Severe Milk-Alkali Syndrome in a Patient with Hypoparathyroidism Associated with 1,25(OH)2D, Hydrochlorothiazide and Anthranoid Laxative Consumption

BACKGROUND: Milk-alkali syndrome is a life-threatening condition defined by the triad of hypercalcaemia, metabolic alkalosis and acute renal failure, and is associated with consumption of calcium and absorbable alkali. METHODS: We report the case of a patient admitted to a step-down unit of a large hospital in Italy. RESULTS: The patient was a 59-year-old woman with hypoparathyroidism and mild chronic kidney insufficiency, treated for a preceding episode of hypocalcaemia with high doses of calcitriol and calcium carbonate, who was also taking hydrochlorothiazide and unreported herbal anthranoid laxatives. The patient was admitted to hospital with severe hypercalcaemia, severe metabolic alkalosis and acute renal insufficiency. The patient was successfully treated with urgent dialysis, loop diuretics and calcitonin administration. CONCLUSIONS: This case underlines the need for caution when treating patients with impaired calcium metabolism regulation, and suggests that herbal anthranoid laxatives might act as triggers for milk-alkali syndrome. LEARNING POINTS: Patients with hypoparathyroidism are more prone to develop milk-alkali syndrome. Patients need careful follow-up and review of their need for calcium supplements. Non-prescription and complementary medicines can aggravate hypercalcaemia.