Herpes Simplex Meningitis

Herpes simplex meningitis is a viral infection that causes swelling in the protective membranes surrounding the brain and spinal cord. While it can cause severe symptoms, most people recover within weeks with proper treatment.

Table of contents

• What is herpes simplex meningitis?
• What causes this condition?
• How does it spread?
• Signs and symptoms
• How is it diagnosed?
• Treatment options
• Possible complications
• Recovery and outlook
• Prevention
• Mollaret’s meningitis: A recurrent form

What is herpes simplex meningitis?

Herpes simplex meningitis is a type of viral infection that affects the meninges, which are the three protective layers of tissue that surround your brain and spinal cord^[1]. These layers include a delicate inner layer called the pia mater, a middle web-like layer filled with cushioning fluid called the arachnoid, and a tough outer layer called the dura or dura mater that provides protection^[1].

When these membranes become inflamed due to a herpes virus infection, the condition is called herpes meningitis. This swelling increases pressure on the brain and causes the characteristic symptoms of the disease^[8].

• Brain
• Spinal cord
• Meninges (protective membranes)

What causes this condition?

Herpes simplex meningitis results from infection with a herpes virus. Three main types of herpes viruses can cause this condition^[1]:

• Herpes simplex virus type 1 (HSV-1): This virus most commonly causes sores on the mouth but can also affect the genital area. According to research, HSV-1 is responsible for about 4% of viral meningitis cases in adults^[1].
• Herpes simplex virus type 2 (HSV-2): This virus typically causes sores on the genitals but can also affect the mouth. HSV-2 is the most common cause of herpes meningitis in adults, accounting for approximately 31% of viral meningitis cases. It is particularly the most common cause among adults overall^[1][3].
• Varicella-zoster virus (VZV): This virus causes chickenpox and shingles. It accounts for about 11% of viral meningitis cases^[1].

According to research from 2008, herpes simplex virus is the second leading cause of viral meningitis in developed countries^[1]. The condition primarily affects people aged 35 to 40, elderly individuals, and women^[3].

Herpes viruses remain in your body for life after the initial infection. Most often, herpes meningitis occurs when the virus reactivates from an earlier infection rather than during the first exposure to the virus^[4][6].

How does it spread?

The viruses that cause herpes simplex meningitis can spread from person to person in several ways. They can transmit through coughs and sneezes, or through contact with surfaces contaminated with the virus^[1].

Herpes simplex viruses can also spread through direct contact, including kissing or sexual contact^[1][6]. Once a person is infected, the virus stays in their body for life. Various triggers can cause periodic active outbreaks, during which the virus is most contagious^[1].

It is important to know that the virus can pass from a person with an HSV infection to a baby during childbirth^[1]. Babies who have contracted HSV often show symptoms by the end of their first week of life. Signs may include irritability, blisters, yellowing of the skin and eyes (called jaundice), labored or intermittent breathing, rapid breathing, blue coloration of the skin, and bleeding easily^[1].

Signs and symptoms

The symptoms of herpes simplex meningitis can range from mild to severe. Mild cases may cause flu-like symptoms that are similar to many other common illnesses^[1].

Common symptoms include a persistent, severe headache, often described as worse than usual headaches. This may be accompanied by one or more of the following^[1][3][6]:

• Fever
• Stiff neck
• Nausea and vomiting
• Lack of appetite
• Irritability
• Lethargy or excessive tiredness
• Sleepiness or difficulty waking
• Sensitivity to light, called photophobia
• Weakness and fatigue

People with meningitis caused by HSV-2 may also have genital lesions. However, most cases of HSV-2 meningitis occur without symptoms of genital herpes^[3]. About one-fifth of people infected with HSV-2 experience symptoms of meningitis during their initial infection, with men affected more commonly than women^[3].

People with mild cases of herpes simplex meningitis typically recover within 7 to 10 days, and symptoms are self-limiting over about 2 weeks^[1][3].

How is it diagnosed?

Diagnosing herpes simplex meningitis requires several steps. A doctor will begin by asking about your symptoms and medical history^[1][4].

If the doctor suspects viral meningitis, several tests may be needed^[4]:

Neurological exam: Your healthcare provider will perform a neurological exam to check for changes in motor and sensory function, vision, coordination, and balance. They will also assess your mental status and look for changes in mood or behavior^[4].

