In a developing country there may be multiple reasons for dietary rickets and so each cause must be considered (dietary calcium, vitamin D intake, gastrointestinal disease, poor sunlight exposure, etc)..
Clinical features:
(1) evidence of rickets (clinical, radiologic, biochemical)
(2) low to normal serum calcium
(3) low to normal serum phosphate
(4) normal serum 25-hydroxyvitamin D
(5) positive clinical response to calcium supplementation
(6) absence of alternative explanations
where:
• A low serum 25-hydroxyvitamin D may reflect concomitant vitamin D deficiency.
• An elevated serum alkaline phosphatase for age was used as biochemical evidence of rickets.
Criteria for response to calcium supplementation:
(1) radiographic correction of bone deformities after 3 months
(2) decrease in serum alkaline phosphatase levels to the age-related reference range
(3) normal serum calcium
