Meningitis is an inflammation of the membranes, called meninges, that surround the brain and spinal cord. According to the Centers for Disease Control and Prevention, the illness is most commonly caused by either viral or bacterial infection. Depending on the severity of the disease, meningitis can cause brain damage, hearing loss and learning disabilities.
Bacterial Meningitis
According to the Mayo Clinic, several strains of bacteria are known to cause meningitis. Streptococcus pneumoniae is a bacterium frequently implicated in sinus or ear infections. Left untreated, it is possible for the infection to spread to the meninges. Neisseria meningitidis and Haemophilus influenzae are two other bacteria that may cause meningitis following an upper respiratory infection. The former is notorious for causing meningitis outbreaks among people living in crowded conditions, such as college dormitories. Both N. meningitidis and H. influenzae are preventable by vaccination. Finally, Listeria monocytogenes, a bacteria found in soil, dust and contaminated food, can cause meningitis. The people who are most at risk of infection from L. monocytogenes are newborns, pregnant women and individuals with weakened immune systems.
Viral Meningitis
According to MedLinePlus, the most common cause of meningitis is viral infection. There are several different viruses that can cause meningitis, but the course of illness is usually less severe than infection caused by bacteria. According to the Centers for Disease Control and Prevention, people with healthy, normal immune systems can expect to recover from viral meningitis in about 7 to 10 days.
Other Causes
The Mayo Clinic explains that meningitis may have other causes, including fungal infection or invasion of the meningeal tissues by other slow-growing microorganisms. Additionally, certain drug allergies, cancers and inflammatory diseases, such as lupus, may cause meningitis. These types of meningitis are relatively rare.
Symptoms
According to MedLinePlus, meningitis symptoms in people over the age of two years include severe headache, sudden fever and neck stiffness. The Centers for Disease Control and Prevention adds that other symptoms include nausea, confusion and sleepiness. Importantly, newborns and children under the age of two years should be watched for slow movement, poor feeding and irritability if meningitis is suspected.
