Rheumatoid arthritis is a chronic inflammatory systemic disease of young or middle age adults, characterized by destructive and proliferate changes in synovial membrane, periarticular structures, skeletal muscle and perineural sheaths. Eventually, joints are destroyed, ankylosed and deformed.
Anemia of moderate severity occurs frequently in rheumatoid arthritis patients, and these patients show abnormalities of iron metabolism such as lower serum iron concentration and occurrence and distribution of iron in the synovial membrane. It has been suggested that the mechanism of iron deposits in rheumatoid arthritis is continuous oozing of blood from vascular granulation tissue into the synovial cavity and this is also the cause of anemia in rheumatoid arthritis.
We collected samples of serum and knee joint fluid in 21 cases of rheumatoid arthritis
for chemical estimation of the ferritin concentration by radio immunoassay, and compared
with ferritin concentration of serum and synovial fluid in osteoarthritis. The following results were obtained:
1. The mean hemoglobin concentration(11.4 gm%) in rheumatoid arthritis was lower than the mean hemoglobin concentration(13.4 gm%) in osteoarthritis.
2. The mean serum ferritin concentration (118. 4 ng/ml) in rheumatoid arthritis was lower than the mean serum ferritin concentration (135.6 ng/ml) in osteoarthritis, but the mean synovial fluid ferritin concentration(279. 8 ng/ml) in rheumatoid arthritis was higher than the mean synovial fluid ferritin concentration(190.4 ng/ml) in osteoarthritis.
3. The mean ratio of synovial fluid ferritin on serum ferritin was 2.36 in rheumatoid arthritis, in contrast with 1.4 in osteoarthritis. There was significant correlation between the ferritin concentration in synovial fluid and the serum.
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