Does Herpes Simplex Virus (HSV) encephalitis require precautions?

From the Guidelines

HSV encephalitis does require precautions, specifically standard precautions, to prevent transmission of the virus through contact with bodily fluids. These precautions include hand hygiene, use of personal protective equipment (gloves, gowns, masks) when contact with bodily fluids is anticipated, and proper handling of contaminated materials 1. However, specific transmission-based precautions are not typically necessary as HSV encephalitis itself is not transmitted person-to-person through casual contact. The virus is already present in most adults (as latent HSV-1 or HSV-2) and encephalitis represents reactivation or primary infection affecting the brain.

Key Considerations

• Treatment for HSV encephalitis consists of intravenous acyclovir at 10mg/kg every 8 hours for 14-21 days, which should be started immediately upon suspicion of the diagnosis, even before confirmatory testing results are available 1.
• Early treatment significantly improves outcomes, as untreated HSV encephalitis has a mortality rate exceeding 70% 1.
• Healthcare workers should be aware that the virus can be present in oral secretions, so care should be taken when handling respiratory equipment or performing procedures involving the mouth or airway.
• The risk of relapse may be highest in children aged 3 months-12 years, up to 29%, and some have advocated that this group should receive a minimum of 21 days of intravenous aciclovir 1.

Management and Treatment

• Intravenous aciclovir treatment should be continued for 14-21 days, and a repeat LP performed at this time to confirm the CSF is negative for HSV by PCR 1.
• If the CSF is still positive, aciclovir should continue intravenously, with weekly PCR until it is negative 1.
• Oral aciclovir does not achieve adequate levels in the CSF and is not suitable for treating HSV encephalitis; however, its valine ester valaciclovir has good oral bioavailability, and is converted to aciclovir after absorption 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION CAUTION—RAPID OR BOLUS INTRAVENOUS INJECTION MUST BE AVOIDED (see WARNINGS and PRECAUTIONS). Herpes Simplex Encephalitis Adults and Adolescents (12 years of age and older): 10 mg/kg infused at a constant rate over 1 hour, every 8 hours for 10 days

Precautions for Herpes Simplex Virus (HSV) encephalitis:

• The administration of acyclovir requires precautions to avoid rapid or bolus intravenous injection.
• The dose for adults and adolescents (12 years of age and older) with HSV encephalitis is 10 mg/kg infused at a constant rate over 1 hour, every 8 hours for 10 days 2.
• Key considerations:
  • Avoid rapid or bolus intravenous injection
  • Infuse at a constant rate over 1 hour
  • Monitor patients closely during administration
  • Adjust dosage based on renal function if necessary 2

From the Research

Precautions for Herpes Simplex Virus (HSV) Encephalitis

• HSV encephalitis is a life-threatening condition that requires prompt diagnosis and treatment 3, 4, 5
• The International Herpes Management Forum (IHMF) has issued guidelines for the diagnosis and treatment of HSV encephalitis, including the use of antiviral therapy such as acyclovir 3
• Precautions should be taken to prevent the spread of HSV, especially in healthcare settings, as the virus can be transmitted through contact with infected bodily fluids 3, 5
• Patients with HSV encephalitis should be isolated to prevent transmission to others, and healthcare workers should wear personal protective equipment (PPE) when interacting with these patients 5

Treatment and Management

• Antiviral therapy, such as acyclovir, is the primary treatment for HSV encephalitis, and should be initiated as soon as possible after diagnosis 3, 6, 4, 5, 7
• The treatment regimen for HSV encephalitis typically consists of intravenous acyclovir for 14-21 days, although the optimal duration of treatment is still unclear 3, 6, 4
• In cases where patients are allergic to acyclovir, desensitization protocols may be used to allow for continued treatment 7

Diagnostic Precautions

• Diagnosis of HSV encephalitis should be made using a combination of clinical characteristics, magnetic resonance imaging (MRI), and polymerase chain reaction (PCR) analysis of cerebrospinal fluid (CSF) 3, 4, 5
• Precautions should be taken when collecting and handling CSF samples to prevent contamination and ensure accurate test results 3, 4