Week 9 - Musculoskeletal System Flashcards
What are common pathologies of bone?
- fractures
- osteoporosis
- arthritis
- osteomyelitis
- tumours
How does a fracture heal?
- Rupture of blood vessels causes a haematoma which fills the fracture gap
- Provides a fibrin meshwork to allow formation of granulation tissue
- Inflammatory cells release cytokines to activate osteoblasts and osteoclasts
- Development of cartilage cap (callous) by 1 week
- Bone deposition begins to strengthen callous
- Repair tissue reaches maximum girth - 2-3 weeks - remodelling
What are the obstacles of fracture healing?
- if bones aren’t aligned
- if area isn’t immobilised
- if fracture side contains dead bone
- infection
What is osteoporosis?
- decrease in bone mass and density
- can lead to fractures
- very common
What causes osteoporosis?
- imbalance between bone reabsorption and bone production
- inadequate peak bone mass
- excess bone resorption
- inadequate bone production
What influences/causes the risk of developing osteoporosis?
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
How can osteoporosis be treated?
Alendronic acid - bisphosphate that prevents osteoclast activity
(Osteoclasts - bone resorption)
What does arthritis mean?
Inflammation of a joint
What is arthritis characterised by?
Pain, swelling, stiffness
May be redness (erythema) and warmth over joint
Restricted movement
What is the most common type of arthritis?
Osteoarthritis
How does osteoarthritis deteriorate and what joints does it effect?
- progressive deterioration
- usually in weight bearing joints
What is the difference between primary and secondary osteoarthritis?
Primary:
- no initiating cause
Secondary:
-at any age with previous joint trauma or congenital abnormality
What are the risk factors of osteoarthritis?
- 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)
What is the pathogenesis of osteoarthritis?
- wear and tear
- breakdown of articular cartilage
- underlying bone exposed
- fragments of cartilage can fall in to joint
- bony thickening and outgrowths (osteophytes) develop
What are the symptoms of osteoarthritis?
- morning stiffness
- pain, worse with movement
- reduced range of movement
- progressive reduction in mobility
- joint effusions (fluid)
- crepitus
Who is affected by rheumatoid arthritis more?
- women affected three times more than men
- familial association
Which antigen has rheumatoid arthritis got a link with?
HLA - human leukocyte antigen
What is the pathogenesis of rheumatoid arthritis?
- 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
What are the features of 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
What deformities can late stage rheumatoid arthritis cause?
Swan neck deformity (finger ends)
Boutonnière deformity (middle knuckles)
Severe foot deformity
How is rheumatoid arthritis diagnosed?
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
What are crystal arthropathies?
Associated with intra-articular crystal formation
- gout
- pseudogout
What is 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
What do repeated attacks of gout cause?
Chronic arthritis
What are the causes of gout?
- drugs (aspirin/diuretics)
- alcohol
- renal disease
- hypothyroidism
- dehydration
What are the features/symptoms of gout?
- sudden onset excruciating burning joint pain
- redness, warmth, tenderness, stiffness
- usually first attack involves big toe
- subsequent attacks are less severe
What is pseudogout?
- 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
What are the causes of pseudogout?
- can be hereditary
- associated with osteoarthritis
- trauma or surgery
- more common with increasing age
What is septic arthritis?
Inflammation of a joint caused by bacterial infection
-commonly affects the knee
What symptoms does septic arthritis cause?
- 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
How is septic arthritis treated?
Needs treatment with IV antibiotics
May require washout of the joint
Can be serious and cause sepsis
What is osteomyelitis?
- bone infection usually caused by bacteria
- trauma, surgery, presence of foreign bodies
- diabetics at increased risk
- haematogenous spread
What is the most common bone tumour?
-metastatic disease from a distant cancer - e.g. prostate, kidney, breast
What primary bone tumours can occur?
Relatively rare
- benign - osteoid osteoma
- malignant - sarcoma
What are the 3 types of muscle in the body?
- striated
- smooth
- cardiac
What is striated muscle and what is it involved in?
- skeletal muscle
- visible striations on microscopy
- involved in voluntary movements e.g. biceps, muscles of arms and legs etc.
What is smooth muscle and what is it involved in?
- 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
What pathological issues occur with skeletal/striated muscle?
- muscular dystrophies
- neuromuscular disorders
What pathological issues occur with smooth muscle?
Leiomyomas
What categories is the skeleton split up in to?
Axial (skull, sternum, ribs, vertebral column)
Appendicular (limbs, pelvis)
