Meningitis is an inflammation of the meninges, the protective layers surrounding the brain and spinal cord. The most common cause is a viral infection; however, the most serious cause is a bacterial infection (bacterial meningitis).
There are an estimated 1.2 million cases of bacterial meningitis in the world every year and about 180,000 deaths. [1] Bacterial meningitis is estimated to cause 2% of all child deaths in the world. [2]
Meningitis is an inflammation of the brain's protective layers, called the meninges.
Entry into the body of microorganisms that can reproduce and cause disease.
A bundle of nerve tissue that runs from the brain through the spinal column and connects the brain to the body, transmitting sensory and motor signals.
Control of epidemic meningococcal disease. WHO practical guidelines. 2nd edition. World Health Organisation. Accessed 27 April 2015 from
Luksic I. Mulic R. Falconer R. et al. (2013) Estimating global and regional morbidity from acute bacterial meningitis in children: assessment of the evidence. Croatian Medical Journal 54: 510-518.
There are several possible causes of meningitis. The inflammation can be the result of infection with bacteria, viruses or fungi. It can also result from non-infectious causes such as inflammatory diseases.
Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.
Entry into the body of microorganisms that can reproduce and cause disease.
Bacterial meningitis can be extremely serious and is treated as a medical emergency as it can be fatal, if not appropriately treated. Bacterial meningitis can be spread through contact with saliva and nasal droplets. It can be caught through close contact, such as sharing a room or household with an infected person.
About one in 10 people is a healthy carrier of the bacteria that cause meningitis. [3] These people do not suffer any symptoms, but can transfer the bacteria to others.
Some of the most common bacterial species that cause meningitis include:
Other bacterial species known to cause meningitis are
Viral meningitis is more common and normally milder than bacterial meningitis, though it can be highly contagious. Most people recover from viral meningitis without any permanent damage. It is common in children and young adults.
Viruses that can cause meningitis include:
Viruses that cause diseases such as measles, mumps and the flu can also result in meningitis, as a complication of these diseases. However, infection with these viruses can be preventable by vaccination.
Fungal meningitis is rare and not contagious. It can develop when a fungus gets into your bloodstream or central nervous system. Fungal meningitis can develop very slowly and generally occurs in people with a weak immune system.
Infection is often a result of inhalation of the fungal spores. These spores are normally found in the soil or in animal droppings, but are sprayed into the air when dust or droppings are disturbed, such as by being kicked or stepped on.
Rarely, meningitis is caused by infection with single-celled parasites, such as amoebas. This typically occurs when a person swims in water where the parasites are found and the contaminated water enters the nose. This rare condition is dangerous and often fatal.
Inflammation of the meninges can also occur without any infection. Some causes of non-infectious meningitis include:
Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.
The part of the body's nervous system that includes the brain and the spinal cord.
An organism from the fungi kingdom, which is a separate group to plants or animals, and includes yeasts, molds and mushrooms. Fungi feed on organic matter.
Entry into the body of microorganisms that can reproduce and cause disease.
An organism that lives off another organism.
A microscopic infectious agent that replicates itself only within cells of living hosts; a piece of nucleic acid (DNA or RNA) wrapped in a protein coat.
Any group of viruses that is transmitted from insects to humans, causing diseases such as yellow fever.
Meningococcal meningitis. World Health Organisation. Accessed 20 April 2015 from
Factors that can affect the immune system include:
People in an environment where meningitis infections are more likely to occur include:
A medication-based treatment, usually used in the treatment of cancers. There are numerous, different types of chemotherapy drugs that can be prescribed by a specialist. These can commonly be used alongside other cancer treatments such as surgery and radiotherapy.
The signs and symptoms of meningitis can closely resemble those of the flu. They can appear quickly, sometimes hours after infection, or over a few days. It is not possible for a person to diagnose themselves or family members with meningitis. It is therefore very important to seek professional medical help if you suspect meningitis.
The 'classic' symptoms of meningitis in adults include:
At least two of these symptoms appear in nearly all people with bacterial meningitis. Additional symptoms of meningitis may include:
In infants, the symptoms of meningitis might appear slightly different. They include:
Symptoms of meningitis in infants.
Entry into the body of microorganisms that can reproduce and cause disease.
Meningitis can be difficult to diagnose in the early stages, because the symptoms can be similar to the flu. If your doctor suspects that you have meningitis, they may perform one or more of the following tests:
A scan that uses X-rays to create a 3D image of the body. This can detect abnormalities more effectively than a simple X-ray can.
Entry into the body of microorganisms that can reproduce and cause disease.
A type of imaging that uses a magnetic field and low-energy radio waves, instead of X-rays, to obtain images of organs.
A bundle of nerve tissue that runs from the brain through the spinal column and connects the brain to the body, transmitting sensory and motor signals.
A procedure that uses a needle to collect a sample of cerebrospinal fluid, which is the clear fluid surrounding the brain and spine, from the lower back (lumbar region) for analysis. It can also be performed to remove any excess fluid or to deliver medications.
The type of treatment depends on the cause of the meningitis.
Bacterial meningitis is promptly treated in a hospital with high doses of antibiotics, given intravenously.
Treatment of non-bacterial meningitis is usually managing the symptoms, providing plenty of fluids and making sure that the inflammation does not cause pressure on the brain. Meanwhile, the person's immune system takes care of the infecting virus.
In some cases of viral meningitis where the immune system is weak, specific antiviral therapy may be recommended.
Fungal meningitis is normally treated with antifungal medication, such as amphotericin B or fluconazole. Parasitic meningitis is treated with antiparasitic medications.
A microscopic infectious agent that replicates itself only within cells of living hosts; a piece of nucleic acid (DNA or RNA) wrapped in a protein coat.
Bacterial meningitis is still a dangerous condition today, and can lead to serious complications and death. Untreated bacterial meningitis is usually fatal. Even with treatment, there is still a real chance of death or serious disability.
After-effects of the infection are also more pronounced in bacterial meningitis than in other kinds.
Viral meningitis is usually less severe and will normally clear up on its own in 2-4 weeks, but complications can still occur.
Meningitis complications result from the damage that the inflammation causes to various areas of the brain. Complications can include:
Some people recovering from meningitis may suffer from after-effects of the inflammation. These problems can linger for some time after the episode has passed, but usually get better eventually. They can include:
Bacterial meningitis can lead to contamination of the bloodstream with the infecting bacteria (septicemia or bacteremia), a dangerous complication of meningitis. Blood infections can lead to arthritis, gangrene, kidney failure, septic shock and death.
Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.
The death of a mass of body tissue, usually resulting from obstructed blood supply or bacterial infection.
The abnormal accumulation of fluid in the brain.
Entry into the body of microorganisms that can reproduce and cause disease.
An inability to move or feel; a loss of muscle function or sensation.
A life-threatening condition in which the blood pressure falls to dangerously low levels due to a widespread infection.
There is no guarantee against meningitis; complete prevention is not yet available. You can lower the risk of bacterial meningitis by avoiding close contact (sharing a room, household, dormitory, kissing or sharing food and cutlery) with an infected person.
Close contacts (family, household members) of people that have been diagnosed with bacterial meningitis may receive antibiotic treatment to prevent infection and development of disease.
Vaccines are available against the most dangerous types of bacteria that cause bacterial meningitis, as well as against some of the viruses that cause meningitis. The vaccines do not cover all possible infectious causes of meningitis. In many countries, these vaccines are offered as part of the regular childhood vaccination schedule. Vaccination is also often recommended for:
Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.
Entry into the body of microorganisms that can reproduce and cause disease.