Vitamin D toxicity presenting as hypercalcemia and complete heart block: An interesting case report

Vitamin D deficiency is widely prevalent across the globe. This has lead to widespread use of vitamin D supplements in populations. We present our experience of vitamin D toxicity in a subject resulting in hypercalcemia and CHB (Complete Heart Block). A 70-year-old female, known hypertensive for thirty five years and diabetic for seven years underwent total knee replacement (TKR) for osteoarthritis left knee in December 2010. For perioperative glycemic control, multiple subcutaneous injections of insulin were advised. Patient later presented with poor glycemic control, decreased appetite and constipation for last 1 month with history of episodes of transient loss of consciousness for 15 days and recurrent vomiting. Biochemical work-up showed hypercalcemia (Serum calcium 12.4 mg/dL). Sr. albumin, ALP, Sr. phosphorus and PTH levels were normal, thus suggesting PTH independent hypercalcemia. Strong suspicion led us to check vitamin D levels in dilution which were 2016 ng/mL, thus confirming vitamin D toxicity. Retrospective analysis of treatment history revealed patient receiving 4 injections of Architol (6 Lac units im) prior to presentation. Work-up for malignancy was negative, brain imaging and EEG were normal. Holter was suggestive of intermittent CHB. Patient was given hydration, injection calcitonin 100 I.U. subcutaneously, injection pamidronate 60 mg infusion, with serum calcium levels normalizing, with relief in constipation, vomiting and behavioral improvement. However, persistence of rhythm disturbances led to permanent pacemaker placement. The present case highlights the dangers of indiscriminate vitamin D usage, exposing patients to potentially life threatening complications.