Endocrine Abstracts

An 89-year-old female family physician presented to an orthopaedic surgeon with a short history of aches and pains. She was suspected to have vitamin D deficiency and was empirically prescribed three intramuscular injections of 6 million units of cholecalciferol at monthly intervals. A few days after the third dose she presented with nausea, generalised weakness, confusion and ataxia. She appeared drowsy and dehydrated. Vital parameters were normal and there were no focal neurological signs. Her calcium was 4.53 mmol/l (2.2–2.6), serum creatinine 396 μmol/l (44–100), serum vitamin D3 >160 ng/dl (30–100). She was diagnosed to have hypervitaminosis D manifesting with severe hypercalcaemia and acute renal failure.

Management included normal saline infusion, intranasal calcitonin and supportive treatment. In view of severe hypercalcemia and worsening oliguria, she underwent two cycles of haemodialysis which were complicated by disequilibrium syndrome. Serum calcium normalised and she gradually recovered and she was discharged. 3 months later calcium was 2.43 mmol/l, serum creatinine 114 μmol/l although serum vitamin D3 remained >160 ng/dl. Clinically she recovered completely and has now returned to active professional life.

With the rising prevalence of vitamin D deficiency and high cost of its biochemical confirmation there is an increasing trend amongst medical practitioners in India to prescribe vitamin D supplements empirically. This approach is generally safe in view of the wide gap between the therapeutic and toxic doses of vitamin D. However elderly patients or those with renal failure or primary hyperparathyroidism are pre-disposed to toxicity and may develop hypervitaminosis D especially with use of higher doses.

Our case here highlights the need to use modest doses of vitamin D therapy and to maintain clinical and biochemical vigilance for side-effects in high-risk individuals.