera toxin. The B subunit binds to receptors on the intestinal cells, while the A subunit enters the cells and activates the production of cyclic AMP (cAMP).

What role does cyclic AMP (cAMP) play in cholera's pathophysiology?

Cyclic AMP (cAMP) plays a crucial role in cholera's pathophysiology by increasing the secretion of chloride ions (Cl-) into the intestinal lumen, which is followed by the movement of water, bicarbonate, and sodium, causing diarrhea.

Why does Vibrio cholerae survive the stomach's acidic environment?

Vibrio cholerae can survive the stomach's acidic environment due to its ability to resist the effects of stomach acid, allowing it to pass through to the small intestine where it can multiply and cause infection.

How does the small intestine's alkaline pH contribute to cholera infection?

The alkaline pH of the small intestine provides a more favorable environment for Vibrio cholerae to survive and multiply, as the bacteria thrive in less acidic conditions.

How does cholera toxin affect sodium chloride (NaCl) absorption?

Cholera toxin reduces the absorption of sodium chloride (NaCl) in the intestine by disrupting the normal functioning of sodium absorption mechanisms, contributing to the loss of fluid and electrolytes.

What is the purpose of oral glucose rehydration in cholera treatment?

Oral glucose rehydration helps in the treatment of cholera by facilitating the absorption of sodium and water in the intestine. The presence of glucose in the intestinal lumen encourages sodium absorption, which helps counteract the dehydration caused by diarrhea.

Why is it important to replenish both sodium and glucose in cholera treatment?

Replenishing both sodium and glucose is important because sodium helps to retain water in the body, while glucose enhances sodium absorption, thus helping to restore fluid balance and prevent dehydration.

What happens when chloride ions are secreted into the intestinal lumen during cholera infection?

When chloride ions are secreted into the intestinal lumen during cholera infection, they are followed by water, sodium, and bicarbonate ions, leading to excessive fluid loss, which manifests as watery diarrhea characteristic of cholera.