title: Risk factors for pediatric arachnoid cyst rupture/hemorrhage: a case-control study.
abstract: BACKGROUND
  As the availability of imaging modalities has increased, the finding of arachnoid cysts has become common. Accurate patient counseling regarding physical activity or risk factors for cyst rupture or hemorrhage has been hampered by the lack of definitive association studies.
  
  
  OBJECTIVE
  This case-control study evaluated factors that are associated with arachnoid cyst rupture (intracystic hemorrhage, adjacent subdural hematoma, or adjacent subdural hygroma) in pediatric patients with previously asymptomatic arachnoid cysts.
  
  
  METHODS
  Patients with arachnoid cysts and intracystic hemorrhage, adjacent subdural hygroma, or adjacent subdural hematoma treated at a single institution from 2005 to 2010 were retrospectively identified. Two unruptured/nonhemorrhagic controls were matched to each case based on patient age, sex, anatomical cyst location, and side. Risk factors evaluated included arachnoid cyst size, recent history of head trauma, and altitude at residence.
  
  
  RESULTS
  The proportion of imaged arachnoid cysts that presented either originally or subsequently with a rupture or hemorrhage was 6.0%. Larger cyst size, as defined by maximal cyst diameter, was significantly associated with cyst rupture/hemorrhage (P < .001). When dichotomized with a 5-cm cutoff, 9/13 larger cysts ruptured and/or hemorrhaged, whereas only 5/29 smaller cysts ruptured/hemorrhaged (odds ratio = 16.5 (confidence interval [2.5, ∞]). A recent history of head trauma was also significantly associated with the outcome (P < .001; odds ratio = 25.1 (confidence interval [4.0, ∞]). Altitude was not associated with arachnoid cyst rupture or hemorrhage.
  
  
  CONCLUSIONS
  This case-control study suggests that larger arachnoid cyst size and recent head trauma are risk factors for symptomatic arachnoid cyst rupture/hemorrhage.
authors: Department of Neurosurgery, University of Missouri, Columbia, Missouri, USA.
authors: Marshall
authors: M
authors: Cress
authors: John R W
authors: JR
authors: Kestle
authors: Richard
authors: R
authors: Holubkov
authors: Jay
authors: J
authors: Riva-Cambrin
mesh_terms: D000328:Adult; D000531:Altitude; D016080:Arachnoid Cysts / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D016022:Case-Control Studies; D002533:Cerebral Angiography / Q000706:statistics & numerical data*; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D012421:Rupture / Q000000981:diagnostic imaging / Q000453:epidemiology; D016896:Treatment Outcome; D014589:Utah / Q000453:epidemiology