1. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 43 Disorders of the Skeletal System: Metabolic and Rheumatic Disorders

2. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Normal Bone Remodeling Osteoblasts are “bone building” cells They control bone remodeling by: –Laying down new bone –Secreting a compound (RANK ligand) that controls the osteoclasts, the “bone breaking” cells Normally, bone formation and breakdown are balanced to: –Replace damaged bone –Maintain the amount and density of bone

3. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Growth Bone cells and bone marrow cells produce OPG –It blocks the action of RANK ligand –The osteoclasts are not told to function –Bone breakdown decreases –Bones grow

4. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Tell whether the following statement is true or false. When osteoblasts work harder than osteoclasts, bones grow.

5. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer True Rationale: Osteoblasts build bone tissue: when they are more active than osteoclasts, bone grows. When osteoclasts work harder than osteoblasts, more bone is broken down.

6. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Discussion How is bone remodeling affected by the following? Vitamin D? Mechanical stress? Calcitonin? Vitamin C?

7. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Osteopenia –Decreased bone Osteoporosis –Decreased bone mass –Decreased cancellous (spongy) bone strength Osteopenia and Osteoporosis

8. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Discussion Why are each of these people prone to osteoporosis? A postmenopausal woman A 70-year-old man A hyperthyroid alcoholic An Olympic figure skater who takes steroids to reduce joint inflammation A man with a lung tumor that secretes PTH

9. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Discussion (cont.) Who would be most helped by the following? Exercise Increased Ca 2+ and vitamin D in the diet Estrogen receptor stimulators Inhibitors of bone resorption

10. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Osteomalacia Bone is not mineralized properly; it is not rigid It is caused by: –Insufficient calcium absorption –Insufficient phosphate It results in: –Bone pain and tenderness –Fractures –Deformities

11. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Rickets Vitamin D deficiency Inadequate calcium absorption from diet

12. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Paget Disease Regions of excessive bone turnover New bone is disorganized Deformation and fracture common

13. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Which bone disorder is characterized by “soft” bones? a.Osteopenia b.Osteomyelitis c.Rickets d.Paget disease

14. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer c.Rickets Rationale: Calcium needs vitamin D in order to be absorbed. In the case of vitamin D deficiency (rickets), calcium cannot be absorbed, and bones become soft.

15. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Rheumatoid Arthritis Autoimmune disorder Antibodies against IgG fragments Cause inflammation in the joint Abnormal healing responses lay down granulation tissue (pannus)

16. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Treatment of Rheumatoid Arthritis NSAIDs Corticosteroids Leflunomide Infliximab

17. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Systemic Lupus Erythematosus (SLE) Autoantibodies include: –Antinuclear antibodies (ANA) –Antibodies against RBCs –Antibodies against platelets –Antibodies against coagulation factors

18. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins SLE Can Damage Any Tissue Arthralgia Skin lesions (butterfly rash) Glomerulonephritis Pleuritis Pericarditis Atherosclerosis CNS inflammations

19. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Question SLE produces antibodies against all but which of the following? a.RBCs b.WBCs c.Platelets d.Coagulation factors

20. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer b.WBCs Rationale: SLE is an autoimmune disease that results in the production of the following antibodies: antinuclear antibodies and antibodies against RBCs, platelets, and coagulation factors. WBCs are not affected.

21. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Collagen deposits in skin and internal organs Systemic Sclerosis (Scleroderma) Spondyloarthropathies Inflammation at the insertions of tendons and ligaments

22. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Reactive Arthropathies Sterile joint inflammations caused by previous infection The joints are not infected at the time of inflammation Can follow infection with many agents including: –Chlamydia –Pseudomonas –Streptococcus –HIV

23. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Osteoarthritis Syndrome Degenerative joint disease Inflammation of the joints often secondary to physical damage Damaged joint cartilage tries to heal itself –Creating osteophytes or spurs Cartilage contains more water, less collagen –Cartilage becomes weak, rough, eroded –No longer protects the surface of the bone

24. Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Gout Syndrome Increased serum uric acid Crystals precipitate in the joint Inflammation results Tophi are deposits containing monosodium urate crystals