Lumbar puncture (also called a spinal tap): This is a key test for diagnosing meningitis. Your healthcare provider will insert a special needle into your lower back to remove a small amount of spinal fluid. Cells and other substances in this fluid will be examined in a laboratory^[3][4].

In herpes meningitis, the cerebrospinal fluid (CSF) shows specific patterns. There is typically an increase in white blood cells (called lymphocytic pleocytosis), normal glucose levels, and normal-to-elevated protein levels^[3].

Polymerase chain reaction (PCR): This is considered the gold standard for detecting herpes virus in patient CSF fluid because of its high accuracy^[3]. PCR testing can detect the HSV-2 virus even in patients who do not have genital lesions and in those experiencing recurrent meningitis^[3].

Brain imaging: CT scans or MRI scans may be performed to create images of your brain^[4].

Electroencephalogram (EEG): This test measures brain waves by placing small sensors called electrodes on your scalp^[4].

Blood tests: Testing the blood helps identify infection^[4].

The diagnosis can be challenging because many conditions can cause similar symptoms. Doctors must rule out other causes of meningitis, including bacterial infections, fungal infections, drug-induced meningitis, systemic infections, blood vessel inflammation, autoimmune diseases, and cancer^[3].

Treatment options

Treatment for herpes simplex meningitis focuses on managing symptoms and preventing complications. Although there are currently no specific treatment guidelines for herpes meningitis like there are for herpes encephalitis (brain infection), antiviral medication may be recommended^[3].

Acyclovir is the main antiviral medicine used to treat herpes meningitis. This medication is given through an intravenous (IV) line, meaning it is delivered directly into a vein. Treatment typically lasts for 10 to 14 days^[4].

Although herpes meningitis is typically self-limiting, meaning it resolves on its own within about 2 weeks, treatment with antiviral medication may be recommended to prevent the condition from progressing to herpes meningoencephalitis, a more serious condition where both the meninges and the brain become infected^[3][4].

Your healthcare provider may also prescribe medicine to reduce swelling in the brain and to treat or prevent seizures if needed^[4].

For babies with this disease, healthcare providers may treat them with acyclovir for several weeks^[4].

Depending on the severity of your infection, you may need to be treated in the hospital. With treatment, most people with this disease start to feel better within a day or two and tend to recover fully^[4].

Possible complications

While most cases of herpes simplex meningitis are self-limiting and people recover well, severe cases can lead to complications^[6]:

• Seizures
• Memory difficulties
• Cognitive difficulty or trouble thinking clearly
• Personality changes
• Lack of body control
• Difficulty hearing or speaking
• Vision problems
• Loss of consciousness

People who are immunocompromised (have weakened immune systems) may be at higher risk for complications and may present with atypical or subtle symptoms^[2].

Recovery and outlook

Most people with mild herpes simplex meningitis recover within 7 to 10 days^[1]. The condition is typically self-limiting over about 2 weeks, with symptoms resolving without long-term effects^[3].

With proper treatment, most people start to feel better within a day or two and tend to recover fully^[4].

However, between 20% and 50% of cases may experience clinical recurrences, meaning the infection can come back^[3].

Prevention

Preventing herpes simplex meningitis involves reducing the risk of herpes virus transmission. Since herpes viruses can spread through coughs, sneezes, and contact with contaminated surfaces, good hygiene practices are important^[1].

Because herpes simplex viruses spread through kissing and sexual contact, taking precautions during intimate contact can help reduce transmission. However, it is important to know that most people with herpes infections do not have visible symptoms, and transmission can occur even when no sores are present.

For people who already have herpes, understanding that the virus stays in the body for life and can reactivate is important. Various triggers can cause the virus to become active again, potentially leading to meningitis^[1][6].

Mollaret’s meningitis: A recurrent form

HSV-2 is the most common cause of a special type of recurrent viral meningitis called Mollaret’s meningitis^[3]. This condition was first described in 1944 by French neurologist Pierre Mollaret.

Herpes simplex viruses have been linked to this type of meningitis that can recur, commonly called recurrent lymphocytic meningitis. This recurring form of meningitis involves sporadic periods of symptoms lasting 2 to 7 days^[1].

Recurrences usually last a few days or a few weeks and resolve without treatment. They may recur weekly or monthly for approximately 5 years following the primary infection^[3].