Pathology: Herpes Simplex Virus (HSV)is a DNA virus.
Pathologically characterized by a necrotizingmicroencephalitis associated with oedema, haemorrhage, and encephalomalacia
Aetiology: HSV-1 is associated withorofacial infection
HSV-2 is associated withgenital infections.
Herpes simplex encephalitis should be strongly suspectedwhen there are focal features clinically or radiologically suggestive oftemporal lobe or orbitofrontal cortex involvement.
Symptoms: Headache, fever, personalitychanges, alteration of consciousness
Signs: Seizures, focal deficits such as dysphasia,hemiparesis, visual field defects, loss of sense of smell.
Investigations: Imaging: MRI brain - Temporal/orbitofrontallobe high signal changes
Lumbar Puncture: Lymphocytosis withelevated protein and normal glucose
Viral PCR for HSVis usually positive
EEG: Focalchanges in temporofrontal areas
Treatment: Medical IV acyclovir for14-21 days, antiepileptic drugs may be required
Complications: Long term neurological sequelae suchas cognitive impairment and seizures
Prognosis: Early suspicion andcommencement of antiviral therapy is vital for good prognosis. If untreated,mortality can be as high as 70%. Complete recovery is only seen in a very smallpercentage of patients (2.5%).
