Clinical Studies on Canine Dirofilarial Hemoglobinuria:Blood Coagulation System Findings

Abstract

To elucidate the relationship between intravascular hemolysis and disseminated intravascular coagulation (DIC) in dogs with dirofilarial hemoglobinuria (venae cavae syndrome), blood coagulation test and histopathologic examination were carried out. Blood caogulation test results in most of 21 dogs were within the normal ranges, but a few cases showed decrease in platelet counts, slight prolongation or shortening of prothrombin time and activated partial thromboplastin time, slight increase or decrease of fibrinogen level, significant increase of factor VIII level and slight increase of fibrinogen-fibrin degradation products. However, no cases showed clearly the so-called "consumptive coagulopathy" and "secondary activation of fibrinolysis" in blood coagulation tests. Histopathologically, the thrombi existed in the middle and large arteries of the lung in 9 of 15 cases, in the middle and large veins of the liver in 2 cases, and in the kidney in 1 case. However, no thrombi were found in capillaries or glomerulus. Typical DIC was not seen. Therefore, it seems that DIC is not the principal cause of intravascular hemolysis in this disease.