Postinfectious autoimmune-mediated encephalitis versus relapse of herpes encephalitis?

Aims: There have been reports on relapses after herpes simplex encephalitis (HSE) occurring within 1–4 months after antiviral treatment. Two pathomechanisms thought to be involved are viral reactivation or an autoimmune process.

Case: We report on a 14 year old female school student with unremarkable past medical history, who presented with fever and headache in May 2008. In the following days she became agitated, confused, encountered speech difficulties and enuresis. She developed edema of the legs and pericardial effusion. In the CSF Herpes PCR was negative, but there was increased cell-count and protein and an elevation of Herpes simplex IgG on subsequent lumbar punctures. The MRI showed cortical hyperintense lesions involving both temporal lobes, basofrontal and insular regions (mainly of the right hemisphere) and the anterior part of the corpus callosum. Treatment and follow up. Following treatment with intravenous aciclovir for 4 weeks acute symptoms i.e. fever, headache, edema subsided. Our patient was discharged to rehabilitation with impairment of memory and attention, anomic dysphasia, dyscalculia, impulsive behaviour, lack of distance, anosmia and hypogeusia. While in rehabilitation our patient showed intermittent enuresis again, persistent behavioural abnormalities, multifocal paresthesias and pain sensations (face, arms, legs, abdomen). A second hospitalisation showed a tremendous increase of Herpes simplex- IgG in CSF, progressive demyelination and development of an atrophic, cystic encephalomalacia. After treatment with immunoglobulines and methylprednisolon she showed remarkable improvement.

Conclusions: Following an acute encephalitis, our patient manifested clinical, laboratory and radiological signs which were consistent with an HSE relapse. However, there was no symptom-free interval between the two phases of her disease. In addition, the effectiveness of immunglobulines and methylprednisolon suggest that a postinfectious autoimmune-mediated process after HSE complicated her disease course.