9.2.3.1 Acute headache attributed to other systemic infection

Patient: Male, 35 years old, recently traveled to a malaria-endemic region (Brazilian Amazon). History: Reports sudden onset of diffuse, throbbing, and intense headache for 24 hours, associated with high fever (40°C), chills, profuse sweating, and generalized myalgia. Describes prostration, but without neck stiffness, vomiting, or visual disturbances. Physical Examination: Mild hepatosplenomegaly, slight jaundice. Complementary Tests: Complete blood count: Anemia (Hb 10 g/dL), thrombocytopenia (platelets 90,000/mm³), mild leukocytosis (11,000/mm³). Thick blood smears and blood smear: Positive for Plasmodium vivax. PCR for malaria: Positive. CSF (lumbar puncture performed due to intense headache): Normal (excluding meningoencephalitis). Total bilirubin and AST/ALT: Slightly elevated (suggesting hemolysis).