Musculoskeletal disease 1 Flashcards
What is arthritis?
Literally means inflammation of the joint
What are the 2 commonest types of chronic arthritis?
1) Osteoarthritis
2) Rheumatoid arthritis
What is OA also known as?
Degenerative joint disease
What is the initiating cause?
There is no apparent initiating cause - but age related
Secondary OA can occur in sports players, give 2 examples?
Knee in basketball players
Elbow in baseball players
What conditions is OA often associated with?
Underlying systemic diseases:
1) Diabetes
2) Obesity
What are the 2 most common sights of OA in women?
Knees and hands
What is the most common sight of OA in men?
Hip
What is the pathogenesis of OA? 4
1) Deterioration or loss of cartilage that acts as a protective cushion in between bones
2) As the cartilage is worn away the bone forms spurs
3) Fluid filled cysts form in the marrow - subchondral cysts
4) Results in pain and limitation of movement
What cell is the cellular basis of OA?
Chondrocytes
What is the role of chondrocytes in OA?
Chondrocytes produce interleukin 1 which initiates matrix breakdown
What is the role of prostaglandins in the pathogenesis of OA?
Prostaglandin derivative induce the release of lytic enzymes which prevents matrix synthesis
What is primary OA due to?
Abnormal stress in weight bearing joints
Which 4 sights does primary OA often affect?
Fingers
Knees
Cervical and Lumbar spine
What are Heberden’s or Bouchard’s nodes?
Form on hands in OA with involvement of fingers
Does RA only affect the joints?
No - it is a chronic systemic disorder which whilst principally affects the joints can affect skin, muscles, heart, lungs and blood vessels
Which sex is RA more common in?
Women
What is the basic pathogenesis of RA?
Chronic systemic disorder which produces a non suppurative proliferative synovitis - destruction of articular cartilage and ankylosis (abnormal stiffening due to fusion of bones) of joints
What are the 3 steps in the Robbins-Pathological basis of RA?
1) Thickening of synovium with synoviocyte hyperplasia, producing a pannus that erodes the articular cartilage
2) Continued growth of the pannus and penetration of the subchondral bone and cyst formation
3) Filling of joint space with pannus producing ankylosis of the joint space
What kind of disease course does RA take?
Can be slow or rapid, often fluctuating over 4-5 years
Which joints are frequently affected in RA?
Small joints of the hands and feet
What are the 4 clinical features of RA?
1) Malaise
2) fatigue
3) Generalised musculoskeletal pain
4) Involved joints inflamed and often stiff in morning or after activity
What are the 5 steps in the pathogenesis of RA?
1) Genetic susceptibility - HLA, DR4, DR1
2) Primary exogenous arthritogen - ie virus, EBV, Borrelia
3) Autoimmune reaction within the synovial membrane - CD4 positive T cells
4) Mediators of joint damage - cytokines
5) IL1-6 and TNF alpha and beta
You need 4 of what 6 criteria for a diagnosis of RA?
1) Morning stiffness
2) Arthritis in 3 or more joint areas
3) Arthritis of hand joints
4) Symmetric arthritis
5) Rheumatoid nodules
6) Serum rheumatoid factor
Is Rheumatoid factor present in all cases of RA?
Not all but most
What would confirm a diagnosis of RA in analysis of synovial fluid?
Presence of neutrophils, inflammatory picture
What is the commonest cutaneous manifestation of RA?
Rheumatoid nodules in the skin in areas of pressure
What is sero-negative arthritis?
Arthritis lacking rheumatoid factor
Give 4 examples of sero negative arthritides?
1) Ankylosing spondylitis
2) Reiter’s syndrome
3) Psoriatic arthritis
4) Enteropathic arthritis
Uric acid is the end product of what metabolic pathway?
Purine metabolism
Gout occurs as a result of deficiencies of enzymes in what pathway?
Purine metabolism
What are the 4 clinical features of gout?
1) transient attacks of acute arthritis due to crystallization of urates in joints
2) Leads to chronic gouty arthritis and
3) Tophi (uric acid crystals) at various sites
4) Gouty nephropathy (high levels of uric acid in urine lead to poor kidney function)
What is meant by renal osteodystrophy?
Skeletal changes in chronic renal disease
What are the 5 skeletal changes in chronic renal disease?
1) Increased osteoclastic bone resorption
2) Delayed matrix mineralisation
3) Osteosclerosis
4) Growth retardation
5) Osteoporosis
Lymphangiomas are benign tumours of what structure?
Lymphatic system
What are sarcomas?
