Domain† | Definitions and special considerations |
---|---|
1. Pattern of joint/bursa involvement during symptomatic episode(s) ever Categories are defined as per the description of the distribution of joints involved | Distribution of joints: involvement (ever) of
|
2. Characteristics of symptomatic episode(s) ever Categories are defined as
| Characteristics to consider: presence (ever) of
|
3. Time course of symptomatic episode(s) ever Categories are defined as
| ‘Typical symptomatic episode’: presence (ever) of >2 of the following, irrespective of anti-inflammatory treatment
|
4. Clinical evidence of tophus Categories are defined as
| Appearance: draining or chalk-like subcutaneous nodule under transparent skin, often with overlying vascularity (figure 2) Location: classic locations—joints, ears, olecranon bursae, finger pads, tendons (eg, Achilles) |
5. Serum urate level, off-treatment Categories are defined as
| Which serum urate measurement to use: highest reading on record, off urate-lowering therapy Special considerations: Ideally, the serum urate level should be scored if tested at a time when the patient was not receiving urate-lowering therapy and it was >4 weeks from the start of an episode; if practicable, retest under those conditions. If serum urate level is ≥10 mg/dL, no need to retest |
6. Synovial fluid analysis Categories are defined as
| Location: symptomatic (ever) joint or bursa Special considerations: assessment should be performed by a trained observer Note: MSU positive is a sufficient criterion. |
7. Imaging evidence of urate deposition Categories are defined as
| Modality: ultrasound or DECT Appearance: double-contour sign on ultrasound (figure 3A)‡ or urate deposition on DECT (figure 3B)§ Location: symptomatic (ever) joint or bursa |
8. Imaging evidence of gout-related joint damage Categories are defined as
| Modality: radiography Appearance of gout-related erosion: cortical break with sclerotic margin and overhanging edge; excludes gull wing appearance (figure 3C) Location: radiograph of hands and/or feet; excludes distal interphalangeal joints |
*Symptomatic (ever) refers to pain and/or swelling.
†Categories within each domain are hierarchical; if a subject fulfills more than 1 category, the highest category should be selected.
‡A false-positive double-contour sign (artifact) may appear at the cartilage surface, but should disappear with a change in the insonation angle of the probe.31 ,32
§Images should be acquired using a dual-energy computed tomography (DECT) scanner, with data acquired at 80 kV and 140 kV and analysed using gout-specific software with a 2-material decomposition algorithm that color-codes urate.33 A positive scan result is defined as the presence of color-coded urate at articular or periarticular sites. Nailbed, submillimeter, skin, motion, beam hardening, and vascular artifacts should not be interpreted as DECT evidence of urate deposition.34