Hypercalcemia with methotrexate pneumonitis: A rare, important and intriguing adverse event

Methotrexate leading to hypercalcaemia is a rarely reported adverse event. We present three elderly patients with inflammatory arthritis who developed hypercalcemia probably due to methotrexate-induced granulomatous pneumonitis. All patients presented with worsening non-productive cough with dyspnea, nausea, loss of appetite, and confusion. Their clinical and radiologic features were consistent with methotrexate-induced pneumonitis. On evaluation, all patients concurrently had hypercalcemia with normal 25OH D3, and low PTH with markedly elevated levels of 1,25OH D3 seen in two patients. In all three patients, hypercalcemia and pneumonia responded to hydration, corticosteroids, and methotrexate withdrawal. There was no relapse of symptoms on long term follow-up. In these three patients with inflammatory arthritis, methotrexate-induced pneumonitis led to symptomatic hypercalcemia. Unless hypercalcemia is looked for and treated in this setting, the morbidity can be high.