Increased total concentration of amino acids in the cerebrospinal fluid of patients with purulent meningitis.

Total concentrations of amino acids, as measured by fluorometry of primary amino nitrogen with the use of fluorescamine, were determined in the cerebrospinal fluid (CSF) of 50 patients with purulent meningitis, 40 patients with aseptic meningitis, and 36 control subjects. On admission total concentrations of amino acids in the CSF were significantly higher in patients with purulent meningitis (mean +/- SEM, 2.27 +/- 0.27 mM) than in patients with aseptic meningitis (1.07 +/- 0.03 mM, P less than 0.001) or in control subjects (1.16 +/- 0.04 mM, P less than 0.001). This value was higher when the patients with purulent meningitis were reexamined one to two days later and reached a maximum after three to four days of illness. The fluorometry method proved to be simple, rapid, and precise and may be used as an additional test in diagnosing bacterial meningitis, especially in patients who are treated with antibiotics before admission. For patients with bacterial meningitis, a high concentration of amino acids in the CSF on admission may indicate a poor outcome.