A 30-year-old woman with no previous medical history presented to the emergency department with a seizure and aggressive behavior. After extensive blood work and imaging studies, she was admitted with HIV inaugural infection (CDC stage C3) and cerebral toxoplasmosis. As the first line of treatment, the patient was started on sulfadiazine and pyrimethamine¹1. Elsheikha HM, Marra CM, Zhu XQ. Epidemiology, pathophysiology, diagnosis, and management of cerebral toxoplasmosis. Clin Microbiol Rev. 2020;34(1):e00115–19. doi: http://dx.doi.org/10.1128/CMR.00115-19. PubMed PMID: 33239310.
https://doi.org/10.1128/CMR.00115-19... ,²2. Perazella MA, Herlitz LC. The crystalline nephropathies. Kidney Int Rep. 2021;6(12):2942–57. doi: http://dx.doi.org/10.1016/j.ekir.2021.09.003. PubMed PMID: 34901567.
https://doi.org/10.1016/j.ekir.2021.09.0... ,³3. Chebion G, Bugni E, Gerin V, Daudon M, Castiglione V. Drug-induced nephrolithiasis and crystalluria: the particular case of the sulfasalazine derivatives. C R Chim. 2022;25(S1):295–306. doi: http://dx.doi.org/10.5802/crchim.109.
https://doi.org/10.5802/crchim.109... . After one week, she developed non-oliguric acute kidney injury. Urinary sediment analysis revealed sulfonamide crystals with the morphologic appearance of shocks of wheat (Figures 1 and 2), confirmed by infrared spectroscopy⁴. Sulfadiazine was replaced with clindamycin, and a notable enhancement was observed after to the implementation of vigorous fluid hydration using an alkaline solution (sodium bicarbonate).

Figure 1
Sulfadiazine crystals have an amber color and radial striations (contrast phase microscopy, 400× magnification). Urinary analysis results – density: 1.008; pH: 5; proteins: 15 mg/dL; hemoglobin: 0.75 mg/dL; nitrites/glucose/ketones/bilirubin/urobilinogen: negative.

Figure 2
Sulfadiazine crystals are strongly birefringent under polarized light (polarized light, magnification 400×).

Acknowledgments

We thank Dr. Vincent Frochot for the infrared spectroscopy analysis.

References

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