Kidney biopsy from a child with hemolytic uremic syndrome characteristically most likely presents features of –
**Core Concept**
Hemolytic uremic syndrome (HUS) is a complex condition characterized by microangiopathic hemolytic anemia, acute kidney injury, and thrombocytopenia. The kidney biopsy findings in HUS are crucial for diagnosis and understanding the pathophysiology of the disease.
**Why the Correct Answer is Right**
In HUS, the kidney biopsy typically shows thrombotic microangiopathy (TMA), which is characterized by the presence of microangiopathic changes, including endothelial injury, thrombosis, and fibrin deposition within the small blood vessels of the kidney. This leads to renal failure due to the occlusion of the microvasculature. The hallmark feature of HUS is the presence of schistocytes (fragmented red blood cells) in the peripheral blood smear and the characteristic TMA changes in the kidney biopsy.
**Why Each Wrong Option is Incorrect**
* **Option A:** Acute interstitial nephritis (AIN) is characterized by inflammation of the interstitial tissue of the kidney, often due to allergic reactions or infections, and is not typically associated with HUS.
* **Option B:** Focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome in children, characterized by scarring of the glomeruli, and is not directly related to HUS.
* **Option C:** Membranoproliferative glomerulonephritis (MPGN) is a type of glomerulonephritis characterized by changes in the glomerular basement membrane and proliferation of mesangial cells, and is not typically associated with HUS.
**Clinical Pearl / High-Yield Fact**
In children, the most common cause of HUS is Shiga toxin-producing Escherichia coli (E. coli) infection, particularly after a diarrheal illness. This highlights the importance of a thorough history and physical examination in patients presenting with HUS.
**Correct Answer:** C.