Background: The diagnosis of gout in the intercritical phase can be difficu
lt.
Objective: To determine whether synovial fluid analysis allows the diagnosi
s of intercritical gout.
Design: Cross-sectional study.
Setting: Outpatient rheumatology clinics.
Patients: 101 patients with gout.
Intervention: Arthrocentesis of 80 knees and 21 first metatarsophalangeal j
oints teach joint from a different patient) that had been inflamed but were
currently asymptomatic.
Measurements: Frequency with which arthrocentesis yielded synovial fluid; p
resence of monosodium urate crystals in the synovial fluid sample; and, for
synovial fluid with crystals, the number of microscope fields that had to
be scanned before crystals were found.
Results: Synovial fluid was obtained from 91 of 101 joints. The fluid from
all 43 patients not receiving hypouricemic agents contained monosodium urat
e crystals. These crystals were found in the synovial fluid of only 34 of 4
8 patients receiving hypouricemic agents. In 90% of the synovial fluid samp
les that contained crystals, crystals were seen in the first five microscop
e fields examined.
Conclusions: Arthrocentesis of asymptomatic knees and first metatarsophalan
geal joints and synovial fluid analysis are simple procedures that facilita
te the diagnosis of gout during intercritical periods.