title: Axonal damage and outcome in subarachnoid haemorrhage.
abstract: BACKGROUND
  On the basis of preliminary evidence from patients with subarachnoid haemorrhage (SAH), axonal degeneration is thought to be an underestimated pathological feature.
  
  
  METHODS
  A longitudinal study in 17 patients with aneurysmal SAH. Ventricular CSF was collected daily for up to 14 days. The neurofilament heavy chain(SMI35) (NfH(SMI35), a biomarker for axonal damage) was quantified using a standard ELISA (upper limit of normal 0.73 ng/ml). The primary outcome measure was the Glasgow Outcome Score (GOS) at 3 months.
  
  
  RESULTS
  Of 148 samples from patients with SAH, pathologically high NfH levels in the CSF were found in 78 (52.7%) samples, compared with 20 (5%) of 416 samples from the reference population (p<0.0001). A pathological increase in NfH was observed in all patients with a bad outcome (GOS 1-3) compared with 8% of those with a good outcome (GOS 4-5, p<0.0001). This increase typically became significant 7 days after the haemorrhage (p<0.01). The result was confirmed by analysing the individual mean NfH concentrations in the CSF (3.45 v 0.37 ng/ml, p<0.01), and was reinforced by the inverse correlation of NfH in the CSF with the GOS (r = -0.65, p<0.01). Severity of injury was found to be correlated to NfH(SMI35) levels in the CSF (World Federation of Neurological Surgeons, r = 0.63, p<0.01 and Glasgow Coma Score, r = -0.61, p<0.01).
  
  
  CONCLUSIONS
  Patients with SAH thus have secondary axonal degeneration, which may adversely affect their outcome.
authors.affiliation: Department of Neuroimmunology, Institute of Neurology, The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK. a.petzold@ion.ucl.ac.uk
authors.forename: A
authors.initials: A
authors.lastname: Petzold
authors.forename: G
authors.initials: G
authors.lastname: Keir
authors.forename: A
authors.initials: A
authors.lastname: Kay
authors.forename: M
authors.initials: M
authors.lastname: Kerr
authors.forename: E J
authors.initials: EJ
authors.lastname: Thompson
mesh_terms: D000328:Adult; D000368:Aged; D001369:Axons / Q000473:pathology*; D015415:Biomarkers / Q000134:cerebrospinal fluid*; D005260:Female; D023261:Glasgow Outcome Scale; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016900:Neurofilament Proteins / Q000134:cerebrospinal fluid*; D011379:Prognosis; D012720:Severity of Illness Index; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000503:physiopathology
chemical_list: D015415:Biomarkers; D016900:Neurofilament Proteins; C051774:neurofilament protein H