Prothrombin levels in yellow fever

Abstract

Since hemorrhagic manifestations constitute one of the most constant clinical features of yellow fever, we set out to study this diathesis in an attempt to analyze the vascular and physicochemical factors that might explain its causes. Tourniquet tests in 30 patients were negative, hence we decided no capillary fragility existed. Contrary to some statements in the literature, we found that coagulation and bleeding times were considerably increased in some cases, while in others they fell within normal limits. Furthermore we noted at times that both were prolonged, while at other times only the coagulation time was prolonged and the bleeding time was normal. In spite of prolonged bleeding time the platelet counts were maintained between 100,000 and 200,000 in 9 cases so studied.