Guidelines: Why is gout so difficult to treat?

Treatment of gout is clarified with new guidelines for primary care, writes Dr Louise Warburton.

Gout: diagnosis can be difficult to differentiate from rheumatoid arthritis (Photograph: Dr P Marazzi/SPL)
Gout: diagnosis can be difficult to differentiate from rheumatoid arthritis (Photograph: Dr P Marazzi/SPL)

Gout brings a patient to the surgery because it is so painful and the condition usually demands immediate treatment. However, treating gout in primary care never seems to be straightforward.

There is often the diagnostic dilemma of whether the presentation of a swollen, red ankle is gout or rheumatoid arthritis. Gout is such a good mimic. It can be mistaken for a septic joint, chondrocalcinosis, inflammatory arthritis or even a flare-up of osteoarthritis.

Without demonstrating uric acid crystals within joint fluid, the diagnosis is only a clinical hunch; however, demonstrating uric acid crystals within joint fluid requires joint aspiration, which many GPs are not comfortable performing.

Treatment difficulties

Once the diagnosis is reached, immediate treatment can be difficult in those patients who cannot take NSAIDs. Many GPs are still anxious about using colchicine, but newer regimens are more forgiving.

Starting urate-lowering therapy (ULT) can be a minefield for GPs.

Patients actually develop gout when they start ULT and therefore prophylaxis with NSAIDs, colchicine or steroids cannot be forgotten. Many patients stop their ULT before it can have any effect.

Untreated chronic gout is the most common cause of inflammatory arthritis in men in the UK and can cause severe and permanent joint damage.1

Treatment of gout in secondary care is also flawed. The British Society for Rheumatology (BSR) is currently running an audit on the treatment of gout in secondary care, with the aim of identifying inconsistencies in treatment.

Developing guidelines

The BSR produced its own guidance a couple of years ago, as did the European League Against Rheumatism (EULAR).2

However, there is no NICE guidance on this important disease and for non-specialists, locating gout guidance is difficult.

For this reason, the Primary Care Rheumatology Society (PCRS), the BSR and Keele University's primary care and health sciences faculty decided to produce user-friendly guidance for GPs.

The guidance is deliberately brief (one side of paper) to allow lamination and display in the GP surgery for quick reference.

Its development has been part of a larger project to produce a website, Integrated Services for Patients In Rheumatology (INSPIRE), which will be hosted on the BSR site and hold resources for both primary and secondary care.

Key points in the guidelines

Hyperuricaemia is the most important risk factor for gout; however, just being hyperuricaemic does not mean the patient has gout.

Gout occurs when urate crystals reach saturation in the serum (about 6mg/dl or 360mmol/L) and begin to precipitate out in joints, causing a painful inflammatory process.

Episodes are self-limiting but can progress to chronic tophaceous gout when crystals are deposited in soft tissues as well as joints, and the symptoms are persistent.

Many patients with hyperuricaemia will not develop gout and other physical features have to be present to cause an attack, such as dehydration or trauma.

Serum urate may be normal during an acute attack.

Treating an acute attack

NSAIDs with PPI cover can be used, such as naproxen 250mg three times a day.

Colchicine can be used in a dose of 0.5mg two to four times a day for treatment of an acute attack. There is no need for higher doses. Colchicine does not interact with warfarin.

Intra-articular injection of steroids is an effective way to treat an acute attack. Oral steroids are also useful if the joint cannot be injected.

Another important concept in gout treatment is treating to target. Urate crystals precipitate out of solution at 360mmol/L; conversely, if serum levels are lower than this, any urate crystals within joints and soft tissues will dissolve into serum and be excreted. Gouty tophi will start to disappear and any joint damage will begin to repair.

It is important to check urate levels every two to four weeks and titrate up the level of ULT until a therapeutic serum target of 360mmol/L is reached. Once a steady state is achieved, annual monitoring of urate levels is acceptable, along with fasting lipids and glucose (gout can be associated with metabolic syndrome, in which diabetes and cardiovascular disease are more common).

Most patients will achieve this with up to 300mg of allopurinol daily, but some may require as much as 600mg.

Always check compliance in patients requiring these high doses.

  • With acknowledgment to Dr Lorna Clarson, GP research fellow, Arthritis Research UK Primary Care Centre, Keele, Staffordshire, and Dr Priyanka Chandratre, rheumatology specialist trainee and NIHR School for Primary Care Research doctoral training fellow
  • Dr Warburton, a GPSI in rheumatology in Telford, Shropshire, and a senior lecturer at Keele University, reviewed the guidelines.
BSR GUIDELINES

Dr Chris Deighton, president of the BSR, said at the launch:

'We want to reach out to all GPs to improve the care of all patients with rheumatological conditions, and not just the GPs who are interested in musculoskeletal problems. These are common conditions where even small improvements in care would result in big changes to the quality of patients' lives.'

References

1. Doherty M. New insights into the epidemiology of gout. Rheumatology 2009; 48 (suppl 2): ii2-ii8.

2. Zhang W, Doherty M, Bardin T et al. EULAR evidence based recommendations for gout. Part II: management. Report of a task force of the EULAR Standing Committee for International Clinical Studies including Therapeutics (ESCISIT). Ann Rheum Dis 2006; 65: 1312-24.

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