Viral infections are the most common cause of meningitis in the United States, but the illness can also be caused by bacterial, parasitic, and fungal infections, according to the Mayo Clinic. (2) Other types of infections can also cause meningitis, and there are noninfectious causes as well, such as injuries, cancer, and certain medication. (1) Viral meningitis, the most common type of meningitis, is typically mild and frequently goes away on its own. (2) However, bacterial meningitis can be life-threatening within days if it’s not treated or lead to permanent brain damage, so be sure to seek medical care immediately if you think you may have the infection. Signs and symptoms in people over the age of 2 may include:
High fever that comes on suddenlyStiff neckSevere headache that seems unusualHeadache with nausea or vomitingConfusion or trouble concentratingSeizuresSleepiness or difficulty waking upSensitivity to lightLack of appetite or thirstSkin rash (in some types of meningitis — e.g., meningococcal meningitis)
Signs and symptoms in newborns and infants may include:
High feverNonstop cryingAtypical sleepiness or irritabilityLack of activity or sluggishnessFailure to feed wellA bulge in the soft spot on top of a baby’s head (fontanel)Stiffness in a baby’s body and neckA baby that is difficult to comfort
Learn More About Signs and Symptoms of Meningitis
Causes of Viral Meningitis
In the United States, viral meningitis is typically caused by enteroviruses, a group of viruses that are most common in late summer and early fall, according to the Mayo Clinic. (2) However, few people infected with enteroviruses actually develop meningitis. (3) Other viruses, including herpes simplex virus, HIV, mumps, and West Nile virus, can also cause viral meningitis. (2)
Causes of Bacterial Meningitis
Various types of bacteria can cause bacterial meningitis, according to the CDC. (4) In the United States, the main causes of bacterial meningitis are:
Streptococcus pneumoniaeGroup B streptococcusNeisseria meningitidisHaemophilus influenzaeListeria monocytogenes
The germs that cause bacterial meningitis typically spread from person to person, but certain germs, such as Listeria monocytogenes, are usually acquired through contaminated food. Bacterial meningitis is very serious and can be fatal. Although most people recover, permanent complications may include brain damage, hearing loss, and learning disabilities. If you have meningitis symptoms, be sure to see a doctor right away, as prompt treatment is critical.
Causes of Fungal Meningitis
Fungal meningitis can occur after a fungus spreads from part of the body to the brain or spinal cord, according to the CDC. (5) Some causes of fungal meningitis include:
Cryptococcus, which lives in soil, on decaying wood, and in bird droppingsHistoplasma, which lives in environments with large amounts of bird or bat droppingsBlastomyces, which lives in moist soil and in decaying wood and leavesCoccidioides, which lives in the soil in the southwestern United States and areas of Central and South AmericaCandida, which normally lives inside the body and on the skin without causing any issues, but can cause an infection in people who are high risk
Fungal meningitis doesn’t spread between people, so it’s not contagious, and it’s rare in the United States. People with weakened immune systems are at increased risk, such as those who have HIV and cancer, or those who take certain medication. Premature babies with very low birth weights also have a greater risk of getting a Candida bloodstream infection.
Causes of Parasitic Meningitis
Certain parasites can cause a rare type of meningitis called eosinophilic meningitis, eosinophilic meningoencephalitis, or EM, according to the CDC. (6) The top three parasites that can cause EM are:
Angiostrongylus cantonensis Baylisascaris procyonis Gnathostoma spinigerum
When people get infected with parasitic meningitis, it’s usually because they’ve ingested infected animals or contaminated foods. Examples include raw or undercooked snails or slugs, contaminated produce, parasite eggs found in raccoon feces or dirt, or raw or undercooked freshwater fish or eels, frogs, poultry, or snakes.
Causes of Amebic Meningitis
Primary amebic meningoencephalitis (PAM), a rare brain infection that is deadly in most cases, is caused by the amoeba Naegleria fowleri, according to the CDC. (7) Naegleria fowleri can be found in:
Warm fresh water, such as lakes and riversGeothermal (naturally hot) water, such as hot springsWarm water discharge from industrial plantsUntreated geothermal drinking water sourcesPoorly maintained swimming poolsWater heatersSoil
Very rarely, Naegleria infections can be caused by contaminated water getting in the nose. For example, this can occur when people submerge their heads in water or cleanse their noses during religious practices, or irrigate their sinuses using contaminated tap water. But most cases in the United States have been linked to swimming in Southern states like Florida and Texas.
Causes of Noninfectious Meningitis
According to the CDC, causes of noninfectious meningitis (meningitis that is not caused by a microorganism) include: (8)
CancerLupusSome medicationHead injuryBrain surgery
Risk Factors
There are several factors that can increase your risk of getting meningitis. According to the Mayo Clinic, these include: (2)
Skipping vaccinationsBeing young. Viral meningitis usually occurs in children under age 5. Bacterial meningitis is common in people younger than age 20.Living in a community setting, such as a college dorm, military base, or boarding schoolBeing pregnant. Meningitis can be caused by listeriosis, an infection caused by Listeria bacteria, and pregnancy increases the risk of listeriosis.Having a compromised immune system, which can be due to factors including AIDS, alcoholism, diabetes, and taking immunosuppressant drugsHaving your spleen removed
Tests used to diagnose meningitis include:
Blood Cultures Blood cultures may be ordered to detect bacteria.Computerized tomography (CT) or Magnetic resonance imaging (MRI) scans of the head may reveal swelling or inflammation, and X-rays or CT scans of the chest or sinuses may also show infection.Spinal Tap A spinal tap (lumbar puncture) is done to collect cerebrospinal fluid (CSF) and definitively diagnose meningitis. If you have meningitis, the CSF frequently shows a low sugar (glucose) level as well as an elevated white blood cell count and increased protein.CSF Analysis CSF analysis may be done to pinpoint which bacteria caused the meningitis. In cases of viral meningitis, your doctor may order a DNA-based test known as a polymerase chain reaction (PCR) amplification or a test to check for antibodies against certain viruses.
