Vitamin D-dependent rickets: a resurgence of the rachitic lung in the 21st century.

Respiratory complications of rickets may be life-threatening particularly in developing countries. A 7-month-old boy presented with recurrent infections, seizures, failure to thrive, wheezing and respiratory distress progressing to global respiratory failure. Several antimicrobial regimens, bronchodilators and corticosteroids resulted in only short-term improvement. He was transferred from Cape Verde to a third-care hospital in Portugal. He was hypotonic and undernourished, with respiratory anguish and classical skeletal signs of rickets, despite vitamin D supplementation. Hypocalcaemia, normal phosphate levels and normal vitamin D status 25(OH)D3 and 1.25(OH)2D3) pointed to vitamin D-dependent rickets type II. Treatment with high doses of calcium and calcitriol allowed progressive respiratory, musculoskeletal and neurological recovery. Although respiratory manifestations of rickets were described many years ago, the present case raises relevant issues about the level of diagnostic support, the risk of complications and how they should be assessed and monitored.