Lecture 21 - Musculoskeletal Pathology

Question 1

Osteoporosis

Answer 1

• disease in bone development
• increase in pore size in bone = decreases bone density
• due to disruption of bone formation and reabsorbtion
• causes bone fragility (doesn’t change bone shape)

Question 2

Pagets Disease

Answer 2

• results in increased mass of disordered bone

- 3 stages: Osteolytic stage, osteoclastic-osteblastic stage, osteoclerotic stage (scarring)

Question 3

Rickets/Osteomalacia

Answer 3

• nutritional disease
• results from decreased Vitamin D or abnormal absorption
• bone has decreased mineralization = bone softening due to lack of calcium
• Rickets = childhood disease
• Osteomalacia = adult disease

Question 4

Osteonecrosis/Avascular necrosis

Answer 4

• ischemic injury of bone results in infarct of the bone tissue. (decreased blood supply to bone)
• can be subchondral (painful, leads to osteoarthritis) or medullary (silent)

Question 5

Osteomyelitis

Answer 5

• inflamation of bone and bone marrow
  1. Pyogenic = typically due to bacteria
  2. Tuberculosis = Tuberculosis osteomyelitis due to hematogenous spread

Question 6

Osteoma

Answer 6

• benign tumor of bone

- most common location in head and neck (nasal sinuses)

Question 7

Osteosarcoma

Answer 7

• malignant tumor of bone
• 75% of patients are <20 yo (when bones are growing)
• most common location = around knees

Question 8

Osteochondroma

Answer 8

• AKA exostosis
• cartilage forming tumor of bone
• attached to bone by stalks

Question 9

Osteoarthritis

Answer 9

• degenerative joint disease
• inflammation of bone and joints
• primary feature = degeneration of articular cartilage
• Pathologic changes:
  1. Fibrillation - granulatity of cartilage due to chemical mediators eating away at cartilage making pits
  2. Eburnation -smooth bone devoid of cartilage. All cartilage is worn away = polished= bone on bone

Question 10

Tophus

Answer 10

• uric acid crystals due to gout (excessive uric acid accumulation)
• synovial fluid + uric acid = crytalline material that bring inflammation and white blood cells.
• crystals + inflammation = tophus (white material)

Question 11

Myasthenia gravis

Answer 11

• muscle pathology
• autoimmune disorder of neuromuscular junction against acetylcholine receptors on muscle (chemicals that signal muscle to move) = muscle weakness

Question 12

Osteogenesis Imperfecta

Answer 12

• congential disease of bone
• AKA - brittle bone disease
• cartilage is abnormally laid down leading to development of too little bone
• results in intrauterine fractures