Written by Ada’s Medical Knowledge Team
What is viral meningitis?
Viral meningitis, or aseptic meningitis, is a viral infection of the meninges, which are the membranes around the brain and spinal cord. Viral meningitis is usually less severe than bacterial meningitis, though all suspected cases of meningitis should be assessed by a doctor. There are thought to be around 75,000 cases of viral meningitis in the United States each year, up to 50,000 of which require hospitalization. 1 2
There are a number of common viruses that can cause viral meningitis. Symptoms include headache, nausea, vomiting, irritability, loss of appetite and drowsiness.
Viral meningitis is most common in newborns, young children and people with weakened immune systems. Although most people do not require any specific treatment for viral meningitis, some may need antiviral medications. The prognosis for someone with viral meningitis is generally good.
Viral meningitis vs. bacterial meningitis
Whereas viral meningitis is caused by a virus, bacterial meningitis is caused by certain bacterial infections and can be far more serious than viral meningitis. Bacterial meningitis includes the potentially lethal meningococcal disease. Because early symptoms of different types of meningitis can look similar, it is very important to be assessed by a doctor as soon as possible to identify the cause. 3 4
Read more about Bacterial Meningitis »
Symptoms of viral meningitis
Typical symptoms of viral meningitis include: 1 5 6
- Photophobia, or sensitivity to bright light
- Stiff neck
- Lack of appetite
- Feeling sleepy or having trouble waking up
- Lack of energy
- Lack of coordination
- Inability to concentrate
Symptoms in newborn babies and young children can include: 1 5 7 8
- Stiff neck
- Bulging fontanel, the soft spot on the head
- Lack of energy
- Feeling sleepy or having trouble waking up
- Being unwilling to feed
- Muscle aches
- Runny nose
- Slightly red rash
A person with viral meningitis may also show symptoms of the virus that is making them ill. For example, a person with enterovirus may also experience: 9 10
- Skin rash
- Runny nose
- Aching muscles
- Blisters in the mouth and throat
People experiencing possible symptoms associated with viral meningitis should consult a doctor. In addition, the free Ada app can be used to carry out a symptom assessment.
Causes of viral meningitis
Viral meningitis is caused by various viruses that sometimes cause inflammation of the meninges, which are the membranes that surround the brain and spinal cord.
Good to know: Only a small number of people who catch the following viruses will develop viral meningitis. People with compromised immune systems, for example, because of chemotherapy, organ transplant or autoimmune disease, and young children are more at risk of developing viral meningitis. 1
Non-polio enteroviruses cause 85 percent of cases of viral meningitis. Enteroviruses generally cause mild illnesses, such as the common cold or produce no symptoms at all. Babies and people with compromised immune systems are most likely to develop complications, such as viral meningitis from an enterovirus. 2 9 10
Herpes viruses, including the herpes simplex virus and varicella zoster (chickenpox) virus, are the next most common cause of viral meningitis. Herpes simplex virus 2, or HSV-2, is more associated with viral meningitis. Herpes simplex-related cases of viral meningitis may cause Mollaret meningitis and can be very serious for newborn babies. 11 12
Mumps and measles can cause viral meningitis. Due to a fall in vaccination rates in some areas, viral meningitis caused by mumps and measles is most often seen in young adult populations where immunization rates have fallen. 11 12
Other viruses that can cause viral meningitis include: 1 11 12 13 14 15
- Arboviruses such as West Nile virus and dengue
- Japanese B encephalitis
- Tick-borne encephalitis
- Cytomegalovirus, mainly of risk to people with weakened immune systems
- HIV, occurring shortly after infection
- Lymphocytic choriomeningitis, or LCM, which is carried by rodents
Diagnosis of viral meningitis
Diagnosis is based on the symptoms, a physical examination and testing a sample of cerebrospinal fluid, which is a clear, colorless liquid in the brain and spinal cord.
The cerebrospinal fluid is taken in a procedure called a lumbar puncture, also known as a spinal tap. To have a lumbar puncture performed, a person sits upright while a healthcare professional cleans their lower back. A needle is then inserted between two vertebrae to remove a small amount of cerebrospinal fluid for testing. A lumbar puncture should take no more than five minutes. 16 17
The cerebrospinal fluid will be tested to assess whether the meningitis is viral or caused by another organism, and also to identify the virus responsible. These results will inform treatment. 5
In some cases, other samples may be needed to identify which virus is causing the meningitis. These samples can include: 1 6
- Throat or nose swab
Treatment of viral meningitis
Most people with viral meningitis will recover without treatment within 7 to 10 days. People with the condition may find over-the-counter medications such as paracetamol helpful to ease symptoms and should drink plenty of fluids. 1
An important early step in treating meningitis is to identify whether the condition is viral or bacterial in nature. As bacterial meningitis is typically more severe than the viral variety, it is likely that intravenous antibiotics will be promptly administered if it is suspected, even if it has not been fully confirmed through testing. Antibiotics are ineffective against viral meningitis.
