Cortex rheumatology - Inflammatory arthropathies 4 Flashcards
What is gout ?
A crystal arthropathy caused by deposition of urate crystals within a joint, usually due to high serum uric acid levels (hyperuricaemia)
What is the typical presentation of gout ?
- Uric acid crystals precipitate in joints.
- The classic joint affected is the first metatarsalphalangeal (MTP) (big toe), ankle and knee the other most commonly affected joints.
- Presents with an intensely painful red, hot swollen joint
- Gouty tophi are painless white accumulations of uric acid which can occur in the soft tissues and occasionally erupt through the skin
What sign is shown here and what condition is it associated with ?
Gouty tophi - painless white accumulations of uric acid which can occur in the soft tissues and occasionally erupt through the skin.
How is gout diagnosed ?
Diagnosed by analysing a sample of synovial fluid with polarised microscopy
1st line - arthrocentesis with synovial fluid analysis
Uric acid crystals are needle shaped and display negative birefringence (change from yellow to blue when lined across the direction of polarization).
Also check inflam markers + X-ray (same with pseudogout)
Describe the treatment of gout
Acute gout:
- 1st line: non-steroidal anti-inflammatory drug (NSAID)
- 2rd line: colchicine
- 3nd line: corticosteroid
Recurrent gout - not started until acute attack subsided:
- 1st line - xanthine oxidase inhibitor - allopurinol
What is pseudogout?
Is another crystal arthropathy causing an acute arthritis but, in contrast to gout, it is caused by calcium pyrophosphate crystals.
How is pseudogout diagnosed ?
Diagnosed by:
Arthrocentesis with synovial fluid analysis - showing Positively birefringent crystals of calcium pyrophosphate
Who does pseudogout typically occur in ?
CPPD typically occurs in older patients but can occur in younger patients with associated metabolic conditions, such as hyperparathyroidism, hypothyroidism, renal osteodystrophy, haemochromatosis and Wilson’s disease.
What are the key features of pseudogout ?
Key factors:
- presence of risk factors
- painful and tender joints
- osteoarthritis-like involvement of joints (wrists, shoulders)
- sudden worsening of osteoarthritis
Other diagnostic factors:
- red and swollen joints
- joint effusion and fluctuance
- fever and malaise
What are the key differences between gout and pseudogout ?
- Gout - caused by uric acid crystals and has negative brifringement
- Pseudogout - caused by calcium pyrophosphate crystals and has slightly positive bifringement
- In pseudogout - x-ray: chondrocalcinosis
in the knee this can be seen as linear calcifications of the meniscus and articular cartilage
What is the treatment of pesudogout ?
- 1st line = NSAIDs
- 2nd line = Corticosteroids (systemic and intra‐articular)
- and occasionally colchicine
What is polymyalgia rheumatica ?
- Common chronic inflammatory condition affecting mainly elderly people (>50)
- Characterized by proximal myalgia of the hip and shoulder girdles with accompanying morning stiffness that lasts for more than 1 hour.
What condition is strongly associated with polymyalgia rheumatica ?
GCA - giant cell arteritis
How is a diagnosis of PMR reached and what is its treatment?
(hint diagnosis and treatment tie in with each other)
- No specific test but almost always CRP and PV/ESR are raised (hence inflammatory condition)
- Patients respond to treatment very quickly (basically fine the next day)
- Treatment = prednisiolone, dose is gradually reduced over the course of around 18 months (should resolve by then)
What is giant cell arteritis (GCA) ?
A granulomatous vasculitis of large and medium-sized arteries.