Musculoskeletal Flashcards
(141 cards)
Osteoarthritis definition
Non-inflammatory degenerative arthritis. The result of mechanical and biological events that destabilise the normal process of degradation and synthesis of articular cartilage chondrocytes, extracellular matrix and subchondral bone. It involved the entire joint, including the articular cartilage, subchondral bone, pericapsular muscles, capsule and synovial, The condition leads to loss of cartilage, sclerosis and eburnation (degeneration of bone) of the sunchondral bone, osteophytes, subchondral cysts. It is clinically characterised by joint pain, stiffness and functional limitation.
Osteoarthritis epidemiology
Ver common condition
Osteoarthritis aetiology
No single cause. High bone mineral density and low oestrogen, such as in post-menopausal women.
Primary (idiopathic): no preceding injury to the joint, further categorised into localised OA, mostly affecting the hands, hip or foot or generalised OA, usually affecting the hands and another joint.
Secondary: a previous insult to the joint such as a congenital abnormality, trauma, inflammatory arthropathies and ongoing strenuous physical activities.
Osteoarthritis risk factors
Age, female sex, obesity, genetic factors
Osteoarthritis signs and symptoms
Pain: usually associated, pain at rest is unusual except in advanced OA
Functional difficulties: for example a knee giving way to locking. Can reflect internal derangement such as partial meniscus tear or a loose body within the joint
Knee, hip, hand or spine involvement: commonly involved joints are the knee, hip, hands and lumbar and cervical spine.
Hand OA spares the metacarpophalangeal (CP) joints and the proximal interphalangeal (PIP) and distal interphalangeal joints, which helps distinguish it from rheumatoid arthritis.
Bones deformities: particularly in the hands and leads to enlargement of proximal interphalangeal (PIP) joints (Bouchard’s nodes) and distal interphalangeal (DIP) joints (Heberden’s nodes)
Limited range of motion
Malalignment
Osteoarthritis 1st line investigations
X-ray of affected joints: LOSS
- loss of joint space
- osteophytes
- subarticular sclerosis
- subchondral cysts
Serum CRP and ESR: normal, should be ordered if inflammatory arthritis suspected
Rheumatoid factor (RF): if RA suspected
Osteoarthritis management
‘Analgesic ladder’
Knee replacement
Rheumatoid arthritis definition
Rheumatoid arthritis is a chronic inflammatory condition affecting around 1% of the population. It primarily affects the small joints of the hands and feet and can cause major work loss, decreased quality of life, need for joint replacement surgery and mortality
Rheumatoid arthritis aetiology
Unknown. DRw4 antigen is more common in RA patients. Infection may be a triggering factor in genetically susceptible individuals.
Rheumatoid arthritis risk factors
50-55yrs, female sex
Rheumatoid arthritis pathophysiology
Inflamed synovial showing increased angiogenesis, cellular hyperplasia, influx of inflammatory cells, changes in adhesion molecules and cytokines. Cytokines such as TNF, IL-1 and IL-6 are abundant in the joints.
Rheumatoid arthritis signs and symptoms
Active symmetrical arthritis lasting > 6 weeks
Joint pain and swelling: commonly bilateral MCP, PIP and MTP joints are involved. Painful to touch and when range of motion exercises are performed.
Morning stiffness (may be present with OA but lasts longer in RA)
Less common but specific:
- ulcer deviation
- boutonniere deformity
- swan neck/Z-thumb
- extra-articular involvement - eg lung (pulmonary nodules), eyes (scleritis) and cord compression
Important to note onset can be at any time and progress quickly compared to OA. There will often by systemic symptoms unlike in OA
Rheumatoid arthritis 1st line investigations
Bloods: CRP and/or ESR raised
Rheumatoid factor: positive in about 60-70% of patients
Anti-CCP antibody: positive in about 70% of patients. Helpful in RF-negative patients because it may be positive in these patients
X-ray: LESS
- L-loss of joint space
- E-erosion (periarticular)
- S-soft tissue swelling
- S- soft bones (osteopenia)
Rheumatoid arthritis management
Joint stiffness/pain - NSAIDs and aspirin
Analgesic ladder
Suppress disease - corticosteroid
DMARDS - methotrexate
Rheumatoid arthritis complications
Extra-articular involvement - lung (pulmonary nodules), eye (scleritis) and cord compression
Crystal arthropathy - gout definition
A syndrome characterised by hyperuricemia and deposition of rate crystals causing attacks of acute inflammatory arthritis; top around the joints and possible joint destruction, renal glomerular, tubular and interstitial disease and uric acid urolithiasis
Crystal arthropathy - gout aetiology
Under excretion of uric acid
- diabetes - nephropathy
- chronic kidney disease
- drugs - aspirin (decreases renal excretion) and diuretic eg thiazides
- dehydration
Overproduction of uric acid
- high purine diet - alcohol, purine rich food (red meat and shellfish), fructose sweetened drinks
- increased cell turnover - leukaemia, lymphoma, psoriasis
Crystal arthropathy - gout risk factors
More common in middle aged males
Crystal arthropathy - gout pathophysiology
Purines from diet
Purines -> hypoxanthine -> xanthine
Xanthine -> uric acid (catalysed xanthine oxidase) and excreted in kidneys
Process not efficient so excess uric acid can be converted to monosodium crystals
Crystal arthropathy - gout key presentations
Rapid onset of severe pain
Obese man with a toe pain who had an alcohol and shellfish
Crystal arthropathy - gout investigations
Joint aspiration - rule out septic arthritis
Polarised light microscopy
- negatively birefringent
- needle-shaped monosodium crystals
Bloods - raised WBC, ESR and urate
X-ray
Crystal arthropathy - gout management
Weight loss, less alcohol, hydration and dairy products - protective
NSAIDs - naproxen, ibuprofen or colchicine if contraindicated
Prophylaxis - allopurinol - xanthine oxidase inhibitor
Crystal arthropathies - pseudogout definition
Calcium pyrophosphate deposition (pseudo gout) is associated with both acute and chronic arthritis. Acute CPP crystal arthritis occurs in one more joints.
Chronic CPP arthritis mimics OA or RA and is associated with variable degrees of inflammation
Crystal arthropathies - pseudogout aetiology
Possible causes:
- direct trauma to the joint
- intercurrent illness
- hypothyroidism
- hyperparathyroidism - more calcium production
- surgery - especially parathyroidectomies
- hypercalcaemia
- blood transfusions - excess iron