Primary osteoporosis.

Primary osteoporosis, as defined by bone loss associated with significant fracture, is most commonly caused in children by one or other of the forms of osteogenesis imperfecta (OI). These are a group of disorders that are characterised by abnormalities in type I collagen synthesis or processing. Other types of primary osteoporosis, such as those caused by abnormalities of osteoblasts, are not discussed in this chapter. There are now eight types of OI described. Most are autosomal dominant and they vary in severity from a slight increase in bone fragility with occasional fractures and no bone deformity to severe forms with poor growth, intrauterine fractures and severe bone deformity. The most seriously affected children may not survive. Diagnosis depends on taking a good personal and family history together with a thorough examination. This may be supported by genetic testing or bone biopsy although neither of these is performed routinely. DXA scanning will usually support the diagnosis. Good management requires a multidisciplinary approach involving paediatricians, surgeons, occupational and physiotherapists, dentists, social workers etc. The mainstay of medical treatment is bisphosphonates which, over the past ten years, have revolutionised the approach to management. Surgery is required in more severe cases to straighten limbs or stabilise the spine. Physiotherapy is particularly important to try to maintain mobility.