SHM Converge Scientific Abstract ePoster Gallery-Phenazopyridine Associated Crystalline Nephropathy in a Renal Transplant Recipient

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This case describes phenazopyridine-associated crystalline nephropathy in a 66-year-old renal transplant recipient with chronic kidney disease who developed an abrupt, fivefold rise in serum creatinine after finishing phenazopyridine for post-cystoscopy dysuria. On exam, she had tenderness over the transplant site. Labs showed marked renal dysfunction and elevated serum uric acid. Urine microscopy revealed rhomboid crystals, prompting transplant nephrology consultation and biopsy of the allograft.<br /><br />Pathology demonstrated acute tubular injury with yellow crystalline material obstructing the renal tubules, confirming crystal-induced kidney injury. The patient was treated with intravenous sodium bicarbonate infusion and discontinuation of nephrotoxic medications, leading to gradual improvement in kidney function. By 14 weeks, her creatinine had nearly returned to baseline.<br /><br />The case highlights that phenazopyridine, a common urinary analgesic used for UTI symptoms and post-procedural dysuria, can cause significant nephrotoxicity, especially at high doses or in patients with preexisting kidney disease. Reported toxicities include acute interstitial nephritis, renal tubular necrosis, hemolysis, jaundice, and methemoglobinemia. Although the exact mechanism is unclear, injury appears dose dependent and related to reduced renal excretion.<br /><br />The key clinical message is that phenazopyridine should be used with extreme caution in patients with any degree of renal impairment and generally avoided in renal transplant recipients unless specifically supervised by transplant nephrology.

Asset Subtitle

Aisha T. Amuda

Meta Tag

Author List Aisha T. Amuda, Tatvam T. Choksi

Category Clinical Vignettes

Concept Phenazopyridine

Concept Crystal-Associated Nephropathy

Concept Acute Kidney Injury

Concept Urinary Crystal

Concept Kidney Biopsy

Distinguished Non-Finalist

Presenter Organization University of Chicago Medicine

Presenting Author Aisha T. Amuda

Track Adult

Keywords

phenazopyridine

crystalline nephropathy

renal transplant recipient

acute kidney injury

chronic kidney disease

allograft biopsy

rhomboid crystals

acute tubular injury

nephrotoxicity

urinary analgesic

Phenazopyridine

Crystal-Associated Nephropathy

Acute Kidney Injury

Urinary Crystal

Kidney Biopsy