A patient who was being treated for pneumonia with trimethoprim-sulfamethoxazole developed fatigue and decreased urinary output. The doctors diagnosed him with crystal-induced acute kidney injury secondary to trimethoprim-sulfamethoxazole use.
A 42-year-old man, during his hospital stay for the treatment of Pneumocystis jirovecii pneumonia, developed fatigue and decreased urinary output. The patient had a history of infection with the human immunodeficiency virus (HIV) and the CD4+ T-cell count was 122/mm3, and the HIV viral load was 1,430,000 copies/mm.
One week after the patient started receiving intravenous trimethoprim–sulfamethoxazole, his symptoms had begun.
- Blood urea nitrogen – 46 mg/dL (16.4 mmol/L)
- Creatinine – 3.7 mg/dL (327 μmol/L)
- Potassium – 3.8 mmol/L (reference range, 3.4 to 5.0).
Urinalysis showed a red-cell count of 0 to 1 cell and a white cell count of 5 to 10 cells/HPF. Evaluation of spun urine under light microscopy revealed numerous fan-shaped crystals with a “shock of wheat” appearance.
Ultrasonography excluded hydronephrosis. The patient received a diagnosis of sulfonamide-crystal–induced acute kidney injury secondary to trimethoprim-sulfamethoxazole (TMP-SMX) use.
The doctors stopped the culprit drug, started intravenous hydration, and replaced TMP-SMX with clindamycin–primaquine. Therefore, the patient’s renal function improved and the renal function test results returned to baseline levels within 1 week.
Microscopy no longer revealed crystals in the urine.
At the 1-week follow-up after his discharge, the pneumonia had resolved, and the renal function remained stable. The doctors started him on antiretroviral therapy.
Some drugs produce crystals that are insoluble in human’s urine. Moreover, the precipitation of these crystals within the kidneys tubules can lead to acute renal injury. Immediate management in such cases is the discontinuation of the culprit drug. Prompt diagnosis is imperative to reverse the damage. it is equally crucial to establish intravenous hydration. However, in some severe cases, dialysis may be necessary.
Thammavaranucupt K and Spanuchart I, Sulfonamide Crystals; The New England Journal of Medicine; 2021;3:18