This document discusses metabolic bone diseases including osteoporosis, osteomalacia, and rickets. It describes the components of bone, common metabolic bone disorders, clinical assessment, x-ray findings, bone density measurement techniques, biochemical tests, and treatment approaches for various conditions like postmenopausal osteoporosis, vitamin D deficiency rickets, hypophosphatemic rickets, and osteomalacia in adults.

1. Dr.Hasan Abdul Hadi mohammed..
University of AL-Anbar /college of medicine..
Orthopedic department..

2. Bone is made up of four major components:
1. Mineral (mainly calcium and phosphorus)
2. Matrix (collagen fibers)
3. Osteoclasts (bone-removing cells)
4. Osteoblasts (bone-producing cells).

3. Most of the common metabolic bone disorders are
associated with depletion of bone tissue. They fall into
three groups:
1. Osteoporosis, in which the quantity of bone (bone
mass) is abnormally low.
2. Osteomalacia, in which the osseous connective
tissue (osteoid) is present but insufficiently
mineralized.
3. Osteitis fibrosa, there is bone resorption and
replacement by fibrous tissue.

5. Clinical assessment
Metabolic bone disease usually presents with features of:
1. Skeletal failure: (bone pain, fractures and deformity).
2. Hypercalcaemia: (anorexia, abdominal pain, depression,
renal stone or metastatic calcification).
3. Endocrine disorder: such as the 'moon face' and cushingoid
build of hypercortisolism

6. X-ray examination
The commonest x-ray signs are:
• Non-specific loss of radiographic density (osteopenia).
• Vertebral compression fractures.
• Cortical stress fractures.
• Cortical erosions.
• Children may show features of rickets.

7. Measurement of bone
mass
• X-ray signs of bone loss are late and unreliable.
• The most accurate ways of measuring bone mineral
density (BMD) and bone mass is dual-energy X-ray
absorptiometry(DEXA).
• The principle that a beam of energy is attenuated as it
passes through bone, and the degree of attenuation is
related to the mass and mineral content of the bone.
• BMD is expressed in grams per unit area (g/cm2) and is
recorded in comparison to the location, sex and age-
specific distribution of these values in the general
population.

8. Biochemical tests
• Serum calcium and phosphate concentrations
• Serum alkaline phosphatase concentration is an index of
osteoblastic activity;
• Parathyroid hormone activity
• Vitamin D activity is assessed by measuring the serum 25-HCC
concentration.
• Urinary calcium and phosphate excretion.
• Urinary hydroxyproline excretion is a measure of bone resorption.
• Excretion of pyridinium compounds and telopeptides more
sensitive index of bone resorption.

9. OSTEOPOROSIS
• Osteoporosis literally means “porous bones”
• Osteoporosis is a common bone disease that affects both men and women,
usually as they grow older.
• Osteoporosis is a silent disease of the bones that makes them weaken and
prone to fracture.
• This insidious disease is sometimes called “the silent thief” because there are
no symptoms.
• In osteoporosis the bone is qualitatively normal but there is less (quantitively)
of it than would be expected in a person of that age and sex.

10. Types
1. Localized osteoporosis due to disuse (e.g. paralysis or
nearby inflammation).
2. Generalized osteoporosis may be:
1. Primary; physiological (age related).
2. Secondary; a feature of many systemic disorders.

11. PRIMARY OSTEOPOROSIS
Bone mass decreases slowly but steadily from the age of 40
years. Around the menopause this process is accelerated.
This is due to estrogen withdrawal and less restrained
osteoclastic resorption; the same changes are seen in
younger women after oophorectomy. Similar changes occur
in men, starting about 15 years later than in women.

12. Risk factors
1.Family history.
2.Hysterectomy.
3.Cigarette smoking.
4.Dietary deficiency.
5.Race.

13. From about 70 years onwards, additional factors come into
play. There is a gradual decrease in the rate of bone
formation, a type of involutional change affecting both
men and women; in many cases bone loss is further
increased because of diminished activity, chronic illness
and dietary deficiencies.

14. Clinical features
Postmenopausal osteoporosis
Women between the ages of 55 and 65 may present
with acute back pain due to vertebral compression;
with repeated minor fractures, they develop
progressive kyphosis. If they fall, they are liable to
sustain a fracture of one of the long bones, usually the
distal end of the radius (Colles' fracture).

15. Involutional osteoporosis
Over the age of 70, patients (women and men) are
more likely to be seen with a fracture of the
femoral neck or the proximal end of the humerus.
They may already have a history of previous
fractures, or obvious vertebral osteoporosis.

16. X-ray
X-ray examination may show a typical osteoporotic
fracture of one of the long bones or the spine (wedge
fracture). There is also a general reduction in radiographic
bone density and abnormal thinning of the cortices. Bone
density can be measured more accurately by DEXA
scanning.

17. Treatment
• Initially, treatment is directed at management of the fracture. This will
often require internal fixation; the sooner these patients are
mobilized and rehabilitated, the better.
• Thereafter, the question of general treatment must be considered.
Obvious factors such as concurrent illness, dietary deficiencies, lack of
exposure to sunlight and lack of exercise will need attention. If there
is any doubt about the adequacy of vitamin D and calcium intake,
dietary supplements should be prescribed.
• Treatment with bisphosphonates (Alendronate) or Hormonal
replacement therapy (HRT) should also be considered, even in older
women; although lost bone will not be restored, at least further loss
may be prevented.

