In Shigella dysentery associated hemolytic uremic syndrome, the false statement is –
**Core Concept**
Shigella dysentery associated hemolytic uremic syndrome (HUS) is a complication of Shigella infection, characterized by the formation of thrombi in small blood vessels, leading to microangiopathic hemolytic anemia and acute kidney injury. The pathogenesis involves the production of Shiga toxin by Shigella bacteria, which damages the endothelial cells lining the blood vessels.
**Why the Correct Answer is Right**
The Shiga toxin produced by Shigella dysenteriae causes damage to the endothelial cells by inhibiting protein synthesis, leading to the formation of microthrombi and the activation of the coagulation cascade. This results in the consumption of clotting factors, leading to a coagulopathy and the formation of thrombi in small blood vessels. The toxin also causes damage to the renal endothelium, leading to acute kidney injury.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because Shiga toxin does not cause direct damage to the renal tubules.
**Option B:** Incorrect because the primary mechanism of HUS is not due to the production of cytokines.
**Option C:** Incorrect because the formation of microthrombi is a direct result of the Shiga toxin's action on the endothelial cells.
**Clinical Pearl / High-Yield Fact**
Shigella dysentery associated HUS is a medical emergency that requires prompt recognition and treatment to prevent long-term renal damage and mortality.
**Correct Answer:** C. The formation of microthrombi is a direct result of the Shiga toxin's action on the endothelial cells.