Fatal lumbar puncture: fact versus fiction--an approach to a clinical dilemma.

Recent reports and commentaries have emphasized the alleged risk of cerebral herniation complicating lumbar puncture performed to diagnose acute bacterial meningitis. Instead, knowledge of facts relevant to the disease process can provide a rational and reassuring approach to management. All cases of purulent meningitis are associated with increased intracranial pressure, but herniation is a rare complication (5%). Despite suggestions to the contrary, cranial computed tomography (CT) is normal in most cases of purulent meningitis, including those with subsequent herniation. Additionally, CT may be associated with long-term radiation effects. An accurate clinical history combined with recognition of the early systemic and neurologic findings of bacterial meningitis will indicate a safe setting for performance of a diagnostic lumbar puncture with little likelihood of complicating herniation. In contrast, in patients in whom the disease process has progressed to the neurologic findings associated with impending cerebral herniation, a delay of the diagnostic procedure is indicated. In this latter circumstance, a different approach in management can be developed.