18. SECONDARY OSTEOPOROSIS
There are numerous causes of secondary osteoporosis:
1. Nutritional 2. Malignant disease
Scurvy Carcinoma
Malnutrition Multiple myeloma
Malabsorption Leukemia
1. Endocrine disorders 4. Non-malignant disease
Hyperparathyroidism Rheumatoid arthritis
Gonadal insufficiency Ankylosing spondylosis
Cushing's disease Tuberculosis
Thyrotoxicosis Chronic renal disease
5. Drug-induced
Corticosteroids
Alcohol
Heparin

19. RICKETSAND OSTEOMALACIA
Rickets and osteomalacia are different expressions of the
same disease:
incomplete mineralization of bone due to inadequate
absorption and/or utilization of calcium.
Osteomalacia is the more general term, which describes the
most obvious pathological feature - bone 'softening'.
Rickets refers specifically to children, in whom there is also
defective bone growth.

20. Causes
The condition is usually due to:
1. Lack of vitamin D or its active metabolites.
2. Hypophosphataemia or severe calcium deficiency.

21. Pathology
Rickets the characteristic changes arise from the inability
to calcify the intercellular matrix in the deepest layers of
the physis. The cellular part of the physis is thicker than
normal but the newly formed bone in the metaphysis is
weak and may be indented and cup-shaped. Further
away from the physis, the changes are essentially those
of Osteomalacia.

22. Pathology
Osteomalacia is characterized by the appearance of thin
trabeculae surrounded by unusually wide uncalcified
osteoid seam. In mild cases the bones may look normal
but they can be more easily crushed and fractured. In
severe cases the long-bone cortices are thinner than
normal and may show signs of new or old stress fractures.
Vertebral compression fractures are common. In the most
advanced cases there may be severe bone deformities.

23. VITAMIN D DEFICIENCY RICKETS
• Vitamin D deficiency rickets is due to a combination of dietary lack
and under-exposure to sunlight. Infants may present with tetany or
convulsions. There is failure to thrive, listlessness and muscular
flaccidity.
• Early bone changes are deformity of the skull (craniotabes) and
thickening of the knees, ankles and wrists from physeal overgrowth.
Enlargement of the costochondral junctions ('rickety rosary') and
lateral indentation of the chest (Harrison's sulcus) may also appear.
Distal tibial bowing has been attributed to sitting or lying cross-
legged. Once the child stands, lower limb deformities increase. In
severe rickets there may be spinal curvature, coxa vara and bending
or fractures of the long bones.

25. X-rays
In active rickets there is thickening and widening of
the physis, distortion of the metaphysis and,
sometimes, bowing of the long bones.

26. Investigations
• S. calcium and phosphate conc. are diminished.
• Alkaline phosphatase is increased.
• Urinary calcium excretion is diminished.

27. Treatment
• The condition responds rapidly to vitamin D
administration in the form of calciferol 400-1000
IU per day. After normal growth, residual
deformities are usually slight.
• Untreated patients develop long-bone
deformities which may later require corrective
osteotomy.

28. HYPOPHOSPHATAEMIC RICKETS
Chronic hypophosphataemia occurs in a number of disorders in
which there is impaired renal tubular reabsorption of phosphate.
Calcium levels are normal but bone mineralization is defective.

29. Familialhypophosphataemicrickets
(vitaminD-resistantrickets)
It is an X-linked genetic disorder with dominant inheritance,
starting in infancy or soon after and causing severe bony
deformity. The children are below normal height, and
deformities such as genu valgum or genu varum are
common. There is no myopathy.
X-rays show changes similar to those of vitamin D-
deficiency rickets. Serum calcium levels are normal but
phosphate is reduced.

30. Treatment
Treatment is by large doses of vitamin D (50000 IU or
more) and up to 4 g of inorganic phosphate per day
(with careful monitoring to prevent overdosage)
treatment continued until growth ceases.
Bony deformities may require bracing or osteotomy. If
the child needs to be immobilized, vitamin D must be
stopped temporarily to prevent hypercalcaemia from
the combined effects of treatment and disuse bone
resorption.

31. OSTEOMALACIA IN ADULTS
Osteomalacia may result from
1. Defects anywhere along the metabolic pathway for vitamin D.
2. Nutritional lack.
3. Under-exposure to sunlight.
4. Intestinal malabsorption.
5. Defective conversion to the active metabolites in the liver or kidney.

32. Clinical features
Symptoms usually appear insidiously and are rather vague. Bone
pain, backache and muscle weakness may be present for years before
the diagnosis is made. Unexplained pain in the hip or one of the long
bones may presage a stress fracture. Often the condition is suspected
only when the patient is admitted to hospital with a vertebral
compression fracture or a 'stress fracture' of the femur or tibia.
Others again suffer from intestinal malabsorption or disorders of the
liver or kidney which affect conversion of vitamin D to the active
metabolites. All of these diagnostic possibilities should be explored.

33. X-ray
Suspicious features are generalized
rarefaction of bone and signs of previous
fractures of the vertebrae, ribs, pubic rami or
long bones. Almost pathognomic is the
Looser zone, a thin transverse band of
rarefaction due to a poorly healing stress
fracture.

34. Investigations
• Serum calcium and phosphate concentrations may be
diminished.
• Alkaline phosphatase is raised.
• More significant are diminished values for 25-HCC and 1,
25-DHCC.
• Biopsy may be needed for diagnosis; excessive amounts
of unmineralized osteoid can be demonstrated.
• Patients should be investigated for malabsorption
syndromes, liver disorders and renal disease

35. Treatment
Treatment with vitamin D and calcium supplements is
usually effective. Elderly people often need large
doses of vitamin D (up to 2000 IU per day).
Underlying disorders of the gut, liver or kidney will
need treatment as well

36. Thank you