A 26 year old man is referred for gastroscopy because of a history of several months of dyspepsia. He has routine bloods checked and is found to have a serum calcium level=3.2mmol/l What is the most likely cause of his hypercalcemia?

The key is C. Milk alkali syndrome. [In medicine, milk-alkali syndrome is characterized by high blood calcium caused by taking in too much calcium and absorbable alkali; common sources of calcium and alkali are dietary supplements taken to prevent osteoporosis and antacids. If untreated, milk-alkali syndrome may lead to kidney failure or death].