Meningitis is an infection and swelling, called inflammation, of the fluid and membranes around the brain and spinal cord. These membranes are called meninges.
The inflammation from meningitis most often triggers symptoms such as headache, fever and a stiff neck.
Viral infections are the most common cause of meningitis in the United States. Bacteria, parasites and fungi also can cause it. Sometimes meningitis improves in a few weeks without treatment. But meningitis also can cause death. It often needs quick treatment with antibiotics.
Seek medical care right away if you think that you or someone in your family has meningitis. For meningitis caused by bacteria, early treatment can prevent serious complications.
Early meningitis symptoms may be like those of the flu. Symptoms may come on over several hours or over a few days.
The following may be symptoms of meningitis in people older than 2 years:
The following may be symptoms of meningitis in newborns and infants:
Seek medical care right away if you or someone in your family has meningitis symptoms such as:
Bacterial meningitis can cause death within days without fast antibiotic treatment. Delayed treatment also increases the risk of long-term brain damage.
Talk with your healthcare professional if you've been near someone with meningitis. That may be a family member or someone you live or work with. You may need to take medicines to prevent getting an infection.
Viral infections are the most common cause of meningitis in the United States, followed by bacterial infections and, rarely, fungal and parasitic infections. Because bacterial infections can lead to death, finding the cause is vital.
Germs that enter the bloodstream and travel to the brain and spinal cord cause bacterial meningitis. But bacterial meningitis also can happen when bacteria directly enter the meninges. This may be caused by an ear or sinus infection or a skull fracture. Rarely, some surgeries can cause it.
Several strains of bacteria can cause bacterial meningitis. The most common are:
Neisseria meningitidis. This germ causes a bacterial meningitis called meningococcal meningitis. These germs most often cause an upper respiratory infection. But they can cause meningococcal meningitis when they enter the bloodstream.
This is an easy-to-catch infection that affects mainly teenagers and young adults. It may cause local outbreaks in college dorms, boarding schools and military bases.
A vaccine can help prevent infection. Even if vaccinated, anybody who has been in close contact with a person with meningococcal meningitis should get an oral antibiotic. This can help prevent the disease.
Viral meningitis is most often mild and clears on its own. A group of viruses known as enteroviruses is most often the cause in the United States. Enteroviruses are most common in late summer and early fall. Viruses such as herpes simplex virus, HIV, mumps virus, West Nile virus and others also can cause viral meningitis.
Chronic meningitis is meningitis whose symptoms last at least four weeks without letup. There are many causes of chronic meningitis. Symptoms can be like those of new-onset meningitis. But they come on slower and last longer. Symptoms may include headache, fever, vomiting and brain fog.
Fungal meningitis isn't common in the United States. It may act like bacterial meningitis. But symptoms may start slower and build over time. Breathing in fungal spores found in soil, decaying wood and bird droppings can be the cause.
Fungal meningitis doesn't spread from person to person. Cryptococcal meningitis is a common fungal form of the disease. It affects people with weakened immune systems, such as from AIDS. It can cause death if not treated with an antifungal medicine. Even with treatment, fungal meningitis may come back.
This type of meningitis is a rare complication of tuberculosis, also called TB. But it can be serious. Like fungal meningitis, its symptoms can start slowly and build up over days to weeks. Tuberculosis passes easily from person to person. Tuberculous meningitis needs treatment with TB medicines.
Parasites can cause a rare type of meningitis called eosinophilic meningitis. A tapeworm infection in the brain or cerebral malaria also can cause parasitic meningitis. Amoebic meningitis is a rare type that sometimes comes from swimming in fresh water. It can quickly become life-threatening.
The main parasites that cause meningitis most often infect animals. People can get infected by eating foods that have these parasites. Parasitic meningitis isn't spread from person to person.
Causes of meningitis that aren't infections include chemical reactions, medicines, allergies, some types of cancer and diseases such as sarcoidosis.
