A 32-year-old woman from Mumbai presents with fever, chills, and headache for 3 days. Blood smear microscopy confirms Plasmodium vivax malaria with parasitemia of 2%. She is haemodynamically stable and has no signs of severe malaria. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has uncomplicated P. vivax malaria (parasitemia <5%, haemodynamically stable, no organ dysfunction). ## Treatment Algorithm for P. vivax **Key Point:** Uncomplicated P. vivax malaria is treated with chloroquine as first-line therapy in most endemic regions of India, followed by a hypnozoiticide to prevent relapse. **High-Yield:** The standard regimen for P. vivax is: - **Chloroquine base:** 600 mg stat → 300 mg at 6, 24, and 48 hours (total 1.5 g over 3 days) - **Primaquine:** 0.5 mg/kg/day for 14 days (to eliminate hypnozoites and prevent relapse) **Clinical Pearl:** P. vivax remains chloroquine-sensitive in most of India. Primaquine is essential because P. vivax forms hypnozoites in the liver; without it, relapse occurs in 40–50% of patients. **Warning:** Primaquine must be preceded by G6PD screening in high-risk populations (Africans, Mediterranean, Asian descent) to avoid haemolysis. This patient's G6PD status should be assessed, but empiric initiation of the standard regimen is the immediate next step. ## Why Not the Other Options? Artemether/artesunate are reserved for severe malaria (cerebral involvement, acute kidney injury, pulmonary oedema, parasitemia >5%). This patient is uncomplicated. Quinine is second-line for severe malaria or chloroquine-resistant P. falciparum; it is not indicated here.