MED-19. Severe thrombocytopenia secondary to Plasmodium vivax infection.

As implied by its descriptive name, "benign tertian malaria," infection due to Plasmodium vivax is generally not fatal. While severe thrombocytopenia is one of the well-recognized complications of malaria due to P falciparum, it has been documented only rarely in association with P vivax. We report the case of a Mexican immigrant who presented to a rural Georgia hospital following the clinical onset of malaria due to P vivax and whose course was marked by profound thrombocytopenia initially unresponsive to platelet transfusions. A 30-year-old Mexican farm laborer presented with a 1-week history of intermittent severe headaches, fever and chills. He had been in good previous health and took no regular medications. He had been in the US for 1 year. On physical examination, he was a well-developed, well-nourished male who appeared his stated age. He was febrile with a temperature of 103[degrees]F. The remainder of the physical exam was normal. Initial laboratory studies were remarkable for a platelet count of 19,000/[micro]l. Many red blood cells contained parasites characteristic of P vivax. The patient was begun on quinine sulfate and doxycycline. Three hours later, his platelet count dropped to 6,000/[micro]l. He received 10 units of platelets, but his platelet count rose to only 24,000/[micro]l. Eighteen hours later he experienced spontaneous epistaxis and received 10 additional units of platelets. His platelet count rose to 64,000/[micro]l; the bleeding stopped. His platelet count remained in the 50-60,000/[micro]l range for 3 days and then normalized. He also received chloroquine to treat residual hepatic forms (hypnozoites). While mild thrombocytopenia is frequently seen in malaria due to P vivax, there are only two previous cases in the world literature of associated severe thrombocytopenia. The mechanism remains speculative but is believed due to increased peripheral platelet consumption rather than to decreased marrow production.

Benjamin H. Holland, Anna N. Walker, MD, Lee Collier, MD, and Jeffrey L. Stephens, MD. Mercer University School of Medicine, Macon GA. Department of Internal Medicine, Taylor Regional Hospital, Hawkinsville GA.