Crystal arthropathy (gout, pseudogout) Flashcards
How long does a flare of gout last?
~5 days - this is less than most other forms of inflammatory arthritis
Who is most affected by pseudogout?
Older women
Which joints are most affected by pseudogout?
Wrists and knees
What dermatological side effect is associated with allopurinol use?
SJS - if any rash appears then start Febuxostat instead (XO inhibitor)
How do you manage an acute flare of pseudogout?
Intra-articular corticosteroid injection
NB: there is no role for allopurinol or hydroxychloroquine in management of calcium pyrophosphate dihydate deposition arthritis
What is the regimen for starting allopurinol?
Allopurinol 100mgs OD, escalating by 100mgs every two weeks to 300mgs OD
+ colchicine 500mcg BD (because allopurinol alone can precipitate flares)
What is the EULAR classification of CPPD?
They do not use the term ‘pseudoarthritis’
- Type A - acute CPP arthritis usually mono-articular, affecting large joints
- Type B - chronic CPP inflammatory arthritis, affecting large and small joints
- Type C - OA with CPP attacks with inflammation
- Type D - OA with CPP but no inflammation
- Type E - ianthanic/asymptomatic
- Type F - pseudo-neuropathic which is destructive
What is deposited in pseudogout? Which joints are affected?
Calcium pyrophosphate
Knees, wrists, shoulders, ankles, elbows, or hands can be affected typically in older people.
What is seen on a radiograph in pseudogout?
Chondrocalcinosis - although this alone will miss 60% of cases
What is calcium pyrophosphate produced by?
Chondrocytes
CPP crystals can be shed from cartilage into the articular space to cause an inflammatory response.
What are the risk factors for pseudogout?
- Advanced age
- Injury esp meniscal
- Hyperparathyroidism
- Haemochromatosis
- FH
- Hypomagnesaemia
- Hypophosphatasia
What are the clinical features of pseudogout?
- Painful and tender joints
- OA-like involvement of joints (wrists, shoulders)
- Sudden worsening of OA
- Red and swollen joints
- Joint effusion and fluctuance
Other:
- Fever and malaise - uncommon
What investigations would you do for pseudogout?
Bloods/bedside:
- Serum calcium
- Serum parathyroid hormone
- Iron studies
- Serum magnesium
- Serum ALP - to exclude hypophosphatasia
Imaging/invasive:
- Arthrocentesis with synovial fluid analysis
- XR joints
What is seen on synovial fluid analysis in pseudogout?
Intracellular or extracellular positively birefringent rhomboid-shaped crystals under polarised light confirms CPPD; fluids are often bloody
What is the mangement of pseudogout?
1st line:
- Simple analgesia e.g. paracetamol
- Intra-articular steroids - preferred for an acute attack ; triamcinolone hexacetonide is the longest-acting and most used.
2nd line: NSAIDs - COX-2 have lower GIT side-effects but same CVD risk
For those with polyarticular disease = systemic steroids
Surgery - in recurrent involvement associated with severe joint degeneration
What are the complications of pseudogout and its management?
Intra-articular corticosteroid-related adverse effects e.g. bleeding and bruising around injection site
What is the prognosis in pseudogout?
Most will recover over days to weeks but many will relapse
Define gout.
Gout is a syndrome characterised by:
- hyperuricaemia and deposition of urate crystals causing attacks of acute inflammatory arthritis;
- tophi around the joints and possible joint destruction;
- renal glomerular, tubular, and interstitial disease;
- and uric acid urolithiasis.
Which joints are most affected in gout?
- first toe (podagra),
- foot,
- ankle,
- knee,
- fingers,
- wrist,
- elbow;
However, it can affect any joint.
How common is gout?
Affects 3% to 6% of men and 1% to 2% of women
Gout is rare in pre-menopausal women
What are the risk factors for gout?
- older age
- male sex
- use of drugs including aspirin, ciclosporin (cyclosporine), tacrolimus, or pyrazinamide
- consumption of meat, seafood, or alcohol
- genetic susceptibility
- conditions with a high cell turnover rate
What are the causes of gout?
Aetiology is hyperuricaemia
Hyperuricaemia is due to renal under-excretion of urate in 90% of cases and to over-production in 10%,
What medications increase uric acid levels?
Increasing uric acid re-absorption:
- aspirin
- ciclosporin
- tacrolimus
- pyrazinamide
Reduced excretion of uric acid:
- diuretics
Increased uric acid production:
- chemotherapy
- haematological cancers
Why does gout commonly present as podagra?
Solubility of urate in the joints depends on temperature, pH, non-aggregated proteoglycans, and other factors.
1st MTP is a cool part of the body
