Effect of Triphenylarsine on the Number of Blood Platelets.

Abstract

The blood platelets show characteristic variations in number after the intravenous injection of certain toxic substances and during certain acute infectious diseases. At first, following the injection of the substance or during the febrile period of the disease the number of platelets is diminished. The period of thrombopenia is then usually followed by a rapid rise to the normal number (350,000 per cu. mm.) and often by a period of thrombocytosis, the number occasionally reaching 750,000 per cu. mm. or more.

It has been suggested that thrombosis may occur more readily as a result of the excessive number of platelets, although they are not the sole factor in the formation of thrombi. 1 Hartmann 2 has pointed out that the appearance of thrombosis which occurs during convalescence from typhoid fever coincides with the period of thrombocytosis. Recently a case in this hospital of cerebral thrombosis developing 5 days after the intravenous injection of 0.6 gm. of neoarsphenamin suggested the possibility of a similar relationship, although platelet counts were not made at the time.

Several investigators have observed the immediate diminution of the number of platelets following arsphenamin therapy and numerous cases of purpura occurring after arsphenamin treatment are recorded. However, little or no attention has been given to the later period when thrombocytosis may occur. The following observations were made to determine whether or not thrombocytosis follows the period of thrombopenia subsequent to the intravenous injection of neoarsphenamin (novarsenobenzol “Billon”).

The effect of the injection of the drug on the number of platelets of 14 patients was studied. The usual dosage given was 0.1 g. per kg. of body weight. The direct method of counting 3 was employed. Counts were made before the injection and then at intervals of from 10 minutes to 1 day after the injection for 5 days.