Overview
Meningitis means inflammation of the meninges, the thin layers that cover the brain and spinal cord. It may happen because of infection or, less commonly, because of medicines, cancer, autoimmune disease, or other non-infectious causes. The illness can range from mild to very severe, but bacterial meningitis is especially dangerous and can worsen within hours.
Key Symptoms
Common symptoms include sudden fever, severe headache, stiff neck, nausea or vomiting, sensitivity to light, confusion, and extreme sleepiness. Some people also have seizures or a rash, especially with certain bacterial infections. Infants may not show the classic symptoms and may instead be irritable, feed poorly, vomit, seem floppy or unusually stiff, or have a bulging soft spot on the head.
Causes and Risk Factors
Viruses are a common cause of meningitis and may lead to milder illness, while bacteria can cause rapidly serious disease. Fungi and parasites are less common causes, and some non-infectious conditions can also inflame the meninges. Risk can be higher in very young infants, older adults, people with weakened immune systems, those living in close quarters, and people who are not up to date on recommended vaccines.
Who Is Affected
Meningitis can affect people of any age anywhere in the world. Babies and young children are at higher risk for some types, and teenagers and young adults may be more affected in settings such as dormitories or military housing. People with HIV, cancer treatment, certain immune conditions, or without a working spleen may also have higher risk of severe infection.
Prevention
Vaccination is one of the most important ways to prevent several forms of bacterial meningitis, including infections linked to meningococcal, pneumococcal, and Hib bacteria. Good hand hygiene, covering coughs and sneezes, and avoiding sharing drinks or utensils can also lower spread of some germs. In some situations, public health teams or clinicians may advise preventive medicine for close contacts of a person with certain bacterial meningitis infections.
Diagnosis and Tests
Meningitis is diagnosed urgently by a healthcare professional using symptoms, physical examination, and tests. These may include blood tests, imaging in some cases, and a lumbar puncture, which collects spinal fluid to look for infection and inflammation. Finding the cause matters because treatment depends on whether the meningitis is bacterial, viral, fungal, or non-infectious.
Treatment Categories
Treatment depends on the cause and how ill the person is. Bacterial meningitis usually requires urgent hospital care and antibiotics, while viral meningitis may be managed differently depending on the virus and the person's condition. Supportive care may include fluids, pain control, monitoring, and treatment of complications such as seizures or breathing problems.
When to Seek Medical Care
Get medical care right away for symptoms such as fever with severe headache, stiff neck, confusion, unusual sleepiness, seizures, or a new rash with illness. Seek prompt care for a baby who is hard to wake, feeding poorly, vomiting repeatedly, crying unusually, or has a bulging soft spot. Do not wait to see if symptoms improve, because some forms can progress very fast.
When It May Be an Emergency
Call emergency services or go to the nearest emergency department immediately if someone has trouble breathing, becomes difficult to wake, has a seizure, develops confusion, faints, or has a rapidly worsening rash with fever. Emergency help is also needed for an infant with severe lethargy, repeated vomiting, limpness, or signs of dehydration. Fast treatment can be critical.