title: Primary continuous unilateral headaches: a nosologic model for hemicrania continua.
abstract: BACKGROUND
  Hemicrania continua was originally described as a strictly unilateral, continuous headache with an absolute response to indomethacin. Recognition of an increasing number of patients with the same clinical features except for a lack of response to indomethacin has generated controversy about whether the responsive/non-responsive phenotypes belong to the same disorder.
  
  
  CONCLUSIONS
  We suggest that the non-responsive phenotype should be differentiated from the original concept of hemicrania continua, because it probably indicates a separate type of headache of undetermined nature, i.e. hemicrania incerta. However, differentiating hemicrania incerta from hemicrania continua does not imply that the two headaches are unrelated. Both hemicranias may outline a continuum, giving rise to a broader diagnostic field.
  
  
  CONCLUSIONS
  There seems to be a syndrome of 'primary continuous unilateral headache' with at least two distinctive categories: hemicrania continua and hemicrania incerta, which are differentiated by their respective response to indomethacin. This division means plurality but adds precision, and allows a clear-cut diagnosis of some controversial cases.
authors.affiliation: Fundación Alcorcón University Hospital, Alcorcón, Madrid, Spain. japareja@fhalcorcon.es
authors.forename: Juan A
authors.initials: JA
authors.lastname: Pareja
authors.forename: María-Luz
authors.initials: ML
authors.lastname: Cuadrado
authors.forename: César
authors.initials: C
authors.lastname: Fernández-de-las-Peñas
authors.forename: Teresa
authors.initials: T
authors.lastname: Montojo
authors.forename: Mónica
authors.initials: M
authors.lastname: Álvarez
authors.forename: Carlos
authors.initials: C
authors.lastname: López-de-Silanes
mesh_terms: D003937:Diagnosis, Differential; D051270:Headache Disorders, Primary / Q000145:classification* / Q000175:diagnosis*; D006801:Humans; D038801:International Classification of Diseases; D008881:Migraine Disorders / Q000145:classification* / Q000175:diagnosis*