An 8 yr old boy presents to casualty with history of diarrhea, followed by decreased urine output. Blood examination shows thrombocytes: 90,000/cm3. Diagnosis is
**Core Concept**
Hemolytic uremic syndrome (HUS) is a complex disorder characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. It often follows a diarrheal illness, particularly those caused by Shiga toxin-producing Escherichia coli (E. coli).
**Why the Correct Answer is Right**
The boy's presentation is consistent with HUS. The thrombocytopenia (low platelet count) is a hallmark of the disease, and the decreased urine output is a sign of acute kidney injury. The microangiopathic hemolytic anemia is not directly assessed in this scenario but can be inferred from the thrombocytopenia and acute kidney injury. Shiga toxin produced by E. coli can cause damage to the endothelial cells lining the blood vessels, leading to thrombocytopenia and kidney injury.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not match the clinical presentation of HUS. HUS is characterized by thrombocytopenia and acute kidney injury, not anemia.
* **Option B:** This option is incorrect because it does not match the clinical presentation of HUS. HUS is characterized by thrombocytopenia and acute kidney injury, not a high platelet count.
* **Option D:** This option is incorrect because it does not match the clinical presentation of HUS. HUS is characterized by thrombocytopenia and acute kidney injury, not a normal platelet count.
**Clinical Pearl / High-Yield Fact**
In cases of suspected HUS, it is essential to investigate for the underlying cause of the diarrheal illness, as treatment may involve addressing the source of the Shiga toxin.
**Correct Answer:** C.