Topic 4 Musculoskeletal Conditions

Question 1

3 bone cells

Answer 1

Osteoblasts
Osteoclasts
Osteocytes

Question 2

Role of Osteoblasts

Answer 2

Make bone in response to growth factors and mechanical stress on the bone

Question 3

Role of Osteoclasts

Answer 3

Make and secrete digestive enzymes that break up or dissolve the bone tissue. Related to monocytes/macrophages

Question 4

Role of Osteocytes

Answer 4

Derive from osteoblasts, or bone-forming cells, and are essentially osteoblasts surrounded by the products they secreted. Live in the Lacuna.

Question 5

Bone remodelling process

Answer 5

Activation by a stimulus
Resorption by osteoclasts
Formation by osteoblasts in successive layers
Whole process takes 3-4 months

Question 6

Bone repair process

Answer 6

Stage 1: Inflammation / haematoma formation
Stage 2: Procallus formation
Stage 3: Callus formation
Stage 4: Callus replacement

Question 7

Types of fractures

Answer 7

Transverse - Horizontal break

Linear - Vertical break

Oblique - Fracture at oblique angle

Greenstick - Break in only one cortex of the bone

Impacted - One end wedged into opposite end of inside fractured fragment

Compound - Skin broken

Spiral - Curves around cortices and may become displaced by twist

Comminuted - With two or more pieces or segments

Pathological - Transverse, oblique or spiral fracture of bone weakened by tumour pressure

Question 8

What is rhabdomyolysis

Answer 8

Breakdown of muscle tissue that releases a damaging protein into the blood

Excess myoglobin in urine. Muscle damage disrupts sarcolemma, releasing myoglobin acting as a nephrotoxin which can cause acute renal failure.

Question 9

What is compartment syndrome

Answer 9

Pressure build-up from internal bleeding or swelling of tissues. The pressure decreases blood flow, depriving muscles and nerves of required nourishment

Restriction of outward swelling caused by a collection of blood in injured tissue resulting in increased pressure.

Question 10

What is osteomyelitis

Answer 10

Inflammation of bone caused by infection, generally in the legs, arm or spine.

Exogenous: caused by open fractures, surgery or contiguous spread from infected local tissue.

Endogenous: caused by pathogens carried in the blood from sites of infection elsewhere in the body

Question 11

What is osteomalacia

Answer 11

Softening of the bones

Question 12

Aetiology of osteomalacia

Answer 12

Caused by impaired bone metabolism due to inadequate levels of phosphate, calcium, and vitamin D or because of resorption of calcium. Does not involve loss of bone matrix.

Vitamin D deficiency causes the decrease in [plasma calcium] -> increased synthesis and secretion of parathyroid hormone -> increased concentration and renal clearance of plasma phosphate -> decrease bone [phosphate] -> mineralisation cannot precede normally -> trabeculae in spongy bone become thinner and fewer -> Haversian systems in compact bone develop large channels and are irregular -> abnormal quantities of osteoid build up leading to deformities of long bone, pelvis, spine and skull.

Question 13

CM of osteomalacia

Answer 13

Diffuse skeletal pain
Tenderness
Pain in hips
Low back pain
Hesitancy to walk
Muscle weakness
Waddling gait
Uraemia
Psuedofractures

Question 14

Dx of osteomalacia

Answer 14

Blood test for serum Ca, serum phosphate (over 1.8mmol/L) and Vit D
Bone biopsy
Urinalysis (low phosphate)

Question 15

Tx of osteomalacia

Answer 15

Adjust serum Ca and Phosphate levels to normal
Suppress secondary hyperthyroidism
Renal dialysis
Renal transplant
Medications: calcium carbonate, vitamin D

Question 16

What is osteoporosis

Answer 16

Decreased bone density and demineralisation of bones.

Question 17

Aetiology of osteoporosis

Answer 17

Imbalance between new bone formation and old bone resorption. Body fails to form enough new bone or too much old bone may be reabsorbed.

