title: Mastoid air sinus abnormalities associated with lateral venous sinus thrombosis: cause or consequence?
abstract: BACKGROUND
  Mastoiditis is a known cause of lateral venous sinus thrombosis (LST). We have encountered patients with LST associated with mastoid abnormality on MRI without any clinical signs of infection; the significance of these abnormalities is uncertain. This study examines the relationship of LST and mastoid air sinus abnormalities systematically.
  
  
  METHODS
  We performed a retrospective clinical and radiological review of a series of 26 patients with cerebral venous thrombosis. Mastoid abnormalities were detected ipsilateral to 9 of 23 thrombosed lateral sinuses (39%) and 0 of 29 unaffected lateral sinuses (P<0.001). No patient had clinical evidence of mastoiditis. Eight of 9 patients with mastoid abnormalities were treated without antibiotics; all made uneventful clinical recoveries. Repeated MRI in 1 patient revealed reversal of the mastoid changes.
  
  
  CONCLUSIONS
  The mastoid changes observed are likely to be due to venous congestion as a consequence of LST, not mastoiditis.
authors.affiliation: Department of Neurology, Christchurch Hospital, (New Zealand). john.fink@cdhb.govt.nz
authors.forename: John N
authors.initials: JN
authors.lastname: Fink
authors.forename: David L
authors.initials: DL
authors.lastname: McAuley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D020227:Lateral Sinus Thrombosis / Q000175:diagnosis / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008416:Mastoid / Q000473:pathology*; D008417:Mastoiditis / Q000175:diagnosis; D008875:Middle Aged; D012189:Retrospective Studies; D020246:Venous Thrombosis / Q000175:diagnosis / Q000473:pathology