Gout Flashcards
what is gout?
Inflammatory arthritis
microcrystal synovitis caused by the deposition of monosodium urate monohydrate in the synovium
What causes gout?
chronic hyperuricaemia (uric acid > 0.45 mmol/l)W
What drugs can cause gout?
diuretics - thiazides, furosemide
ciclosporin
alcohol
cytotoxic agents
pyrazinamide
aspirin
how long does an episode of gout take to come on, and how long does it usually last?
acute episodes typically develop maximal intensity with 12 hours
episodes last several days
Main features of gout flare
pain
swelling
erythema
Most common joint to be affected first in gout
1st metatarsophalangeal (MTP) joint
Other joints (excluding MTP) which can develop gout
Ankle
Knee
Wrist
If untreated repeated acute episodes of gout can damage the joints resulting in a more chronic joint problem. TRUE/FALSE?
TRUE
How can gout be identified on Synovial fluid analysis
needle shaped
negatively birefringent
monosodium urate crystals
under polarised light
When should uric acid levels be checked in relation to the acute gout episode
once the acute episode has settled down
(typically 2 weeks later)
XR findings seen in gout
joint effusion
‘punched-out’ erosions with sclerotic margins
preservation of joint space
eccentric erosions
no periarticular osteopenia
soft tissue tophi
Acute gout management options
NSAIDs or colchicine are first-line
PPI if starting these
Explain the mechanism of action of colchicine
inhibits microtubule polymerization by binding to tubulin, interfering with mitosis.
Also inhibits neutrophil motility and activity
Colchicine has a slower onset of action than NSAIDs. TRUE/FALSE?
TRUE
Colchicine should be used with caution in renal impairment. Explain when the dose should be reduced and when colchicine is contraindicated
reduce dose if eGFR is 10-50 ml/min
avoid if eGFR < 10 ml/min BNF
Main side effect of colchicine
diarrhoea
What can be used if NSAIDs and colchicine are contraindicated?
oral steroids
- prednisolone 15mg/day is usually used
another option is intra-articular steroid injection
if the patient is already taking allopurinol during an acute gout flare, should it be continued whilst they take NSAIDs or colchicine?
Yes
When should urate lowering therapy be offered to patients with gout?
British Society of Rheumatology Guidelines advocate:
- after the first attack of gout
ULT is particularly recommended if:
>= 2 attacks in 12 months
tophi
renal disease
uric acid renal stones
prophylaxis if on cytotoxics or diuretics
When should urate lowering therapy be started in relation to an acute attack
should not be started until 2 weeks after an acute attack,
First line urate lowering therapy
Allopurinol
Explain how allopurinol is initiated
Start with 100 mg od
dose titrated every few weeks to aim for a serum uric acid of < 360 µmol/l
Lower initial dose of allopurinol if patient has reduced eGFR
Colchicine cover can be considered when starting allopurinol
When may a lower target uric acid level (<300 µmol/L) be considered?
patients who have:
- tophi
- chronic gouty arthritis
- OR continue to have ongoing frequent flares despite having a uric acid <360
Second line agent when allopurinol is not tolerated
Febuxostat
Mechanism of action of allopurinol and febuxostat
Xanthine oxidase inhibitor
In cases of gout refractory to allopurinol and febuxostat, what other agents could be tried?
- uricase (urate oxidase) [THINK RASBURICASE!]
- pegloticase (polyethylene glycol modified mammalian uricase)
- given as infusion once every two weeks
Important lifestyle modifications in the treatment of gout
reduce alcohol intake and avoid during an acute attack
lose weight if obese
avoid food high in purines e.g. Liver, kidneys, seafood, oily fish (mackerel, sardines) and yeast products
Medication changes which may help in the treatment of gout
stop precipitating drugs (e.g. thiazides)
losartan = specific uricosuric action
=> suitable for the patients who have coexistent hypertension
Two main mechanisms of high uric acid
Excess production
- myeloproliferative/lymphoproliferative disorder
- cytotoxic drugs
- severe psoriasis
Reduced excretion
- drugs: diuretics
- chronic kidney disease
- lead toxicity
Eponymous syndrome associated with gout
Lesch-Nyhan syndrome:
- hypoxanthine-guanine phosphoribosyl transferase (HGPRTase) deficiency
- x-linked recessive
Features:
- gout, renal failure, neurological deficits, learning difficulties, self-mutilation
