A case of acetaminophen-induced acute tubulointerstitial nephritis in adult

We report a case of allergic acute tubulointerstitial nephritis (TIN) induced by acetaminophen in a 48-year-old Japanese man with no past medical history. Two days after receiving the non-steroidal anti-inflammatory drug (NSAID) loxoprofen for left shoulder pain, he developed cold symptoms such as fever and sore throat. He then took a 300 mg dose of acetaminophen three times a day and a 100 mg dose of minocycline hydrochloride twice a day for 7 days. Because there was no improvement in his symptoms, he consulted a local clinic again, where blood tests revealed renal insufficiency, and he was, then, referred to our hospital for evaluation of kidney function. Renal biopsy revealed acute TIN, and Ga-67 scintigraphy showed diffuse uptake in bilateral kidneys. A drug-induced lymphocyte stimulation test (DLST) was positive for acetaminophen and negative for loxoprofen and minocycline. Based on these findings, we made a diagnosis of acetaminophen-induced TIN. We treated the patient with three courses of semi-pulse steroid therapy, after which his fever went down, and his serum creatinine level recovered from 2.09 to 1.43 mg/dL. Although we medical doctors think that therapeutic dose of acetaminophen retains high safety, it is important to keep in mind that acetaminophen can cause allergic acute TIN.