Musculoskeletal

Gout

An inflammatory arthritis caused by monosodium urate crystals; treat the flare promptly, exclude septic arthritis when the diagnosis is uncertain, and prevent recurrence with treat-to-target urate-lowering therapy.

In a nutshell

Gout is monosodium urate crystal arthritis. Treat the flare with an NSAID, colchicine or a short oral corticosteroid; exclude septic arthritis when the diagnosis is uncertain. Offer treat-to-target urate-lowering therapy when recurrence or complications justify it, usually aiming for serum urate below 360 micromol/L.

Classic presentation

A patient develops a rapidly severe, red, hot and swollen first metatarsophalangeal joint, often overnight, with previous similar attacks or other evidence of hyperuricaemia.

Key points

A typical podagra supports gout but does not by itself exclude septic arthritis or CPPD.
A serum urate of 360 micromol/L or more supports the diagnosis; a lower value during a flare does not exclude it, so repeat at least 2 weeks after the flare settles if suspicion remains high.
If diagnosis is uncertain, aspirate for crystal analysis and culture; crystals do not exclude coexisting infection.
First-line flare treatment is an NSAID, colchicine or a short oral corticosteroid, selected by comorbidity and interactions.
Offer urate-lowering therapy for multiple or troublesome flares, tophi, chronic gouty arthritis, CKD stage 3 to 5 or diuretic therapy; discuss it after any first or subsequent flare.
Start ULT 2 to 4 weeks after a flare has settled, or during a flare if attacks are frequent; start low and titrate monthly to target.
Use a target below 360 micromol/L, considering below 300 for tophi, chronic gouty arthritis or ongoing frequent flares despite the higher target.
Allopurinol or febuxostat are first-line options; choose allopurinol first in major cardiovascular disease and use prophylaxis while titrating.

First-line investigation

Serum urate supports the diagnosis, but aspiration for crystals and culture is the key test when the diagnosis is uncertain or infection is possible.

Management

Recognise the flare and exclude infection

Assess the acutely hot joint for septic arthritis; if uncertain, aspirate for microscopy and culture rather than relying on the history of gout.^1,3
Use serum urate to support diagnosis, remembering that it can be below 360 micromol/L during a flare.¹

Suppress the inflammation safely

Offer an NSAID, colchicine or a short oral corticosteroid; check renal function, gastrointestinal risk, interactions and the BNF before prescribing.^1,6,7
If standard options are unsuitable or ineffective, consider local or specialist corticosteroid options; interleukin-1 inhibitors are specialist treatments.¹

Plan prevention after the flare

Review serum urate, renal and cardiovascular comorbidity, current medicines, tophi and flare burden before discussing long-term urate lowering.^1,2
Offer ULT for multiple or troublesome flares, tophi, chronic gouty arthritis, CKD stage 3 to 5 or diuretic therapy, and discuss it after a first or subsequent flare even without these features.¹

Titrate and refer

Start allopurinol or febuxostat at low dose, usually 2 to 4 weeks after the flare settles, and increase monthly until serum urate is below target; frequent flares allow starting during the flare.^1,4,5
Use flare prophylaxis, consider a lower target for severe disease, and seek rheumatology advice for uncertainty, intolerance, treatment failure or CKD stage 3b to 5/transplant.^1,6

Maintain the target and safety-net

Continue ULT as a long-term, usually lifelong treatment, monitor monthly during titration and consider annual urate monitoring once stable.^1,4,5
Give clear advice to seek urgent help for fever, systemic illness or a worsening hot joint, and explain how to manage recurrent flares within the agreed plan.^1,2

Exam traps

A normal or low serum urate during an acute flare does not rule gout out.
Crystals in synovial fluid do not rule out septic arthritis.
Do not use a specific diet as if it were proven to prevent flares; advise balanced diet, weight management where appropriate and avoidance of excess alcohol.
Do not stop established urate-lowering therapy without clinical advice; when starting new ULT, use prophylaxis and titrate to serum urate.
If flares are frequent, NICE allows ULT to start during the flare; the older absolute rule never to start it during a flare is incorrect.

Illustrations

Podagra of the first MTP jointClinical photograph of an acutely red, swollen first metatarsophalangeal joint typical of a first gout attack.James Heilman, MD, Wikimedia Commons · CC-BY-SA-3.0

Monosodium urate crystals under polarised lightPolarised-light microscopy of synovial fluid showing needle-shaped monosodium urate crystals; urate crystals are negatively birefringent.Atlas of Medical Foreign Bodies, Wikimedia Commons · CC-BY-SA-2.0

Gout of the first metatarsophalangeal jointAn illustration of acute gout (podagra), showing a red, swollen first metatarsophalangeal joint and monosodium urate crystal deposition.www.scientificanimations.com, Wikimedia Commons · CC-BY-SA-4.0

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.