Manifestations of severe vitamin D deficiency in adolescents: effects of intramuscular injection of a megadose of cholecalciferol.

We recorded the manifestations of severe vitamin D deficiency (VDD) in 40 adolescents before and 3 and 6 months after treatment with a mega dose of cholecalciferol (10 000 IU kg(-1), max 600 000 IU). Significant improvement of symptoms related to VDD was reported in 34/40. Three months after the injection, serus calcium, phosphate, alkaline phosphatase and parathormone were normal in all adolescents with VDD with 25-hydroxyvitamin D (25OHD) level = or >20 ng ml(-1). After 6 months, the majority had 25OHD level <20 ng ml(-1). Two patterns of radiological changes have been recorded with complete healing achieved in all patients after a year of therapy. A mega dose of cholecalciferol is an effective therapy for treatment of VDD in adolescents for 3 months but not for 6 months. Radiographs of the ends of long bones are still valuable tool for diagnosis and follow-up of these patients.