['Meningococcal 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.', 'Prospective, nonrandomized study.', 'Tertiary referral pediatric intensive care unit.', 'Children admitted with a clinical diagnosis of meningococcal disease.', 'Blood 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.', "Twenty-two children were studied. In 19, the final diagnosis was meningococcal disease. Of the 19 children with meningococcal disease, 7 had a Glasgow meningococcal septicemia prognostic score of <8 (mild) and 12 had a Glasgow meningococcal septicemia prognostic score > or = 8 (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 p 0.742; p = .0003)."] Is nitric oxide production in meningococcal disease directly related to disease severity?