Cerebral herniation after lumbar puncture in sarcoid meningitis.

A patient with chronic meningitis due to neurosarcoidosis became comatose within minutes of a lumbar puncture and died 24 h later. The diagnosis of neurosarcoidosis was made post mortem. Development of cerebral herniation may have been exacerbated by lumbar puncture. It was proposed that arachnoid villi dysfunction may have contributed to very high intracranial pressures in this patient, since post mortem examination revealed communication between the ventricles and outlet foramina of the fourth ventricle, and that herniation was in part due to an acute pressure differential caused by lumbar puncture.