BACKGROUND: The circulating cholinesterases acetyl- and butyrylcholinesterase may be suppressed and subsequently released from the brain in acute bacterial meningitis.

METHODS: We report serum activities of acetylcholinesterase and butyrylcholinesterase in paired arterial and jugular venous samples from seven patients with acute bacterial meningitis and eight healthy controls. Paraoxonase 1, which protects these enzymes from oxidative inactivation, was also measured.

FINDINGS AND CONCLUSION: Acetyl- and butyrylcholinesterase activities were lower in patients, independently of changes in paraoxonase 1. Arterial and jugular venous enzyme activities were similar both in patients and controls, suggesting that no cerebral release was present.