Meningitis typically occurs due to an infection, which may be viral or bacterial. Viral and bacterial meningitis have similar symptoms but differ in severity.

This information comes from the Meningitis Research Foundation.

Meningitis is inflammation of the meninges, the lining of the brain. It can also result from the use of certain medications, as well as from injury or a medical condition such as cancer. The severity of the inflammation and the best treatment depends on the cause.

In this article, we look at the similarities and differences between viral and bacterial meningitis, including their symptoms, treatments, and outlook.

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Meningitis is inflammation of the meninges, the brain’s lining. The meninges consist of three protective tissue layers that surround and support the brain. Meningitis occurs when one or more layers becomes inflamed.

Viral meningitis happens when a virus spreads to the brain or spinal cord. Different viruses can cause it, but in the United States, non-polio enteroviruses are the most common causes.

Viruses that cause the following health conditions can also cause meningitis, in some cases:

Only a small number of people who contract these viruses develop meningitis as a result. Children under 5 years old and people with weakened immune systems have the highest risk.

Bacterial meningitis is less common than viral meningitis. It occurs when bacteria infect the brain or spinal cord. In the U.S., this type of meningitis is most commonly associatedwith these bacteria:

  • Streptococcus pneumoniae
  • Neisseria meningitidis
  • group B Streptococcus
  • Haemophilus influenzae
  • Escherichia coli
  • Listeria monocytogenes

More rare types of meningitis include:

  • fungal meningitis
  • parasitic meningitis
  • amebic meningitis, which stems from infection with Naegleria fowleri, an ameba in soil and warm water
  • noninfectious meningitis, which is linked with some types of cancer, lupus, medications, brain surgery, or head injuries

The symptoms of viral and bacterial meningitis are very similar. Because of this, it is essential not to try and self-diagnose. Bacterial meningitis is potentially life threatening, so anyone with any symptoms of meningitis should receive immediate medical care.

Viral or bacterial meningitis can cause:

  • a fever
  • chills
  • a headache
  • sensitivity to light
  • neck stiffness
  • nausea or vomiting
  • extreme tiredness
  • a rash

Bacterial meningitis can also cause:

  • limb pain
  • pale skin
  • cold hands and feet
  • an altered mental state, such as confusion

Either type of meningitis can cause a rash. If this develops, its appearance can depend on the specific virus or bacterium that is causing the infection.

The most well-known meningitis rash is caused by N. meningitidis, and it consists of tiny dots that look like pin pricks. The rash may instead resemble bruising, with areas of reddish or purplish discoloration.

Typically, these marks do not disappear when a person presses a glass to them. In this case, the rash is “nonblanching,” and it can signal that the meningitis is serious.

In babies and newborns, viral and bacterial meningitis may cause:

  • irritability
  • a high-pitched cry
  • poor feeding
  • bulging of the soft spot on the front of the head
  • arching of the back

The mostcommon type of meningitis is viral. Around 54.6% of all meningitis cases are viral, while 21.8% are bacterial.

Parasitic and fungal infections account for around 7.3% of meningitis cases, while 17.2% of cases have no identifiable cause.

Doctors diagnose meningitis by taking different samples of fluid and sending them to a laboratory for analysis. This helps determine whether the person has a bacterial or viral infection. Sometimes, the lab can also identify the type of virus or bacteria.

A healthcare professional may take samples of:

  • blood
  • stool
  • mucus from the throat or nose
  • cerebrospinal fluid (CSF), which comes from near the spinal cord

The doctor will also consider whether the person is taking any medications or has any health conditions that may cause meningitis.

Often, it is not possible to identify a specific pathogen from CSF, so the doctor needs to look at other test results to make a diagnosis. For example, a high white blood cell count can indicate bacterial meningitis. Higher protein and lower glucose levels in CSF can also point to bacterial meningitis, as can procalcitonin in the blood.

If it is unclear whether a person has bacterial or viral meningitis, the doctor may treat for bacterial meningitis, just in case. This is because bacterial meningitis is more serious and requires medication, while viral meningitis often gets better on its own.

While the symptoms of viral and bacterial meningitis are similar, their treatments are different.

The treatment for bacterial meningitis is antibiotics, and the type depends on the bacteria causing the infection. Beginning treatment as soon as possible is essential, as this increases the chances of a full recovery.

There is no specific treatment for viral meningitis. Many people recover on their own, but a doctor may prescribe an antiviral medication if the condition stems from influenza or herpes viruses. One drug they might prescribe is acyclovir.

A person may also benefit from medication to reduce the symptoms of viral meningitis, such as a pain reliever to ease headaches or antinausea medication to reduce vomiting. If the condition is severe, the person may need treatment in a hospital.

In most cases, viral meningitis is not life-threatening and does not result in serious or permanent ill health. Many people with mild viral meningitis recover without medical treatment within 7–10 days.

After recovering from viral meningitis, some people experience lingering symptoms, such as headaches, fatigue, problems with attention, short-term memory loss, and unexplained anxiety for a period of time.

Most people with bacterial meningitis also recover, but it can become very serious and even life threatening. Around 10–15% of people who develop bacterial meningitis die from it.

Bacterial meningitis can occur alongside sepsis, a very serious condition that involves bacteria entering the bloodstream. This triggers an extreme immune response that can damage healthy tissues. Without proper treatment, sepsis can cause widespread tissue damage, organ failure, and eventually death.

Bacterial meningitis is more likely to have long term effects than viral meningitis. Approximately 25% of people with bacterial meningitis develop complications. Some examples include:

  • seizures
  • vision or hearing loss
  • difficulty speaking
  • difficulty focusing, remembering, or learning
  • problems with balance, coordination, and movement

If a pregnant person develops meningitis as a result of a Listeria infection, it increases the risk of pregnancy loss, preterm delivery, and stillbirth. It is also possible for a Listeria or B Streptococcus infection to pass from parent to newborn.

Anyone with meningitis symptoms should receive medical attention right away. Only a doctor can confirm whether the cause is viral or bacterial. If it is bacterial, the person needs antibiotics as soon as possible.

It is also important to speak with a doctor about immunization. Many safe, effective vaccines offer protection against some of the viruses that can cause meningitis. Some examples include the:

  • measles, mumps, and rubella vaccine, sometimes called the MMR vaccine
  • varicella vaccines, which protect against chickenpox
  • flu shot, which people need every year

In the U.S., two vaccines offer protection against meningococcal disease — a bacterial infection that can result in meningitis. These are the meningococcal conjugate (MenACWY) and serogroup B meningococcal (MenB) vaccines.

The CDC recommends that all teenagers get the MenACWY vaccine because this age group has the highest risk. People aged 16–23 can get the MenB vaccine, as well.

Meningitis is inflammation of the brain’s lining. It can occur for a number of reasons, but usually the cause is a viral or bacterial infection. Viral meningitis is most common type, accounting for 54.6% of cases.

Viral and bacterial meningitis have similar symptoms, including a fever, headache, neck stiffness, nausea, and vomiting. Some people also develop a rash.

Viral meningitis is almost never fatal, but bacterial meningitis can be. Because it is difficult to tell them apart, anyone with any meningitis symptoms needs swift medical attention.