title: Delayed cerebral hyperperfusion syndrome caused by prolonged impairment of cerebrovascular autoregulation after carotid endarterectomy: case report.
abstract: OBJECTIVE
  Cerebral hyperperfusion syndrome is a rare but potentially devastating complication that typically occurs within several days after carotid endarterectomy.
  
  
  METHODS
  A 66-year-old man experienced asymptomatic cerebral hyperperfusion as demonstrated by single-photon emission computed tomography (SPECT) during a 2-week period after undergoing right carotid endarterectomy. This phenomenon occurred despite intensive pharmacological control of blood pressure. On the 28th postoperative day, repeat SPECT demonstrated resolution of hyperperfusion, and intensive blood pressure control was discontinued.
  
  
  METHODS
  Twelve hours later, the patient experienced left motor seizures with secondary generation. SPECT performed 36 hours after the onset of seizures demonstrated the reappearance of hyperperfusion. Intensive blood pressure control was reinstituted and maintained until the 36th postoperative day. On the next day, SPECT demonstrated resolution of hyperperfusion.
  
  
  CONCLUSIONS
  The present case suggests that cerebral hyperperfusion syndrome may occur at later time points (e.g., 1 mo) after carotid endarterectomy. This delayed hyperperfusion syndrome may be related to prolonged impairment of cerebrovascular autoregulation.
authors.affiliation: Department of Neurosurgery and Cyclotron Research Center, Iwate Medical University, Morioka, Japan. kuogasa@iwate-med.ac.jp
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Ogasawara
authors.forename: Chiaki
authors.initials: C
authors.lastname: Mikami
authors.forename: Takashi
authors.initials: T
authors.lastname: Inoue
authors.forename: Akira
authors.initials: A
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D016894:Endarterectomy, Carotid / Q000009:adverse effects*; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D011877:Radionuclide Imaging; D012640:Seizures / Q000209:etiology*; D013577:Syndrome; D013997:Time Factors