Plasma glutamine and glutamate concentrations in Gabonese children with Plasmodium falciparum infection

Background: Low plasma glutamine levels in critical illness, neonates and burns patients are associated with poor outcome and increased risk of intercurrent infection. Aim: To investigate the relationship between plasma glutamine/glutamate levels and severity/outcome of malaria. Design: Two-hospital prospective study, with both febrile and healthy controls. Methods: We measured plasma glutamine and glutamate concentrations in 239 Gabonese patients: 145 children with malaria (86 with severe, 36 with moderate and 23 with uncomplicated disease), 42 healthy children, 44 febrile controls and eight healthy adults, and related findings to conventional markers of disease severity such as plasma lactate. Results: Median (IQR) plasma glutamine was lower in uncomplicated falciparum malaria and in moderate malaria than in healthy controls. 353 (287-474) and 379 (293-448) vs. 485 (428-531) mumol/l, respectively; p<0.01 for both malaria groups vs. controls. In contrast, plasma glutamine was within the normal range in those with severe malaria and in febrile control children: 431 (342-525) and 472 (338-547) mumol/l, respectively. Furthermore, plasma glutamine was significantly higher in the children who died with malaria than in survivors: 514 (374-813) (n=12) vs. 399 (316-475) mumol/l (n=133), respectively; p=0.001. There were no significant differences in plasma glutamate concentrations between any of the study groups. Discussion: In severe malaria, there was a positive correlation between plasma glutamine and lactate levels (p=0.009, r=0.281). This correlation may reflect impaired gluconeogenesis. Glutamine supplementation is probably not justified in severe P. falciparum infection.