Risk factors for meningitis include:
Meningitis complications can be serious. The longer someone has the disease without treatment, the greater the risk of seizures and long-term nervous system damage. Damage can include:
Common germs that can cause meningitis can spread through coughing, sneezing or kissing. Germs also can spread by shared eating utensils, toothbrushes or cigarettes.
These steps can help prevent meningitis:
Vaccinations can help prevent some forms of bacterial meningitis. Vaccinations include:
Pneumococcal polysaccharide vaccine. This vaccine also is called PPSV23. Older children and adults who need protection from pneumococcal germs might get this vaccine. The CDC suggests the PPSV23 vaccine for all adults older than 65.
It's also for younger adults and children ages 2 and older who have weak immune systems or ongoing illnesses such as heart disease, diabetes or sickle cell anemia. And it's for anyone who doesn't have a spleen.
Meningococcal conjugate vaccine. This vaccine also is called MenACWY. The CDC suggests giving a single dose of MenACWY to children ages 11 to 12, with a booster shot given at age 16. Children who get the first vaccine between ages 13 and 15 can have the booster between ages 16 and 18. Those who get the first shot at age 16 or older don't need a booster.
Children between the ages of 2 months and 10 years who are at high risk of bacterial meningitis can get this vaccine. So can children in this age range who have been around someone with the disease. It's also a vaccine for people who haven't been vaccinated who have been exposed to meningitis but aren't sick.
Serogroup B meningococcal vaccine (MenB). The CDC suggests this vaccine for adults and children 10 years and older who are at increased risk of meningococcal disease. They include adults and children with sickle cell disease, those who have a damaged spleen or those who have had their spleen removed.
This vaccine also is for people with the rare immune disorder called complement component deficiency or who take certain medicines. People who are exposed to an outbreak of serogroup B meningococcal disease also might get this vaccine.
A healthcare professional can diagnose meningitis based on a medical history, a physical exam and certain tests.
Common tests to diagnose meningitis include:
Spinal tap. This procedure collects fluid from around the spine. In people with meningitis, the fluid often shows a low sugar level along with a higher white blood cell count and more protein.
Studying the fluid also may help show which germ caused the meningitis. For viral meningitis, you may need a DNA-based test known as a polymerase chain reaction amplification. You also may have other tests.
Treatment depends on the type of meningitis.
New-onset bacterial meningitis needs treatment right away with antibiotics given through a vein, called intravenous antibiotics. Sometimes corticosteroids are part of the treatment. This helps you recover and cuts the risk of complications, such as brain swelling and seizures.
The antibiotic or mix of antibiotics depends on the type of germ causing the infection. Until your healthcare professional knows the exact cause of the meningitis, you may get a broad-spectrum antibiotic that fights a range of germs.
Your healthcare professional may prescribe corticosteroids to reduce swelling in the brain and a medicine to control seizures. If a herpes virus caused your meningitis, you may get an antiviral medicine.
Antibiotics can't cure viral meningitis. Viral meningitis tends to get better in a few weeks. Treatment of mild viral meningitis includes:
If the cause of your meningitis is not known, you may need to wait to start antibiotic treatment until your healthcare professional finds the cause.
Treatment for ongoing meningitis, called chronic meningitis, depends on the cause.
Antifungal medicines treat fungal meningitis. A mix of antibiotics can treat tuberculous meningitis. But these medicines can have serious side effects. So you might wait for treatment until a lab confirms that the cause is fungal or tuberculous.
Corticosteroids may treat meningitis due to allergic reaction or autoimmune disease. Sometimes, you don't need treatment because the condition clears up on its own. Cancer-related meningitis needs treatment for the cancer.
Some types of meningitis can lead to death. If you've been around bacterial meningitis and you get symptoms, go to an emergency room. Tell the healthcare team that you may have meningitis.
If you're not sure what you have and you call your healthcare professional for an appointment, here's how to prepare for your visit.
For meningitis, some basic questions to ask include:
Your healthcare professional is likely to ask you questions, such as: