title: Nonconvulsive status epilepticus after subarachnoid hemorrhage.
abstract: OBJECTIVE
  Although in-hospital seizures have been reported for 3 to 24% of patients with aneurysmal subarachnoid hemorrhage (SAH), nonconvulsive status epilepticus (NCSE) has not been previously described. We sought to determine the frequency and clinical features of NCSE among comatose patients with SAH.
  
  
  METHODS
  Between November 1997 and February 2000, we performed continuous electroencephalographic (cEEG) monitoring for at least 24 hours for all patients with aneurysmal SAH who were treated in our neurological intensive care unit and exhibited unexplained coma or neurological deterioration. NCSE was diagnosed when cEEG monitoring demonstrated continuous or repetitive electrographic seizures exceeding 1 hour in duration. Refractory NCSE was treated aggressively with intravenous anticonvulsant administration and continuous-infusion midazolam therapy.
  
  
  RESULTS
  Of 233 patients with SAH who survived the first 48 hours of hospitalization, 101 were stuporous or comatose at some point during their hospitalization. Twenty-six of those patients underwent cEEG monitoring, and eight were diagnosed as having NCSE, an average of 18 days (range, 5-38 d) after SAH. All eight patients were receiving prophylactic anticonvulsant therapy. Four patients were persistently comatose and four demonstrated deterioration to stupor or coma; only one exhibited overt tonicoclonic activity. A worst Hunt and Hess grade of IV or V, older age, ventricular drainage, and cerebral edema on computed tomographic scans were identified as risk factors for NCSE (all P < 0.01). NCSE was successfully terminated for five patients (63%), but only one experienced clinical improvement, which was transient; all eight patients eventually died after a period of prolonged coma.
  
  
  CONCLUSIONS
  cEEG monitoring detected NCSE for 8% of patients with SAH and otherwise unexplained coma or neurological deterioration. The seizures were highly refractory to therapy, and the prognosis for these patients was extremely poor. Routine postoperative cEEG monitoring of patients with SAH who are at high risk for NCSE, allowing earlier diagnosis and treatment, offers the best chance of improving the outcomes for patients with this disorder.
authors.affiliation: Division of Critical Care Neurology, Department of Neurology, College of Physicians and Surgeons, Columbia University, 710 West 168th Street, New York, NY 10032, USA.
authors.forename: Lyle J
authors.initials: LJ
authors.lastname: Dennis
authors.forename: Jan
authors.initials: J
authors.lastname: Claassen
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Hirsch
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Emerson
authors.forename: E Sander
authors.initials: ES
authors.lastname: Connolly
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Mayer
mesh_terms: D000368:Aged; D000927:Anticonvulsants / Q000008:administration & dosage / Q000627:therapeutic use; D004569:Electroencephalography; D005260:Female; D006801:Humans; D015994:Incidence; D007260:Infusion Pumps; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008297:Male; D008874:Midazolam / Q000008:administration & dosage / Q000627:therapeutic use; D008875:Middle Aged; D012307:Risk Factors; D013226:Status Epilepticus / Q000188:drug therapy / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D016896:Treatment Outcome
chemical_list: D000927:Anticonvulsants; D008874:Midazolam