Walsh & Hoyt: Diagnosis

Malaria usually is suspected when the typical symptoms and signs occur in the appropriate epidemiologic setting. Laboratory studies consistent with the diagnosis include a normochromic normocytic hemolytic anemia, leukopenia, and thrombocytopenia. There is no peripheral eosinophilia. The urine of affected patients frequently contains small amounts of protein, probably related to the effects of fever. Electrolyte balance may be disturbed by several factors, including dehydration, vomiting, tissue hypoxia, tachypnea, renal failure, and homeostatic responses to decreased effective plasma volume. The serum may contain increased concentrations of transaminases and bilirubin, consistent with abnormal liver function.