Herpes simplex virus encephalitis: clinical manifestations, diagnosis and outcome in 106 adult patients.

BACKGROUND

Herpes simplex virus (HSV) is one of the most common causes of sporadic encephalitis worldwide.

OBJECTIVE

We aimed to determine clinical characteristics and prognosis of HSV encephalitis (HSVE) cases reviewed retrospectively from several collaborating centers.

STUDY DESIGN

We searched hospital archives of the last 10 years for patients with HSVE diagnosis, i.e. clinical presentation compatible with encephalitis and brain involvement on magnetic resonance imaging (MRI) and/or detection of HSV DNA in the cerebrospinal fluid by polymerase chain reaction (PCR). Clinical characteristics were noted and patients were phone-interviewed. HSVE cases were grouped and analyzed as proven and probable, based on virological confirmation by PCR. Univariate and multivariate analyses were used to determine factors associated with prognosis.

RESULTS

A total of 106 patients (63 males and 43 females; mean age, 44 years; range, 18-83 years) were included. Most common symptoms were changes in mental status, fever, headache, and seizure. HSV PCR was positive in 69% of patients tested, while brain involvement was detected on MRI in 95%. Acyclovir was started mostly within five days of main symptom and continued for ≥14 days. Case fatality rate was 8%, while 69% of patients recovered with sequelae. Favorable prognosis was observed in 73% of patients. Multivariate analysis identified the duration of disease before hospital admission (odds ratio (OR)=1.24) and the extent of brain involvement on MRI at the time of admission (OR=37.22) as two independent risk factors associated with poor prognosis.

CONCLUSIONS

Although HSVE fatality regressed considerably with acyclovir treatment, many patients survive with sequelae. Our results emphasize the importance of early diagnosis and prompt treatment of HSVE.