In the United States, HSV causes 10-20% of all cases of sporadic viral encephalitis, and 95% of these cases are due to HSV-1 (either primary or reactivated infection). The estimated annual incidence is 2.3 cases per 1 million persons.

• Pts present with an acute onset of fever and focal neurologic symptoms and signs, especially in the temporal lobe. In severe cases, RBCs can be found in the CSF as a result of hemorrhagic necrosis.
• Given the potential severity of infection, antiviral treatment should be started empirically until the diagnosis is confirmed or an alternative diagnosis is made.
• HSV meningitis, which is usually seen in association with primary genital HSV infection, is an acute self-limited disease manifested by headache, fever, and mild photophobia and lasting 2-7 days.
  • - Of cases of aseptic meningitis, 3-15% are due to HSV.
  • - HSV is the most common cause of recurrent lymphocytic meningitis (Mollaret's meningitis).
• Autonomic dysfunction caused by either HSV or VZV most commonly affects the sacral region, resulting in numbness, tingling of the buttocks or perineal areas, urinary retention, constipation, and impotence.
  • - Symptoms take days or weeks to resolve.
  • - In rare instances, transverse myelitis or Guillain-Barré syndrome follows HSV infection.