Herpes Simplex Virus (HSV) Encephalitis

What is herpes simplex virus (HSV) encephalitis?

Herpes simplex virus encephalitis (HSV) is brain swelling from a viral infection. It can happen if a new or reactivated herpes simplex virus infection moves to your brain. It can lead to permanent brain damage or death.

Call 911 or get to the nearest emergency room if you or someone you know if experiencing symptoms of HSV encephalitis, including seizures, confusion or personality changes.

What are the symptoms of HSV encephalitis?

Symptoms of HSV encephalitis include:

• Headache
• Fever
• Extreme lack of energy or decrease in consciousness (lethargy)
• Confusion or altered mental state
• Personality or behavior changes
• Seizures
• Difficulty remembering or understanding words (aphasia)
• Nausea and vomiting

People with HSV encephalitis don’t usually have herpes sores when encephalitis symptoms start.

What causes HSV encephalitis?

Herpes simplex virus (HSV) causes HSV encephalitis. Most cases are caused by HSV-1 (the main cause of oral herpes) but some are caused by HSV-2 (which can cause genital herpes).

Once you’re infected with herpes simplex virus, it never really leaves your body. You can go for long periods of time without symptoms when it’s inactive. But sometimes, it can reactivate and start causing symptoms again. You can get HSV encephalitis when you first get infected with HSV (primary infection) or from a reactivation.

How do you get herpes encephalitis?

You get herpes encephalitis when HSV travels to your brain. You can get HSV through:

• Kissing/kisses
• Skin-to-skin contact with sores
• Oral, anal or vaginal sex
• Sharing utensils or personal items (like razors)
• Vertical transmission (from a pregnant woman to the fetus or baby)

Is HSV encephalitis contagious?

Encephalitis — brain swelling — isn’t contagious, but the virus that causes it is. That means that HSV spreads between people, but the infection doesn’t usually spread to your brain.

What are the complications of herpes encephalitis?

Complications of HSV encephalitis include:

• Fluid in your brain (cerebral edema)
• Increased intracranial pressure (pressure inside of your head)
• Seizures that last a long time or don’t stop (status epilepticus)
• Brain herniation (when part of your brain sticks out through small holes into areas it shouldn’t)
• Long-term or permanent neurological (brain and nerve) issues, like memory loss, movement disorders and difficulty with speech and language

How is HSV encephalitis diagnosed?

Healthcare providers diagnose HSV encephalitis by testing your spinal fluid with a lumbar puncture (spinal tap). They’ll also use a CT scan or MRI to get pictures of your brain. Other tests providers might use to determine the cause of the infection or evaluate brain function include:

• Blood tests
• Nasal swab
• EEG (electroencephalogram)
• Polymerase chain reaction (PCR) test, which detects the genetic material of the virus in your cerebral spinal fluid

How is HSV encephalitis treated?

Healthcare providers treat HSV encephalitis with intravenous (IV) acyclovir. This is an antiviral medication given directly into a vein. They may also treat you with corticosteroids to reduce swelling.

Can HSV encephalitis be prevented?

If you have herpes, there aren’t any specific ways to prevent it from spreading to your brain. Ways to reduce your risk of getting and spreading the virus that causes HSV encephalitis include:

• Avoid contact with herpes sores.
• Get tested for sexually transmitted infections (STIs) and ask sex partners to get tested, too. Some STIs can spread even when you don’t have symptoms.
• Use condoms or dental dams during sex.
• Don’t share utensils or personal items.

Can you recover from herpes encephalitis?

Yes, you can recover from herpes encephalitis. But many people have long-term health issues, including:

• Memory loss
• Seizure disorders (like epilepsy)
• Movement issues or involuntary muscle movements that make walking or everyday tasks difficult
• Language or speech issues
• Trouble thinking clearly
• Personality or behavior changes

These issues may get better over time but might not ever completely go away. Sometimes, people get better but their symptoms come back again (relapse), usually within two months. This is more likely to happen in kids.

What can I expect if I have HSV encephalitis?

If you have HSV encephalitis, you’ll need to be diagnosed and treated at a hospital as soon as possible. Quick treatment gives you the best chance of recovery. You’ll need antiviral treatment for a few weeks. If you have ongoing neurological issues, you may need physical, occupational or speech therapy to manage your symptoms.

When should I see my healthcare provider?

If you’ve been diagnosed with herpes simplex in the past, talk to your healthcare provider about what you should do if you have a reactivation and what symptoms of encephalitis to look out for.

When should I go to the ER?

Go to the emergency room if you have symptoms of herpes encephalitis. It’s often fatal if left untreated.

What questions should I ask my doctor?

It might be helpful to ask your healthcare provider:

• How do I take care of myself at home?
• How do I take this medication?
• Are there any symptoms I should look out for?
• When should I follow up with you?