Herpes simplex virus type 2 encephalitis in an elderly immunocompetent male

Area of Science:

• Neurology
• Infectious Diseases
• Virology

Background:

• Herpes simplex virus type 2 (HSV-2) is a common cause of genital herpes but is rarely associated with encephalitis, particularly in immunocompetent individuals.
• Elderly patients presenting with neurological symptoms often have atypical disease manifestations.

Observation:

• An 85-year-old immunocompetent male presented with acute confusion and disorientation.
• Neurological examination revealed disorientation to person only and inability to follow commands, without focal deficits.
• Brain MRI demonstrated extensive perivascular demyelination.

Findings:

• Cerebrospinal fluid analysis was unremarkable for infection, with normal pressure, glucose, and protein levels.
• Cerebrospinal fluid PCR confirmed the presence of herpes simplex virus type 2.
• The patient was diagnosed with herpes simplex type 2 encephalitis.

Implications:

• This case represents the first reported instance of HSV-2 encephalitis in an elderly, immunocompetent patient.
• The findings suggest that HSV-2 should be considered in the differential diagnosis of encephalitis in the elderly, even in the absence of typical risk factors.
• This case underscores the need for prompt diagnostic evaluation, including PCR testing of cerebrospinal fluid, for atypical neurological presentations.