title: Posterior circulation infarcts simulating anterior circulation stroke. Perspective of the acute phase.
abstract: OBJECTIVE
  Ischemic stroke patients whose initial clinical presentation suggests an involvement of the anterior circulation (AC) are sometimes found to have a posterior circulation (PC) infarct, a fact that may generate erroneous decisions in clinical management. We investigated the prevalence of this misdiagnosis in the first few hours after stroke onset.
  
  
  METHODS
  We performed a cohort study of 158 patients hospitalized within 5 hours of onset of a presumed AC ischemic stroke, as diagnosed on clinical grounds.
  
  
  RESULTS
  Final CT or pathology diagnosis was AC infarct in 128 patients (81%), a repeatedly negative CT in 14 (9%), PC infarct (5 pons, 1 midbrain and cerebellum, 6 supratentorial territory of the posterior cerebral artery) in 12 (8%), and other or undiagnosed lesions in 4 (3%). AC and PC stroke patients did not differ in terms of age, vascular risk factors, and initial severity, but the latter were more frequently men (83% versus 53%; P = .04), were hospitalized later (mean +/- SD, 168 +/- 86 versus 109 +/- 55 minutes; P = .001), and presented a pure motor hemiparesis or a sensorimotor stroke (50% versus 33%) more often than their counterparts. At baseline CT, PC stroke patients never exhibited an early parenchymal hypodensity in the carotid territory or a hyperdense middle cerebral artery, which were instead found in 59% (P = .0003) and 31% (P = .02) of AC stroke patients, respectively. Early neurological deterioration, 1 month case-fatality rate, and disablement in survivors were comparable in the two groups.
  
  
  CONCLUSIONS
  Shortly after onset the clinical discrimination between AC and nontypical PC infarcts is not reliable, which explains the frequent occurrence of this misdiagnosis. Emergency CT scan helps in the differential diagnosis only when it demonstrates an early focal hypodensity within the carotid territory.
authors.affiliation: Department of Neurological Sciences, University La Sapienza, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Argentino
authors.forename: M
authors.initials: M
authors.lastname: De Michele
authors.forename: M
authors.initials: M
authors.lastname: Fiorelli
authors.forename: D
authors.initials: D
authors.lastname: Toni
authors.forename: M L
authors.initials: ML
authors.lastname: Sacchetti
authors.forename: C
authors.initials: C
authors.lastname: Cavalletti
authors.forename: G
authors.initials: G
authors.lastname: Sette
authors.forename: A
authors.initials: A
authors.lastname: Falcou
authors.forename: S
authors.initials: S
authors.lastname: Bastianello
authors.forename: L
authors.initials: L
authors.lastname: Bozzao
mesh_terms: D000208:Acute Disease; D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014057:Tomography, X-Ray Computed