title: [Hypnic headache: characteristics of a series of 13 new cases and proposal for modification of the diagnostic criteria].
abstract: BACKGROUND
  Hypnic headache is a rare condition, since less than 150 cases have been reported to date. The second edition of the International Headache Classification (IHC2) has set out the diagnostic criteria of this condition, although some of them can be considered excessively strict.
  
  
  OBJECTIVE
  To present a series of 13 new cases of hypnic headache that were dealt with in the headache unit of a tertiary hospital and to analyse how well they fit the diagnostic criteria of the IHC2.
  
  
  METHODS
  Between January 2008 and January 2011, 13 patients (11 females and 2 males), out of a total of 1180 who visited the above-mentioned service (1.1%), were diagnosed with hypnic headache. The characteristics of the pain and the response to prophylactic treatment were evaluated.
  
  
  RESULTS
  The age of onset of the clinical signs and symptoms was 56.7 ± 9.3 years (range: 40-76 years); in two patients (15.4%) it was prior to the age of 50. The number of symptomatic nights per month was 14.5 ± 7.6 (range: 5-25); in seven cases (53.8%) the number was less than 15 nights. All the patients presented one single episode per night, with a mean duration of 53.8 ± 24.6 minutes (range: 25-120 minutes). Thirty point seven per cent of the patients did not describe their pain as dull. Sixty-one point five per cent satisfied all the IHC2 diagnostic criteria.
  
  
  CONCLUSIONS
  The characteristics of our series were similar to others that have recently been published. We propose that the next criteria in the IHC should include the possibility of the pain not being dull and that it occurs on fewer than 15 nights per month. The lower limit for the age of onset could be reduced to 40 years.
authors.affiliation: Servicio de Neurología, Hospital Clinico Universitario de Valladolid, 47005 Valladolid, Espana.
authors.forename: Patricia
authors.initials: P
authors.lastname: Mulero
authors.forename: Angel L
authors.initials: AL
authors.lastname: Guerrero-Peral
authors.forename: Elisa
authors.initials: E
authors.lastname: Cortijo
authors.forename: Najaty S
authors.initials: NS
authors.lastname: Jabary
authors.forename: Sonia
authors.initials: S
authors.lastname: Herrero-Velázquez
authors.forename: Sara
authors.initials: S
authors.lastname: Miranda
authors.forename: M Luz
authors.initials: ML
authors.lastname: Penas-Martinez
authors.forename: María
authors.initials: M
authors.lastname: Pedraza
authors.forename: Rosa
authors.initials: R
authors.lastname: Fernández-Herranz
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D005260:Female; D051270:Headache Disorders, Primary / Q000175:diagnosis* / Q000503:physiopathology* / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies