Thrombophlebitis and pulmonary embolism.

ACUTE venous thrombosis and its conmplilAw eations continue to be a challenging problem to the physician. Ineomplete understanding of the pathogenetic mechanisms, lack of objective measures for diagnosis, and differences of opinion coneerning therapy are parts of this problem. These difficulties, however, should not discourage the physician in his attempts to diagnose and treat venous thrombo-einbolism. Although thrombophlebitis may occur without pulmonary embolism, and vice versa, thev are frequently associated. It bas been suggested that venous thrombosis can be divided into two types, thrombophlebitis and phlebothrombosis. Since the distinction has no practical value in management or prognosis, the generic terni "thrombophlebitis" seems preferable when the clinical findings permit the diagnosis of acute venous thrombosis. Three factors, known as Virchow 's triad, stasis of blood flow, damage of endothelium, and hypercoagulability of the blood, have been considered important in the genesis of venous thrombosis, but the relative importance and interdependenee of these factors are not understood. Nonetheless, they serve as a valuable starting point in the management of thrombophlebitis. The pathologic picture of venous thrombosis includes both thrombosis and variable inflammatory changes in the wall of the vein. In throinbophlebitis of more than a few days' duration, organization of the clot is also seen. The end result of thrombophlebitis usually is thickening of the vXenous wall with partial restoration of the lumen and variable destruction of the valves. The clinical manifestations of both the inflammatory and obstructive components of aeute venous thrombosis are important. Although there is no adequate explanation,