Hypervitaminosis D induced hypercalcemia leading to coma: A case report

An elderly female presented with abdominal pain, vomiting and easy fatigability. Her sensorium gradually declined and became comatose. She was on Methotrexate, folic acid and prednisolone for her rheumatoid arthritis. The neurological examination and neuroimaging did not contribute in making the diagnosis. It is challenging to diagnose a metabolic cause of coma. Once diagnosis is established, the management becomes easier. On detailed investigation, she was found to have severe hypercalcemia with corrected serum calcium level being 18.2 mg%. Serum vitamin D level was also high, 150 ng/ml. On probing for detailed history, it was revealed that she had been taking a weekly dose of 60,000 IU of vitamin D for nearly 5 years. In recent times, association of various diseases has been reported with vitamin D deficiency. Vitamin D supplementation seems justified in this patient considering her age and the fact that she had rheumatoid arthritis; she was also taking corticosteroid. The recommended dose of vitamin D has been 400–800 IU/day. However, it is often prescribed at a dose of 60,000 IU/week, and sometimes patients self-medicate. There are no guidelines available for prescribing vitamin D at such a strength. Though safety of vitamin D has been established, vitamin D toxicity can occur sporadically with serious consequences. This was managed with intravenous fluids and diuretics. The patient also required subcutaneous calcitonin and low dose of corticosteroid, in addition to a session of haemodialysis for her hypercalcemia. The patient’s sensorium gradually improved as her calcium level returned to normalcy.