Validated Diagnostic Rule to Help with Clinical Diagnosis of Gout without Joint Aspiration.
NB: Always consider other causes in the Ddx of a patient suspected of having gout e.g. Septic arthritis, pseudogout, etc.
If you suspect gout, you may use the following validated scoring system. You may add up the points yourself or use a resource like MDCalc.
- Male Sex (2 points)
- Previous patient-reported attack of joint pain or arthritis (2 points)
- Acute onset with maximum symptoms within 1 day (0.5 points)
- Joint redness/erythema (1 point)
- 1st MTP joint involvement (2.5 points)
- Hypertension or >1 Cardiovascular diseases* (1.5 points)
- Angina / MI
- CVA / TIA
- Heart Failure
- PVD
- Serum uric acid >5.88 mg/dL (3.5 points)
Score Interpretation
| Score | Prevalence of gout |
|---|---|
| ≤4 points | 2.2% |
| >4 and <8 points | 31.2% |
| ≥8 points | 80.4% |
Midrange scores (>4 to <8) are unable to rule out or rule in gout diagnosis. Further laboratory testing is suggested by the original study, using analysis of synovial fluid from the affected joint for the presence of monosodium urate (MSU) crystals.
>8 points: Prevalence of gout is 82.5%. Gout is very likely. And joint aspirate is unnecessary for a considering management as per guidelines using NSAIDs, Colchicine, and urate-lowering therapy where appropriate
The maximum score is 13 points. A score of ≥8 points would constitute a clinical diagnosis of gout. If the score is ≤4 points, consider another diagnosis other than gout. For a score of >4 and <8 points, pursue joint aspiration or refer to a rheumatologist.
If possible and needed, confirmation may always be done with joint aspirate which is the gold standard for definitive diagnosis.
References
Arch Intern Med. 2010; 170: 1120-1126. A diagnostic rule for acute gouty arthritis in primary care without joint fluid analysis.
http://jamanetwork.com/journals/jamainternalmedicine/fullarticle/225738
Am Fam Physician 2016;94(6):505-506. Clinical diagnosis of gout without joint aspirate.