Focal status epilepticus: Clinical features and significance of different EEG patterns

Purpose: Focal status epilepticus is typically diagnosed by the observation of continuous jerking motor activity, but many other manifestations have b een described. EEG evidence of focal status may take several forms, and the ir interpretation is controversial. We detailed the clinical spectrum of fo cal status in patients diagnosed by both clinical deficit and EEG criteria and contrasted clinical manifestations in patients with different EEG patte rns. Methods: Patients were diagnosed with a neurologic deficit and discrete rec urrent focal electrographic seizures or rapid, continuous focal epileptifor m discharges on EEG. Clinical findings were determined by chart review. Results: Of 41 patients with focal status, acute vascular disease was the c ause in 21; 10 of 41 had exacerbations of prior epilepsy. A variety of clin ical seizure types occurred, both before and after the EEG diagnosis, but t he diagnosis was not expected in 28 patients before the EEG. Three had no o bvious clinical seizures. Focal motor seizures and an abnormal mental statu s were the most common manifestations at the time of the EEG. With antiepil eptic drugs, almost all had control of clinical seizures, and most improved in mental status. Patients with rapid continuous focal epileptiform discha rges were nearly identical in presentation, likelihood of diagnosis, subseq uent seizures, response to medication, and outcome to those with discrete s eizures on EEG. Conclusions: Focal status epilepticus may be seen with a wide variety of cl inical seizure types or without obvious clinical seizures. The diagnosis is often delayed or missed and should be considered after strokes or clinical seizures when patients do not stabilize or improve as expected. The diagno sis should be made equally whether patients have discrete electrographic se izures or continuous rapid focal epileptiform discharges on the EEG, and th e same response to medications and outcome should be anticipated for the tw o groups.