Meningitis is an inflammation of the membranes (meninges) surrounding your brain and spinal cord.
The swelling from meningitis typically triggers symptoms such as headache, fever and a stiff neck.
Most cases of meningitis in the United States are caused by a viral infection, but bacterial, parasitic and fungal infections are other causes. Some cases of meningitis improve without treatment in a few weeks. Others can be life-threatening and require emergency antibiotic treatment.
Seek immediate medical care if you suspect that someone has meningitis. Early treatment of bacterial meningitis can prevent serious complications.
Early meningitis symptoms may mimic the flu (influenza). Symptoms may develop over several hours or over a few days.
Possible signs and symptoms in anyone older than the age of 2 include:
Newborns and infants may show these signs:
Infants with meningitis may be difficult to comfort, and may even cry harder when held.
Seek immediate medical care if you or someone in your family has meningitis symptoms, such as:
Bacterial meningitis is serious, and can be fatal within days without prompt antibiotic treatment. Delayed treatment increases the risk of permanent brain damage or death.
It's also important to talk to your doctor if a family member or someone you work with has meningitis. You may need to take medications to prevent getting the infection.
Viral infections are the most common cause of meningitis, followed by bacterial infections and, rarely, fungal infections. Because bacterial infections can be life-threatening, identifying the cause is essential.
Bacteria that enter the bloodstream and travel to the brain and spinal cord cause acute bacterial meningitis. But it can also occur when bacteria directly invade the meninges. This may be caused by an ear or sinus infection, a skull fracture, or, rarely, after some surgeries.
Several strains of bacteria can cause acute bacterial meningitis, most commonly:
Viral meningitis is usually mild and often clears on its own. Most cases in the United States are caused by a group of viruses known as enteroviruses, which are most common in late summer and early fall. Viruses such as herpes simplex virus, HIV, mumps, West Nile virus and others also can cause viral meningitis.
Slow-growing organisms (such as fungi and Mycobacterium tuberculosis) that invade the membranes and fluid surrounding your brain cause chronic meningitis. Chronic meningitis develops over two weeks or more. The signs and symptoms of chronic meningitis — headaches, fever, vomiting and mental cloudiness — are similar to those of acute meningitis.
Fungal meningitis is relatively uncommon and causes chronic meningitis. It may mimic acute bacterial meningitis. Fungal meningitis isn't contagious from person to person. Cryptococcal meningitis is a common 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.
Meningitis can also result from noninfectious causes, such as chemical reactions, drug allergies, some types of cancer and inflammatory diseases such as sarcoidosis.
Meningitis is an infection and inflammation of the fluid and three membranes (meninges) protecting your brain and spinal cord. The tough outer membrane is called the dura mater, and the delicate inner layer is the pia mater. The middle layer is the arachnoid, a weblike structure containing the fluid and blood vessels covering the surface of the brain.
Risk factors for meningitis include:
Meningitis complications can be severe. The longer you or your child has the disease without treatment, the greater the risk of seizures and permanent neurological damage, including:
With prompt treatment, even patients with severe meningitis can have good recovery.
Common bacteria or viruses that can cause meningitis can spread through coughing, sneezing, kissing, or sharing eating utensils, a toothbrush or a cigarette.
These steps can help prevent meningitis:
Some forms of bacterial meningitis are preventable with the following vaccinations:
Meningococcal conjugate vaccine. The Centers for Disease Control and Prevention recommends that a single dose be given to children ages 11 to 12, with a booster shot given at age 16. If the vaccine is first given between ages 13 and 15, the booster is recommended between ages 16 and 18. If the first shot is given at age 16 or older, no booster is necessary.
This vaccine can also be given to children between the ages of 2 months and 10 years who are at high risk of bacterial meningitis or who have been exposed to someone with the disease. It's also used to vaccinate healthy but previously unvaccinated people who have been exposed in outbreaks.
Your family doctor or pediatrician can diagnose meningitis based on a medical history, a physical exam and certain diagnostic tests. During the exam, your doctor may check for signs of infection around the head, ears, throat and the skin along the spine.
You or your child may undergo the following diagnostic tests:
Spinal tap (lumbar puncture). For a definitive diagnosis of meningitis, you'll need a spinal tap to collect cerebrospinal fluid (CSF). In people with meningitis, the CSF often shows a low sugar (glucose) level along with an increased white blood cell count and increased protein.
CSF analysis may also help your doctor identify which bacterium caused the meningitis. If your doctor suspects viral meningitis, he or she may order a DNA-based test known as a polymerase chain reaction (PCR) amplification or a test to check for antibodies against certain viruses to determine the specific cause and determine proper treatment.
The treatment depends on the type of meningitis you or your child has.
Acute bacterial meningitis must be treated immediately with intravenous antibiotics and sometimes corticosteroids. This helps to ensure recovery and reduce the risk of complications, such as brain swelling and seizures.
The antibiotic or combination of antibiotics depends on the type of bacteria causing the infection. Your doctor may recommend a broad-spectrum antibiotic until he or she can determine the exact cause of the meningitis.
Your doctor may drain any infected sinuses or mastoids — the bones behind the outer ear that connect to the middle ear.
Antibiotics can't cure viral meningitis, and most cases improve on their own in several weeks. Treatment of mild cases of viral meningitis usually includes:
Your doctor may prescribe corticosteroids to reduce swelling in the brain, and an anticonvulsant medication to control seizures. If a herpes virus caused your meningitis, an antiviral medication is available.
If the cause of your meningitis is unclear, your doctor may start antiviral and antibiotic treatment while the cause is determined.
Treatment for chronic meningitis is based on the underlying cause. Antifungal medications treat fungal meningitis, and a combination of specific antibiotics can treat tuberculous meningitis. However, these medications can have serious side effects, so treatment may be deferred until a laboratory can confirm that the cause is fungal.
Noninfectious meningitis due to allergic reaction or autoimmune disease may be treated with corticosteroids. In some cases, no treatment may be required because the condition can resolve on its own. Cancer-related meningitis requires therapy for the specific cancer.
Meningitis can be life-threatening, depending on the cause. If you've been exposed to bacterial meningitis and you develop symptoms, go to an emergency room and let medical staff know you may have meningitis.
If you're not sure what you have and call your doctor for an appointment, here's how to prepare for your visit.
For meningitis, some basic questions to ask your doctor include:
Your doctor is likely to ask you a number of questions, such as:
When you call your doctor's office for an appointment, describe the type and severity of your symptoms. If your doctor says you don't need to come in immediately, rest as much as possible while you're waiting for your appointment.
Drink plenty of fluids and take acetaminophen (Tylenol, others) to reduce your fever and body aches. Also avoid any medications that may make you less alert. Don't go to work or school.