title: Cerebral venous thrombosis at high altitude: A systematic review.
abstract: OBJECTIVE
  High altitude may be a factor associated with cerebral venous thrombosis (CVT). As our knowledge of CVT at high altitude is limited, it was decided to pool such information from the available case studies to determine whether high altitude can predispose to CVT.
  
  
  METHODS
  A systematic review of the literature was performed for cases reporting CVT at high altitude. Searches of the PubMed database (up to July 2016) were performed for publications, using 'cerebral venous thrombosis' and 'high altitude' as keywords. Cross-referencing was also done to complete the search.
  
  
  RESULTS
  Ultimately, 13 articles were included in our systematic review. The population consisted of 17 patients, predominately male (14/17), with a mean age of 32 (range: 19-47) years. Altitude range was 3000-8200m. Nine patients stayed at high altitude for>2 weeks; the duration of high altitude stay was unknown for the remainder. A hypercoagulable state was found in nine patients: secondary polycythemia in five; protein C deficiency in one; protein S deficiency in one; and factor V Leiden mutations in two. No comorbidities were found in any of these patients.
  
  
  CONCLUSIONS
  Long-term stays at high altitude in association with a hypercoagulable state - in particular, congenital or acquired thrombophilia - appears to predispose to CVT. The association of CVT with a single exposure to high altitude seems low, but the risk cannot as yet be specifically estimated.
authors.affiliation: UPMC Paris 6, centre de recherche de l'Institut du cerveau et de la moelle epinière, Inserm 1127, CNRS S_975, ARAMIS, 75013 Paris, France; Neurorehabilitation Unit, hôpital Pitié-Salpêtrière, AP-HP, 75013 Paris, France. Electronic address: chiara.zavanone@aphp.fr.
authors.forename: C
authors.initials: C
authors.lastname: Zavanone
authors.affiliation: Department of Molecular and Clinical Pharmacology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom; Department of Internal Medicine, Neurologic Unit, Garibaldi Hospital, Catania, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Panebianco
authors.affiliation: Neurology Department, Saint-Antoine Hospital, AP-HP, UPMC Paris 6, 75013 Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Yger
authors.affiliation: Neurological Rehabilitation Unit, hôpital Pitié-Salpêtrière, AP-HP, UPMC Paris 6, 75013 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Borden
authors.affiliation: Department of Internal Medicine, Neurologic Unit, Garibaldi Hospital, Catania, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Restivo
authors.affiliation: Neurology Department, Padova University, Padova, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Angelini
authors.affiliation: Department of Internal Medicine, Neurologic Unit, Garibaldi Hospital, Catania, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Pavone
authors.affiliation: Neurosurgery Department, Alessandro Manzoni Hospital, Lecco, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Grimod
authors.affiliation: Urgences cérébro-vasculaires, hôpital Pitié-Salpêtrière, AP-HP, 75013 Paris, France; UPMC Paris 6, centre de recherche de l'Institut du cerveau et de la moelle epinière, Inserm 1127, CNRS S_975, CONAM, 75013 Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Rosso
authors.affiliation: UPMC Paris 6, centre de recherche de l'Institut du cerveau et de la moelle epinière, Inserm 1127, CNRS S_975, ARAMIS, 75013 Paris, France; Neurorehabilitation Unit, hôpital Pitié-Salpêtrière, AP-HP, 75013 Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Dupont
mesh_terms: D000328:Adult; D000531:Altitude; D001778:Blood Coagulation Disorders / Q000209:etiology; D005260:Female; D006801:Humans; D020767:Intracranial Thrombosis / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging; D020246:Venous Thrombosis / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology*; D055815:Young Adult
keywords: Cerebral venous thrombosis; High altitude; Hypercoagulable state; Mountain; Risk factors; Thrombophilia