ObjectivesMeningococcal disease is a homogeneous and well-characterized form of sepsis. Cardiovascular collapse is prominent in severe meningococcal disease. Nitric oxide overproduction may be a mediator of cardiovascular collapse. We relate the level of nitric oxide metabolites, nitrates and nitrites, to disease severity in meningococcal disease.DesignProspective, nonrandomized study.SettingTertiary referral pediatric intensive care unit.PatientsChildren admitted with a clinical diagnosis of meningococcal disease.InterventionsBlood was sampled from children with meningococcal disease. Disease severity was scored using the Glasgow meningococcal septicemia prognostic score and pediatric risk of mortality score. Plasma nitrates and nitrites were measured in stored plasma using the Greiss reaction after conversion of all the nitrate to nitrite.Measurements and Main Resultsor=to8 (severe). Three children died, all of these being in the severely affected group. Higher levels of nitrates and nitrites were seen in the more severely affected children (median admission nitrates and nitrites, 27.5 vs. 59.7 nmol/mL; p = 0.063; median peak nitrates and nitrites, 49.9 vs. 114 nmol/mL; p = .01) or those with an increased predicted mortality using pediatric risk of mortality (Spearman's rho 0.742; p = .0003).ConclusionsHigher levels of nitrates and nitrites are seen in sicker children with meningococcal disease. (Crit Care Med 1999;27:1187-1190)