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In recent years, the number of drug-induced renal injuries has significantly increased in medical practice due to the continuous expansion of the pharmaceutical arsenal. The aim of this study was to describe the epidemiological, clinical, laboratory, histological, and etiological aspects of biopsied drug-induced acute interstitial nephritis (AIN).
This was a retrospective observational descriptive study with an analytical approach focusing on histologically proven drug-induced AIN cases between January 2006 and December 2021.
The study included 15 patients with biopsied drug-induced AIN. The average age of these patients was 51 years, with a gender ratio of 7 women to 8 men. Clinical symptoms presented by patients included asthenia in 66% of the patients, fever in 30%of the patients, arthralgia in two patients. Oliguria was present in 20% of our patients. Skin manifestations were observed in 40% of them, in the form of urticarial or erythematous lesions. For laboratory findings, the average creatinine level at admission was 831 µmol/l, with a peak of 1949 µmol/l. Eosinophilia was observed in 60% of patients. The triad of fever, skin rash, and eosinophilia was present in 26% of them. Total IgE levels were elevated in 3 patients, with a peak at 4080 IU/ml. In urine sediment, leukocyturia was noted in 60% of patients, hematuria in 46%, and proteinuria in 26%. Renal size was normal for most patients and increased in 13%. Histological characteristics showed that the inflammatory infiltrate was significant in 53% of cases, and edema in 73% of cases. Granuloma was found in one patient, eosinophils in one patient, tubulitis in one patient, and acute tubular necrosis in two of them. Immunofluorescence analysis revealed C3 deposits in 3 patients.
The implicated drugs included non-steroidal anti-inflammatory drugs (NSAIDs) (42.85%), antibiotics (28.56%), primarily beta-lactams, a combination of NSAIDs and antibiotics (14.28%), captopril (7.14%), and acetaminophen (7.14%). The last cause implicated was rituximab (anti-CD20) in one patient, who had a sarcoid-like reaction and was treated with r-CHOP (rituximab + cyclophosphamide, doxorubicin, vincristine, and prednisone) for mantle cell lymphoma.
For immediate management, 4 patients required hemodialysis, and 13 were put on corticosteroid therapy at a dose of 0.5 to 1 mg/kg/day. Regarding the outcome, complete remission was observed in 64%, and partial remission in 26%.
Drug-induced AIN is the leading cause of AIN. It should be considered even in the absence of clinical or laboratory signs of hypersensitivity. Prompt discontinuation of any suspected medication and corticosteroid therapy remain the appropriate management to improve prognosis.