title: The usefulness of the head-up tilt test in patients with suspected epilepsy.
abstract: OBJECTIVE
  It is estimated that approximately 20-30% of patients diagnosed with epilepsy have been misdiagnosed, and neurocardiogenic syncope (NCS) might frequently be the real cause of transient loss of consciousness (TLOC) episodes. We assessed the role of the head-up tilt test (HUTT) in patients previously diagnosed with refractory epilepsy to evaluate the ability of this test to correctly diagnose patients with NCS.
  
  
  METHODS
  We retrospectively analysed the clinical records of 107 consecutive patients with a previous diagnosis of refractory epilepsy that were taking antiepileptic drugs and who were referred for HUTT between January 2000 and December 2010. During the subsequent follow-up, we recorded the treatments performed and the recurrence of symptoms.
  
  
  RESULTS
  Complete follow-up data were available for 94 (88%) patients, and the mean follow-up period was 80±36 months. The HUTT was positive in 54% of patients. Thirty-one (33%) patients were misdiagnosed with epilepsy, and 20 (21%) patients had a dual diagnosis of NCS and epilepsy. The recurrence of TLOC was reported in 55% of the patients, but it was significantly lower in the misdiagnosed group (42% versus 64%; P=0.039).
  
  
  CONCLUSIONS
  NCS is an important cause of epilepsy misdiagnosis. The HUTT is often critical for making an accurate diagnosis and subsequently selecting the appropriate treatment for patients presenting with TLOC. The diagnostic overlap between epilepsy and NCS is not uncommon, suggesting that electroencephalographic monitoring during a HUTT may play an important role in diagnosing patients with recurrent, undiagnosed TLOC episodes.
authors.affiliation: Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal. Electronic address: inesrang@gmail.com.
authors.forename: Inês
authors.initials: I
authors.lastname: Rangel
authors.affiliation: Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Freitas
authors.affiliation: Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
authors.forename: Ana Sofia
authors.initials: AS
authors.lastname: Correia
authors.affiliation: Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Sousa
authors.affiliation: Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Lebreiro
authors.affiliation: Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: de Sousa
authors.affiliation: Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
authors.forename: Maria Júlia
authors.initials: MJ
authors.lastname: Maciel
authors.affiliation: Neurology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
authors.forename: Elsa
authors.initials: E
authors.lastname: Azevedo
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control / Q000706:statistics & numerical data; D004827:Epilepsy / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D019462:Syncope, Vasovagal / Q000175:diagnosis*; D018667:Tilt-Table Test; D055815:Young Adult
keywords: Epilepsy; Head-up tilt test; Misdiagnosis; Neurocardiogenic syncope