Mesalamine-Induced Minimal Change Disease

Introduction: Minimal change disease frequently manifests as a nephrotic syndrome that is mediated by inflammatory effacement of podocytes, either due to a hypersensitivity reaction or direct toxin effect. The etiology is often idiopathic, but some inciting factors include cancer, infections, and medications. Mesalamine, also known as 5-aminosalicylic acid (5-ASA), is commonly used to treat IBD. Nephrotoxicity is a known but rare adverse effect of 5-ASA with an incidence of 0.17% per year. The most common manifestations include chronic interstitial nephritis, renal calculi, papillary nephritis, idiopathic nephrotic syndrome, and FSGS. However, minimal change disease remains a rare complication and has only been described with the chronic use of mesalamine. We present a case of rapid development of acute nephrotic syndrome after 5-ASA overdose. Case Description: A 24-year-old man with a history of ulcerative colitis on mesalamine presented with generalized swelling after ingestion of extra doses of his mesalamine. On the day of presentation, he noticed lower extremity and abdominal swelling. His exam was remarkable for 4+ pitting edema of the lower extremities, abdominal distention, and mild periorbital edema. Labs were notable for Na+ 128 mmol/L, creatinine 1.44 mg/dL, albumin 1.4 g/dL, CK 128 IU/L. Urinalysis showed 4+ protein and 2+ blood. His 24-hr urine protein was 16.3g. Testing for HIV, hgb A1C, syphilis, ANA, C3, C4, anti-GBM, and ANCA panel were normal. Renal biopsy showed effacement of podocytes on electron microscopy. He was treated with prednisone during admission with symptom improvement and near-resolution of proteinuria at 3 month follow up with full remission expected. Discussion: This case report illustrates rapid development of MCD within days of overdose of mesalamine. While previous case reports described patients who developed MCD with chronic mesalamine use, it remains a rare adverse effect. While most adult patients with MCD remain in remission following adequate treatment, approximately 5% will develop a relapsing-remitting disease course that progresses to end-stage renal disease despite treatment. Several organizations have proposed routine intervals to monitor serum creatinine and 24-hour urine protein in patients on 5-ASA. However, recommendations vary and no consensus for monitoring exists. Future guidelines should promote standardization of monitoring.