Vitamin D toxicity presenting as hypercalcemia and complete heart block: An interesting case report
A 70-year-old female, known hypertensive for thirty five years and diabetic for seven years underwent total knee replacement for osteoarthritis left knee in December 2010. For perioperative glycemic control, we started multiple subcutaneous injections of insulin and discharged on same with good glycemic control.\nPatient consulted us again in February 2011 (2 months later), with poor glycemic control, decreased appetite and constipation for last 1 month. There was history of episodes of transient loss of consciousness for 15 days and recurrent vomiting. Each episode of loss of consciousness occurred around meal time (30 min after injecting regular insulin, however blood glucose was never checked to confirm hypoglycemia). Relatives also noticed behavioral changes in patient in terms of increased irritability, minimal social interaction and lack of sleep. Clinical examination was unremarkable except for mild dehydration.\nOn biochemical evaluation, the biochemical profile and serial ECGs were within normal limits except serum Calcium of 12.4 mg/dl. The corresponding serum phosphorus, serum albumin, serum alkaline phosphatase values 3.6 mg/ dl, 3.6 gm/dl and 154 I.U., respectively. Records of the early post-operative period were not suggestive of any hypercalcemia.\nInitially hypercalcemia was thought to be due to dehydration, however a decision to send repeat calcium along with serum PTH. Serum calcium was 12.4 mg% with corresponding serum PTH value of 12.17 pg/ml. Thus, it was a case of PTH independent hypercalcemia. In view of serum 25 OH vitamin D levels more than 120 ng/ml. , we kept the possibility of vitamin D toxicity and repeated serum 25 OH vitamin D levels by dilution, which came as high as 2016 ng/ml.\nReview of past treatment revealed that patient had received 4 injections of Arachitol 6 lac units each over a period of few weeks (total dose 24 Lac units) in January for complaints of generalized weakness.\nWork-up for malignancy was negative, brain imaging and EEG was normal. Patient was started on anti-depressants after psychiatry opinion. Holter was suggestive of intermittent CHB (Complete Heart Block) and patient was considered for temporary pacemaker insertion.\nPatient was given hydration, under hemodynamic monitoring and injection Calcitonin100 I.U. subcutaneously and injection Pamidronate 60 mg infusion, with serum calcium levels coming down to 8.8 gm%, and relief in constipation, vomiting and behavioral improvement.\nHowever, persistence of rhythm disturbance, despite resolution of hypercalcemia, permanent pacemaker was implanted.\nPatient was discharged in march 2011 and was advised adequate hydration, however she was admitted again in May 2011 with recurrent vomiting, serum calcium levels of 11 mg% and serum 25 OH vitamin D level (by dilution): 880 ng/ml. Patient was managed with intravenous hydration and injection Calcitonin.