The factors influencing the prognosis of herpes simplex virus encephalitis

Abstract

Objective To evaluate the factors influencing prognosis and to explore the pathological mechanism in which herpes simplex virus encephalitis(HSE) was one of the severe types of acute viral encephalitis in children and had poor prognosis. Methods Twenty-one children with HSE were diagnosed by the clinical syndrome of focal encep-halitis and HSV DNA-PCR positive in cerebrospinal fluid(CSF) from Jan.2012 to Oct.2013, among whom, 19 patients were treated with intravenous Acyclovir, 30 mg/(kg·d) 48 hours after onset and were followed up for 6 to 24 months.Clinical data were collected including Glasgow Coma Score, the brain magnetic resonance imaging(MRI), and electroencephalography(EEG). All MRI examinations including plain scan and contrast enhancement were carried out at the beginning of admission and 1 month after the onset of symptoms.The clinical outcomes were divided into two levels according to the severity of the neurological deficit, then the data were analyzed by using Logistic regression and Fisher's exact probability method.The OR value was calculated. Results Eighteen children survived, of whom 5 cases had no neurological deficit(27.8%), 3 cases were left with mild impairment(16.7%), and the above 8 cases were thought to have better outcome.Six cases had moderate impairment(33.3%) and 4 cases had severe impairment(22.2%) and 1 child died, and these 11 cases were thought to have worse outcome.Patients aged between 1 month and 10 years, average(2.03±2.23) years old.The mean GCS score was(9.68±2.65) scores, the GCS of the patients were more than 7 except for one death child with 3 scores.The multiple factor analysis showed that EEG, age, GCS and the range and character in MRI were significantly correlative to the prognosis(P<0.05). The single factor analysis illustrated that age 1-4 years old(OR=30, 95%CI 2.066-366.510, P=0.002), GCS ≤10 scores(OR=27.518, 95%CI 2.066-366.510, P=0.004)and the wide necrosis existence involving diffuse white matter or deep nuclei of MRI findings(OR=12, 95%CI 1.294-111.323, P=0.017) indicated the worse outcome. Conclusions Age, GCS score, nature and damage degree of MRI lesions are the main important factors affecting the prognosis of children's HSE.HSE in children is apt to involve the cortex such as frontal lobe, parietal lobe even diffuse white matter or deep nuclei, which indicates the poor prognosis. Key words: Herpes simplex encephalitis; Child; Prognosis; Magnetic resonance imaging; Follow-up study