Question

A patient presents with proximal tubule proteinuria. Which metal is most likely associated with it?

• A. Cadmium
• B. Mercury
• C. Gold
• D. Lead

Hint:

Think of itai-itai disease and low molecular weight tubular proteinuria.

Answer 1

The Correct Option is A

Step 1: The clue here is proximal tubule proteinuria, which signals damage to the segment of the nephron that normally retrieves small filtered proteins.

Step 2: Among heavy metals, cadmium has a strong affinity for the proximal tubular cells and accumulates there over years, producing tubular injury and leakage of low molecular weight proteins into the urine.

Step 3: This pattern is seen in workers and populations chronically exposed to cadmium and is detected early by raised urinary beta-2 microglobulin, making cadmium the metal that fits the described tubular proteinuria.

Step 4: By contrast, gold and mercury typically trigger immune-mediated glomerular disease with heavy albuminuria, and lead tends to cause interstitial nephropathy, so none of them matches proximal tubular proteinuria as well as cadmium. \[\boxed{\text{Cadmium}}\]