Serum ionized calcium, serum and intracellular phosphate, and serum parathormone concentrations in acute malaria

Previous studies have shown depressed serum corrected calcium and phosphate concentrations in acute falciparum malaria. To characterize malaria-associated disturbances in mineral homoeostasis further, serum ionized calcium and intracellular phosphate were measured in 18 patients (10 with falciparum malaria, 8 with vivax malaria) and 10 healthy controls. Six patients (4 falciparum, 2 vivax) had admission serum ionized calcium concentrations below the absolute control range ( 0·1), but serum and intracellular phosphate correlated significantly ( r s = 0·71, n = 17, P < 0·001) with a regression line slope of 0·49 and intercept of 0·27 mmol/litre of red cells. These results confirmed that mild ionized hypocalcaemia in the presence of a depressed parathormone response is common in acute malaria; although the serum phosphate may also be low, intracellular phosphate does not necessarily fall by an equivalent amount.