• 
• 

Three Part Question

In [a patient presenting with joint swelling] will [a normal serum uric acid] rule out [acute gout]?

Clinical Scenario

A middle age male presents to emergency department with sudden onset of painful, swollen, red and tender joint at the base of big toe. Blood test showed normal serum uric acid level. There is no previous history of gout. The patient asks if he suffers from gout. Does normal serum uric acid level rules out gout?

Search Strategy

EMBASE 1974 to date and MEDLINE 1950 to date using Dialog Datastar interface using different strategies
Extensive search was made in EMBASE 1974 to date and MEDLINE 1950 to date using Dialog Datastar interface using different strategies, but no relevant clinical trail or meta-analysis was found providing the answer of the question.
URIC-ACID.MJ. AND GOUT.W..MJ. AND BLOOD-CHEMICAL-ANALYSIS.MJ."- This search strategy produced 26 results but they were not relevant.
Search in EMBASE - (uric ADJ acid).TI,AB., [URIC−ACID#.DE. AND GOUT#.W..DE.] AND [(investigation OR diagnosis).TI,AB.,], repeat in MEDLINE and drop duplicates.- This search strategy produced 277 results but they were not relevant

Search Outcome

No relevant clinical trail or meta-analysis was found providing the answer of the question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses

Comment(s)

No trials of any kind was found that was conducted to rule out gout when serum uric acid was within normal limits. On the contrarary, few studies have reported normo-uraecemia in acute gout (Urano W et al, 2002; Pittman JR et al, 1999; Snaith ML, et al 1977; Hadler N et al, 1976;). The incidence of normal serum urate has been reported varying from 12% (Park YB et al, 2003) to 39-43% (Logan JA, et al 1997, Schlesinger N, et al 1997). Despite higher levels of serum urate in gouty patients, there was no lower level of serum urate level from which gout was not diagnosed, which vindicates its removal from the New York criteria set for the diagnosis of gout (Schlesinger N, 2005; Rigby AS et al, 1994;). Demonstrating the presence of monosodium urate (MSU) crystals in the joint fluid or tophus has been the gold standard for the diagnosis of gout (Jiang GY et al,2006; Schlesinger N, 2005; O'Neill S et al, 2005; Janson R W, 2000; Perkins P et al, 1999;); and is mandatory if septic arthritis is suspected ( O'Neill S et al, 2005). Few studies have suggested that serum urate can fall during acute gout (Perkins P et al 1999; Logan JA et al, 1997).

Clinical Bottom Line

There is no evidence supports that a normal serum urate level can exclude acute gout. Demonstrating the presence of monosodium urate (MSU) crystals in the joint fluid or tophus has been the gold standard for the diagnosis of gout. However, many physicians do not perform synovial fluid analysis. In the absence of demonstrating the presence of MSU crystals in aspirated joint fluid or tophus, clinical, radiologic, and laboratory criteria are helpful (Schlesinger N,.2005). The bottom line is that we should not exclude the diagnosis of gout on the basis of normal serum urate level.

References

1. Hadler N, Frank WA, Bress N, Robinson DR Polyarticular gout Am J Med 1976;56:715–19.
2. Janson R W Diagnosis and management of acute gout and symptomatic hyperuricemia. Primary Care Case Reviews 2000, Vol/Iss/Pg. 3/1 (3−11).
3. Jiang GY, Yang XL Diagnostic evaluation and clinical characteristics of gout. Chinese Journal of Clinical Rehabilitation 25 JUL 2006, Vol/Iss/Pg. 10/28(150−155).
4. Logan JA, Morrison E, McGill PE Serum uric acid in acute gout Ann Rheum Dis 1997;56:696–7.
5. McCarty DJ Gout without hyperuricemia. JAMA 1994;4:302–3.
6. Morrison E, McGill PE Serum uric acid in acute gout. Ann Rheum Dis 1997;56:696-7.
7. O'Neill S, Youssef PP, PokornyCS How to approach the patient with a painful swollen joint. Medicine Today, 2005, Vol/Iss/Pg. 6/9 (49−55)
8. Park YB, Park YS, Lee SC, Yoon SJ and Lee SK Clinical analysis of gouty patients with normouricaemia at diagnosis. Annals of the rheumatic diseases Jan 2003, vol. 62, no. 1, p. 90−2
9. Perkins P, Jones AC GOUT. Ann Rheum Dis 1999;58;611-617
10. Pittman JR. Bross MH Diagnosis and management of gout. American Family Physician 1999 Apr 1;59(7):1799-806.
11. Rigby AS. Wood PH Serum uric acid levels and gout: what does this herald for the population? Clinical & Experimental Rheumatology. 12(4):395-400, 1994 Jul-Aug.
12. Schlesinger N. Diagnosis of Gout: Clinical, Laboratory, and Radiologic Findings. Am J Manag Care 2005;11:S443-S450
13. Schlesinger N, Baker DG, Schumacher HR Jr Serum urate during bouts of acute gouty arthritis. J Rheumatol 1997;24:2265-6.
14. Snaith ML, Coomes EN Gout with normal serum urate concentration. BMJ 1977;i:686–7.
15. Urano W, Yamanaka H, Tsutani H, Nakajima H, Matsuda Y, Taniguchi A, Hara M, Kamatani N. The inflammatory process in the mechanism of decreased serum uric acid concentrations during acute gouty arthritis. Journal of Rheumatology 2002; Vol/Iss/Pg: 29/9 (1950−1953).