Prognosis of Meningitis
Some cases of meningitis get better without treatment in a few weeks, according to the Mayo Clinic. In other cases, emergency treatment is necessary to prevent serious complications, including death. (2) Viral meningitis is typically mild and frequently goes away on its own. Early diagnosis and treatment of bacterial meningitis are critical to prevent permanent neurological damage, according to MedlinePlus. (10) In most cases, people with very mild meningitis can make a full recovery, per the National Institute of Neurological Disorders and Stroke. (11) People who have bacterial meningitis generally show some improvement 48–72 hours after treatment but are more likely to experience complications. (11)
Medication Options
Medication for bacterial meningitis may include:
Intravenous antibioticsCorticosteroids to reduce inflammation
Your doctor may also drain any infected sinuses or mastoids, which are the bones behind the outer ear that connect to the middle ear.
Treatment for Viral Meningitis
Antibiotics can’t cure viral meningitis. For mild cases, treatment usually includes bed rest and lots of fluids.
Medication Options
Medication options for viral meningitis include:
Over-the-counter pain medication (for fever and body aches)Corticosteroids to reduce swelling in the brainAnticonvulsant medication to control seizuresAntiviral medication, if a herpes virus caused your meningitis
Treatment for Other Types of Meningitis
There are various treatments for other types of meningitis, including
Antifungal medication to treat fungal meningitisCorticosteroids to treat noninfectious meningitis
Learn More About Treatment for Meningitis: Medication, Alternative and Complementary Therapies, Surgery Options, and More
Prevention of Meningitis
The following steps can help prevent meningitis, per the Mayo Clinic: (2)
Wash your hands well and teach children to do the same.Don’t share drinks, foods, straws, eating utensils, lip balms, or toothbrushes with other people.Stay healthy and boost your immune system by getting enough rest, exercising regularly, and eating a healthy diet with plenty of fresh fruit, vegetables, and whole grains.When you need to cough or sneeze, cover your mouth and nose.If you’re pregnant, reduce your risk of listeriosis by cooking meat, including hot dogs and deli meat, to 165 degrees F. Avoid cheeses made from unpasteurized milk, and eat only cheeses made with pasteurized milk.
Vaccines for Meningitis
According to the Mayo Clinic, you can prevent bacterial meningitis by keeping yourself and your children up-to-date on the following vaccines:
Haemophilus Influenzae Type B (Hib) Vaccine Children in the United States routinely receive this vaccine starting at about 2 months old. It’s also recommended for some adults, including people who have sickle cell disease or AIDS and individuals who don’t have a spleen.Pneumococcal Conjugate Vaccine (PCV13) This vaccine is routinely given to American children younger than 2 years old. Additional doses are recommended for children older than 2 years old and younger than 5 years old who are at increased risk of pneumococcal disease, such as those who have chronic heart or lung disease or cancer.Pneumococcal Polysaccharide Vaccine (PPSV23) This vaccine may be recommended for older children and adults who need protection from pneumococcal bacteria, including all adults older than 65; younger adults and children age 2 and older who have weak immune systems or illnesses such as heart disease, diabetes, or sickle cell anemia; and anyone who doesn’t have a spleen.Meningococcal Conjugate Vaccine The CDC recommends that children receive a single dose of this vaccine at age 11 or 12, and a booster shot at age 16. It can also be given to children between 2 months old and 10 years old who are at increased risk of bacterial meningitis, and to unvaccinated people who have been exposed in outbreaks.
Hearing lossMemory problemsLearning disabilitiesBrain damageGait problemsSeizuresKidney failureShockDeath
While enteroviruses cause most cases of viral meningitis and most people are exposed to these viruses, fewer than 1 in every 1,000 people infected with enteroviruses actually develops meningitis. (13) While the outbreaks are not fully understood, the following characteristics of the region may play a role:
Dry and dusty conditions during the dry season, from December to JuneImmunological susceptibility of the populationTravel and large population displacementsCrowded living conditions
Septicemia
The same bacteria that cause bacterial meningitis can also be associated with sepsis, or septicemia, which is the medical term for a bacterial infection that spreads throughout the body. (4) Septicemia is the body’s extreme response to an infection, and it can be fatal without prompt treatment, according to Johns Hopkins Medicine. (15) RELATED: What Is Sepsis? Symptoms, Causes, Diagnosis, Treatment, and Prevention The CDC is the nation’s health protection agency. Its website offers information about the types of meningitis, plus information about how it spreads. Mayo Clinic Mayo Clinic is a nonprofit organization that specializes in clinical practice, education, and research. Its website offers information about the symptoms, causes, risk factors, complications, and prevention of meningitis, plus diagnosis and treatment. MedlinePlus MedlinePlus is a service of the National Library of Medicine (NLM), the world’s largest medical library, which is part of the National Institutes of Health (NIH). It offers information about the causes, symptoms, diagnosis, treatment, prognosis, complications, and prevention of meningitis.
