Meningitis: Types and Causes, Symptoms, Complications, Risk Factor, Diagnosis, Testing and Prevention


Meningitis is an inflammation of the meninges which occur when fluid surrounding the meninges becomes infected.

May 7, 2018

Meningitis is an inflammation of the meninges which occur when fluid surrounding the meninges becomes infected.The meninges are the three membranes that cover the brain and spinal cord.
Headache, fever and a stiff neck are the most common symptoms of Meningitis. Mostly meningitis is caused by a viral infection, but bacterial and fungal infections can also be the other causes. Viral and bacterial meningitis are contagious. They can be transmitted by coughing, sneezing, or close contact.
Some cases of meningitis improve without treatment in a few weeks while others can be life threatening and require emergent antibiotic treatment. Early treatment of bacterial meningitis can prevent serious complications.

Types and Causes of Meningitis:

The most common causes of meningitis are viral and bacterial infections. There are also several other forms of meningitis which are rare. Examples include cryptococcal, which is caused by a fungal infection and carcinomatous, which is cancer-related. 

Viral meningitis:

Viral meningitis is the most common type of meningitis. It is usually mild and often clears on its own without treatment. Viruses in the Enterovirus category such as coxsackievirus A, coxsackievirus B and echoviruses are the cause of viral meningities. These are most common in late summer and early fall. Viruses such as herpes simplex virus, HIV, mumps, West Nile virus and others also can cause viral meningitis.

Bacterial Meningitis:

Bacterial meningitis is contagious and caused by infection from certain bacteria. Because bacterial infections can be fatal, identifying the cause is essential. Acute bacterial meningitis can be caused by bacteria that enter the bloodstream and travel to the brain and spinal cord. However, bacteria can directly invade the meninges. In case of an ear or sinus infection, a skull fracture, or, rarely, after some surgeries it can happen.
The most common types of bacteria that cause bacterial meningitis include:

Streptococcus pneumoniae (pneumococcus):

This bacterium is the most common cause of bacterial meningitis in infants, young children and adults. It is typically found in the respiratory tract, sinuses, and nasal cavity and commonly causes pneumonia or ear or sinus infections. A vaccine can help prevent this infection.

Neisseria meningitidis (meningococcus):

Another leading cause of bacterial meningitis is neisseria meningitidis. These bacteria commonly cause an upper respiratory infection. But can also cause meningococcal meningitis when they enter the bloodstream. This is a highly contagious infection and spread through saliva and other respiratory fluids . It affects mainly teenagers and young adults. It may cause local epidemics in college dormitories, boarding schools and military bases. A vaccine can help prevent infection.

Haemophilus influenzae (haemophilus):

Haemophilus influenzae type b (Hib) bacterium can cause bacterial meningitis in children. This bacteria can cause not only meningitis but infection of the blood, inflammation of the windpipe, cellulitis, and infectious arthritis.
Hib vaccines have greatly reduced the number of cases of this type of meningitis now a days.

Listeria monocytogenes (listeria):

This is a foodborne bacteria which can be found in unpasteurized cheeses, hot dogs and luncheon meats. Pregnant women, newborns, older adults and people with weakened immune systems are most susceptible to this. Listeria can cross the placental barrier, and infections in late pregnancy may be fatal to the baby.

Chronic meningitis:

Chronic meningitis occurs when slow growing organisms such as fungi and Mycobacterium tuberculosis invade the membranes and fluid surrounding your brain. It develops over two weeks or more. Headaches, fever, vomiting and mental cloudiness are some of the common symptoms of chronic meningitis which are similar to those of acute meningitis.

Fungal meningitis:

Fungal meningitis can cause chronic meningitis which is is relatively uncommon. The symtoms are almost similar to acute bacterial meningitis. Fungal meningitis isn't contagious from person to person. The most common fungal form of the disease is Cryptococcal meningitis that affects people with weaken immune system, such as AIDS. It is life-threatening if not treated with an antifungal medication.

Other meningitis causes:

Meningitis can also result from noninfectious causes, such as chemical reactions, drug allergies, some types of cancer and inflammatory diseases such as sarcoidosis.