Malignant tumours of mesenchymal tissue
How do sarcomas commonly spread?
By blood - lymph node involvement is uncommon
Give 4 syndromes associated with soft tissue tumours and the type of tumour they are associated with?
1) Neurofibromatosis 1 - neurofibroma
2) Gardner syndrome - fibromatosis
3) Carney syndrome - myxoma, melanotic schwannoma
4) Turner syndrome - cystic hygroma
What are the 4 techniques used in diagnosis of soft tissue tumours?
1) US guided core biopsy
2) wide excision
3) Cytogenetics - culture of fresh tissue and karyotypic analysis
4) Molecular genetics - FISH and PCR and RT PCR
What are the 2 types of benign bone tumours?
Osteomas and osteoblastomas
What is the name for a benign cartilage tumour?
Chondroma
What is the name for a mixed bone and cartilage tumour?
Osteochrondroma
What is the name for a malignant bone tumour?
Osteosarcoma
Which age group do osteosarcomas commonly occur in?
Young age
What is the most common site of osteosarcoma?
Around the knee
Give 3 other less common bone tumours?
1) Chondrosarcoma
2) Ewing’s sarcoma
3) Giant cell tumours
Give 5 common metastatic bone tumours?
1) Thyroid
2) Prostate
3) Kidneys
4) Breast
5) GI tract
Systemic lupus erythematosus predominantly affects what sex?
Females
What 4 body systems are mainly affected in SLE?
1) Cutaneous
2) Cardiac
3) CNS
4) renal
What are the cutaneous features of SLE?
Butterfly rash typically affecting the bridge of the nose and cheeks
What are the 2 cardiac features of SLE?
1) Cardiomegaly
2) Endocarditis
What is the most important cause of mortality in SLE?
CNS effects
What are the 2 CNS symptoms of SLE?
Convulsions and hemiplegia
What percentage of patients experience renal features in SLE, what are they? 2
45% of patients
1) Nephrotic syndrome
2) Glomerulonephritis
What are the 6 clinical features of systemic sclerosis?
1) Vessel damage
2) Widespread cutaneous lesions
3) Renal effects
4) Cardiorespiratory involvement
5) GI tract
6) Osteoarticular involvement - arthralgia and arthritis
Is the pathogenesis of systemic sclerosis understood?
No, it is poorly understood
What is the prognosis of systemic sclerosis?
Poor
What is the localised variant of systemic sclerosis?
Get limited cutaneous involvement + oesophageal involvement and SI malabsorption
What is CREST syndrome?
1) Calcinosis (formation of calcium deposits in any soft tissue)
2) Raynaud’s phenomenon
3) Oesophageal dysfunction
4) Sclerodactlyly (thickening and tightness of the skin over fingers and toes)
5) Telangiectasia (dilation of capillaries causing them to appear as red clusters on the skin or surface of an organ)
What is polymyalgia rheumatica?
Stiffness, weakness, aching and pain in the muscles of the neck, limb girdles and upper limbs
What condition is polymyalgia rheumatica associated with?
Giant cell arteritis
Is the pathogenesis of polymyalgia rheumatica understood?
A immunological mechanism has been suggested
What is meant by the term myopathy?
Muscle disease unrelated to any disorder of innervation or neuromuscular junction
What is meant by the term myositis?
Muscle fibres and overlying skin are inflamed and damaged resulting in muscle weakness
Are muscular dystrophies inherited?
yes
What is muscular dystrophy?
Progressively severe muscle weakness and wasting which begins in childhood
What is malignant hyperthermia?
An inherited disease in which there is a fast rise in body temp and severe muscle contraction when the affected person is given general anaesthesia
How would the colour of the urine change in malignant hyperthermia?
Dark brown
When is malignant hyperthermia likely to be discovered?
When patient given anaesthetic
What is rhabdomyolysis?
Destruction of skeletal muscle, get release of muscle fibre content into the blood
How does the urine appear in rhabdomyolysis and why?
Brown - as muscle is broken down myoglobin is released into the blood stream, this is filtered through the kidneys and enters the urine resulting in myoglobinuria
What is one of the most important complications of rhabdomyolysis?
Acute renal failure
What are the 6 possible causes of rhabdomyolysis?
1) Trauma - crush injuries
2) Drugs - cocaine amphetamine
3) Extreme temperature
4) Severe exertion - marathon running
5) Lengthy surgery
6) Severe dehydration
Metabolic myopathies can involve what 2 pathways?
1) Disorders of glycogen synthesis and degradation
2) Disorders of mitochondrial metabolism
