A 31 year old man presented with a four day history of anxiety, insomnia, and confusion. Over the past few months he had intermittently noticed red eyes and a “tummy ache.” A concomitant history from his parents revealed a previous episode of confusion and concern about excessive alcohol intake—he had been drinking 10 units of vodka a day for the past six years. He denied any medical history or current drugs. On examination, he was agitated, tachycardic (heart rate 110 beats/min), and he had bilateral conjunctivitis. Initial investigations showed a calcium concentration of 3.54 mmol/L (reference range 2.15-2.6) and metabolic alkalosis (table⇓). He was treated for acute hypercalcaemia with fluids and discharged when levels normalised.

Before further outpatient investigations were performed, he was readmitted two weeks later with confusion and a witnessed seizure. Investigations again showed a raised calcium (3.80 mmol/L), metabolic alkalosis, and new onset acute renal failure (table). Plasma glucose was normal. He was once again treated for acute hypercalcaemia and stabilised. On day three of admission, calcium carbonate tablets were discovered on his bedside table. He reported regularly ingesting up to three packets a day to treat symptoms of indigestion.