1. Metabolic bone diseases
There is a clinical problem?

3. Osteopertrosis
Hereditary decreased osteoclastic function. Decreased resoprtion leads to thick sclerotic bones.
Pathology
Problems with the osteoclast resorption pit
Increased bone density -> thick brittle bones -> fracture
Marrow decreased by bone growth, may cause pancytopenia.
Extramedullarly haematopoeisis
Cranial nerve compression -> blindness, deafness, vision loss

4. Osteopetrosis X ray Clinical features Treatment
Osteosclerosis, long bones -> Erlenmeyer flask shaped deformity
Clinical features
Autosomal recessive (malignant)
Infants and children, multiple fractures, early death
Autosomal dominant (benign type)
Adults, fractures, mild anaemia, cranial nerve impingement
Carbonic anhydrase II deficiency
Renal tubular acidosis, cerebral calcificaiton
Treatment
Bone marrow transplant

6. Paget’s disease (osteitis deformas)
Localised disorder of bone remodelling caused by excessive resorption and disorganised replacement leading to thickened but weaker bone.
Epidemiology – begins after age 40, european ancestry
Etiology – possible genetic predisposition, possibly paramyxovirus
Forms of involvement
Monostotic (15%), polystotic (85%)
Commonly – skull, pelvis, femur, vertebrae
Pathology
Three stages
Osteolytic – otseoclastic activity predominates
Mixed osteoclastic and osteoblastic
Osteosclerotic – osteoblastic activity predominates -> burnout stage
Micro haphazard arrangement leads to mosiac pattern of lamellar bone
Bone is weak, fractures easily
Skull involvement
Increase in head size
Foraminal narrowing leading impingement of the cranial nerves
Facial bones can be involved leading to a lion like face

7. Paget’s disease (osteitis deformas)
X-ray
Bone enlargement with lytic and sclerotic areas.
Complications
AV shunts within marrow can cause high output cardiac failure.
Osteosarcoma or other sarcomas.

9. Osteoporosis Osteopenia Epidemiology Pathogenesis Clinical features
Most common bone disease
Elderly, post menopausal
Pathogenesis
Primary……………………….
Secondary…………………..
Clinical features
Bone pain and fractures
Weight bearing bone predisposed to fracture
Loss of height and kyphosis

10. Osteoporosis X-ray Treatment General translucency of bone
Oestrogen replacement therapy – controversial
Weight bearing exercise
Calcium and vitamin D
Biphosphonate
Calcitonin

12. Osteomalacia and Rickets
Decreased mineralisation of newly formed bones, usually caused by deficiency or abnormal metabolism of vitamin D.
Etiology – deficiency of vit D, intestinal malabsorption, lack of sunlight, renal or liver disease.
Epidemiology
Osteomalacia – adults
Rickets - children

13. Osteomalacia and Rickets
Pathogenesis
Osteomalacia -> poor mineralisation of newly formed bone -> thin fragile bones -> fracture
Rickets
Remodelled bone and bone at growth plates are undermineralised
Endochondral bone formation also affected -> deformity
Fractures also occur
Clinical presentation
Osteomalacia -> bone pain, fracture (vertebrae, hips, wrist)
Rickets -> bow legs, craniotabes, lumbar lordosis,

14. Hyperparathyroidism Primary Secondary Tertiary?
Adenoma or autonomous hyperplasia (Robbins)
Secondary
Caused by prolonged states of hypocalcemia leading to hyperplasia
Tertiary?
Autonomous hyperplasia
Severe cases lead to osteitis cystic fibrosa (no longer though…)
Presentation
Asymptomatic hypercalcamia
Treatment
Curvative parathyroidectomy

15. Renal Osteodystrophy
Describes clinically all of the skeletal changes of chronic renal disease.
Increased osteoclastic bone resorption mimicking osteoitis fibrosa cystica.
Delayed matrix mineralisation.
Osteosclerosis.
Growth retardation.
Osteoporosis.
Main types
High turnover -> increased resorption and bone formation (dominates)
Low turnover (aplastic) -> adynamic bone, less commonly osteomalacia

16. Renal Osteodystrophy Pathogenesis (long..)
Chronic renal failure results in phosphate retention and hyperphosphatemia
Hyperphospatemia induces secondary hyperparathyroidism (via regulating PTH secretion)
Hypocalcaemia develops due vitamin D problems (kidneys)
PTH secretion markedly increases at all levels of serum calcium
In renal failure decrease in the binding of 1,25-(OH)2D3 to parathyroid cells
Decreased degradation and excretion of PTH (kidneys)
Secondary hyperparathyroidism produces increased osteoclastic activity
Metabolic acidosis associated with renal failure leads to bone resorption