[Clinical characteristics of adult patients with herpetic meningoencephalitis: a nested case control study]

Herpes simplex virus (HSV) is the most common etiology of sporadic encephalitis and presents with an estimated mortality of 50-70%.

To describe baseline characteristics of patients with herpetic encephalitis admitted to a tertiary teaching hospital and their difference with patients with non herpetic encephalitis.

Nested case control study using a retrospective cohort of patients with suspected encephalitis admitted to the Hospital Italiano de Buenos Aires (2006-2013). Adult patients included had a lumbar puncture with a positive or negative polimerase reaction for HSV. A case of herpetic encephalitis was defined as a positive polimerase reaction in spinal fluid. For each case, 5 controls were randomly selected.

There were no baseline differences present between cases and controls. The only covariate associated with herpetic encephalitis was an abnormal brain magnetic resonance imaging (MRI) (OR: 5.37, IC 95% 1.42-20.38, p < 0.01). The most frecuent alterations in the MRI were extratemporal lesions or temporal ones with or without haemorrhage.

There are no apparent baseline clinical differences between patients with or without herpetic encephalitis. A positive finding in a brain MRI should be taken into account during clinical workup.