[Herpes simplex encephalitis in Cáceres. An analysis of the last five years]

Herpes simplex encephalitis (HSE) is a rare disease, although it is still the most common serious viral infection of the central nervous system. Little is currently known about its epidemiology and clinical features in our area. This paper presents a retrospective description of the clinical, diagnostic and progressive characteristics of patients diagnosed with HSE in Cáceres General Hospital, and confirmed by means of a polymerase chain reaction (PCR) study for the DNA of the herpes simplex virus over the last 5 years.

We found four patients who had been diagnosed with HSE in the last 5 years (3.3 cases/million inhabitants/year; CI at 95% of 2.42-4.18), two males and two females, with an age interval between 58 and 75 years. All the patients had high temperatures and three of them also presented neurological focus. A computerised axial tomography scan of the head performed on admission was interpreted as being normal in all cases, while magnetic resonance imaging of the head carried out in two patients showed lesions compatible with HSE in both cases. Electroencephalographic studies were carried out in two patients and revealed focusing in one of them and severe generalised involvement in the other. Analysis of the cerebrospinal fluid (CSF) disclosed lymphocytic meningitis in four cases, although in one of them the study was normal on admission. In two of the patients, viral meningoencephalitis was suspected from the moment the patient was admitted to hospital. For this reason, early treatment with IV acyclovir was established and the clinical progression was good in both patients, although one of them was left with mild neurological sequelae. The other two cases, who died, had a severe underlying pathology and alternative clinical diagnoses that were reasonable on admission (extensive pneumonia and delirium tremens in one of them, and hypercapnic encephalopathy with severe chronic obstructive pulmonary disease in the other), and the clinical suspicion of HSE and the establishment of treatment were late.

The incidence of HSE in our environment is in the upper interval of that reported in the literature. PCR analysis for the herpes simplex virus in CSF seems to have replaced brain biopsy studies as the diagnostic technique. The underlying severe chronic pathology makes it more difficult to diagnose and worsens the prognosis. A multicentre epidemiological study should be conducted to confirm these findings.