Vitamin D Intoxication Caused by a Manufacturing Error in a Prescribed Vitamin D3 Supplement, Successfully Managed with Low-Dose Zoledronic Acid

Abstract

We describe a male toddler with a history of operated posterior urethral valves who developed vitamin D toxicity with hypercalcemia after he was prescribed orally 6,000 IU of cholecalciferol daily for two months for vitamin D deficiency. The disordered calcium metabolism was discovered during hospitalization in our hospital for a urinary tract infection, along with evidence of renal failure. Serum calcium on admission was 4.22 mmol/L, with an ionized calcium level of 2.26 mmol/L. The measured 25(OH)D level was extremely high (3,555 ng/mL), along with a low serum parathyroid hormone, suggestive of severe vitamin D overdose. Despite aggressive hydration, administration of corticosteroids, and a low calcium diet, he required the administration of a single dose of zoledronic acid for resolution of the hypercalcemia. It was later discovered that the patient received an oral solution of vitamin D3 that was recalled due to a higher content of vitamin D3 than stated on its label. Therapy with low-dose bisphosphonates is effective in cases of symptomatic hypercalcemia that does not respond to intravenous hydration, administration of corticosteroids, and elimination of oral calcium intake. Any child presenting with hypercalcemia and low parathyroid hormone should be investigated for the possibility of vitamin D toxicity.