title: Secondary headaches.
abstract: OBJECTIVE
  This article identifies the pertinent historical issues that lead to the identification of those headaches needing additional testing to exclude a serious underlying cause.
  
  
  RESULTS
  Recurrences of giant cell arteritis, even after presumed successful treatment, are common. Postural orthostatic tachycardia syndrome is an often unrecognized cause of headache.
  
  
  CONCLUSIONS
  Patients with a primary headache disorder are more susceptible to the development of headache when a secondary cause occurs. Their headaches may be phenotypically similar to their primary headache disorder. Therefore, a secondary cause should be considered in patients with preexisting headache disorders who develop a significant increase in the number and severity of those attacks.
authors.affiliation: Mount Sinai School of Medicine, New York, NY, USA. mark.green@mssm.edu
authors.forename: Mark W
authors.initials: MW
authors.lastname: Green
mesh_terms: D000328:Adult; D001927:Brain Diseases / Q000150:complications*; D002561:Cerebrovascular Disorders / Q000150:complications*; D005260:Female; D006261:Headache / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D001523:Mental Disorders / Q000150:complications*; D054972:Postural Orthostatic Tachycardia Syndrome / Q000150:complications*; D019966:Substance-Related Disorders / Q000150:complications