Hyponatraemia and hypokalaemia in adults with uncomplicated malaria in Thailand.

In a retrospective study of 1415 patients aged 15 and over, we determined the incidence of clinically important hyponatraemia and hypokalaemia in adults with uncomplicated malaria. On admission, serum concentrations of sodium (135-145 mmol/L) and potassium (3.5-5.0 mmol/L) were found outside these reference ranges in 81% of patients. Severe hypokalaemia (K+ <3.0 mmol/L) and severe hyponatraemia (Na+ <125 mmol/L occurred in 4.4% and 0.6% of the patients, respectively. For hypokalaemia (43%) and hyponatraemia (37%), hypovolaemia, blood urea to creatinine ratio and high serum glucose (>100 mg/dL) were all independent factors (P < 0.001). Other independent predictors for hypokalaemia were Plasmodium vivax infection, female gender; and for hyponatraemia, P. falciparum infection, male gender, concentrations of G-6-PD and serum bicarbonate.