Vitamin D deficiency

1. Big picture

Vitamin D deficiency in children is important because it affects calcium-phosphate metabolism and bone mineralization. The classical pediatric disease is nutritional rickets, especially in rapidly growing infants and toddlers.

For the exam, the examiner wants you to recognize this pattern:

Breastfed infant / dark skin / little sunlight / poor vitamin D intake → delayed motor milestones, sweating/irritability, craniotabes, widened wrists, rachitic rosary, bowed legs → low 25-hydroxyvitamin D, high alkaline phosphatase, secondary hyperparathyroidism → vitamin D + calcium treatment.

The dangerous acute presentation is hypocalcemic tetany or seizure, especia