Objectives: to compare clinical, biochemical and radiological manifestations of severe vitamin D deficiency (VDD - serum 25 OH - vitamin D level <10 ng/ml) in adolescents and children and to investigate the effects of an intramuscular injection (IM) of vitamin D3 megadose.
Design: in this prospective study 36 adolescents and 45 children with severe VDD were studied. An IM dose (10,000 IU/kg, max 600,000 IU) of cholecalciferol was injected and parameters of calcium homeostasis were measured at intervals of 3 months.
Results: at presentation, infants and young children (age 1.9 ± 0.5 years) with severe VDD had enlarged wrist joints (42/45), cranial bossing (39/45), wide anterior fontanel (27/45), Harrison's sulcus (11/45) , chest rosaries (27/45), bow legs (29/45), delayed teething (40/45), delayed motor milestones (36/45), short stature (length/height SDS <-2)(12/45), craniotabes (4/45) and hypocalcemic tetany ( 11/45). The most frequent biochemical abnormality was high alkaline phosphatase (ALP) (45/45), followed by low phosphate (PO4) (36/45) and low calcium (Ca) (8/45). Adolescents with severe VDD presented with pain in weight bearing joints, back, thighs, knees, and calves (30/36) difficulty walking and/or climbing stairs and/or running (8/36), muscle cramps and/or facial twitches and/or carpopedal spasms (2/36) and genu valgum (2/36). Biochemical serum abnormalities included high ALP (31/36), low phosphate (10/36) and low Ca (4/36). Variable radiological manifestations due to VDD were detected in all children (45/45) and in some of adolescents (19/35). Two different radiological patterns have been recognized in adolescents. Three months after injecting a mega dose of cholecalciferol all biochemical abnormalities were corrected with significant improvement of symptoms related to VDD had been reported in all children (45/45) and in the majority (33/36) of adolescents with VDD. 3-6 months after the injection, complete healing of the radiological evidence of VDD was achieved in all rachitic children and the majority of adolescents (16/19).
Conclusion: it appears that adolescents adapt better to severe VDD compared to infants, with less severe clinical, biochemical and radiological manifestations. An IM mega dose of cholecalciferol is effective therapy for treatment of VDD in children and adolescents for 3 months but not for 6 months.;