American Board of Internal Medicine (ABIM) Certification Practice Exam

What condition may be triggered by Orlistat that can lead to acute kidney injury?

1. Acute tubular necrosis

2. Acute oxalate nephropathy

3. Interstitial nephritis

4. Chronic kidney disease

The correct answer is: Acute oxalate nephropathy

Orlistat, a weight loss medication, can lead to acute kidney injury through the development of acute oxalate nephropathy. This condition is associated with the increased absorption of oxalate due to fat malabsorption, which can occur when Orlistat inhibits the intestinal absorption of dietary fats. When fat is not absorbed, the calcium that would normally bind to oxalate is not available, leading to higher levels of free oxalate in the intestines. This excess oxalate can be absorbed into the bloodstream and subsequently filtered by the kidneys. High levels of oxalate can lead to the formation of calcium oxalate crystals in the renal tubules, causing obstruction and damage to the renal tissue, which results in the clinical presentation of acute kidney injury. This mechanism highlights the connection between the use of Orlistat and the risk of developing acute oxalate nephropathy, making this the correct answer in relation to the potential adverse effects of the drug on kidney function.