Effect of intramuscular cholecalciferol megadose in children with nutritional rickets

The treatment practices for vitamin D deficiency rickets are highly variable. Though a single intramuscular (IM) megadose of vitamin D is economical, and ensures good compliance, it poses the risk of hypervitaminosis D. This observational study was conducted to assess the duration of effect and safety of single IM megadose of cholecalciferol in the treatment of vitamin D deficiency rickets.

Children younger than 14 years with rickets were enrolled. Baseline investigations included radiograph of wrists and estimation of serum calcium, phosphate, alkaline phosphatase (ALP), 25(OH) vitamin D and parathormone (PTH) levels. All children received a single IM megadose of vitamin D3. Biochemical parameters were re-evaluated at 1.5, 3 and 6 months after the megadose and the values were compared to the baseline.

We enrolled 21 children, out of which nine remained under active follow-up till 6 months. Radiological evidence of rickets was present in all 21 children, 14 had hypocalcemia at the time of presentation. After IM cholecalciferol megadose, median 25 hydroxy vitamin D [25(OH)D] level remained significantly more than the baseline till 6 months after the megadose. At 1.5 months after the vitamin D megadose, three (30%) of the children were found to develop toxic levels of vitamin D (>150 ng/mL), although none had hypercalcemia or any clinical manifestation of vitamin D toxicity. At 3 months and 6 months after the megadose, 25(OH)D levels remained in the sufficient range (20-100 ng/mL) in seven out of the eight children who came for follow-up.

A single IM megadose of vitamin D may be effective in significantly increasing the 25(OH)D levels for at least 6 months in children with rickets, but elevation of 25(OH)D to toxic range raises concern regarding its safety.