Question

A child younger than 6 years has nephrotic syndrome that responds well to steroids. A renal biopsy is done. What will be seen under the light microscope?

• A. Nothing
• B. Loss of foot processes
• C. Tubule atrophy
• D. Crescents

Hint:

Steroid-responsive nephrotic syndrome in a young child points to minimal change disease, which looks normal on light microscopy.

Answer 1

The Correct Option is A

This question is testing the classic light microscopy finding of minimal change disease, the commonest cause of steroid-responsive nephrotic syndrome in children under 6 years.

1. Nothing: correct. Minimal change disease gets its name because the glomeruli look normal under a light microscope. No thickening, no scarring, no cell proliferation is seen.
2. Loss of foot processes: this change is real, but it is only visible on electron microscopy, where the podocyte foot processes appear flattened and fused. A light microscope cannot resolve structures this small.
3. Tubule atrophy: this is a feature of chronic, longstanding renal damage, seen in conditions like chronic glomerulonephritis or long-standing obstruction, not in a steroid-responsive nephrotic child.
4. Crescents: crescents form in Bowman's space in rapidly progressive glomerulonephritis, a severe and steroid-resistant disease pattern, which does not match this child's good response to steroids.

Since the child is young, steroid-responsive, and the light microscope shows a normal-looking glomerulus, the diagnosis is minimal change disease, and the light microscopy finding is nothing.

Let's summarize:

• Minimal change disease has a normal light microscopy picture; the abnormality is only seen on electron microscopy.
• Steroid responsiveness in a young child with nephrotic syndrome strongly points to minimal change disease.

So the correct answer is that nothing abnormal is seen on light microscopy.