University Health Services Communicable Disease Information
Source: Center for Disease Control, Washington, D.C.
Meningitis is an inflammation of the membranes (meninges) and cerebrospinal fluid surrounding your brain and spinal cord, usually due to the spread of an infection.
In the past, most meningitis cases occurred in children younger than 5 years. But as a result of the protection offered by current childhood vaccines, most meningitis cases now occur in young people between the ages of 15 and 24. Older adults also tend to have a higher incidence of meningitis than do young children.
The cause of most cases of meningitis is a viral infection, but bacterial and fungal infections also can lead to meningitis. Bacterial meningitis is generally much more serious than viral meningitis, and timely treatment is necessary.
Left untreated, bacterial meningitis can be fatal. If you suspect that you or someone in your family has signs or symptoms of meningitis, seek medical care right away. There’s no way to tell what kind of meningitis you have without seeing your doctor and undergoing testing.
It’s easy to mistake the early signs and symptoms of meningitis for the flu. They may develop over a period of one or two days and typically include:
A high fever
Vomiting or nausea with headache
Confusion or difficulty concentrating- in the very young, this may appear as inability to maintain eye contact
Sleepiness or difficulty waking up
Sensitivity to light
Lack of interest in drinking and eating
Skin rash in some cases, such as in viral or meningococcal meningitis
Meningitis usually results from a viral infection, but the cause also may be a bacterial infection. Less commonly, a fungal infection may cause meningitis. Because bacterial infections are the most damaging, identifying the source of the infection is an important part of developing a treatment plan.
Acute bacterial meningitis usually occurs when bacteria enter the bloodstream and migrate to the brain and spinal cord. But it can also occur when bacteria invade the meninges directly, as a result of an ear or sinus infection or a skull fracture.
Viruses cause a greater number of cases of meningitis each year than do bacteria. Viral meningitis is usually mild and often clears on its own in 10 days or less. A group of common viruses known as enteroviruses, which cause stomach flu, are responsible for about 90 percent of viral meningitis in the United States.
The most common signs and symptoms of enteroviral infections are rash, sore throat, joint aches and headache. Many older children and adults with enteroviral meningitis describe the “worst headache I’ve ever had.” These viruses tend to circulate in late summer and early fall. Viruses associated with mumps, herpes infection, West Nile virus or other diseases also can cause viral meningitis.
Fungal meningitis is relatively uncommon. Cryptococcal meningitis is a fungal form of the disease that affects people with immune deficiencies, such as AIDS. It’s life-threatening if not treated with an antifungal medication.