Subclinical seizure activity and prophylactic phenytoin infusion in acute liver failure: A controlled clinical

Subclinical seizure activity in the patient with encephalopathy and on vent ilation with acute liver failure (ALF) is a poorly recognized entity, Its i mportance lies in the likely exacerbation of cerebral hypoxia and the contr ibution of such seizure activity to the development of cerebral edema. The aim of the present study was to document the frequency of subclinical seizu re activity in a cohort of patients with ALF by using a cerebral function a nd activity monitor that allows continuous recording of electroencephalogra m activity at the bedside and to determine whether the prophylactic adminis tration of the antiepileptic agent phenytoin would reduce its occurrence. F orty-two patients were enrolled in a controlled clinical trial: 20 patients were given phenytoin and 22 acted as controls. Subclinical seizure activit y was recorded in 3 and 10 patients, respectively, of the treated and contr ol groups. Pupillary abnormalities indicative of seizure activity and/or ra ised intracranial pressure (ICP) were also seen less frequently in the phen ytoin-treated group compared with the controls (5 and 11 patients, respecti vely). Autopsy examinations available in 19 patients showed signs of cerebr al edema in only 2 (22%) of the phenytoin-treated patients compared with 7 (70%) of the controls (P < .033). Based on these findings, we recommend tha t patients with ALF, on reaching the stage of grade III or IV encephalopath y, should be routinely monitored for subclinical seizure activity. In this study, prophylaxis with phenytoin reduced the frequency of such seizure act ivity and its effects, and proved to be safe with the regimen used.