Meningitis – Types, Symptoms,  Treatment &
Prevention

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Meningitis?

Meningitis is inflammation of the meninges and subarachnoid space. It may result from infections, other disorders, or reactions to drugs. Severity and acuity vary. Findings typically include headache, fever, and nuchal rigidity, Diagnosis is by cerebrospinal fluid (CSF) analysis. Treatment includes antimicrobial drugs as indicated plus adjunctive measures.

Meningitis may be classified as acute, subacute, chronic, or recurrent. It may also be classified by its cause: bacteria, viruses, fungi, protozoa, or, occasionally, noninfectious conditions. But the most clinically useful categories of meningitis are

Acute bacterial meningitis is particularly serious and rapidly progressive. Viral and noninfectious meningitides are usually self-limited. Subacute and chronic meningitides usually follow a more indolent course than other meningitides, but determining the cause can be difficult.

Aseptic meningitis, an older term, is sometimes used synonymously with viral meningitis; however, it usually refers to acute meningitis caused by anything other than the bacteria that typically cause acute bacterial meningitis. Thus, aseptic meningitis can be caused by

Types

Viral and bacterial infections are the most common causes of meningitis. There are several other forms of meningitis. Examples include cryptococcal, which is caused by a fungal infection, and carcinomatous, which is cancer-related. These types are less common.

Viral meningitis

Viral meningitis is the most common type of meningitis. Viruses in the Enterovirus category cause about 52 percent of cases in adults and 58 percent of cases in infants. These are more common during the summer and fall, and they include:

Viruses in the Enterovirus category cause about 10 to 15 million infectionsTrusted Source per year, but only a small percentage of people who get infected will develop meningitis.

Other viruses can cause meningitis. These include:

Viral meningitis typically goes away without treatment. However, some causes do need to be treated.

Bacterial meningitis

Bacterial meningitis is contagious and caused by infection from certain bacteria. It can be fatal if left untreated. About 1 in 10 peopleTrusted Source who get bacterial meningitis die, and 1 in 5Trusted Source have serious complications. This can be true even with proper treatment.

The most common types of bacteria that cause bacterial meningitis are:

Fungal meningitis

Fungal meningitis is a rare type of meningitis. It’s caused by a fungus that infects your body and then spreads from your bloodstream to your brain or spinal cord.

People with a weakened immune system are more likely to develop fungal meningitis. This includes people with cancer or HIV.

The most common funguses related to fungal meningitis include:

Parasitic meningitis

This type of meningitis is less common than viral or bacterial meningitis, and it’s caused by parasites that are found in dirt, feces, and on some animals and food, like snails, raw fish, poultry, or produce.

One type of parasitic meningitis is rarer than others. It’s called eosinophilic meningitis (EM). Three main parasites are responsible for EM. These include:

Parasitic meningitis is not passed from person to person. Instead, these parasites infect an animal or hide out on food that a human then eats. If the parasite or parasite eggs are infectious when they’re ingested, an infection may occur.

One very rare type of parasitic meningitis, amebic meningitis, is a life-threatening type of infection. This type is caused when one of several types of ameba enters the body through the nose while you swim in contaminated lakes, rivers, or ponds. The parasite can destroy brain tissue and may eventually cause hallucinations, seizures, and other serious symptoms. The most commonly recognized species is Naegleria fowleri.

Non-infectious meningitis

Non-infectious meningitis is not an infection. Instead, it is a type of meningitis that’s caused by other medical conditions or treatments. These include:

Chronic meningitis

This classification is given to cases of meningitis that last longer than 4 weeks.

The causes of chronic meningitis can be fungi, rheumatological conditions, and cancer, among others. Treatment for chronic meningitis is directed at treating the cause (i.e., managing rheumatoid arthritis).

Symptoms

The symptoms of viral and bacterial meningitis can be similar in the beginning. However, bacterial meningitis symptoms are usually more severe. The symptoms also vary depending on your age.

Viral meningitis symptoms

Viral meningitis in infants may cause:

In adults, viral meningitis may cause:

Bacterial meningitis symptoms

Bacterial meningitis symptoms develop suddenly. They may include:

Seek immediate medical attention if you experience these symptoms. Bacterial and viral meningitis can be deadly. There’s no way to know if you have bacterial or viral meningitis just by judging how you feel. Your doctor will need to perform tests to determine which type you have.

Fungal meningitis symptoms

Symptoms of fungal meningitis resemble the other types of this infection. These may include:

Chronic meningitis symptoms

You’re diagnosed with chronic meningitis when your symptoms last for longer than 4 weeks.

The symptoms of chronic meningitis are similar to other forms of acute meningitis, but can sometimes develop slower.

Meningitis rash

One of the later signs that one bacterial cause of meningitis, Neisseria meningitidis, is in your bloodstream is a faint rash on your skin.

The bacteria from a meningococcal meningitis infection reproduce in your blood and target cells around the capillariesTrusted Source. Damage to these cells leads to capillary damage and mild blood leaks. This shows up as a faint pink, red, or purple rash. The spots may resemble tiny pinpricks and are easily mistaken as a bruise.

As the infection worsens and spreads, the rash can become more obvious. The spots will grow darker and larger.

People with darker skin may have a harder time seeing a meningitis rash. Lighter areas of skin, such as the palms of hands and the inside of the mouth, may show signs of a rash more easily.

