Chance of aneurysm in patients suspected of SAH who have a 'negative' CT scan but a 'positive' lumbar puncture

J Neurol. 2012 Apr;259(4):649-52. doi: 10.1007/s00415-011-6228-1. Epub 2011 Sep 8.


In patients with sudden severe headache and a negative computed tomography (CT) scan, a lumbar puncture (LP) is performed to rule in or out a subarachnoid haemorrhage (SAH), but this procedure is under debate. In a hospital-based series of 30 patients with sudden headache, a negative CT scan but a positive LP (defined as detection of bilirubin >0.05 at wavelength 458 nm), we studied the chance of harbouring an aneurysm and the clinical outcome. Aneurysms were found in none of both patients who presented within 3 days, in 8 of the 18 (44%) who presented within 4-7 days and in 5 of the 10 (50%) who presented within 8-14 days. Of the 13 patients with an aneurysm, 3 (23%) had poor outcome. In patients who present late after sudden headache, the yield in terms of aneurysms is high in those who have a positive lumbar puncture. In patients with an aneurysm as cause of the positive lumbar puncture, outcome is in the same range as in SAH patients admitted in good clinical condition.

MeSH terms

  • Adult
  • Aged
  • Bilirubin / cerebrospinal fluid
  • Female
  • Headache Disorders, Primary / etiology
  • Humans
  • Intracranial Aneurysm / cerebrospinal fluid
  • Intracranial Aneurysm / complications
  • Intracranial Aneurysm / diagnostic imaging
  • Male
  • Middle Aged
  • Spinal Puncture
  • Subarachnoid Hemorrhage / cerebrospinal fluid*
  • Subarachnoid Hemorrhage / complications
  • Subarachnoid Hemorrhage / diagnostic imaging*
  • Subarachnoid Hemorrhage / etiology
  • Time Factors
  • Tomography, X-Ray Computed


  • Bilirubin