A Rare Presentation of Checkpoint Inhibitor Induced Distal RTA

Immune checkpoint inhibitors have opened a new era in treating advanced malignancies, resulting in a rapid increase in utilization, given the remarkable clinical outcomes. The incidence of immune-related adverse events increased due to the immunologic effects of these therapeutic agents. However, immune-related renal adverse events remain low, representing only a small incidence of reported cases. Common renal toxicity described includes acute interstitial nephritis, minimal change disease, and immune complex glomerulonephritis. Renal tubular acidosis has occasionally been reported but is highly uncommon. This report presents a case of a 68-year-old woman with a known history of metastatic melanoma undergoing treatment with ipilimumab+nivolumab, who developed distal renal tubular acidosis requiring stress dose steroids and sodium bicarbonate for treatment. We describe the clinical characteristics, potential mechanisms, and management of this case, highlighting the need among clinicians utilizing immune check inhibitors to be aware of this immune-related disease entity.