American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Cisplatin's primary renal toxicity is due to its effect on which part of the nephron?

1. Glomerulus

2. Proximal tubule

3. Loop of Henle

4. Distal tubule

The correct answer is: Proximal tubule

Cisplatin's primary renal toxicity is mainly associated with its effects on the proximal tubule of the nephron. This is because cisplatin is actively taken up by renal tubular cells, particularly in the proximal convoluted tubules, leading to various cellular changes, including mitochondrial toxicity, oxidative stress, and ultimately apoptosis. The proximal tubule is responsible for the reabsorption of several essential ions and metabolites and is particularly susceptible to damage from nephrotoxic agents. The other areas of the nephron do not demonstrate the same level of vulnerability to cisplatin. The glomerulus functions primarily in filtration, while the loop of Henle and distal tubule are mainly involved in concentrating urine and electrolyte balance, respectively. These parts of the nephron are less impacted by the specific toxic mechanisms induced by cisplatin compared to the proximal tubule, making it the site of the most significant renal toxicity associated with this chemotherapeutic agent.