Protein Concentration of Oedema Fluid in Rheumatoid Arthritis : Part I

Abstract

The protein content of 34 samples of edema fluid from 24 patients with adult and juvenile rheumatoid arthritis of varying degrees of activity and with various complications were analyzed. In fluid from hands which were the site of acute arthritis, the mean protein concentration was 4.6 g. %. In edema fluid from the feet, the mean protein level of 13 samples from patients whose arthritis was locally active was 1-6 g%, only 1 being below 1 g% The 17 samples from patients with inactive arthritis was 0.7 g. %, only 1 being above 1 g. %. This closely resembled the controls in which 12 samples showed a mean of 0.8 g. %. In any patient with rheumatoid arthritis and edema, a number of factors may be operative. Edema in the hand is usually due to inflammatory joint disease and edema fluid is of high protein content. The protein content is lower in the foot. Although the edema is frequently inflammatory with a protein content above 1 g. % in active cases, other factors which assume more importance in inactive arthritis may be operative, (immobility, venous or lymphatic obstruction and salt and water retention from cardiac or renal disease or therapy). Inflammation, producing altered capillary permeability is probably the most important factor in determining the protein content.