Background:
Tenofovir-based regimens remain the first choice for the treatment of human immunodeficiency virus infection and hepatitis B infection. Despite its virologic efficacy and ease of administration, it can lead to significant nephrotoxicity which may not be fully reversible.
Case Description:
An elderly gentleman on Tenofovir disoproxil fumarate (TDF)-based antiretroviral therapy for 10 years presented with vague symptoms of fatigue, poor oral intake and constipation. He was found to have hypokalemia and a volume depleted status. Detailed evaluation revealed hyperchloremic metabolic acidosis, hypophosphatemia, hypouricemia, proteinuria and amino aciduria consistent with a diagnosis of Fanconi syndrome. He was switched to Abacavir-based regimen, and supplements to correct acidosis and electrolytes were given. At the follow-up visit after a month, his proximal renal tubular injury recovered partially and he was symptomatically better.
Conclusion:
Patients on long-term therapy with tenofovir should be monitored for proximal renal tubular injury besides estimation of the glomerular filtration rate. Fanconi syndrome may present late after several years of being on TDF therapy. Partial or complete recovery of the renal tubular function occurs after stopping tenofovir.
Key words: Tenofovir, TDF, Fanconi, Proximal tubule, Hypophosphatemia
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