Symptoms of Meningitis:

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:

  • decreased appetite
  • Constant crying and irritability
  • sleepiness
  • lethargy
  • High fever
  • A bulge in the soft spot on top of a baby's head
  • Stiffness in a baby's body and neck

Viral meningitis in adults may cause:

  • headaches with nausea or vomiting
  • sudden high fever
  • stiff neck
  • confusion or difficulty concentrating
  • seizures
  • sensitivity to bright light
  • sleepiness
  • lethargy
  • nausea
  • decreased appetite
  • skin rash, such as in meningococcal meningitis

Bacterial Meningitis Symptoms:

Bacterial meningitis symptoms develop suddenly. They may include:

  • altered mental status
  • nausea
  • vomiting
  • sensitivity to light
  • irritability
  • severe headache
  • sudden high fever
  • stiff neck

If you or someone in your family experience any of the above meningitis symptoms, immediately seek medical attention. As bacterial meningitis is serious, and can be fatal within days without prompt antibiotic treatment, contact your doctor as soon as possible. Delayed treatment increases the risk of permanent brain damage or death.

Complications from Meningitis:

Meningitis complications can be severe and even life threatening. Without treatment, the risk of seizures and permanent neurological damage is more.
The complications which are associated with meningitis could be:

  • seizures
  • hearing loss
  • brain damage
  • hydrocephalus
  • a subdural effusion, or a buildup of fluid between the brain and the skull
  • Memory difficulty
  • Learning disabilities in children
  • Gait problems
  • Shock
  • Death

Risk factors:

Risk factors for meningitis include:

Compromised Immunity:

People with weaken immune system are more vulnerable to infections including meningitis. Certain disorders and treatments can weaken your immune system. These include:

  • HIV
  • AIDS
  • autoimmune disorders
  • chemotherapy
  • organ or bone marrow transplants

Cryptococcal meningitis, is the most common form of meningitis in people with HIV or AIDS. This is caused by a fungus.

Community Living:

As the bacterium is spread by the respiratory route, and spreads quickly through large groups, Meningitis is easily spread when people live in close quarters. Being in small spaces increase the chance of exposure. College students living in dormitories, personnel on military bases, and children in boarding schools and child care facilities are some of the examples of these locations where the risk of meningococcal meningitis is more.

Pregnancy:

Pregnant women have an increased risk of listeriosis, which is an infection caused by the Listeria bacteria. Infection can spread to the unborn child leading to miscarriage, stillbirth and premature delivery.

Age:

Although all ages of people are at risk for meningitis, certain age groups have a higher risk. Children under the age of 5 are at increased risk of viral meningitis. Infants are at higher risk of bacterial meningitis.

Working with Animals:

Farm workers and others who work with animals have an increased risk of infection with Listeria.

Skipping vaccinations:

Risk rises for anyone who hasn't completed the recommended childhood or adult vaccination schedule.

Diagnosis of Meningitis:

Diagnosis can be made based on a medical history, a physical exam and certain diagnostic tests. Your doctor may check for signs of infection around the head, ears, throat and the skin along the spine during a physical examination. During this examination he will also look for a fever, an increased heart rate, neck stiffness and reduced consciousness.
Common tests that are used for diagnosing meningitis include the following:

Blood cultures:

It identify bacteria in the blood. Bacteria can travel from the blood to the brain. Blood samples are placed in a special dish to see if it grows microorganisms, particularly bacteria. A sample may also be placed on a slide and stained called as Gram's stain. It is then studied under a microscope for bacteria. N. meningitidis and S. pneumoniae can cause both sepsis and meningitis.

Complete blood count test:

CBC with differential is a general index of health. It checks the number of red and white blood cells in your blood. White blood cells fight infection. The count is usually elevated in meningitis.

Chest X-rays:

This test can reveal the presence of pneumonia, tuberculosis, or fungal infections. Meningitis can occur after pneumonia.

Imaging tests:

Computerized tomography (CT) or magnetic resonance (MR) scans of the head may show swelling or inflammation which can be associated with a brain abscess or sinusitis. As bacteria can spread from the sinuses to the meninges, X-rays or CT scans of the chest or sinuses may also show infection in other areas that may be associated with meningitis.

Spinal tap or lumbar puncture:

You will need a spinal tap to collect cerebrospinal fluid (CSF) to find out the exact cause of meningitis. In people with meningitis, the CSF often shows a low glucose level along with an increased white blood cell count and increased protein. It allows your doctor to look for increased pressure in the central nervous system. It can also find inflammation or bacteria in the spinal fluid.
CSF analysis may also help your doctor identify which bacterium caused the meningitis which can also help determine the best antibiotic for treatment. If your doctor suspects viral meningitis, he or she may order a DNA-based test known as a polymerase chain reaction (PCR) amplification. A test can also be done to check for antibodies against certain viruses to determine the specific cause and determine proper treatment.

