Calcium and phosphate metabolism in acute falciparum malaria.

1. Mineral homoeostasis was investigated in 172 Thai adults with acute falciparum malaria at presentation (87 males, 85 females; mean age 30 years), and prospectively in a subgroup of 10 severely ill patients. 2. Mild, asymptomatic hypocalcaemia (corrected plasma calcium concentration 1.79–2.11 mmol/l) was found in 61 cross-sectional study patients (35.5%), with no difference between those with uncomplicated (2.16 ± 0.10 mmol/l, mean ± sd, n = 89) and severe (2.18 ± 0.15 mmol/l, n = 83, P = 0.36) infections. Six prospectively studied patients were hypocalcaemic during treatment; simultaneous serum intact parathormone concentrations were inappropriately low ( 3. Plasma phosphate concentration was decreased ( 1.45 mmol/l) in 15 (8.7%). Severe phosphate depletion (plasma phosphate concentration r = 0.607, P 4. Plasma magnesium concentrations were normal (0.75–1.05 mmol/l) in 108 patients (62.8%); 45 cases (26.1%) had hypermagnesaemia and 19 (11.0%) had hypomagnesaemia. 5. These data suggest that mild hypocalcaemia is common in malaria regardless of disease severity; a depressed parathormone response may contribute. Despite malaria-associated haemolysis, hypophosphataemia is also common, but can be severe. Phosphate replacement should therefore be considered where strict monitoring of plasma phosphate concentrations is feasible.