Plasmodium vivax infection impersonating Plasmodium falciparum malaria

A 73-year-old woman came to the casualty ward with symptoms of syncopal attacks, weakness, fever with chills and rigors. A provisional diagnosis of Plasmodium vivax malaria was made after the blood investigations. She had deranged renal function tests, altered sensorium and low platelet count. Repeated tests for P. falciparum (Card test) were negative. Glucose-6-Phosphate dehydrogenise (G6PD) levels were within normal limits. Treatment for P. vivax was started with intravenous quinine initially followed by oral quinine for a period of seven days and patient responded to the treatment and was discharged within 2 weeks of admission. Most of the cases of P. vivax present with typical and predictable features, although atypical cases with characteristics of P. falciparum can occur, especially in the elderly.