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Atazanavir Crystal Nephropathy — ESENeph MCQ

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HardAcute Kidney InjuryAtazanavir Crystal NephropathyESENeph

A 55-year-old man presents with AKI and kidney biopsy showing intratubular crystal deposits that are fan-shaped and birefringent. He has a history of HIV and has been taking Atazanavir. What is the diagnosis?

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Correct answer: D — Atazanavir crystal nephropathy – the protease inhibitor crystallises in renal tubules causing obstructive nephropathy

Atazanavir is a protease inhibitor that can crystallise in the renal tubules and collecting system. The crystals are characteristically fan-shaped and birefringent under polarised light. Risk factors include high dose, alkaline urine (Atazanavir is more insoluble at higher pH), dehydration, and concurrent ritonavir boosting. Management includes stopping Atazanavir, IV hydration, and switching to an alternative antiretroviral. Atazanavir can also cause kidney stones. Unlike Indinavir (which causes radiolucent stones), Atazanavir stones may be visible on CT.

Reference: Perazella 2019 – Drug-Induced Crystal Nephropathy; BHIVA 2021