title: Lactate as a diagnostic marker in transient loss of consciousness.
abstract: OBJECTIVE
  The diagnostic classification of disorders of consciousness is often challenging, particularly the distinction between epileptic and non-epileptic seizures. The aim of the study was to examine serum lactate as a diagnostic marker of transient loss of consciousness.
  
  
  METHODS
  Serum lactate levels in blood samples drawn within 2h of the event were compared retrospectively between patients with generalized tonic-clonic seizures (n=195) and patients with other seizures (syncopes [n=52], psychogenic non-epileptic seizures [n=17], and complex focal seizures [n=37]), respectively.
  
  
  RESULTS
  Serum lactate in patients with generalized tonic-clonic seizures was significantly (p<0.001, Mann-Whitney-U test) increased in comparison to other forms of seizure incidences. The area under the ROC-curve was 0.94 (95% CI 0.91-0.96). For a cut-off concentration of 2.45mmol/l, the sensitivity was 0.88 and the specificity 0.87.
  
  
  CONCLUSIONS
  Serum lactate levels in the acute diagnosis were an excellent biomarker for the discrimination of generalized seizures from psychogenic non-epileptic and syncopal events, corroborating its importance for the standard work-up of acute disturbances of consciousness.
authors.affiliation: Department of Neurology, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany. Electronic address: omatz@ukaachen.de.
authors.forename: O
authors.initials: O
authors.lastname: Matz
authors.affiliation: Department of Neurology, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Zdebik
authors.affiliation: Department of Neurology, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Zechbauer
authors.affiliation: Department of Medicine III, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Bündgens
authors.affiliation: Department of Neurology, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Litmathe
authors.affiliation: Department of Neurology, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Willmes
authors.affiliation: Department of Neurology, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany; JARA BRAIN Institute II, Jülich Aachen Research Alliance (JARA), FZ Jülich and RWTH Aachen University, Germany.
authors.forename: J B
authors.initials: JB
authors.lastname: Schulz
authors.affiliation: Department of Neurology, University Hospital, Rheinisch-Westfälische Technische Hochschule [RWTH] Aachen University, Aachen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Dafotakis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011602:Psychophysiologic Disorders / Q000097:blood*; D012189:Retrospective Studies; D012640:Seizures / Q000097:blood*; D013575:Syncope / Q000097:blood; D014474:Unconsciousness / Q000097:blood*
chemical_list: D015415:Biomarkers; D019344:Lactic Acid
keywords: Diagnostic marker; Lactate; Loss of consciousness; Seizure; Syncope