A glance into the future of gout

Abstract

Gout is characterized by monosodium urate (MSU) crystal deposits in and within joints. These deposits result from persistent hyperuricaemia and most typically lead to recurrent acute inflammatory episodes (gout flares). Even though some aspects of gout are well characterized, uncertainties remain; this upcoming decade should provide further insights into many of these uncertainties. Synovial fluid analysis allows for the identification of MSU crystals and unequivocal diagnosis. Non-invasive methods for diagnosis are being explored, such as Raman spectroscopy and imaging modalities. Both ultrasound and dual-energy computed tomography (DECT) allow the detection of MSU crystals; this not only provides a mean of diagnosis, but also has furthered gout knowledge defining the presence of a preclinical deposition in asymptomatic hyperuricaemia. Scientific consensus establishes the beginning of gout as the beginning of symptoms (usually the first flare), but the concept is currently under review. For effective long-term gout management, the main goal is to promote crystal dissolution treatment by reducing serum urate below 6 mg/dL (or 5 mg/dL if faster crystal dissolution is required). Current urate-lowering therapies' (ULTs) options are limited, with allopurinol and febuxostat being widely available, and probenecid, benzbromarone, and pegloticase available in some regions. New xanthine oxidase inhibitors and, especially, uricosurics inhibiting urate transporter URAT1 are under development; it is probable that the new decade will see a welcomed increase in the gout therapeutic armamentarium. Cardiovascular and renal comorbidities are common in gout patients. Studies determining whether optimal treatment of gout will positively impact these comorbidities are currently lacking, but will hopefully be forthcoming. Overall, the single change that will most impact gout management is greater uptake of international rheumatology society recommendations. Innovative strategies, such as nurse-led interventions based on these recommendations have recently demonstrated treatment success for people with gout.

Keywords: diagnosis; gout; pathogenesis; treatment; urate.

Figure 1.

MSU crystals in a synovial fluid sample seen under light microscopy (a) using ordinary light, (b) polarized light, and (c) first-order red compensator. λ shows the axis of the first-order red compensator.

Figure 2.

Ultrasound tophi in the first metatarsophalangeal (MTP) joint (left image, dorsal aspect; right image, medial aspect) from two patients with gout. Identification of sonographic deposits in the medial scans of the first MTP is quite common in gout. Note: in the left image, a positive power-Doppler signal inside the tophus, despite the patient being in-between flares, indicating subclinical inflammation.

Figure 3.

Dual-energy CT of the right foot in a patient with tophaceous gout. Three-dimensional volume rendered images demonstrating MSU crystal deposition (colour coded green), including at first metatarsophalangeal joint, fifth metatarsophalangeal joint and the Achilles tendon.