Outcome of and Prognostic Factors for Herpes Simplex Encephalitis in Adult Patients: Results of a Multicenter Study

Abstract

Management of herpes simplex encephalitis (HSE) has been considerably improved by the availability of acyclovir therapy and rapid polymerase chain reaction (PCR)-based diagnostic assays. Prognostic factors for this rare affliction are, however, misestimated. We conducted a large retrospective multicenter study that included 93 adult patients in whom HSE was diagnosed by PCR from 1991 through 1998 and who were treated with intravenous acyclovir. Among the 85 patients assessed at 6 months, 30 (35%) had a poor outcome, which led to death in 13 patients (15%) and severe disability in 17 (20%). The outcome was favorable for 55 patients (65%). A multivariate analysis identified 2 factors that were found to be independently associated with poor outcome: a Simplified Acute Physiology Score II >/=27 at admission and a delay of >2 days between admission to the hospital and initiation of acyclovir therapy. Early administration of antiviral therapy is the only parameter that can be modified to improve the prognosis of patients with HSE.

Herpes Simplex Virus-1 Encephalitis in Adults: Pathophysiology, Diagnosis, and Management

“…Kim et al [160] recently retrospectively reviewed 29 patients with PCR-proven HSVE and found that severe EEG abnormalities were predictive of poor outcome at 6 months, although this was not observed in a series of 45 patients from the Mayo Clinic [57]. Early recognition and timely administration of aciclovir are critically important for improving outcomes, and late administration of aciclovir is the most readily modifiable risk factor for poor outcomes [62,63,161,162]. Factors contributing to delayed treatment include immunocompromise [63], severe comorbid disease, history of alcohol abuse, absence of fever, and CSF leukocytes <10/ml [162].…”

“…Signs and symptoms of encephalitis then progress over the course of several days in most cases of HSVE [57,58]. The most common manifestations include encephalopathy, fever, seizures, headaches, and focal neurological deficits [57][58][59][60][61][62]. Although clinical features of HSVE have been well described in multiple large epidemiological studies, the clinical manifestations lack specificity.…”

“…CT imaging in encephalitis is beneficial for rapid evaluation of patients in whom there is clinical concern for edema and/or shift of brain compartments that might require intervention or contraindicate lumbar puncture. Abnormal findings have been observed in 25-80 % of patients with HSVE imaged soon after admission [62,69]. CT findings suggestive of HSVE include hypodense lesions (typically in the temporal lobe), edema, or contrast enhancement [70][71][72].…”

Neuro-Intensive Care of Patients with Acute CNS Infections

“…The data is similar in patients with herpes simplex virus (HSV) encephalitis. Patients with HSV encephalitis who receive the first dose of acyclovir earlier in the course of disease have significantly lower mortality rates [10][11][12].…”

“…Only 9% of patients with herpes simplex encephalitis (HSE) had an MRI with abnormalities exclusively outside the frontotemporal area. In 57% of HSE patients, the abnormalities were predominantly unilateral [11]. Characteristic MRI changes occur early in the course of HSE and include high-signal intensity lesions on T2-weighted and FLAIR images involving the medial and inferior temporal lobes with extension into the insula.…”