More than 200 instances of periodic synoviosis have been recorded. It is related to periodic oedema (hereditary angioedema). Various autonomic disturbances accompany episodes. Confusion with rheumatoid arthritis persists. Theoretically an inherent rhythm or feedback mechanism operates as the cause.
The disorder in several observed patients has persisted for decades, worsened or abated. In one instance, contraceptive medication failed to suppress episodes in contrast to the effect of pregnancy in some patients. E-aminocaproic acid disturbed the rhythm and gave mild relief. A few episodes were suppressed after two surgical operations. The inhibitor of Cl esterase in one patient lacked as much as it does in periodic oedema.