Diagnosis

A health care provider can diagnose meningitis based on a medical history, a physical exam and certain tests. During the exam, your provider may check for signs of infection around the head, ears, throat and skin along the spine.

Common tests to diagnose meningitis include:

Diagnosing meningitis starts with a health history and physical exam. Age, dorm residence, and daycare center attendance can be important clues. During the physical exam, your doctor will look for:

Condition	Predominant Cell Type*	Protein*	Glucose*	Specific Tests
Normal CSF	All lymphocytes† (0–5 cells/mcL)	< 40 mg/dL	> 50% of blood glucose	None
Bacterial meningitis	Leukocytes (usually PMNs), often greatly increased	Elevated	< 50% of blood glucose (may be extremely low)	Gram staining (yield is high if 105 colony-forming units of bacteria/mL are present)Bacterial cultureMultiplex PCR panel if available
Viral meningitis	Lymphocytes (may be mixed; PMNs and lymphocytes during the first 24–48 hours)	Elevated	Usually normal	Multiplex PCR panel (if available) and/or conventional PCR (to check for enteroviruses or herpes simplex, herpes zoster, or West Nile virus)IgM (to check for West Nile virus or other arboviruses)
Tuberculous meningitis‡	PMNs and lymphocytes (usually mixed pleocytosis)	Elevated	< 50% of blood glucose (may be extremely low)	Acid-fast stainingPCRMycobacterial culture (ideally using a CSF sample of ≥ 30 mL)Interferon-gamma tests of serum and (if available) CSFXpert MTB/RIF§
Fungal meningitis	Usually lymphocytes	Elevated	< 50% of blood glucose (may be extremely low)	Cryptococcal antigen testMultiplex PCR panel if available (an adjunctive test, not to replace other tests)Serologic tests for Coccidioides immitis or Histoplasma species antigen especially if patients have recently spent time in an endemic areaFungal culture (ideally using a CSF sample of ≥ 30 mL)India ink (for Cryptococcus sp)

Treatment

Antibiotics are the mainstay of therapy for acute bacterial meningitis. In addition to antibiotics, treatment includes measures to decrease brain and cranial nerve inflammation and increased intracranial pressure (ICP).

Most patients are admitted to an intensive care unit (ICU).

Antibiotics

Antibiotics must be bactericidal for the causative bacteria and must be able to penetrate the blood-brain barrier.

If patients appear ill and findings suggest meningitis, antibiotics (see table Initial Antibiotics for Acute Bacterial Meningitis ) and corticosteroids are started as soon as blood cultures are drawn and even before lumbar puncture. Also, if lumbar puncture is delayed pending neuroimaging results, antibiotic and corticosteroid treatment begins before neuroimaging.

Appropriate empiric antibiotics depend on the patient’s age and immune status and route of infection (see table Initial Antibiotics for Acute Bacterial Meningitis ). In general, clinicians should use antibiotics that are effective against S. pneumoniae, N. meningitidis, and S. aureus. In pregnant women, neonates, older patients, and immunocompromised patients, Listeria meningitis is possible; it requires specific antibiotic treatment, usually ampicillin. Herpes simplex encephalitis can clinically mimic early bacterial meningitis; thus, acyclovir is added. Antibiotic therapy may need to be modified based on results of culture and sensitivity testing.

Commonly used antibiotics include

Corticosteroids

Dexamethasone is used to decrease cerebral and cranial nerve inflammation and edema; it should be given when therapy is started. Adults are given 10 mg IV; children are given 0.15 mg/kg IV. Dexamethasone is given immediately before or with the initial dose of antibiotics and every 6 hours for 4 days.

Use of dexamethasone is best-established for patients with pneumococcal meningitis.

Other measures

The effectiveness of other measures is less well-proved.

Patients presenting with papilledema or signs of impending brain herniation are treated for increased ICP with the following:

Hyperventilation is used until other measures become effective and is not used for more than 24 hours. When stopped, the PCO2 should be gradually increased to normal because a sudden increase may cause a significant increase in ICP.

Usually, adults are given mannitol 1 g/kg IV bolus over 30 minutes, repeated as needed every 3 to 4 hours or 0.25 g/kg every 2 to 3 hours, and children are given 0.5 to 2.0 g/kg over 30 minutes, repeated as needed.

Additional measures can include

Prevention

Maintaining a healthy lifestyle, especially if you’re at increased risk, is important. This includes:

If you’ve been in close contact with one or more people who have a bacterial meningococcal infection, your doctor can give you preventive antibiotics. This will decrease your chances of developing the disease.

Vaccinations can also protect against certain types of meningitis. Vaccines that can prevent meningitis include the following:

Practicing good personal hygiene may also help you prevent meningitis. Some types of meningitis are spread through close contact with an infected person’s body fluid, such as saliva and nasal secretions. Avoid sharing drinks, utensils, and personal items that may carry saliva or other fluids.

Meningitis and pneumonia

Pneumococcal meningitis is a rare but serious and life-threatening form of bacterial meningitis. Even with treatment, about 1 in 20 people with this type of infection die.

About 40 percent of people carry bacteria called Streptococcus pneumoniae in their throat and the back of the nose. These bacteria are responsible for common illnesses like pneumonia, sinus infections, and ear infections.

From time to time, however, those bacteria manage to cross the blood-brain barrier and cause inflammation and infection in the brain, spinal cord, or fluids immediately surrounding them.

Symptoms of this serious form of meningitis include: