Diurnal variations in rheumatoid synovial effusions.

Diurnal variation in symptoms is characteristic of inflammatory arthritides. We performed serial arthrocenteses on 6 patients with rheumatoid arthritis, chosen because the knee studied had suffered minimal destruction in spite of persistent effusion. Cytology, resting pressures, C3 and C4 were invariant. Glucose, pH, lactate, pO2 showed wide diurnal variation. The direction of change was consistent for the first 2 measures. Such metabolic shifts might underlie symptoms and contribute to the pathophysiology of joint destruction.