Synovial fluid respiratory gases in relation to synovial circulatory-metabolic imbalance due to rheumatoid arthritis

الملخص EN

Aim of work: To investigate the impact of circulatory insufficiency relative to synovial tissue metabolism in rheumatoid arthritis (RA) and its differentiation from other causes of knee effusion and arthritis, Material: Synovial fluid specimens from adult females with age ranging from 18-72 years were studied.

Twenty of those patients suffered from osteoarthritis (OA, group I); 25 suffered from rheumatoid arthritis (RA, group II) and 15 suffered from traumatic knee effusion (controls, group III).

Method: Synovial fluid samples were analyzed for partial pressure of oxygen (PO2), carbon dioxide (PCO2), hydrogen ion concentration (pH), glucose content, cell counts and mucin clot test.

The obtained data were correlated with the severity of the clinical condition.

Results: The least PO2 level was encountered in group II and this was statistically significant as compared to groups I & III.

Moreover, though there was no statistically significant difference as regards PCO2 when comparing the three groups, yet the highest PCO2 mean value was encountered in RA.

Also in the same group, the study of synovial pH and glucose levels demonstrated a statistically significant decrease, while the synovial total leucocytic count showed a significant increase.

Regarding the mucin clot test, it was significantly impaired in RA, while it remained good in the other two groups.

The correlation study in RA patients revealed a statistically significant negative correlation between PO2 and each of the disease duration (r=-0.75) and the duration of morning stiffness (r=-0.7); and a statistically significant positive correlation between PO2 and the functional status (r=0.91).

Furthermore, a significant negative correlation was demonstrated between mucin clot test and the disease duration (r=-0.76) and a significant positive one with the functional status (r=0.78).

Regarding the synovial fluid glucose, it showed a significant positive correlation with PO2 (r=0.76), but a significant negative correlation with the total leucocytic count (r=-0.74).

Conclusion: Synovial PO2 together with mucin clot test might reflect the severity of the clinical condition in RA, being useful for the follow up of the patients during medication.

Also, the test of analysis of variance (ANOVA) was done as a best quantitative method to discriminate between RA & OA.

With its help, synovial PO2 assay proved to be the most sensitive discriminating test.

Finally, rheumatologists would be able to select RA patients who seem to be in need of more aggressive treatment using clinical judgment and simple laboratory measures.