An Underestimated Cause of Hypercalcemia: A Case Report of Milk-Alkali Syndrome.

Milk-alkali syndrome (MAS) was first described as an adverse effect of the Sippy regimen, which contained large amounts of sodium bicarbonate, creating a clinical scenario in which hypercalcemia, metabolic alkalosis, and acute renal failure could develop simultaneous features characteristic of MAS. The syndrome has resurged due to widespread calcium supplement use. A 50-year-old Caucasian female was referred to the emergency department by her general physician after an incidental finding of hypercalcemia during evaluation for fatigue. She was diagnosed with acute renal failure in association with elevated calcium levels. After excluding other causes (e.g., hyperparathyroidism, malignancy, multiple myeloma, and familial hypocalciuric hypercalcemia), detailed history and labs confirmed MAS. Intravenous hydration and discontinuation of calcium carbonate normalized her renal function and calcium levels. The case highlights the importance of regular enquiry into diet and consumption of over-the-counter supplements in the assessment of hypercalcemia.