Abstracts

COMPARISON OF EARLY ELECTROENCEPHALOGRAPHIC FINDINGS IN ACUTE DISSEMINATED EENCEPHALOMYELITIS AND HERPES SIMPLEX ENCEPHALITIS: [italic]USEFULNESS WHEN THE CLINICAL PRESENTATION IS SIMILAR[/italic]

Abstract number : 2.147
Submission category :
Year : 2005
Submission ID : 5451
Source : www.aesnet.org
Presentation date : 12/3/2005 12:00:00 AM
Published date : Dec 2, 2005, 06:00 AM

Authors :
Rajesh RamachandranNair, Jacob M. Muthalaly, Manoj Parameswaran, and Vellani T. Ajithkumar

Both acute disseminated encephalomyelitis (ADEM) and Herpes Simplex encephalitis (HSE) can present with alteration in sensorium and seizures. Access to immediate MRI brain may not be available in developing world. Early diagnosis and treatment determines outcome in HSE. Steroids, used to treat ADEM, can be harmful in HSE. Aim of our study was to compare the early electroencephalographic (EEG) findings in ADEM and HSE to aid dignostic differentiation. Patients presenting with seizures and altered sensorium, who were subsequently diagnosed either as ADEM or HSE based on MRI brain and virological studies (CSF-PCR and rising titer of CSF HSV antibody), were included in the study. EEGs performed within 72 hours after the onset of neurological symptoms were analysed for background activity, interictal epileptiform activity (including periodic lateralized epileptiform discharges-PLEDs) and ictal discharges. Incidence of abnormal EEG patterns in ADEM and HSE were compared using X2/ Fisher[apos]s test. EEGs were performed within 72 hours in 21 patients (age 2-56 years, mean 18.6 yrs) with ADEM and 32 patients (age 4-72 years; mean 23.7 yrs) with HSE. All 53 EEGs were abnormal due to background slowing or epileptic discharges. [table1]Background slowing was seen (generalised [amp] focal) in both ADEM and HSE. But frontotemporal slowing occurred more frequently in HSE. Slowing confined to extra-frontotemporal area was seen only in ADEM. Same pattern was seen with interictal epileptiform discharges also. PLEDs were seen in ADEM also (1-frontoparietal and 1-frontocentrotemporal). In HSE, all the PLEDs were frontotemporal.There was a trend towards higher incidence of electrographic seizures in HSE. Focal background slowing and epileptiform discharges (including PLEDs) confined to frontotemporal areas suggested the possibility of HSE. Presence of focal slowing and interictal epileptiform discharges confined to extra-frontotemporal areas suggested the possibility of ADEM as these features were not seen in HSE. Based on early EEG features, ADEM and HSE with similar clinical presentation can be differentiated in selected cases. This could be important in developing countries where facility for immediate MRI brain is not readily available.