1. Bone disorders

2. Types of Bone Lamellar Woven Forms the adult skeleton
\\ Arrangement of collagen fibers
Few osteocytes
Uniform osteocytes in lacunae // to long axis of collagen fibers
Woven
Irregular
Many osteocytes of various size and shape
In adults signifies always a pathologic condition

3. Cells Osteoblasts: bone forming cells
Produce the protein
Osteoid
Osteocyte: bone maintaining cells
Osteoblast within bone in a lacuna
Osteoclast: bone eating cells
Multinucleated
Resorbs bone
Howship’s lacunae

5. Types of bone disorders
Metabolic Conditions: Osteoporosis, Osteomalacia and rickets
Hereditary and Congenital Disorders
Inflammatory
Neoplasms

6. Metabolic Conditions

7. 1- Osteoporosis : The Silent Thief
- Osteoporosis is a metabolic bone disease characterized by low bone mass and micro-architectural defect of the bone tissue, with a consequent increase in bone fragility and susceptibility to fracture - Are of two types: primary and secondary
Amount of bone resorbed >>> Amount of bone formed by osteoclasts by osteoblasts
BONE LOSS

8. Primary Osteoporosis Most common Uncertain etiology
Postmenopausal women
Elderly persons (senile)
Genetic: peak bone mass
Estrogens: decreased
Aging
Calcium intake
Environmental factors: smoking leads to estrogen

9. Secondary Osteoporosis
Corticosteroids
Inhibition of osteoblastic activity
Impair of vit. D dependant intestinal calcium absorption
Hematologic malignancies
Malabsorption: GI and liver diseases
Alcoholism
Inhibition of osteoblasts,
↓ absorption of calcium

10. Steroid-induced Osteoporosis
Cause
Calcium Urinary Calcium Osteoblast absorption excretion formation and function
Majority of bone loss occurs in the beginning (10-20%)
25% may experience a fracture
4 fold increase in all fractures
Usually affects vertebrae, ribs, hip
Risk higher in patients with higher dose, taking longer duration

11. 2- Osteomalacia and rickets
Inadequate mineralization of newly formed bone matrix (osteomalacia)
Rickets: children, epiphyseal plates open; also problem with cartilage
Beaded appearance of costo-chondral junctions
Dental abnormalities
Vitamin D deficiency
Phosphate deficiency
Defects in mineralization process

12. 3- Hyperparathyroidism
Parathyroid adenoma, hyperplasia, rare malignancy
Promotes excretion of phosphate in the urine and stimulates osteoclastic activity resulting in hypercalcemia

13. Hereditary and Congenital Diseases

14. 1- Osteogenesis imperfecta
Many types
Mutations of collagen type I gene
Multiple fractures (starting in utero)
Dental findings: Dentinogenesis imperfecta

16. 2- Achondroplasia 80% new mutations
Most common form of inherited dwarfism
Absence or decreased area of proliferative cartilage
Epiphyseal disorder (plate closes prematurely preventing bone growth)
Head and torso are normal
Vertebral column and hip abnormality

18. Inflammatory and Non-Inflammatory (Non-neoplastic) Disorders

19. 1- Osteonecrosis Avascular, aseptic
Ischemic death of bone and marrow in absence of infection
Emboli: bone infarction
Trauma Corticosteroids
Radiation Alcoholism
Systemic diseases: sickle cell anemia, gout, metabolic diseases
Osteochondritis dissecans: dead piece of cartilage
Site specific: head of femur

20. 2- Myositis Ossificans
Formation of reactive bone in muscle as a result of injury
More common in lower limbs
Diagnosis: radiographically and histologically

21. 3- Osteomyelitis Inflammation of bone caused by an infectious organism
Staphylococcus, streptococcus, neisseria gonorrhea,…..
Direct penetration
Wounds, fractures, surgery
Hematogenous
Bloodstream, teeth; metaphyses
Knee, ankle, hip

22. Complications of Osteomyelitis
Septicemia
Acute bacterial arthritis
Pathologic fractures
Squamous cell carcinoma
Chronic osteomyelitis

23. 4- Osteoarthritis Most common joint disease
Slow progressive degeneration of articular cartilage
Weight bearing joints
Fingers
Primary: defect in cartilage, not an inflammatory disease
Secondary: trauma, crystal deposits, infection
Interphalangeal joints, knees, hips, cervical and lumbar spine 23

24. Clinical picture Narrowing of joint space (loss of disk)
Increased thickness of subchondral bone
Subchondral bone cysts 24

25. 5- Rheumatoid arthritis
Systemic chronic inflammatory disease
Autoimmune disease
STARTS AS SYNOVIAL DISEASE
More common in women 3:1
Remissions and exacerbations 25

26. 6- Gout
Increase in serum uric acid and deposition of urate crystals in the joints and kidneys
Only 15% of patients with ↑ uric acid suffer from gout
Gout can result from:
Overproduction of purines
Augmented catabolism of nucleic acids
Decreased uric acid secretion
Primary gout
Secondary gout 26

27. Primary gout Hyperuricemia in the absence of other disease
Asymptomatic hyperuricemia can precede gout
Impaired secretion by kidneys 27

28. Secondary gout Tumors Alcoholism Leukemias Lymphomas
After chemotherapy
Alcoholism
Accelerated ATP catabolism 28

29. Clinical features Acute gouty arthritis Painful
Involves one joint initially, then polyarticular
Podagra (painful, red metatarsophalangeal joint)
Tophaceous gout
Development of tophi
Chalky, cheesy, yellow-white, pasty deposits of monosodium urate crystals 29

30. Bone Tumors

31. Bone Forming
Benign: Osteoma Osteoid Osteoma Osteoblastoma
Malignant: Primary and secondary osteosarcoma
Cartilagenous
Benign: Chodroma Osteochodroma
Malignant: Chodrosarcoma
Other
Giant cell tumor of bone Ewing sarcoma

32. Metastatic Tumors of the Jaws
Most common form of cancer involving bone
Breast and prostate carcinomas are most common
Variety of symptoms: pain, swelling, loose teeth, …….
Site from which tooth was removed for local pain or mobility
Prognosis is poor; most patients die within a year