Refractory status epilepticus in suspect encephalitis

The California Encephalitis Project (CEP) is a program designed to determine causes of encephalitis. We sought to determine whether there are any distinguishing characteristics of patients with encephalitis who develop refractory status epilepticus from those who do not.

Data from all patients in the CEP were retrospectively reviewed and analyzed. Diagnostic testing was performed for a panel of infectious agents and medical information collected using a standardized form. Encephalitis patients were subdivided into three categories: (i) patients with status epilepticus unresponsive to standard antiepileptic therapy who required general anesthetic coma for management (Group I), (ii) patients with seizures or status epilepticus responsive to standard antiepileptic therapy (Group II), and (iii) patients without seizures (Group III). Supplementary information was requested on Group I patients.

Of 1,151 patients; 43 (4%) were classified as Group I, 459 (40%) as Group II, and 649 (56%) as Group III. Compared to Groups II and III, Group I patients were younger (median age = 10.0 years), more likely to have fever (93%), prodromal respiratory (57%) or gastrointestinal illness (64%), and less likely to have CSF pleocytosis (47%) or abnormal neuroimaging (16%). A causative infectious agent was verified in three of the Group I patients; and a putative agent in nine others. Supplementary information on Group I revealed that 28% died within 2 years and 56% were neurologically impaired or undergoing rehabilitation.

Encephalitis and refractory status epilepticus occur most commonly in the pediatric age group, an infectious etiology is usually not established, and outcomes are generally poor.