19. Musculoskeletal system and pathology Flashcards Preview

Pathology Year 2 > 19. Musculoskeletal system and pathology > Flashcards

Flashcards in 19. Musculoskeletal system and pathology Deck (35)
Loading flashcards...
1

What is the musculoskeletal system?

Provides support and gives us ability to move

Bones
Muscle
Joints, cartilage and tendons

2

Skeleton

Axial
Skull, sternum, ribs, vertebral column

Appendicular

3

Common Pathologies of Bone

Fractures
Osteoporosis
Arthritis
Osteomyelitis
Tumours

4

Fractures

Result of trauma

Can occur in healthy bone or in bone which is otherwise diseased eg. deposit of cancer in bone weakening the bone

5

Fracture treatment

Aim to realign bone to allow good function after healing.
This can be achieved with a plaster cast +/- surgery depending on the fracture

6

Fracture Healing (1)

Immediately after fracture rupture of blood vessels causes haematoma which fills the fracture gap
This also provides a fibrin meshwork to allow formation of granulation tissue

7

Fracture Healing (2)

Inflammatory cells release cytokines to activate osteoblasts and osteoclasts
Development of cartilage cap (callous) ~1week
Bone deposition begins to strengthen callous
Repair tissue reaches maximum girth ~2-3 weeks

8

Fracture Healing- obstacles

If bones not aligned
If area not immobilised
If fracture site contains dead bone
Infection

9

Osteoporosis (1)

Decrease in bone mass and density
Can lead to fractures
Very common – 3 million people in UK

10

Osteoporosis (2)

Imbalance between bone resorption and bone production
Inadequate peak bone mass
Excess bone resorption
Inadequate bone production

11

Osteoporosis (3)

Hormonal influences- lack of oestrogen (eg. post-menopausal) increases bone resorption and decreases new bone formation
Calcium metabolism and Vitamin D deficiency can also hinder bone formation

12

Treatment

NICE guidelines

Alendronic acid – bisphosphonate that prevents osteoclast activity

13

What is arthritis?

‘Arthritis’ means inflammation of a joint

Characterised by pain, swelling, stiffness
May be redness (erythema) and warmth over the joint
Restricted movement

‘Arthropathy’ means joint disease or disorder

14

Classification of Arthritis

OSTEOARTHRITIS
RHEUMATOID ARTHRITIS
Gouty Arthritis
Seronegative Spondyloarthropathies
- Ankylosing spondylitis
- Reactive arthritis
- Psoriatic arthritis
Infectious arthritis
Juvenile Idiopathic Arthritis
Arthritis secondary to systemic disease

15

Osteoarthritis

Most common
Associated with increasing age and obesity
Progressive deterioration
Usually in weight-bearing joints
Most cases primary – no initiating cause
Secondary – at any age with previous joint trauma or congenital abnormality

16

Risk Factors

Increasing age
Female sex, menopause
Obesity
Pre-existing joint deformity
Excess mechanical stress, e.g. professional sportspeople, miners, farmers
Genetic susceptibility or family history
Hypermobility
Other diseases (Secondary OA)

17

Pathogenesis

wear and tear’
Breakdown of articular cartilage
Underlying bone exposed
Fragments of cartilage can fall into the joint
Bony thickening and outgrowths (osteophytes) develop

18

Features of Osteoarthritis

Morning stiffness
Pain, worse with movement
Reduced range of movement
Progressive reduction in mobility
Joint effusions (fluid)
Crepitus

19

Rheumatoid Arthritis

Affects about 1% of the population
Women affected 3 times more than men
Familial association
Link with HLA (human leukocyte antigen)

20

Pathogenesis

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 eg. in lungs and vessels

21

Features of Rheumatoid Arthritis

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

22

Diagnosis

Need 4 of:

Morning stiffness > 1 hour
Arthritis in 3 or more joints
Arthritis of typical hand joints
Symmetric arthritis
Rheumatoid nodules
Serum rheumatoid factor
Typical radiographic changes

23

Crystal Arthropathies

Associated with intra-articular crystal
formation

Gout
Pseudogout

24

Gout

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
Repeated attacks lead to chronic arthritis
Causes: drugs (aspirin, diuretics), alcohol, renal disease, hypothyroidism, dehydration

25

Features


Sudden onset excruciating burning joint pain

Redness, warmth, tenderness, stiffness

Usually first attack involved big toe

Subsequent attacks are less severe

26

Pseudogout (Calcium pyrophosphate crystal deposition disease)

Precipitation of calcium pyrophosphate crystals in connective tissues
Crystals in cartilage can enlarge and rupture causing “crystal shedding” into joint cavity or soft tissues
inflammatory response and synovitis
Usually in knees and ankles

27

Causes of Pseudogout

Can be hereditary
Associated with osteoarthritis
Trauma or surgery
More common with increasing age

28

Septic arthritis (1)

Inflammation of a joint caused by bacterial infection
Commonly affects the knee
Causes severe pain, swelling, redness and heat in affected joints. These symptoms tend to develop quickly over a few hours or days.
May also have difficulty moving the affected joint and some people have a high temperature.

29

Septic arthritis (2)

Needs treatment with IV antibiotics
May require washout of the joint
Can be very serious and cause sepsis

30

Osteomyelitis

Bone infection usually caused by bacteria
Trauma, surgery, presence of foreign bodies
Diabetics at increased risk

Haematogenous spread