title: Seizure risk from cavernous or arteriovenous malformations: prospective population-based study.
abstract: OBJECTIVE
  To determine the risk of epileptic seizures due to a brain arteriovenous malformation (AVM) or cavernous malformation (CM).
  
  
  METHODS
  In a prospective population-based study of new diagnoses of AVMs (n = 229) or CMs (n = 139) in adults in Scotland in 1999-2003, we used annual medical records surveillance, general practitioner follow-up, and patient questionnaires to quantify the risk of seizures between clinical presentation and AVM/CM treatment, last follow-up, or death.
  
  
  RESULTS
  The 5-year risk of first-ever seizure after presentation was higher for AVMs presenting with intracranial hemorrhage or focal neurologic deficit (ICH/FND: n = 119; 23%, 95% confidence interval [CI] 9%-37%) than for incidental AVMs (n = 40; 8%, 95% CI 0%-20%), CMs presenting with ICH/FND (n = 38; 6%, 95% CI 0%-14%), or incidental CMs (n = 57; 4%, 95% CI 0%-10%). For adults who had never experienced ICH/FND, the 5-year risk of epilepsy after first-ever seizure was higher for CMs (n = 23; 94%, 95% CI 84%-100%) than AVMs (n = 37; 58%, 95% CI 40%-76%; p = 0.02). Among adults who never experienced ICH/FND and presented with or developed epilepsy, there was no difference in the proportions achieving 2-year seizure freedom over 5 years between AVMs (n = 43; 45%, 95% CI 20%-70%) and CMs (n = 35; 47%, 95% CI 27%-67%).
  
  
  CONCLUSIONS
  AVM-related ICH confers a significantly higher risk of a first-ever seizure compared to CMs or incidental AVMs. Adults with a CM have a high risk of epilepsy after a first-ever seizure but achieve seizure freedom as frequently as those with epilepsy due to an AVM.
authors.affiliation: Bramwell Dott Building, Division of Clinical Neurosciences, Centre for Clinical Brain Sciences, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU.
authors.forename: C B
authors.initials: CB
authors.lastname: Josephson
authors.forename: J-P
authors.initials: JP
authors.lastname: Leach
authors.forename: R
authors.initials: R
authors.lastname: Duncan
authors.forename: R C
authors.initials: RC
authors.lastname: Roberts
authors.forename: C E
authors.initials: CE
authors.lastname: Counsell
authors.forename: R
authors.initials: R
authors.lastname: Al-Shahi Salman
mesh_terms: D000328:Adult; D004827:Epilepsy / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D020786:Hemangioma, Cavernous, Central Nervous System / Q000150:complications*; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D011446:Prospective Studies; D012306:Risk; D012606:Scotland / Q000453:epidemiology; D012640:Seizures / Q000453:epidemiology* / Q000209:etiology; D011795:Surveys and Questionnaires