The need to repeat lumbar puncture.

Four patients with bacterial meningitis are reported. On initial examination 1 patient had a slightly abnormal cerebrospinal fluid (CSF), and in the other 3 patients the CSF was completely normal. An obviously purulent CSF was obtained when lumbar puncture was repeated 14-48 hours later. All 4 patients presented initially with pyrexia, and either neck stiffness or convulsions. In 3 of the 4 patients a cause for pyrexia was found on initial examination but lumbar punctures were done for neck stiffness or convulsions to exclude meningitis. The problems and the need to repeat a lumbar puncture, as well as the importance of blood cultures in a patient with suspected meningitis, are discussed. The fact that a normal specimen of CSF does not exclude meningitis is stressed.