Meningitis is a condition characterized by inflammation in the membranes around the brain and spinal cord. These membranes, called meninges, can be infected through viral, bacterial or fungal sources, and can lead to serious symptoms and complications.
Some cases improve without treatment, but others are life-threatening and require immediate attention.
Types of Meningitis
Each type of meningitis is defined by the infection that caused it:
- Viral meningitis: This is the most common form of meningitis. In the United States, most instances are caused by a group of viruses called enteroviruses, but other viruses like HIV, mumps, arboviruses and herpes simplex virus can also cause viral meningitis. In many cases, viral meningitis is less severe than bacterial meningitis.
- Bacterial meningitis: A variety of bacteria can cause meningitis, and these cases of bacterial meningitis are often life threatening and require immediate medical attention. Vaccines are available to prevent both viral and bacterial meningitis.
- Fungal meningitis: Usually caused by inhaling fungal spores, fungal infections can be more common in people with previous medical conditions like cancer, diabetes, or HIV.
- Parasitic meningitis: This is far less common, and is caused by parasites that affect the brain or nervous system.
- Amebic meningitis: Also rare, this condition is an extremely severe infection of the brain caused by an ameba found in warm water and soil.
- Non-infectious meningitis: In some cases, meningitis can be caused by cancers, head injury, brain surgery, or lupus rather than by infection from another person.
Causes and Risk Factors
Each form of the condition is caused by a different factor. Bacterial meningitis, for example can be caused by a few different bacteria:
- Streptococcus pneumoniae: This most common cause of bacterial meningitis in the United States, this bacterium can often be prevented with a vaccine.
- Neisseria meningitidis: This bacterium can also cause an upper respiratory infection, but when it enters the bloodstream, it causes meningitis. It’s extremely contagious and primarily affects teenagers and young adults.
- Haemophilus influenzae: This bacterium used to be the most common cause of the condition in children, but vaccines have reduced the number of new diagnoses.
- Listeria monocytogenes: These are bacteria found in various lunch meats and unpasteurized cheeses. They can affect infants, older adults, pregnant women and any others with weak immune systems. In certain cases, these bacteria can be fatal for the baby if it develops late in pregnancy.
The causes of other forms of meningitis include:
- Viral meningitis: Usually caused by enteroviruses, often in late summer or early fall. Can also be caused by herpes, HIV, mumps and West Nile virus.
- Fungal meningitis: This is not contagious between people, and is caused by direct fungal contact.
- Chronic meningitis: Certain fungi and bacteria can invade the meninges and lead to chronic meningitis, which develops after at least two weeks with the condition.
- Other: Sometimes, chemical reactions, drug allergies, inflammatory diseases and certain types of cancer can also lead to the condition.
Risk factors include:
- Age: Most cases of viral meningitis occur in children under 5 years old, and most cases of bacterial meningitis are diagnosed in people under 20.
- Pregnancy: An infection called listeriosis can lead to the condition.
- Skipping vaccinations
- Community living: College dorms and boarding schools are common breeding grounds for meningitis.
- Immune system issues: AIDS, diabetes, alcoholism and any other factors that weaken the immune system can increase your risk.
Symptoms and Complications
- Sudden fever
- Stiff neck or severe, abnormal headache (often accompanied by nausea or vomiting)
- Skin rash
- Lack of appetite
- Light sensitivity
In newborns, there are a few specific signs:
- Constant crying or irritability
- Extreme sleepiness or inactivity
- Abnormal feeding habits
- High fever
- Bulge in the soft spot on the head
- Stiffness in body and neck
If any of these severe symptoms are present in you or a family member, especially fever, vomiting, confusion or a stiff neck, seek immediate medical attention.
Quick treatment is vital, and can lead to a good recovery even for severe cases. The longer you go without it, the greater the risk of several neurological complications:
- Brain damage or learning disabilities
- Memory issues
- Gait problems
- Hearing loss
- Kidney failure
- Shock or death
Treatment and Prevention
Treatment depends on the type:
- Bacterial: Bacterial meningitis requires immediate treatment with antibiotics and corticosteroids to help promote recovery and reduce risk of major complications. The combination of medications will be determined by your doctor based on the type of bacteria. Your doctor may also drain infected sinuses or mastoids (bones behind the ear).
- Viral: Most of these cases improve on their own, and treatment can include hydration, basic bed rest and pain medication for fever and body aches.
- Other: Other types are treated on an individual basis, including cases where your doctor will start you with basic antiviral and antibiotic treatment while the exact cause is determined.
Preventing the risk of meningitis is possible through the proper hygiene and cleanliness practices and vaccinations. These methods are all meant to stop the contagious spread of the disease.
If you or a family member has symptoms, seek immediate medical attention and speak to your doctor about treatment options to reduce symptoms and risk of long-term complications.
Revere Health Neurology specialists treat patients with a variety of neurological disorders.
“Meningitis.” Centers for Disease Control and Prevention. https://www.cdc.gov/meningitis/
“Meningitis.” The Mayo Clinic. http://www.mayoclinic.org/diseases-conditions/meningitis/home/ovc-20169520