Rheumatology Flashcards
What is the aetiology of osteoarthritis?
Mechanical and biological events that destabilise the normal process of degradation and synthesis of bone
What is the pathophysiology of osteoarthritis?
- Failure in maintaining the homeostatic balance of the cartilage matrix synthesis and degradation
- Increased concentration of matrix metalloproteinases (enzymes that catalyse collagen and proteoglycan degradation)
What are the risk factors of osteoarthritis?
- Age >50
- Female gender
- Obesity
- Joint hyper mobility
- Genetic factors
- Physical/ manual occupation
- Knee malalignment
- High bone mineral density
What is the clinical presentation of osteoarthritis?
- Gradual onset and progressive
- Affects many joints, typically causing mechanical pain with movement and/or loss of function
- Joint pain (made worse by movement, relieved by rest)
- Joint stiffness after rest
- Transient stiffness (e.g. less than 30m of morning stiffness)
- Most commonly affects distal interphalangeal joints first carpometacarpal joints (base of thumb), first metatarsophalangeal joint of the foot, and weight baring joints (vertebra, hips and knees)
- Heberden’s nodes = bone swellings at DIJPs
- Bouchard’s nodes = bone swelling at PIPJs
- Functional difficulties
- Limited range of motion
- Malalignment
- Tenderness
- Crepitus
What are the differential diagnoses of osteoarthritis?
- Rheumatoid arthritis (differentiated by pattern of joint involvement, absence of systemic features and marked early morning stiffness)
- Gout
- Pseudogout
How is osteoarthritis diagnosed?
- XR of affect joint (loss of joint pain, osteophytes, subarticular sclerosis, subchondral cysts)
- Serum CRP
- Serum ESR
- Aspiration of synovial fluid
How is osteoarthritis managed?
- Stepwise analgesia
- Non-pharmacological approaches (patient education, exercise programmes, weight loss)
- Steroids
- Intra-articulation corticosteroid Injections
- Joint replacement surgery
- Limited response to NSAIDs
What is the aetiology of RA?
- Exact aetiology is unknown
- Genetics: HLA alelle is more common in RA patients
- Infection may trigger infection in genetically-predisposed people
What is the pathophysiology of RA?
- Inflamed synovium
- Synovium shows increase angiogenesis, cellular hyperplasia, influx of inflammatory cells
- Lining becomes hyperplastic
What are the risk factors of RA?
- Genetic predisposition
- Smoking
- Women
What is the clinical presentation of RA?
- Symmetrical deforming arthritis lasting >6 weeks
- Joint pain and swelling
- Slowly progressive
- Symptoms are worse in the morning and in the cold
- Morning stiffness lasts longer than 30m
- DIPs are spared
- Wrists, elbows, shoulders, knees and ankles
- Swan neck deformity
- Boutonnière’s deformity
- Ulnar deviation/ drift
- Rheumatoid nodules
- Tendon inflammation
Extra-articular manifestations:
- Lungs: pleural effusions, fibrosing alveolitis, interstitial lung disease
- Heart: rare, pericarditis, Raynaud’s, pericardial effusion
- Eyes: dry eyes, episcleritis, scleritis (can’t look at bright lights, severe pain)
- Neuro: peripheral sensory neuropathies, cord compression
- Kidneys: amyloidosis, CKD
- Skin: sub-cut nodules
What are the differential diagnoses of RA?
- Psoriatic arthritis
- Infectious arthritis
- Gout
- SLE
- Osteoarthritis
How is RA diagnosed?
- Rheumatoid factor
- Anti-CCP antibody
- Radiographs
- Ultrasounds
- Bloods: normochromic normocytic anaemia, raised ESR and/or CRP
- Positive rheumatoid factor in 80%
- Positive anti-CCP in 30%
- XR: soft tissue swelling in early disease, joint space narrowing in late disease, peri-articular erosions
- MRI and USS: erosions at joint margins and bones
- Joint aspiration if effusion present (will be cloudy)
How is RA managed?
