Nonconvulsive Status Epilepticus after Subarachnoid Hemorrhage
Background: In-hospital seizures have been reported in 3–24% of patients with aneurysmal subarachnoid hemorrhage (SAH). Nonconvulsive status epilepticus (NCSE) after SAH has not been previously described. Methods: Between 11/97 and 2/00, we performed continuous electroencephalographic (cEEG) monitoring (Nicolet Bravo system) for at least 24 hours in all SAH patients treated in our NICU with unexplained coma or neurologic deterioration. Electrographic seizures were diagnosed when epileptiform discharges with a discrete onset, offset, and evolution were present on cEEG. All seizures were treated aggressively with intravenous anticonvulsants and continuous-infusion midazolam therapy, as necessary. Results: Of 233 SAH patients who survived the first 48 hours of hospitalization, 100 were stuporous or comatose during their hospitalization. Twenty-six of these patients underwent cEEG monitoring, and 8 (31%) were diagnosed with NCSE average of 18 days (range 5–38) after SAH. Five patients were persistently comatose, two deteriorated to stupor, and one deteriorated to coma with eye blinking; none had focal tonic-clonic activity. All patients were on an anticonvulsant at the time of diagnosis. All seizures were partial, consisting of rhythmic runs of epileptiform discharges; only 4 had focal CT pathology related to the seizure focus. Seizure control was achieved in five patients, but only one experienced clinical improvement, which was transient; in the other 3, the seizures could not be controlled. All 8 patients eventually died in the hospital after a period of prolonged coma (mean LOS 51 days); all but 1 had life support withdrawn. In a univariate analysis, increased mean age (68 vs 54 yrs), higher APACHE-2 scores (16 vs 10), Fisher 3/4 blood on CT (100% vs 54%), worst Hunt/Hess grade 4/5 (100% vs 44%), and ventricular drainage (88% vs 36%) were identified as risk factors for NCSE (all P=.005). Conclusion: NCSE may occur in 5–10% of SAH patients who deteriorate or fail to awaken from coma. Although the seizures can be terminated with medical treatment, the prognosis for these patients is extremely poor.