Crystal Arthropathies Flashcards
Gout is an inflammatory / non-inflammatory condition associated with ______
Inflammatory. Urate crystals
Gout is more common in which sex?
Men
What’s the most common inflammatory arthritis in men?
Gout
Gout is how much more common than RA?
10x
Hyperuricaemia is a serum uric acid greater than what mg/dL?
> 7mg/dL
Risk of developing gout is proportional to degree of hyperuricaemia. True/false?
True
Which 2 genetic conditions can result in over-production of uric acid?
- Lesch-Nyhan Syndrome
- Von Gierke Disease
Psoriasis can predispose to gout. True/false?
True
Which drugs can cause gout? (4)
1) Diuretics (thiazides)
2) Levodopa
3) Cyclosporin A
4) Pyrazinamide
Which foods are rich in purines? (4)
- Red meat
- Offal
- Shellfish
- Legumes
Gout generally affects which joint?
1st MTP
Differential diagnoses for gout include (3)
1) Septic arthritis
2) Trauma
3) Seronegative arthritis (e.g. psoriatic, Reiter’s)
Cutaneous deposition of uric acid leads to which sign?
Tophi
Inflammatory markers are raised in gout. True/false?
True
What is the gold standard investigation for gout diagnosis?
Joint aspiration showing needle-shaped crystals under negative birfringence
Describe the pharmacological management of acute gout attack (4)
1) NSAIDs
2) Colchinine (careful not to overdose - severe diarrhoea)
3) Corticosteroids
4) Other analgesia e.g. paracetamol
Dehydration is a trigger for gout. True/false?
True
Prophylaxis of gout attack is indicated if how many attacks in 6 months?
> 2, or tophi/radiographic signs/ renal stones present
Urate-lowering drugs include
Allopurinol & febuxstat
Urate-lowering therapy is commenced at a high dosage. True/false?
False - start low, go slow
Psuedogout affects which type of cartilage?
Fibrocartillage (e.g. knees, wrists, ankles)
Psuedogout is associated with diet or alcohol intake. True/false?
False - no association
Psuedogout is caused by which chemical?
Calcium pyrophosphate dihydrate
Psuedogout gives which shape of crystals?
Rhomboid
Gout is a risk factor for development of psuedogout. True/false?
True
What’s the important treatment difference between psuedogout and gout?
Psuedogout does NOT respond to allopurinol/febuxostat
Milwaukee shoulder is caused by deposition of which chemical?
Hydroapatite
What’s the common side effect of colchicine?
Diarrhoea
Acute gout treatment options (3)
1) Analgesia (paracetamol PO and topical; NSAIDs if not contraindicated)
2) Colchicine (side effect; diarrhoea)
3) Steroids (IA)
Gout prophylaxis treatment options (3)
1) Allopurinol
2) Febuxostat
3) Uricosurics
Allopurinol and febuxstat work how?
Inhibit xanthine oxidase (blocking conversion of purines into uric acid)
Why are allopurinol / febuxostat NOT used in acute gout attack?
A rapid change in uric acid level can precipitate further gouty attacks
When is febuxostat preferred over allopurinol?
In those with RENAL impairment (allopurinol is renally cleared)
Which general class of condtion contraindicates febuxostat?
Ischaemic heart disease
Probenecid and sulphinpyrazone are examples of what type of drug?
Uricosurics
Side effects of allopurinol (2)
1) Rash
2) Vasculitis
Allopurinol should NEVER be co-prescribed with what drug?
-Azathioprine (due to bone marrow suppression)
Adverse effects of steroids include (5)
1) Central weight gain
2) Muscle wastage
3) Skin atroph
4) DM & Hypertension
5) AVN of femoral head
Serum urate is a useful diagnostic marker for gout attacks, T/F?
False - is normal in 25% of acute attacks
When is the best time to measure serum urate for gout diagnosis?
2 weeks after an attack
What non-foot areas can gout affect?
ankle, knee, upper limb joints, spine
What are the CRP/PV values in gout?
Raised.
X-ray is a useful tool for diagnosis of acute gout attack, T/F?
False - usually positive in acute attacks, will show erosive changes if gout has been present for years
When should gout prophylaxis therapy be commenced following gout?
2-4 weeks post-attack
How is Milwaukee shoulder diagnosed?
Alizarin stain & under aspirate no crystals are seen on polarised light
When is febuxostat contraindicated?
In those with IHD (safe in renal impairment)
