“Meningitis” is an umbrella term that refers to a condition in which the meninges — the protective membrane that surrounds the brain and spinal cord — swells. Meningitis in general is a dangerous condition that, if not treated in a timely and accurate manner, can be deadly. Though treatment varies depending on the type of meningitis a person develops, anyone who suspects they have the condition should seek emergency medical attention immediately.
Meningitis occurs when the protective coating surrounding the brain and spinal cord become swollen. This can occur for one of several reasons. Because of this, meningitis can be subdivided into types. The type of meningitis a person develops or contracts will dictate both treatment and outlook.
That said, though there are various causes of meningitis, most doctors divide the condition into two main categories: infectious and non-infectious. In infectious meningitis, a pathogen invades the meninges and triggers swelling. In non-infectious meningitis, a disease, not a pathogen, attacks the meninges and causes injury to it.
The infections that cause infectious meningitis are typically contagious. However, non-infectious meningitis is not.
In this article, you will learn more about the various types of infectious and non-infectious meningitis, what causes them and the symptoms of each.
Infectious meningitis develops when a pathogen enters the bloodstream and makes its way to the meninges. Several types of infections may do this, contributing to the various types of infectious meningitis.
Viral meningitis is the most common type of meningitis, with thousands of people developing the condition each year. Though serious, viral meningitis is rarely life-threatening. However, it can be life-changing, with many survivors going on to live with debilitating after-effects. Such after-effects include extreme fatigue, memory loss and chronic headaches.
As its name implies, viral meningitis is caused by a virus. Non-polio enteroviruses are the most common causes of viral meningitis, though other illnesses can trigger it as well. Some other viruses that may lead to viral meningitis are as follows:
Though several viruses may cause viral meningitis, the condition rarely affects healthy people. Rather, individuals with compromised immune systems, elderly individuals and babies are the most susceptible populations to viral meningitis.
The symptoms of viral meningitis typically include the following:
Because the symptoms of most types of meningitis are similar, it is nearly impossible for individuals or doctors to make a diagnosis based on presentation alone. For this reason, if you or a loved one develop any of these symptoms, it is critical to seek a clinical diagnosis right away.
Unfortunately, there is no way to treat viral meningitis. However, to account for the risk that the condition is bacterial, a doctor may prescribe antibiotics until he or she can fully rule out the possibility of a bacterial infection.
Though there is no way to treat viral meningitis, there are steps patients can take to increase their comfort during their recovery. Those include getting plenty of fluids, breathing assistance and possibly observation in a hospital setting.
Bacterial meningitis is caused by an infection that reaches the brain’s meninges. This type of meningitis is serious, with some people dying within just a few hours of developing the condition. However, most do recover from the condition. That said, they typically go on to live with permanent disabilities, such as hearing loss, learning disabilities and, in more extreme cases, brain damage.
Several types of bacterial infections can cause bacterial meningitis. The leading causes are as follows:
Though not as common a cause, mycobacterium tuberculosis — the infection that causes tuberculosis — can also lead to bacterial meningitis.
In addition to causing bacterial meningitis, many of these bacteria are also associated with sepsis, which can exacerbate any existing or cooccurring conditions. Sepsis is the body’s extreme response to an infection and is a life-threatening emergency. When sepsis does occur, it triggers a rapid chain reaction response throughout the body that, if not stopped in time, can quickly lead to tissue damage, organ failure and eventual death.
Though bacterial meningitis can affect anyone, it is more likely to occur in certain groups than others. Demographics most likely to be afflicted with bacterial meningitis are as follows:
Symptoms of bacterial meningitis develop suddenly and are typically much more severe than those associated with viral meningitis. Persons who develop bacterial meningitis are typically already sick with another condition. However, they may recognize the transition from a normal illness to the life-threatening one if they develop these symptoms on top of the others:
Another sign of bacterial meningitis is if, when an individual pulls the knees and thighs up against the abdomen, he or she experiences intense thigh or lower back pain.
A specific type of stiff neck called Brudzinski is another sign of severe meningitis. With this condition, a person may involuntarily flex his or her knees or hips when a doctor moves his or her neck up or forward.
Immediate treatment of bacterial meningitis is crucial to a person’s long-term health and possible survival. To treat this condition, a doctor will administer antibiotics to kill the suspected bacteria. To avoid wasting time identifying the bacteria in question, the doctor may administer several antibiotics at once until labs confirm the cause. Once treatment begins, health teams typically recommend that patients remain in the hospital for several days to undergo observation and to receive additional support, such as intravenous fluids and breathing support.
As its name implies, parasitic meningitis is caused by a parasite that enters the body via some means and attacks the brain. Parasitic meningitis is uncommon and typically affects animals. However, people can develop it when they eat either these infected animals or foods contaminated by them. A few ways in which meningitis-causing parasites enter the human body are as follows:
It is difficult for humans to spread parasitic meningitis to one another, though not unheard of.
