Increased coagulation activity of the pleura after tube drainage and quinacrine instillation in malignant pleural effusion.

Chronic malignant pleural effusions are usually treated with an intrapleurally administered irritant that creates an inflammatory reaction. The induced inflammation results in fibrin deposition and termination of fluid exudation. In the present study several factors in the coagulation system in the pleural fluid were followed during treatment with tube drainage and quinacrine instillation into the pleural space. In the chronic exudative phase before treatment, both thrombin activity and fibrinopeptide A (FPA), were present at low levels. During treatment the levels increased markedly. Beta-thromboglobulin, a platelet marker, showed a similar pattern. Prothrombin, antithrombin III, prekallikrein and kallikrein inhibiting activity showed no such variations in activity. The high thrombin activity and FPA level induced by treatment reflect an active process of fibrin formation which seems to play an important role in arresting chronic pleural exudation.