[A Case of Blackwater Fever after Treatment for Plasmodium falciparum Malaria].

Blackwater fever (BWF), which causes massive intravascular hemolysis and the passage of black-colored urine, is a poorly understood condition that is rarely seen during the course of malaria. Here, we present a case of BWF that developed after treatment for falciparum malaria complicated by hyperparasitemia in a Japanese traveler. A 29-year-old woman returning from Ghana visited our travel clinic with complaints of sudden fever and headache on the third day of illness. She had taken anti-malarial drugs for intermittent malaria prophylaxis and the treatment of malaria while in Ghana. Falciparum malaria was diagnosed based on the results of a blood smear and was confirmed using PCR. She was successfully treated with a single artesunate suppository and one dose of intravenous quinine followed by artemether-lumefantrin for 3 days. She was discharged without complications on the 11th day of illness. However, she was re-admitted for fever and headache on the 16th day of illness. The recrudescence of malaria was excluded by peripheral blood smear results. BWF was diagnosed based on the presence of fever, black-colored urine, and laboratory findings suggesting intravascular hemolysis. She was treated with supportive care, including the transfusion of 10 packs of red blood cells and the maintenance of fluid and electrolyte balance, and she gradually improved within two weeks. BWF is a rare but severe complication induced by severe falciparum malaria and/or the use of the aryl-amino alcohol group of antimalarial drugs. Thus, consideration of BWF is particularly important for a rapid and accurate diagnosis.