# Delayed Irreversible Fanconi Syndrome Associated With Vertebral Fracture After Tenofovir Discontinuation

## TL;DR

A woman with HIV developed bone issues years after stopping a drug called TDF, showing long-term effects on her kidneys and bones.

## Contribution

This case report highlights delayed irreversible Fanconi syndrome and bone fractures after TDF discontinuation.

## Key findings

- Fanconi syndrome and vertebral fracture occurred four years after TDF discontinuation.
- Phosphate wasting persisted despite switching to TAF, indicating irreversible effects.
- Conservative treatment failed to reverse the bone and renal issues.

## Abstract

The use of tenofovir disoproxil fumarate (TDF) as an antiretroviral agent has been reported to adversely affect both renal tubules and bone health, leading to pathological fractures. While such an effect is largely reversible, substituting TDF with tenofovir alafenamide (TAF) might result in lower rates of adverse events with the preservation of tenofovir effectiveness. We report a case of a 40-year-old lady with HIV infection who had a vertebral fragility fracture secondary to TDF-associated Fanconi syndrome. The syndrome developed four years after TDF cessation and switching to TAF. Other etiologies for decreased bone mass were excluded, and the diagnosis of Fanconi syndrome was established based on her bone mineral density (BMD) and urine parameters. She was treated conservatively with active vitamin D, calcium, and progesterone/estrogen combination, but her phosphate wasting persisted despite switching to TAF; this likely represents a delayed irreversible effect of TDF on the patient’s bone remodeling. This case report highlights the chronic sequelae of TDF therapy and the importance of monitoring for and early detection of renal tubulopathy and osteoporotic fractures in this patient population.