Paediatric metabolic bone disease

Childhood metabolic bone disease is developing as a specialty in its own right, but many skeletal diseases will present to the general paediatrician as well as those with an interest or specialism in endocrinology, genetics, neonatology, nephrology, or rheumatology. As well as de-novo presentations of skeletal disease, the adverse effects of inflammation, immobilization, altered nutrition, and drugs on the skeleton can become apparent during the management of childhood rheumatological conditions. Childhood metabolic bone diseases typically present with fracture, bony deformity, bone pain, or short stature, either alone or in combination. It is important to distinguish disorders that result in the loss of bone tissue—osteoporoses—from those where mineral is lost but matrix preserved—rickets and osteomalacia. Both have reduced bone density, but treatment is directed in the former group to arresting bone loss and increasing, where possible, bone formation and in the latter group to the appropriate provision of vitamin D or its active metabolites, often with calcium and phosphate supplementation. High bone mass disorders are much less common; in such situations it is again important to distinguish those in which there is reduced bone resorption as opposed to increased bone formation, as treatment options are very different. Treatment options often reflect those in adult practice, but there are important differences in the management of bone disease in the growing skeleton that are detailed here.