Meningitis is a rare condition that affects the membranes that cover the brain and spinal cord. Some forms of meningitis can cause serious complications or even be life-threatening.
What Is Meningitis?
Meningitis is inflammation of the meninges, a thin layer of protective tissue surrounding the brain and spinal cord.
Some types of meningitis, especially bacterial meningitis, can rapidly become serious. Complications may include brain swelling, fluid buildup inside the skull, hearing loss, seizures and even death within a few hours. Other types, such as viral meningitis, require minimal treatment or clear up on their own.
Types and Causes of Meningitis
There are several types of meningitis. Though the symptoms are similar, the underlying causes vary.
- Bacterial meningitis; Several types of bacteria can cause this type of meningitis, including Streptococcus, Listeria and tuberculosis. These germs can spread through personal contact or eating contaminated food.
- Fungal meningitis: This type develops after a fungal infection elsewhere in the body spreads to the brain or spinal cord. Many fungi commonly found in the nature can cause this type of meningitis.
- Parasitic meningitis: Three main types of parasites — rat lungworm, raccoon roundworm and nematode — can cause parasitic meningitis. This type of meningitis is usually acquired by eating infected animals or tainted food.
- Non-infectious meningitis. This type is not due to disease-causing organisms. Causes can include certain medications, head injury, brain surgery or medical conditions such as cancer or systemic lupus erythematosus.
- Viral meningitis: Several viruses can cause this type, including non-polio enteroviruses, mumps virus, herpes viruses such as Epstein-Barr, measles virus, influenza virus, arboviruses such as West Nile virus and lymphocytic choriomeningitis virus. These viruses spread through close contact with an infected person or touching a contaminated surface.
Signs and Symptoms of Meningitis
The first symptoms of meningitis occur suddenly, and usually include:
- fever and chills
- nausea or vomiting
- severe headache
- stiff neck
Symptoms that may appear later include:
- blotchy skin rash anywhere on the body
- cold hands and feet
- confusion, difficulty thinking, irritability
- muscle pain
- sensitivity to light
- sleepiness or difficulty waking
How Is Meningitis Diagnosed?
In addition to physical examination and review of medical history, diagnostic tests may include:
- blood, urine and other body fluid tests
- brain and spinal fluid tests to detect the presence of bacteria, blood and viruses, as well as measure antibodies, blood sugar, protein and white blood cells
- electroencephalography to detect abnormal brain wave patterns
- imaging studies, such as computed tomography scan and magnetic resonance imaging, to look for signs of inflammation, bleeding or other abnormalities in the brain
Prevention of Meningitis
There are several vaccines available to protect against most types of bacterial infections that cause meningitis, including:
- Haemophilus influenzae type b (Hib) vaccine
- meningococcal conjugate vaccine
- pneumococcal conjugate vaccine (PCV13)
- pneumococcal polysaccharide vaccine (PPSV23)
- serogroup B meningococcal vaccine
Vaccines that help prevent some types of viral meningitis include:
- measles, mumps and rubella vaccine
- tuberculosis vaccine (bacillus Calmette-Guérin or BCG)
Treatments for Meningitis
If diagnosed promptly, meningitis can be successfully treated. Options depend on the type:
- Bacterial meningitis. Antibiotics tailored to the specific bacteria are given intravenously
- Fungal meningitis. High doses of antifungal medications are given intravenously.
- Parasitic meningitis. Treatment usually focuses on relieving symptoms and reducing the body’s reaction to the parasite.
- Non-infectious meningitis. Treatment focuses on the underlying cause once it is identified.
- Viral meningitis. Most viral infections resolve without treatment. Antiviral medication is available for cases caused by herpes viruses.
Additional treatments may be needed for specific symptoms, such as corticosteroids to reduce swelling, anti-convulsant drugs, fluid infusion or supplemental oxygen.