Meningitis causes swelling in the meninges, the protective membrane surrounding the spinal cord and brain. It is a serious illness that can be deadly. Treatment will vary depending on the type of meningitis a person has, but anyone who suspects they may have meningitis of any kind should seek immediate medical help.

Meningitis causes swelling in the brain’s meninges, a protective coating covering the brain.

There are many different types of meningitis, with different causes. The type of meningitis a person has can affect the outlook.

Doctors sometimes divide meningitis into two categories: infectious meningitis, which happens when a pathogen invades the meninges, and noninfectious meningitis, which happens when a disease attacks the meninges or an injury affects it.

The viral and bacterial infections that cause infectious meningitis are typically contagious. Noninfectious meningitis is not contagious.

Doctors treat meningitis differently depending on the type and cause.

This article will explore the different types of meningitis, and the symptoms, causes, and treatments for each type. It will also provide information on the meningitis vaccine.

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Infectious meningitis occurs when a pathogen reaches the meninges. There are several different types of infectious meningitis. They are:

Bacterial meningitis

Bacterial meningitis happens when a bacterial infection spreads to the meninges surrounding the brain. Severe cases can cause death in just a few hours or days.

Symptoms

Symptoms may come on suddenly, and are usually much worse than those of viral meningitis.

A person with bacterial meningitis may already be sick from another illness. The infection may have progressed to meningitis if they develop these symptoms:

  • headache
  • fever
  • stiff neck
  • light sensitivity
  • nausea and vomiting
  • confusion or changes in mood

People with meningitis, including bacterial meningitis, may have Kernig sign, which is a specific type of stiff neck.

While a person lays on their back, a doctor will ask a person to bend their knees and move their thighs up against the abdomen. When a doctor or other person attempts to extend the legs, it may cause intense low back or thigh pain.

Another stiff neck sign is the Brudzinski sign. A person lies flat on their back and a healthcare professional flexes the neck up and forward. The test is positive and suggests meningitis if this causes a person to flex their hips and knees.

These signs can occur with any type of meningitis, but are more common with severe meningitis.

Treatment

Treatment for bacterial meningitis involves using antibiotics to kill the suspected bacteria.

A doctor may first prescribe several broad spectrum antibiotics, then change the treatment once laboratory tests confirm which kind of bacteria has affected the meninges.

People with bacterial meningitis may need to stay in the hospital for observation and additional care, such as breathing support and intravenous (IV) fluids.

Viral meningitis

Viral meningitis occurs when a viral infection spreads to the meninges.

The viral infections that cause viral meningitis do not normally lead to meningitis in healthy people. Babies, the elderly, and people with weak immune systems are more vulnerable to meningitis infections from certain viruses.

Those viruses include:

Symptoms

The symptoms of viral meningitis are similar to those of other types of meningitis, and include:

  • headache
  • stiff neck
  • light sensitivity
  • confusion
  • vomiting and nausea

A person cannot distinguish viral meningitis from other forms of this disease based on symptoms alone.

Treatment

Antibiotics will not treat viral meningitis or the infections that cause it, though a doctor may give a person antibiotics until it is possible to fully rule out a bacterial infection.

In many cases, people with viral meningitis do not need any specific treatment.

In some cases, a person may need supportive care such as fluids, help breathing, or observation in a hospital. Most people get better on their own without treatment.

Fungal meningitis

Fungal meningitis happens when a fungal infection travels to the brain.

These infections are more common in very young babies and people with weak immune systems.

For example, cryptococcal meningitis occurs in soil throughout the world, and usually does not make people sick. However, it can cause serious health problems in those with weak immune systems.

The fungi that cause fungal meningitis can spread from the environment to a person, but these fungi do not spread from person to person.

Symptoms

Like other types of meningitis, fungal meningitis may cause:

  • headache
  • stiff neck
  • fever
  • vomiting and nausea
  • light sensitivity
  • confusion or changes in mood

Treatment

To treat fungal meningitis, doctors usually give antifungal drugs, often through an IV in the hospital.

Amebic meningitis

The amoeba Naegleria fowleri can cause amebic meningitis.

Most people get exposed through soil or warm water – usually when the water enters the nose.

Amebic meningitis is very rare, with just 34 reported infections in the United States between 2009 and 2019.

