Cerebrospinal fluid lactic acidosis in bacterial meningitis

A rapid, microenzymatic method was used to measure cerebrospinal fluid lactate levels in 205 children with suspected bacterial meningitis. Fifty children with normal CSF containing fewer than 0.005 X 10(9)/l WBC, no segmented neutrophils, glucose 3.4 +/- 0.8 mmol/l (61.2 +/- 14.4 mg/100 ml), and a protein of less than 0.30 g/l had CSF lactate levels below 2.0 mmol/l (18 mg/100 ml) (mean and standard deviation 1.3 +/- 0.3 mmol/l (11.8 +/- 2.7 mg/100 ml)). In 31 cases of proved viral meningitis as with 58 cases of clinically diagnosed viral meningitis, levels were below 3.8 mmol/l (34.5 mg/100 ml), being 2.3 +/- 0.6 mmol/l (20.9 +/- 5.4 mg/100 ml), and 2.1 +/- 0.7 mmol/l (19.1 +/- 6.4 mg/100 ml) respectively. Sixty-six cases of bacterial meningitis had CSF lactate levels ranging from 3.9 mmol/l (35.4 mg/100 ml) to greater than 10.0 mmol/l (90.0 mg/100 ml). Longitudinal studies in 7 children with bacterial meningitis showed that cerebrospinal fluid lactate levels differentiated bacterial from viral meningitis up to 4 days after starting treatment with antibiotics. Use of CSF lactate measurement for monitoring the efficacy of treatment is illustrated in a case of bacterial meningitis due to Pseudomonas aeruginosa. The origin of the cerebrospinal fluid lactate acidosis and the role of lactate in the pathophysiological cycle leading to intensification of brain tissue hypoxia and cellular damage is discussed with respect to the short-term prognosis and the long-term neurological sequelae.