Gout Flashcards
What factors can predispose a patient to gout?
Decreased excretion of uric acid:
Drugs - diuretics
CKD
Lead toxicity
Increased uric acid production:
myeloproliferative/lymphoproliferative disorder
Cytotoxic drugs
Severe psoriasis
Lesch-Nyhan syndrome:
Caused by HGPRTase deficiency
X-linked recessive so only seen in boys
Includes gout, renal failure, neurological deficit, learning difficulties, self-mutilation
Other risk factors: Male Obesity High purine diet e.g. meat and seafood Alcohol CV disease or kidney disease Family Hx
What investigations are carried out to diagnose gout?
Aspirated fluid analysis: No bacterial growth - excludes septic arthritis Needle shaped crystals Negative birefringent of polarised light Monosodium urate crystals
X-ray:
Joint effusion (Early sign)
Punched-out erosions with sclerotic margins and overhanging edges
Lytic lesions in bone
Relative preservation of joint space until late disease
No periarticular osteopenia (in contrast to RA)
How are acute flare-ups of gout managed?
1st line = NSAIDs:
Max dose of NSAID prescribed until 1-2 days after symptoms have settled
Co-prescribe PPI
2nd line (if NSAIDs contraindicated) = Colchicine: Main side effect is diarrhoea that is dose-dependent
3rd line (if NSAIDs and colchicine contraindicated) = prednisolone 15mg/day
Other options:
intra-articular steroid injections
Continue allopurinol
When should a patient start receiving urate-lowering therapy (ULT)?
Give to all patients after 1st attack
If >=2 attacks in 12 months
Tophi
Renal disease
Uric acid renal stones
Prophylaxis if on cytotoxic or diuretics
What are the ULT medications?
1st line = allopurinol (a xanthine oxidase inhibitor): Initial dose 100mg OD. Titrate every few weeks to aim for serum uric acid <300umol/L Lower initial doses should be given if patient has reduced eGFR Consider colchicine (or NSAIDs if colchicine not tolerated) when starting allopurinol for 6 months
2nd line = febuxostat (a xanthine oxidase inhibitor)
What is the long-term management of gout?
ULT
Stop precipitating drugs e.g. diuretics
Increase vitamin C intake - helps decrease serum uric acid levels
Lifestyle modifications:
Reduce alcohol intake and avoid during attack
Loss weight if obese
Avoid food high in purines
If patient has coexisting hypertension give losartan as this increases uric acid excretion
What type of crystals cause Pseudogout?
Calcium pyrophosphate dihydrate crystals
What are the risk factors for developing Pseudogout?
Old age Haemochromatosis Hyperparathyroidism Low magnesium, low phosphate Acromegaly Wilson's disease
What joints are commonly affected in Pseudogout?
Knee
Wrist
Shoulders
What investigations can be used to diagnose pseudogout?
Aspiration fluid analysis: No bacterial growth - excludes septic arthritis Calcium pyrophosphate crystals Rhomboid shaped crystals Positive birefringent of polarised light
x-ray:
Chondrocalcinosis - thin white line in middle of joint space caused by calcium deposition
Changes similar to osteoarthritis - ‘LOSS’ mnemonic
What is the management for Pseudogout?
NSAIDs Colchicine Joint aspiration Steroid injections Oral steroids Joint washout in severe cases
