In which one of the primary glomerulonephritis the glomeruli are normal by light microscopy but shows loss of foot processes of the visceral epithelial cells and no deposits by electron microscopy:
**Core Concept**
The question is testing the understanding of the histopathological characteristics of primary glomerulonephritis, specifically the involvement of the podocytes and the presence of deposits in the glomeruli. The correct answer requires knowledge of the ultrastructural changes in glomerular diseases.
**Why the Correct Answer is Right**
The correct answer is **Minimal Change Disease (MCD)**, which is characterized by the loss of foot processes of the visceral epithelial cells (podocytes) without the presence of immune deposits. This is due to the disruption of the actin cytoskeleton of the podocytes, leading to the effacement of the foot processes. The absence of deposits is a key feature of MCD, distinguishing it from other glomerulonephritides. Electron microscopy is essential for diagnosing MCD, as it reveals the characteristic changes in the podocytes.
**Why Each Wrong Option is Incorrect**
* **Option A:** Focal Segmental Glomerulosclerosis (FSGS) is characterized by the presence of sclerosis (scarring) in some glomeruli, which is not mentioned in the question.
* **Option B:** Membranous Nephropathy is characterized by the deposition of immune complexes on the subepithelial side of the glomerular basement membrane, which is not mentioned in the question.
* **Option C:** Membranoproliferative Glomerulonephritis is characterized by the deposition of immune complexes in the glomeruli, which is not mentioned in the question.
**Clinical Pearl / High-Yield Fact**
MCD is often associated with nephrotic syndrome, and it responds well to corticosteroid therapy. Electron microscopy is essential for diagnosing MCD, as it reveals the characteristic changes in the podocytes.
**Correct Answer:** . Minimal Change Disease.