- DMARDs (oral methotrexate)
- Corticosteroids (oral prednisolone)
- NSAIDs
- Biological therapy: anti-TNF blockers e.g. infliximab
- Lifestyle: smoking cessation, weight loss, exercise
- Surgery to remove bulk of inflamed tissue and prevent damage
What is the aetiology of gout?
- high urate level (hyperuricaemia)
- high insulin lowers urate excretion
- diuretics impair uric acid excretion
- increased purine turnover
- ischaemic heart disease
- high saturated fat diet
What is the pathophysiology of gout?
- Uric acid is excreted in the kidneys but it’s not very efficient so if uric acid is high (hyperuricaemia) then it’s converted to monosodium urate crystals, causing symptomatic gout and pain
- Monosodium urate crystals tend to form in joints that have had previous trauma e.g. big toe
- The crystals can also trigger intracellular inflammation, causing more pain
What are the risk factors of gout?
- Old age
- Male sex
- Menopausal status
- FHx
- Use of diuretics
- Consumption of meat, alcohol and seafood
- High cell turnover rate
- Diabetes mellitus
What is the clinical presentation of gout?
general, acute and tophaceous
- Rapid onset severe pain
- Joint stiffness
- Foot joint distribution
- Few affected joints
- Swelling and joint effusion
- Tenderness
- Erythema and warmth
ACUTE GOUT:
- Sudden onset of agonising pain, swelling and redness of the big toe (MTP joint 1)
- Usually just one joint affected, but can sometimes be polyarthritic
- Attack may be precipitated by excess food (esp. red meat), alcohol, trauma, dehydration, diuretic therapy, cold or sepsis
TOPHACEOUS GOUT:
- Smooth white deposits (tophi) in the skin around joints, on the ear, fingers or Achilles tendon
- Tophi = aggregates of monosodium urate crystals with inflammatory cells
- Associated with renal impairment ± long-term diuretic use
What are the differential diagnoses of gout?
- Pseudogout
- Septic arthritis
- Trauma
- Rheumatoid arthritis
- Reactive arthritis
- Psoriatic arthritis
How is gout diagnosed?
- Joint aspiration and microscopy = diagnostic (gout crystals are long needle-shape that are negatively bifringent under polarised light)
- Serum uric acid is raised
How is gout managed?
Lifestyle changes, acute gout and prevention
- Lifestyle changes to reduce uric acid level: lose weight, less alcohol, avoid purine-rich foods, increase dairy
Acute gout:
- High dose NSAIDs
- Colchicine if NSAID not well tolerated
- IM, oral, or intra-articular corticosteroid e.g. prednisolone
Prevention:
- Stop diuretics and switch to an angiotensin receptor blocker
- Allopurinol reduces serum urate levels
- Febuxostat if allopurinol is contraindicated
What is the aetiology of pseudogout?
- Not known
- Deposition of calcium pyrophosphate crystals in the mid-zone of articular hyaline and fibre-cartilage
What is the pathophysiology of psuedogout?
Calcium pyrophosphate crystals can be shed from cartilage into the articular space where they may induce an inflammatory response
What are the risk factors of pseudogout
- Advanced age
- Injury
- Hyperparathyroidism
- Haemochromatosis
- Low Mg/phosphate
- Family history
What is the clinical presentation of pseudogout?
- Painful and tender joints
- OA-like involvement of joints (wrists/ shoulders)
- Sudden worsening of OA
- Red and swollen joints
- Joint effusion
- Fever and malaise
What are the differential diagnoses of psuedogout?
- Acute gouty arthritis
- Acute septic arthritis
- Osteoarthritis
- Rheumatoid arthritis
- Polymyalgia rheumatica
How is pseudogout diagnosed?
- Arthrocentesis with synovial fluid analysis
- XR of affected joint
- Serum calcium and PTH
- Iron studies
How is psuedogout managed?
- Intra-articulate corticosteroids
- Paracetamol
- NSAIDs
- Colchicine