Week 9 - Musculoskeletal System

Question 1

What are common pathologies of bone?

Answer 1

• fractures
• osteoporosis
• arthritis
• osteomyelitis
• tumours

Question 2

How does a fracture heal?

Answer 2

1. Rupture of blood vessels causes a haematoma which fills the fracture gap
2. Provides a fibrin meshwork to allow formation of granulation tissue
3. Inflammatory cells release cytokines to activate osteoblasts and osteoclasts
4. Development of cartilage cap (callous) by 1 week
5. Bone deposition begins to strengthen callous
6. Repair tissue reaches maximum girth - 2-3 weeks - remodelling

Question 3

What are the obstacles of fracture healing?

Answer 3

• if bones aren’t aligned
• if area isn’t immobilised
• if fracture side contains dead bone
• infection

Question 4

What is osteoporosis?

Answer 4

• decrease in bone mass and density
• can lead to fractures
• very common

Question 5

What causes osteoporosis?

Answer 5

• imbalance between bone reabsorption and bone production
• inadequate peak bone mass
• excess bone resorption
• inadequate bone production

Question 6

What influences/causes the risk of developing osteoporosis?

Answer 6

Hormonal influences
-lack of oestrogen (e.g. post-menopausal), increases bone resorption and decreases new bone formation

Calcium metabolism and vitamin D deficiency
-deficiency can also hider bone formation

Question 7

How can osteoporosis be treated?

Answer 7

Alendronic acid - bisphosphate that prevents osteoclast activity

(Osteoclasts - bone resorption)

Question 8

What does arthritis mean?

Answer 8

Inflammation of a joint

Question 9

What is arthritis characterised by?

Answer 9

Pain, swelling, stiffness

May be redness (erythema) and warmth over joint

Restricted movement

Question 10

What is the most common type of arthritis?

Answer 10

Osteoarthritis

Question 11

How does osteoarthritis deteriorate and what joints does it effect?

Answer 11

• progressive deterioration

- usually in weight bearing joints

Question 12

What is the difference between primary and secondary osteoarthritis?

Answer 12

Primary:
- no initiating cause

Secondary:
-at any age with previous joint trauma or congenital abnormality

Question 13

What are the risk factors of osteoarthritis?

Answer 13

• increasing age
• female sex - menopause
• obesity
• pre-existing joint deformity
• excess mechanical stress e.g. professional sports people, miners, farmers
• genetic susceptibility/ family history
• hyper mobility
• other diseases (secondary OA)

Question 14

What is the pathogenesis of osteoarthritis?

Answer 14

• wear and tear
• breakdown of articular cartilage
• underlying bone exposed
• fragments of cartilage can fall in to joint
• bony thickening and outgrowths (osteophytes) develop

Question 15

What are the symptoms of osteoarthritis?

Answer 15

• morning stiffness
• pain, worse with movement
• reduced range of movement
• progressive reduction in mobility
• joint effusions (fluid)
• crepitus

Question 16

Who is affected by rheumatoid arthritis more?

Answer 16

• women affected three times more than men

- familial association

Question 17

Which antigen has rheumatoid arthritis got a link with?

Answer 17

HLA - human leukocyte antigen

Question 18

What is the pathogenesis of rheumatoid arthritis?

Answer 18

• rheumatoid factors help form immune complexes in the circulation
• generates inflammation in the synovium
• membranes thicken
• chronic inflammation leads to cartilage and joint destruction
• other tissues involved e.g. in lungs and vessels

Question 19

What are the features of arthritis?

Answer 19

• usually affects small joints of hands and feet
• pain
• swelling and deformity
• fever, fatigue, generalised pain
• joints often stiff without prior activity
• most have fluctuating disease

Question 20

What deformities can late stage rheumatoid arthritis cause?

Answer 20

Swan neck deformity (finger ends)

Boutonnière deformity (middle knuckles)

Severe foot deformity

Question 21

How is rheumatoid arthritis diagnosed?

Answer 21

Need 4 of:

• morning stiffness for >1 hours
• arthritis in 3 or more joints
• arthritis of typical hand joints
• symmetric arthritis
• rheumatoid nodules
• serum rheumatoid factor
• typical radiographic changes

Question 22

What are crystal arthropathies?

Answer 22

Associated with intra-articular crystal formation

• gout
• pseudogout

Question 23

What is gout?

Answer 23

• raised uric acid
• produced by breakdown of purine bases by the enzyme xanthine oxidase
• usually excreted by kidneys
• urate deposited as crystals in the joints

Question 24

What do repeated attacks of gout cause?

Answer 24

Chronic arthritis

Question 25

What are the causes of gout?

Answer 25

• drugs (aspirin/diuretics)
• alcohol
• renal disease
• hypothyroidism
• dehydration

Question 26

What are the features/symptoms of gout?

Answer 26

• sudden onset excruciating burning joint pain
• redness, warmth, tenderness, stiffness
• usually first attack involves big toe
• subsequent attacks are less severe

Question 27

What is pseudogout?

Answer 27

• precipitation of calcium pyrophosphate crystals in connective tissues
• crystals in cartilage can enlarge and rupture causing “crystal shedding” in to joint cavity or soft tissues
• causes an inflammatory response and synovitis
• usually in knees and ankles

Question 28

What are the causes of pseudogout?

Answer 28

• can be hereditary
• associated with osteoarthritis
• trauma or surgery
• more common with increasing age

Question 29

What is septic arthritis?

Answer 29

Inflammation of a joint caused by bacterial infection

-commonly affects the knee

Question 30

What symptoms does septic arthritis cause?

Answer 30

• severe pain, swelling, redness and heat in infected joints
• tend to develop quickly over a few hours/days

-may also have difficulty moving the affected joint and some people have a high temperature

Question 31

How is septic arthritis treated?

Answer 31

Needs treatment with IV antibiotics

May require washout of the joint

Can be serious and cause sepsis

Question 32

What is osteomyelitis?

Answer 32

• bone infection usually caused by bacteria
• trauma, surgery, presence of foreign bodies
• diabetics at increased risk
• haematogenous spread

Question 33

What is the most common bone tumour?

Answer 33

-metastatic disease from a distant cancer - e.g. prostate, kidney, breast

Question 34

What primary bone tumours can occur?

Answer 34

Relatively rare

• benign - osteoid osteoma
• malignant - sarcoma

Question 35

What are the 3 types of muscle in the body?

Answer 35

• striated
• smooth
• cardiac

Question 36

What is striated muscle and what is it involved in?

Answer 36

• skeletal muscle
• visible striations on microscopy
• involved in voluntary movements e.g. biceps, muscles of arms and legs etc.

Question 37

What is smooth muscle and what is it involved in?

Answer 37

• forms muscle layer in walls of GIT, ducts, arteries and internal organs
• involved in involuntary actions such as bowel peristalsis
• controlled by autonomic nervous system

Question 38

What pathological issues occur with skeletal/striated muscle?

Answer 38

• muscular dystrophies

- neuromuscular disorders

Question 39

What pathological issues occur with smooth muscle?

Answer 39

Leiomyomas

Question 40

What categories is the skeleton split up in to?

Answer 40

Axial (skull, sternum, ribs, vertebral column)

Appendicular (limbs, pelvis)