Symptoms

The symptoms begin similar to other forms of meningitis, within 1 to 9 days of exposure. Symptoms include:

  • headache
  • fever
  • vomiting
  • nausea
  • stiff neck

Symptoms can progress to more serious neurological symptoms, including:

  • hallucination
  • seizures
  • confusion
  • loss of balance

Treatment

Some drugs are effective at killing the amoeba in lab settings, but have not worked well in people.

Doctors may try various drugs to save a person’s life, and may also offer supportive care such as breathing support or IV fluids.

Almost all people with amebic meningitis die, usually within just a few days.

Of 34 infections reported to the CDC between 2009 and 2019, just three people survived. For this reason, a doctor may recommend focusing on comfort and alleviating pain.

Parasitic meningitis

Amebic meningitis is similar to parasitic meningitis, which happens when a parasite infects the brain.

In many cases, these are parasites that infect animals, and they can only enter the human brain when a person has exposure to such animals, such as by eating contaminated meat.

Some parasites that can cause this type of meningitis include:

  • A. cantonensis: This comes from eating contaminated produce, or from eating raw or poorly cooked slugs or snails.
  • G. spinigerum: This comes from eating undercooked eels, fish, frogs, snakes, or poultry.
  • B. procyonis: This comes from eating the eggs of the parasite, which are present in raccoon feces. Dirt contaminated with raccoon feces can also spread the infection.

Symptoms

The symptoms are the same as other types of meningitis, and include:

  • headache with stiff neck
  • sensitivity to light
  • changes in mood or perceptions
  • vomiting
  • nausea

Treatment

No treatment specifically targets parasitic meningitis. Instead, a doctor may recommend supportive care to reduce pain and other symptoms.

In some cases, the reaction of the immune system to the parasite is harmful, so a doctor may prescribe medication such as steroids to reduce this reaction.

Noninfectious meningitis does not originate with an external pathogen or parasite. It is not contagious.

Noninfectious meningitis can occur when a drug causes swelling around the brain, a chronic illness irritates the meninges, or cancer affects the brain.

Symptoms

The symptoms are similar to other types of meningitis, and include:

  • headache
  • fever
  • stiff neck
  • nausea and vomiting
  • confusion or changes in personality
  • light sensitivity

A person may suspect they have noninfectious meningitis if they develop these symptoms after taking a new medication, or when they have a serious chronic illness.

Treatment

Treatment of noninfectious meningitis focuses on removing the cause of the meningitis.

For example, if a person develops meningitis after taking a new drug, they need to stop taking that drug.

Doctors then provide supportive care to help the brain and body recover. This may mean staying in the hospital, using a breathing machine, or getting intravenous fluids.

A person may take antibiotics until a doctor has conclusively ruled out meningitis.

The meningitis vaccine does not protect against all forms of meningitis. Instead, it reduces the risk of certain infections that can cause meningitis.

Some vaccine options that help prevent meningitis include:

  • meningococcal vaccination to prevent Neisseria meningitidis
  • pneumococcal vaccine to prevent Streptococcus pneumoniae
  • Haemophilus influenza vaccine to prevent Hib in children under 5 years old

Vaccinations against some other infections may reduce the risk that they spread to the meninges and cause meningitis.

For example, the flu vaccine and the measles, mumps, and rubella (MMR) vaccine can reduce the risk of viral meningitis from these infections.

The outlook varies depending on the type of meningitis a person has.

Healthy people with viral meningitis usually recover within 7 to 10 days without treatment.

Amebic meningitis carries the highest death rate, of 99%.

Death rates for bacterial meningitis vary depending on the type of bacteria involved, how quickly treatment begins, and a person’s underlying health.

A 2012 Lancet article estimated that Streptococcus pneumoniae-induced meningitis has a death rate of 30%, compared to a death rate of 7% for Neisseria-induced meningitis.

This data only applies to high-income countries. In lower resource settings where a person may face delayed or inadequate treatment, the death rate for bacterial meningitis can be as high as 50%. The outlook for meningitis greatly improves with prompt and aggressive medical care.

People who survive meningitis may have long-lasting neurological or other issues, such as behavior changes, hearing impairments, or vision difficulties.

Meningitis is a potentially deadly illness, even in healthy people.

It is important to seek immediate treatment, and to tell a doctor about any potential exposure to infections that cause meningitis.

Early treatment gives a person a better chance of surviving without long-term disabilities.