HMS-related hemolysis after acute attacks of Plasmodium vivax malaria

Among a cohort of 1,213 cases treated for Plasmodium vivax malaria from an isolated Papua New Guinean population, seven adults with severe and sustained hemolytic anemia after clearance of the peripheral parasitemia were prospectively investigated. All the patients fulfilled the criteria for hyper-reactive malarial splenomegaly and in 2 of 7 cases an IgG warm antibody was identified. Hereditary hemolytic anemia was excluded in 5 of 5 patients. All treated cases improved after an initial high dose of prednisone and antimalarial chemoprophylaxis. The persistence of marked anemia in a patient with splenomegaly after a P. vivax attack should raise the suspicion of hyper-reactive malarial splenomegaly.