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Bone Diseases: Metabolic |
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Rickets / Osteomalacia Failure of bone mineralization in children (rickets) and adults (osteomalacia). Can be due to deficiency , failure of synthesis, malabsorption or impaired metabolism of Vitamin D, and also hypophosphataemia, or increased calcium requirement in pregnancy.
Osteoporosis Lack of both bone matrix and mineralization. May be caused by steroid therapy, post-menopause hormone changes, immobilization, and endocrine abnormalities. Hormone replacement therapy in post-menopausal women appears to reduce this.
Hyperparathyroidism Primary hyperthyroidism is usually caused by hyperplasia or adenoma of the parathyroids. Overproduction of the parathormone mobilises calcium and raises the plasma calcium level. A cyst like swelling of the jaw with the histological features of a giant cell lesion is the classical way by which hyperparathyroidism has been detected but is rare. Radiographically the main effects are thinning of bone trabeculae, subperiosteal resorption of the bone of the fingers and resorption of the terminal phalangeal tufts. Alveolar bone may also be resorbed but reforms with treatment.
Bone Diseases of Unknown Cause
Fibrous dysplasia This disorder is characterised by replacement of a part of bone or bones by fibrous tissue, giving rise to associated swelling. It usually presents in childhood and ceases in adolescence with the completion of growth. ¨ Monostotic—one bone involved ¨ Polyostotic—more than one bone Albright’s syndrome— polyostotic fibrous dysplasia, café-au-lait pigmentation and precocious puberty (in girls). Facial asymmetry affects up to 25% of cases
Paget’s disease of bone (Osteitis deformans) Common disorder of the elderly. Normal orderly bone replacement is disrupted and replaced by a chaotic structure of new bone, causing deformity and enlargement. Complications include bone pain and cranial nerve compression, high output cardiac failure and osteosarcoma. More information of Paget’s disease... |
