Salicylate toxicity from chronic bismuth subsalicylate use

A 79-year-old man presented to the emergency department with a 1-week history of worsening confusion, falls and hearing impairment. An initial workup for infectious, metabolic and structural causes was unrevealing. However, further history discovered that he had been ingesting one to two bottles of Pepto-Bismol (bismuth subsalicylate) daily for gastro-oesophageal reflux symptoms. On his second day of admission, the plasma salicylate concentration was 2.08 mmol/L (reference range 1.10-2.20 mmol/L), despite no sources of salicylate in hospital. He was diagnosed with chronic salicylate toxicity and Pepto-Bismol use was discontinued. The patient was treated supportively with isotonic intravenous fluids only and plasma salicylate concentration fell to less than 0.36 mmol/L. Concurrently, all his symptoms resolved. This case highlights the potential adverse effects of over-the-counter medications. The diagnosis of chronic salicylate toxicity is challenging, specifically in the elderly and in undifferentiated presentations, as it can be missed if not suspected.