Bone matrix creates decoy receptor for cytokine -> cytokine binds to decoy -> no effect on osteoclast -> imbalance occurs in amount of cytokine, number of receptors on osteoclast precursors and number of decoy receptors -> imbalance leads to osteoporosis

Question 18

CM of osteoporosis

Answer 18

Pain
Bone deformity
Fractures
Kyphosis

Question 19

Dx of osteoporosis

Answer 19

X-ray
Bone mineral density test
Radiological examiniation
DEXA
Ultrasound
CT
Serum and urinary biomarkers

Question 20

Tx of osteoporosis

Answer 20

Increase dietary Ca, Vit D, and magnesium
Oestrogen/progestin supplements
Raloxifene
Alendronate

Question 21

What is arthritis

Answer 21

Inflammatory joint disease

Question 22

Types of arthritis

Answer 22

Osteoarthritis: characterised by inflammatory damage or destruction in the weight bearing joints

Rheumatoid Arthritis: systemic, inflammatory auto-immune disease associated with swelling and pain in multiple joints.

Question 23

CM of osteoarthritis arthritis

Answer 23

Asymptomatic
Aching pain
Referred pain
Stiffness
Swelling
Decreased ROM

Question 24

Dx of osteoarthritis arthritis

Answer 24

H&P
Clinical assessment
Radiological studies
CT scan
MRI
Arthroscopy

Question 25

Tx of osteoarthritis arthritis

Answer 25

Resting inflamed joint
Analgesia and anti-inflammatory drug therapy
Weight loss if patient obese

Question 26

CM of rheumatoid arthritis

Answer 26

Inflammation
Fever
Fatigue
Weakness
Anorexia
Weight loss
Aching
Stiffness
Painful/tender/stiff joints
Joint deformities

Question 27

Dx of rheumatoid arthritis

Answer 27

H&P
Physical examination
X-ray of joint
Serological tests for rheumatoid factor

Question 28

Tx of rheumatoid arthritis

Answer 28

Resting inflamed joint
Hot and cold packs
Physical therapy
Patient education
Anti-rheumatic drugs
Corticosteroids
Anti-inflammatory drugs
Surgery used to correct deformity
NSAIDs
DMARDs: disease-modifying anti-rheumatic drugs

Question 29

Aetiology of osteoarthritis arthritis

Answer 29

Structural damage to cartilage caused by genetic influences and other risk factors -> alteration in chondrocyte function -> stimulating enzyme release with degradation of collagen and proteoglycans -> cytokine release stimulates synovial inflammation and bone remodelling -> promoting muscle weakness

Question 30

Aetiology of rheumatoid arthritis

Answer 30

Inflammatory autoimmune disease, cartilage damage caused by neutrophil and other cell activation in synovial fluid, cytokines stimulating release of pro inflammatory compounds causing chondrocytes to attack cartilage, synovium digests nearby cartilage.

Question 31

What is gout

Answer 31

Syndrome caused by defects in uric acid metabolism characterised by inflammation and pain in the joints

Question 32

Aetiology of gout

Answer 32

Excessive excretion of uric acid by the kidneys causes hyperuricemia. When high levels of uric acid in the blood and other body fluids accumulates, uric crystals form on connective tissue of joints throughout the body

Slow urate excretion by kidney -> decrease glomerular filtration of urate, increased urate reabsorption -> monosodium urate crystals deposited in renal interstitial tissues -> impaired urine flow -> monosodium urate crystals form in the synovial fluid or membrane -> stimulate inflammatory response -> neutrophils attracted out of circulation -> phagocytosis of crystals -> neutrophils die releasing both the crystals and lysosomal enzymes causing tissue damage and stimulating further inflammation

Question 33

CM of gout

Answer 33

Severe pain
Redness and swelling in joints
Pain in the joints, ankle, foot, knee, or toe
Joint lumps, stiffness, or swelling
Physical deformity
Increase [serum urate]
Renal disease

Question 34

Dx of gout

Answer 34

H&P

Blood test

Question 35

Tx of gout

Answer 35

NSAIDs
Glucocorticoids
Colchicine
Uricosuric drugs
Behavioural modification - diet, exercise, decrease alcohol 
Ice