I already knew that meat, seafood, and alcohol were bad for gout while skimmed milk and weight loss were good for it. To the ‘bad for’ column I can now apparently add fructose and sugar-sweetened soft drinks, and to the ‘good for’ column I can add other dairy products, Vitamin C, and, surprisingly, coffee. (How strong the evidence is for these isn’t clear.)
Acute gout can cause fever. Fever is therefore unhelpful in distinguishing between gout and septic arthritis, which is a shame since the only way to distinguish between them is to aspirate the joint for microscopy and culture and it’s all very well for a bunch of rheumatologists to say that. However, joint aspiration can also work as an effective treatment, especially when coupled with intra-articular steroid injection, which is the most effective acute treatment.
The BNF apparently now has a more sensible regime for colchicine dosing, so I can actually go back to checking that instead of trying to take an educated guess at it.
The recommended cut-off for starting urate-lowering therapies is 3 attacks a year. Tophi, radiographic joint damage, and urate renal calculi/nephropathy are also indications. The most common regime for allopurinol is a starting dose of 100 mg od with increases of 100 mg every four weeks until target serum urate levels are achieved, up to 900 mg daily – halve all this in severe renal failure. Check serum urate levels annually.
The reason why urate-lowering therapies (ULT) can initially precipitate gout attacks is that, as the crystals shrink, they’re more easily shed from articular cartilage into the joint space. This is less likely with the gradual dose escalation outlined above, as this leads to more measured crystal dissolution. Apparently it’s only necessary to wait for 1 – 2 weeks after an acute attack has resolved before starting ULT. Prophylaxis of acute attacks during the initiation period may be done by NSAID or by colchicine 0.5 mg once or twice daily. All this can usually be done in primary care and it isn’t usually necessary to refer to rheumatology unless allopurinol isn’t tolerated. If allopurinol isn’t tolerated, an alternative is febuxostat. Side-effects of both are similar in frequency and include headache, diarrhoea, joint-related symptoms, and abnormal LFTs (Prescriber 5.2.11).
And, finally, don’t forget to screen for other cardiovascular risk factors!
(From Hands On, summer 2011, no. 9)