Etiology, clinical and laboratory features in patients with acute interstitial nephritis diagnosed by kidney biopsy

Summary: Acute interstitial nephritis is a rare but increasingly common cause of acute renal failure. It is frequently seen due to drugs, infections and systemic diseases. The aim of this study was to examine the demographic, clinical, pathological and laboratory characteristics of patients diagnosed with acute interstitial nephritis and the factors determining the response to treatment. Materials and Methods: The files of 31 patients who were diagnosed with acute interstitial nephritis by kidney biopsy between 2006-2021 in Istanbul University İstanbul Faculty of Medicine, and were followed in our Nephrology Clinic, were retrospectively analyzed. Patients' biopsy findings, demographic characteristics, etiology, hemogram findings, serum creatinine, electrolytes, albumin, proteinuria, CKD-EPI, protein electrophoresis, the level of serum ANA, pANCA, cANCA, ENA profile in order to rule out autoimmune diseases, treatment regimens and final status were recorded. Results: 25 of the patients were female (80%), the median age was 46 years. Median admission creatinine was 4.1 mg / dl, CRP 28 mg / dl, albumin 4.1 g / dl, proteinuria 0.8 g / day. 7 patients underwent hemodialysis. In 11 patients etiology could not be determined. In 14 patients in etiology were found drugs, and 6 patients had systemic diseases. 29 patients were treated with corticosteroids. Complete response was obtained in 17 of the patients who were followed up for a median of 14 months, and end-stage renal failure developed in 5 patients. Global sclerosis count and presence of granulomas were determined as pathological findings determining the treatment. Conclusion: Acute interstitial nephritis is most commonly seen due to drugs. Response to treatment is low and may lead to end-stage renal failure.