People who are at risk of developing parasitic meningitis are those who eat slugs, snails, freshwater fish and eels, snakes and frogs. Most infections occur in Hawaii, Southeast Asia, Thailand, Japan and the Pacific Islands. However, children who live in areas where raccoons are common and who put contaminated dirt into their mouths are also at risk.
Symptoms of parasitic meningitis are similar to those of other forms of the disease:
Depending on the parasite, patients may develop a tingling or painful sensation in their skin along with a low-grade fever. All types of meningitis-causing parasites can infect the eyes and cause severe complications, such as weakness/paralysis, loss of coordination, coma, permanent disability and possible death.
Unfortunately, there is no way to treat parasitic meningitis. However, doctors often recommend supportive care and treatment to keep patients comfortable. If the meningitis becomes serious, a doctor may prescribe a dose of steroids or another medication to reduce the body’s reaction to the intruder.
Amoebic meningitis is caused by the amoeba Naegleria fowleri, a free-living amoeba that is found in freshwater and soils around the world. Most people are exposed to this amoeba when they go swimming and get water up their noses.
It is rare that individuals develop amoebic meningitis, with an average number of 235 to 260 cases reported each year. However, when individuals do develop the condition, they rarely survive it.
The amoeba, Naegleria fowleri, lives in fresh waters around the world. However, it grows best in higher temperatures of 46 C or higher, where it can survive for short periods. Sources in which the amoeba is typically found are as follows:
The amoeba does not live in the ocean or other bodies of salt water.
The symptoms of amoebic meningitis are similar to those of other forms of meningitis in the early stages and usually begin one to 12 days after infection. Initial symptoms may include the following:
As the condition progresses, however, an infected person will begin to develop more severe symptoms, such as stiff neck, confusion, inattention to people and surroundings, hallucinations, seizure and coma.
Amoebic meningitis progresses rapidly. Most people die within five days of developing symptoms. However, some die within one day of developing symptoms while others live as many as 18 days from the onset of symptoms.
Though several drugs have proved effective at killing the meningitis-causing amoeba in a lab setting, they have proved mostly ineffective in humans. When health teams do confirm an amoebic meningitis diagnosis, they often go to great efforts to keep the patient alive, offering supportive care such as IV fluids and breathing support. Unfortunately, even with swift action, almost all individuals die within just a few short days. In fact, of the 34 cases reported to the CDC between 2009 and 2019, only three people survived. For this reason, most doctors focus on ensuring patients’ comfort in their final days.
Fungal meningitis occurs when a fungal infection travels from another part of the body to the brain. Fungal infections are fairly common occurrences in humans and typically do not lead to meningitis. However, in more vulnerable populations, they can. Demographics that are more prone to fungal meningitis than others are elderly people, babies and individuals with compromised immune systems.
There are several types of fungi that live in the environment that can cause meningitis. Some of the more common culprits are as follows:
These fungi are too small to see with the naked eye. However, individuals can become sick if they breathe in spores from these fungi and if those spores travel to the spinal cord or brain.
One type of non-environmental fungi, Candida, can also cause fungal meningitis. Candida lives on the skin and inside the body and usually does not cause any health problems. However, in vulnerable people, it can.
Symptoms of fungal meningitis are similar to those of the other types of meningitis:
Fungal meningitis is treatable with long courses and high doses of antifungal medications. For utmost effectiveness, doctors typically administer the medications via an IV. Once the initial dose or two is complete, providers may allow patients to go home with oral medications. For how long patients must take medications depends on the type of fungus that causes the infection, the patient’s immune system and the severity of symptoms. For people with compromised immune systems, the course of treatment is often longer.
Unlike the aforementioned types of meningitis, non-infectious meningitis does not have an outside cause. Rather, internal factors, such as an illness or injury, causes swelling around the meninges. Typical causes of non-infectious meningitis include:
Though the causes of non-infectious meningitis are drastically different than those of the infectious types, the symptoms look more or less the same:
Individuals typically develop these symptoms after a long-term illness, upon being diagnosed with a long-term condition or after starting a new medication.
Treating non-infectious meningitis entails identifying and removing its cause. For instance, if you develop non-infectious meningitis after starting a new medication, your doctor may take you off that medication. If cancer is the cause of your symptoms, your medical team will work rapidly to kill the cancer cells or remove the infectious tumour.
To help your body recover from meningitis symptoms, your doctor may offer or recommend supportive care. Depending on the extent of your symptoms, this may include hospitalization, breathing support and IV fluids.
Until your doctor has fully ruled out the possibility of bacterial meningitis, he or she may put you on antibiotics.
Meningitis is a severe and potentially deadly illness even in healthy people. For individuals with compromised immune systems or who are otherwise vulnerable, a meningitis diagnosis can be devastating.
If you or a loved one develop symptoms of meningitis, or if you suspect meningitis, seek emergency medical care right away. Inform your doctor or the attending physician about potential exposures so that he or she can run appropriate tests and take appropriate treatment measures. The sooner you or your loved one seek treatment, the better your chance of surviving without long-term disabilities.