Clinical Manifestations and Outcomes of Fluoroquinolone-Related Acute Interstitial Nephritis

Objective To describe the clinical presentation, diagnosis, and outcomes of patients with biopsy-proven acute interstitial nephritis (AIN) related to fluoroquinolone (FQ) therapy. Patient and Methods We conducted a retrospective review of biopsy-proven AIN attributed to FQ use at Mayo Clinic's campus in Rochester, Minnesota, from January 1, 1993, through December 31, 2016. Cases were reviewed by a renal pathologist and attributed to FQ use by an expert nephrologist. We also reviewed and summarized all published case reports of biopsy-proven AIN that were attributed to FQ use. Results We identified 24 patients with FQ-related biopsy-proven AIN at our institution. The most commonly prescribed FQ was ciprofloxacin in 17 patients (71%), and the median antibiotic treatment duration was 7 days (interquartile range [IQR], 5-12 days). The median time from the initiation of FQ to the diagnosis of AIN was 8.5 days (IQR, 3.75-20.75 days). Common clinical manifestations included fever (12; 50%), skin rash (5; 21%), and flank pain (2; 8%), and 9 (38%) had peripheral eosinophilia. However, 4 (17%) of the patients were asymptomatic at the time of diagnosis and AIN was suspected on the basis of routine laboratory monitoring. Most patients (17; 71%) recovered after the discontinuation of antibiotic therapy, and renal function returned to baseline at a median of 20.5 days (IQR, 11.75-27.25 days). Six patients (25%) required temporary hemodialysis, and 14 patients (58%) received corticosteroid therapy. Conclusion The onset of FQ-related AIN can be delayed, and a high index of suspicion is needed by physicians evaluating these patients. Overall outcomes are favorable, with recovery to baseline renal function within 3 weeks of discontinuing the offending drug.