Pseudogout

Gout: management

Gout is a form of microcrystal synovitis caused by the deposition of monosodium urate monohydrate in the synovium. It is caused by chronic hyperuricaemia (uric acid > 450 µmol/l)

Acute management

• NSAIDs or colchicine are first-line
  • the maximum dose of NSAID should be prescribed until 1-2 days after the symptoms have settled
  • gastroprotection (e.g. a proton pump inhibitor) may also be indicated
• colchicine
  • inhibits microtubule polymerization by binding to tubulin, interfering with mitosis. Also inhibits neutrophil motility and activity
  • has a slower onset of action
  • may be used with caution in renal impairment: the BNF advises to reduce the dose if eGFR is 10-50 ml/min and to avoid if eGFR < 10 ml/min BNF
  • the main side-effect is diarrhoea
• oral steroids may be considered if NSAIDs and colchicine are contraindicated.
  • a dose of prednisolone 15mg/day is usually used
• another option is intra-articular steroid injection
• if the patient is already taking allopurinol it should be continued

Indications for urate-lowering therapy (ULT)

• the British Society of Rheumatology Guidelines now advocate offering urate-lowering therapy to all patients after their 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

Urate-lowering therapy

• it has traditionally been taught that urate-lowering therapy should not be started until 2 weeks after an acute attack, as starting too early may precipitate a further attack. The evidence base to support this however looks weak
• in 2017 the BSR updated their guidelines. They still support a delay in starting urate-lowering therapy because it is better for a patient to make long-term drug decisions whilst not in pain
  • the key passage is: 'Commencement of ULT is best delayed until inflammation has settled as ULT is better discussed when the patient is not in pain'
• allopurinol is first-line
  • initial dose of 100 mg od, with the dose titrated every few weeks to aim for a serum uric acid of < 360 µmol/l
  • a lower target uric acid level below 300 µmol/L may be considered for patients who have tophi, chronic gouty arthritis or continue to have ongoing frequent flares despite having a uric acid below 360 µmol/L
  • a lower initial dose of allopurinol should be given if the patient has a reduced eGFR
  • colchicine cover should be considered when starting allopurinol. NSAIDs can be used if colchicine cannot be tolerated. The BSR guidelines suggest this may need to be continued for 6 months
• the second-line agent when allopurinol is not tolerated or ineffective is febuxostat (also a xanthine oxidase inhibitor)
• in refractory cases other agents may be tried:
  • uricase (urate oxidase) is an enzyme that catalyzes the conversion of urate to the degradation product allantoin. It is present in certain mammals but not humans
  • in patients who have persistent symptomatic and severe gout despite the adequate use of urate-lowering therapy, pegloticase (polyethylene glycol modified mammalian uricase) can achieve rapid control of hyperuricemia. It is given as an infusion once every two weeks

Lifestyle modifications

• reduce alcohol intake and avoid during an acute attack