Granulomatous Interstitial Nephritis Secondary to Levetiracetam

Introduction: Granulomatous interstitial nephritis is detected in approximately 0.5-0.9% of kidney biopsies. Retrospective studies and clinical experience suggest that removal of the offending agent and prompt treatment with corticosteroids result in improvement of renal function. Levetiracetam has not been typically implicated to cause renal toxicity. Here, we report a case of non-necrotizing granulomatous interstitial nephritis secondary to levetiracetam in a patient with APOL1 G1 homozygocity. Case Description: 53-year-old male with epilepsy and chronic pain presented with severe acute interstitial nephritis after taking omeprazole prescribed by his primary care physician for gastritis with serum creatinine rising from a baseline of 1mg/dL to 4mg/dL. Proton pump inhibitors were added to patient's allergy list and the patient was treated with prednisone taper. Renal function initially improved and subsequently worsened, potentially implicating another culprit. Patient had 312mg of mostly tubular proteinuria which remained unchanged, but his serum creatinine worsened from 2mg/dL to 4mg/dL prompting a repeat kidney biopsy. Kidney biopsy demonstrated a drug-related, active severe granulomatous interstitial nephritis. At the time, patient also experienced a breakthrough seizure and his levetiracetam dose was increased. Discussion: This case highlights association between levetiracetam, a common and essential anti-seizure therapy, in inducing granulomatous interstitial nephritis in a patient with a background of APOL1 nephropathy. This comes following repeat kidney biopsy after initial corticosteroid treatment for acute interstitial nephritis thought to be secondary to proton pump inhibitors. This case also enforces the significance of repeat kidney biopsy following insufficient response to corticosteroids and removal of a commonly implicated offending agent.