Hypercalcaemia as the initial presentation of Graves' disease

Hypercalcaemia in patients with hyperthyroidism is usually asymptomatic. It occurs due to increased bone turnover and demineralisation. There are only a few case reports where symptomatic hypercalcaemia was the presenting complaint of hyperthyroidism. An Asian man in his 40s presented to us with intractable vomiting for the last 6 months which was not controlled despite multiple antiemetic medications. On routine biochemistry performed at our institute, he was found to have hypercalcaemia and concomitant hyperthyroidism. Classical symptoms suggestive of hyperthyroidism were not present in our patient thus delaying the diagnosis. His symptoms resolved after the correction of hypercalcaemia. Hypercalcaemia did not recur after achieving an euthyroid status on treatment with carbimazole. Other common and more sinister causes for hypercalcaemia like malignancy were ruled out. This case highlights that symptomatic hypercalcaemia could be the initial presentation of hyperthyroidism and amelioration of hyperthyroidism corrects the hypercalcaemia.