Milk-Alkali Syndrome in the Context of Pulmonary Tuberculosis: An Overlooked Aetiology of Hypercalcaemia

A 64-year-old male with a history of alcoholism and newly diagnosed pulmonary tuberculosis (TB) developed hypercalcaemia during anti-TB treatment (Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol). He manifested right leg bone pain and hallucinations. Hypercalcaemia workup, including parathyroid hormone (PTH), vitamin D, myeloma screen, and imaging, revealed no underlying malignancy or granulomatous bone involvement. Despite stopping vitamin D/calcium supplements and receiving fluids, bisphosphonates, calcitonin, and steroids, his calcium levels remained elevated. Further history revealed excessive milk intake (1-2 L/day). Cessation of dairy led to gradual symptom resolution and normalisation of serum calcium within two weeks. This case highlights milk-alkali syndrome as a rare but reversible cause of hypercalcaemia in TB patients.