If viral meningitis is caused by the herpes simplex virus, it should be treated intravenously with the antiviral drug acyclovir. 11 18 If a person displays signs of disturbed consciousness or any other neurological problems, acyclovir should be administered early to halt the potential development of encephalitis. People in an unstable condition should be admitted to a critical care unit for airway protection, neurological checks and in order to help reduce the possibility of secondary complications. Treatment methods may be altered, depending on the results of gram staining, cultures and other tests.
Viral meningitis caused by enteroviruses or the herpes simplex virus is capable of causing viral septic shock in newborn babies and infants. For this reason, acyclovir and a broad range of other antiviral therapies should be introduced as soon as the diagnosis is suspected.
Antiretroviral drugs can be used to treat viral meningitis in people with HIV. 6
Good to know: Viral meningitis is caused by a virus so antibiotics will not help to combat symptoms. Antibiotics treat illnesses caused by bacteria. However, if a person presents as seriously ill, they will likely be given antibiotics until it is confirmed whether meningitis is bacterial or viral. 6
Preventing viral meningitis
Protection against some viruses that cause viral meningitis can be obtained through vaccination, such as for mumps, measles and varicella zoster. 1
There are no vaccinations for enteroviruses, but maintaining good hygiene practices, such as handwashing and avoiding close contact with people who are ill, can restrict their spread. 1
Using barrier devices, such as condoms, during sexual activity can help restrict the spread of herpes simplex viruses. 2
Taking precautions to avoid mosquito bites, such as repellent sprays and clothes which cover arms and legs, can prevent the spread of some viruses carried by mosquitoes and which can cause viral meningitis. Some viruses, such as dengue and Japanese encephalitis, are primarily encountered while travelling. However, some mosquito-borne viruses, such as the West Nile virus, are found within the United States. 14 19
Complications of viral meningitis
In rare cases, viral meningitis can cause more serious conditions. People most at risk include babies less than one month old and people with compromised immune systems.
Complications may include persistent headaches and a feeling of general illness (malaise), which may last for up to three weeks. Seizures are also possible and should be treated with intravenous anticonvulsant medications, such as lorazepam, phenytoin and midazolam. In some instances of severe encephalitis, cerebral edema (fluid on the brain) may also occur. Treatment may involve intracranial pressure control through an infusion of mannitol, intravenous dexamethasone or intubation.
Viral meningitis caused by West Nile virus, Japanese B encephalitis and tick-borne encephalitis can be life-threatening and cause long-term neurological problems. 11
Mollaret meningitis, also called Recurrent Lymphocytic Meningitis, is a rare form of viral meningitis that recurs repeatedly, separated by weeks or months without symptoms. People with Mollaret meningitis may also experience seizures, double vision, hallucinations and other neurological problems. It is thought that the herpes simplex virus causes most cases. 17
Long-term effects of viral meningitis
The majority of people who experience viral meningitis will experience no long-term effects as a result of the condition. There is research to suggest, however, that a small percentage of affected people may develop short-term memory loss and behavioral changes. Children under the age of one may also develop slight neurological problems later in life. 12
People concerned about the long-term effects of meningitis should talk to their doctor.
Neonatal herpes simplex meningitis
Herpes simplex virus affects around 1,500 to 2,000 newborn babies in the United States each year. If left untreated, the virus can cause viral meningitis. This condition can be life-threatening and can cause lasting brain damage. 18 19
Viral meningitis FAQs
Q: Is viral meningitis contagious?
A: Viral meningitis itself is not contagious, meaning it cannot be transmitted from person to person. However, some of the viruses that can cause viral meningitis, notably enteroviruses, are highly contagious, though only a small number of people with these viruses will go on to develop viral meningitis.
Q: What is the difference between viral and bacterial meningitis?
A: Viral meningitis and bacterial meningitis are caused by different organisms. Viral meningitis is caused by viruses and bacterial meningitis is caused by bacteria. Bacterial meningitis can be life-threatening within just a few hours of onset. While viral meningitis is usually far less serious, people in at-risk groups such as babies and immunocompromised people may experience significant complications.
Read more about Bacterial Meningitis »
Q: Is there a vaccine for viral meningitis?
A: There is no vaccine available for non-polio enteroviruses, the underlying cause of 85 percent of cases of viral meningitis. There are vaccines for other possible causes, such as the flu, measles and chickenpox. It is advised that people stay up to date on their vaccinations to help prevent viral meningitis. 1
Other names for viral meningitis
- Aseptic meningitis
- Viral meningoencephalitis
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