What Is Mollaret Meningitis?

Mollaret meningitis is a type of recurrent aseptic meningitis. Aseptic meningitis is inflammation or a viral infection of the meninges, which are the three-layer membranes that surround the brain and spinal cord. Mollaret meningitis specifically refers to recurrent viral meningitis.

The symptoms are the same as individual episodes of viral meningitis and include headaches, fever, and neck stiffness. The key feature of Mollaret meningitis is that it is chronic or recurs.

The diagnosis is made after other types of meningitis (such as those caused by bacteria or noninfectious inflammation) have been ruled out. Treatment can include management of symptoms, anti-inflammatory medication, and antiviral medication. 

Causes 

Several viruses can cause Mollaret meningitis. It is most often associated with herpes simplex virus 2 (HSV-2), which doesn't usually cause meningitis. Typically, HSV-2 causes genital herpes. However, many patients don't have a history of herpes or symptoms of it at the time of developing meningitis.

Less commonly, other viruses can cause Mollaret meningitis, including:

• Epstein-Barr virus (EBV), which causes upper respiratory infections
• Herpes simplex virus 1 (HSV-1), which usually causes cold sores
• Varicella zoster virus, which normally causes chickenpox 
• West Nile virus

Normally, viral meningitis resolves when the body’s immune system gets the infection under control. But in Mollaret meningitis, the symptoms recur.

Pathophysiology 

Meningitis is inflammation of the meninges. The meninges are three layers of connective tissue that surround and protect the brain and spinal cord.

The three meningeal layers are:

• Pia layer: Adherent to the brain 
• Arachnoid: Middle layer 
• Dura: The strongest outer layer

Cerebrospinal fluid (CSF) flows around the brain and meninges, providing nourishment, lubrication, and cushioning to these structures. Meningitis typically causes infection of the CSF, as well as the meninges.

A viral infection can occur when a virus reaches the meninges by passing through the blood-brain barrier, which is a protective feature of the blood vessels surrounding the brain.

Symptoms 

The symptoms of Mollaret meningitis are the same as symptoms of a single episode of aseptic meningitis. That condition does not usually cause effects as severe as symptoms of bacterial or fungal meningitis. 

The episodes can last for several days, and rarely, up to a few weeks. However, what distinguishes Mollaret meningitis from typical episodes of viral meningitis is that the episodes recur within weeks to years, and sometimes mild effects can remain between episodes. 

Symptoms can include:

• Headaches
• Neck stiffness 
• Neck tenderness or pain 
• Back pain when bending the neck 
• Fevers and/or chills
• Fatigue and sleepiness 
• Photophobia (discomfort when looking at bright light) 
• Discomfort when hearing a loud noise
• Diminished appetite 
• Nausea 
• Double vision

Recurrences can be associated with persistent tinnitus (ringing in the ears) and balance problems.

Complications 

Sometimes viral meningitis can cause more severe symptoms if it progresses to meningoencephalitis, which is an infection of the brain and meninges. The effects can include seizures, personality changes, altered vision, impaired muscle control, and/or changes in consciousness. 

In almost half of the people with Mollaret meningitis, lasting neurological deficits are seen. These include problems with thinking ability, memory, balance, coordination, hearing, and vision. Rarely, Mollaret meningitis can lead to a stroke or other types of brain damage. with lasting neurological deficits.

Diagnosis 

Mollaret meningitis is diagnosed based on the clinical pattern of recurrence and diagnostic signs of viral meningitis. 

A history of symptoms may point to meningitis. A physical examination that will include a comprehensive neurological examination may show a fever and neck stiffness. Sometimes neck stiffness can be more severe when you flex your neck or your legs. Deep tendon reflexes, such as the patellar reflex of the knee (in which the knee jerks when tapped with a hammer), can be brisk. 

Diagnostic testing may be needed to rule out other possible conditions and identify inflammation or evidence of the virus in the CSF. 

Tests that may be part of the diagnostic process for Mollaret meningitis can include:

Blood tests: While a blood test, such as complete blood count (CBC), is not diagnostic of meningitis, it can sometimes show changes associated with a viral infection.

Lumbar puncture (LP): LP, also described as a spinal tap, is a procedure that is done for sampling the CSF. It involves the insertion of a needle in the lower back to reach the spinal canal. It can be uncomfortable, but it is safe.

CSF analysis may identify a viral infection or a pattern of white blood cells and proteins suggestive of aseptic meningitis. This test can also help diagnose other illnesses (such as multiple sclerosis) or other types of infectious or inflammatory meningitis.

Brain imaging: Images of the brain, such as computed tomography (CT) and magnetic resonance imaging (MRI), may show signs of inflammation of the meninges. These tests can also identify other potential causes of the symptoms, such as demyelination.

Differential Diagnosis

Recurrent meningitis can be caused by serious medical issues, including leptomeningeal carcinomatosis due to cancer. Additionally, human immunodeficiency virus (HIV) can cause recurrent meningitis.

While these are technically aseptic meningitis, they would not be considered Mollaret meningitis and would require treatment of the primary illness.

Treatment 

Often a single episode of viral meningitis is treated symptomatically, and the viral infection usually resolves on its own without treatment. However, with Mollaret meningitis, the repeated infections often warrant antiviral therapy to help resolve the infection, in addition to symptomatic therapy.

Antiviral treatments, such as acyclovir and valacyclovir, are often prescribed to help resolve the viral infection and prevent it from returning, with varying degrees of success.

Sometimes anti-inflammatory medications are prescribed to reduce the inflammation. Symptomatic treatment is used to reduce a fever, alleviate discomfort, and manage headaches. If necessary, treatment is used to manage complications, such as seizures. 

Prognosis 

Mollaret meningitis is not common. It has been shown to usually resolve after three to five years, but it can continue for longer than that. 

Early treatment may improve the outcome. In many people, the effects are temporary. However, in almost half, there are permanent complications such as weakness, vision deficits, or cognitive changes. A longer duration of the condition is associated with a higher chance of lasting neurological deficits.

Summary

Mollaret meningitis is a rare type of recurring aseptic meningitis. It is most often associated with HSV-2. Episodes may cause symptoms such as headache, stiff neck, fever, and neurologic symptoms. These usually clear up in a few days. Antiviral medications may be given, as well as treatment for the symptoms.

A Word From Verywell

Being diagnosed with repeated episodes of meningitis can be stressful. Aseptic meningitis is not usually dangerous, but it can be problematic if it isn’t treated. It may take some time to reach a diagnosis and for your treatment to be effective, but the prognosis of Mollaret meningitis is good.