A 59-year-old woman diagnosed with acute myeloid leukemia received successfully an allogeneic hematopoietic stem cell transplantation from an HLA-compatible unrelated donor following a reduced-intensity conditioning. The GvHD prophylaxis regimen was mycophenolate mofetil and cyclosporine. In the post-transplantation phase, the patient presented several complications, such as reactivation of CMV disease (CMV serostatus: D+, R+). Foscarnet was initiated and phosphonoformate crystalluria (proven by infrared spectrometry) was observed 7 days after onset of therapy associated with renal tubular epithelial cells in urine sediment. No hematuria was observed. The patient developed AKI KDIGO stage 1 24 days after foscarnet initiation.
This patient was a 63-year-old man who underwent liver transplantation for alcohol-induced cirrhosis. Despite anti-CMV (serostatus D+, R−) prophylaxis, the patient developed CMV infection against what he first received valganciclovir. The viral load of CMV further increasing, the patient was switched to foscarnet; however, phosphonoformate crystalluria (proven by infrared spectrometry) was observed 1 month after onset of the treatment with foscarnet and was accompanied by glomerular haematuria, leukocyturia, and renal tubular epithelial cells in urine sediment. The patient developed AKI KDIGO stage 1 47 days after onset of the treatment with foscarnet. CMV viral load decreased but remained present under bitherapy (foscarnet/ganciclovir, then ganciclovir/letermovir). Elevated creatinine persisted despite discontinuation of foscarnet.