EBM Consult

Lumbar Punture: Risk Factors for Brain Stem Herniation in Adults Suspected of Having Bacterial Meningitis


Diagnostic lumbar puncture (LP) results in a mild and transient reduction in cerebral spinal fluid (CSF) pressure due to removal of CSF for diagnostic purposes and ongoing low-volume leakage of CSF from the site of arachnoid membrane puncture.  In the presence of intracranial space occupying lesions (inflammatory, neoplastic, or hemorrhagic) or other inflammatory conditions that increase CSF pressure, diagnostic LP can create an acute pressure gradient that results in downward displacement of the cerebrum and brainstem. This places patients at risk for cerebral herniation, a rare but often-terminal complication. While the clinical entities for which LP is used as a diagnostic tool (ie. subarachnoid hemorrhage and acute bacterial meningitis) demand prompt treatment, every effort should be made to protect against LP-induced cerebral herniation.

Current Recommendations:

Adult patients with suspected bacterial meningitis with any one of the following baseline characteristics should be considered for a head CT scan prior to undergoing LP:

  • Age ≥ 60 years of age
  • Immunocompromised state (e.g., HIV, AIDS, receiving immunosuppressive drugs, organ transplantation)
  • History of CNS disease (mass lesion, stroke, and focal infection)
  • Seizure within 1 week prior to presentation
  • Papilledema (showing absence of venous pulsations)
  • Neurologic findings (abnormal level of consciousness, inability to answer 2 questions correctly or follow 2 commands correctly, gaze palsy, abnormal visual fields, facial palsy, arm drift, leg drift, abnormal language [aphasia, dysarthria, etc])

If all of the above characteristics are negative, the negative predictive value (for abnormality on head CT) is 97%.

Clinical Considerations:

  • The best prospective data for risk of major adverse event from LP is in the context of patients with bacterial meningitis. 
  • Choosing to perform CT prior to LP prolongs time to LP by 2-3 hours and may also increase the time to initiation of antimicrobial therapy.   The IDSA recommends blood cultures and initiation of antimicrobials prior to CT in these patients.
  • A normal head CT does not rule out risk of LP-induced cerebral herniation. Indeed, patients with bacterial meningitis are at risk for cerebral edema and nearly one third of deaths are related to cerebral herniation. In patients with signs of impending herniation, LP should be avoided regardless of CT findings.


  • Anthony J. Busti, MD, PharmD, FNLA, FAHA
  • Jeremiah Hinson, MD, PhD

Last Reviewed:  October 2015

Supporting Guidelines

  • IDSA (Infectious Disease Society of America):

    "Adult patients with suspected bacterial meningitis and have any of the following criteria (immunocompromised states, history of CNS disease, new onset seizures, papilledema, abnormal level of consciousness, focal neurological deficit) should get a head CT prior to getting an LP."

    • Guideline Rating:  Class B-II
    • Reference:  IDSA Practice Guidelines for the Management of Bacterial Meningitis:  Clin Infec Dis 2004;39:1267-84.  PubMed

Landmark or Original Studies

  • Hasbun R et al. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med 2001;345:1727-33. PubMed

Supporting Studies

  • Gopal AK et al. Cranial computed tomography before lumbar puncture. Arch Intern Med 1999;159:2681-2685. PubMed
  • Baker ND et al. The efficacy of routine head computed tomography (CT scan) prior to lumbar puncture in the emergency department. J Emerg Med 1994;12(5):597-601. PubMed

Related Articles & Reviews

  • Joffe AR. Lumbar puncture and brain herniation in acute bacterial meningitis: a review. J Intensive Care Med 2007;22(4):194-207. PubMed
  • Van Crevel H et al. Lumbar puncture and the risk of herniation: when should we perform CT? J Neurol 2002;249(2):129-137. PubMed

Other EBM Consult Related Content


  • Lumbar Puncture, LP, Brainstem Herniation