[Prostaglandin E2 liberation in the synovial fluid induced by organo-iodinated contrast media. Interrelations with the genesis of post-arthrographic pain].

RCM have been observed to cause--during arthrography--the appearance of a slow onset painful symptomatology with the clinical characteristics of a slight and transient acute arthritis. These substances are supposed to set in a production of humoral mediators of inflammation with algogenic action--PGE2 in particular. During arthrography of the knee the release of synovial fluid PGE2 after RCM introduction was studied. Two RCM were compared: meglumine iothalamate and iopamidol. Twenty patients underwent arthrography of the knee: synovial fluid PGE2 concentration was measured both before and 15' after RCM introduction with 125I-RIA method. Results show a significant increase in PGE2 concentration after both iothalamate (p less than 0.0001) and iopamidol (p less than 0.01) --especially in iothalamate--treated patients (p less than 0.01). A physiopathologic mechanism about post-arthrographic pain and, more generally, about RCM toxicity is thus hypothesized.