Treatments of Meningitis:

The treatment depends on the type and stage of meningitis.

Bacterial meningitis:

Bacterial meningitis requires immediate hospitalization. Early diagnosis and treatment will prevent brain damage and death. Acute bacterial meningitis must be treated immediately with intravenous antibiotics and corticosteroids. This helps a quick recovery and reduce the risk of complications, such as brain swelling and seizures.
There is no specific antibiotic for bacterial meningitis. Depending on the type of bacteria causing the infection, the antibiotic or combination of antibiotics will be use for treatment.
Until the exact cause of the meningitis is determined, your doctor may recommend a broad spectrum antibiotic. Any infected sinuses or mastoids will be drained by your doctor. Mastoids is the bones behind the outer ear that connect to the middle ear.

Viral meningitis:

Most of the cases of viral meningitis improve on their own without any treatment in several weeks. Treatment of mild cases of viral meningitis usually includes:

  • Bed rest
  • Plenty of fluids
  • Over the counter pain medications to help reduce fever and relieve body aches

Viral meningitis can't get cure by antibiotics. However, corticosteroids are prescribed to reduce swelling in the brain, and an anticonvulsant medication to control seizures.
An antiviral medication is available if meningitis is caused by herpes virus.

Other types of meningitis:

Until the cause is determined, your doctor may start the treatment with antiviral and antibiotic. Chronic meningitis is treated based on the underlying cause. Antifungal medications treat fungal meningitis and a combination of specific antibiotics can treat tuberculous meningitis. As these medications can have serious side effects, these are not used unless it is confirm that the cause is fungal.
Noninfectious meningitis due to allergic reaction or autoimmune disease may be treated with corticosteroids. In some cases the condition can resolve on its own without any treatment. Cancer related meningitis requires therapy for the individual cancer.

Prevention of Meningitis:

Maintaining a healthy lifestyle is important, especially if you are at increased risk. This includes getting adequate amounts of rest, quit smoking and avoiding contact with sick people. Common bacteria or viruses that can cause meningitis can spread through coughing, sneezing, kissing, or sharing eating utensils, a toothbrush or a cigarette.
The following steps can help prevent meningitis:

Wash your hands:

Often washing hand as required helps prevent germs. Teach children to wash their hands often, especially before eating and after using the toilet, spending time in a crowded public place or petting animals. Teach them how to vigorously and thoroughly wash and rinse their hands.

Practice good hygiene:

Avoid sharing drinks, foods, straws, eating utensils, lip balms or toothbrushes with anyone else. Teach children and teens to avoid sharing these items too.

Stay healthy:

Maintain your immune system by getting enough rest, exercising regularly, and eating a healthy diet with plenty of fresh fruits, vegetables and whole grains.

Cover your mouth:

When you need to cough or sneeze, be sure to cover your mouth and nose.

Take care with food in pregnency:

Reduce your risk of listeriosis by cooking meat, including hot dogs and deli meat, to 165 F. Avoid cheeses made from unpasteurized milk. Choose cheeses that are clearly labeled as being made with pasteurized milk.

Vaccinations:

Some forms of bacterial meningitis are preventable with the following vaccinations:

Haemophilus influenzae type b (Hib) vaccine:

This vaccine is given to the children as part of the recommended schedule of vaccines, starting at about 2 months of age. The vaccine is also recommended for some adults, including those who have sickle cell disease or AIDS and those who don't have a spleen.

Pneumococcal conjugate vaccine (PCV13):

This vaccine also is part of the regular immunization schedule for children younger than 2 years. Additional doses are recommended for children between the ages of 2 and 5 who are at high risk of pneumococcal disease, including children who have chronic heart or lung disease or cancer.

Pneumococcal polysaccharide vaccine (PPSV23):

Older children and adults who have not received the vaccine before and need protection from pneumococcal bacteria may receive this vaccine. The Centers for Disease Control and Prevention recommends the PPSV vaccine for all adults older than 65, for younger adults and children age 2 and up who have weak immune systems or chronic illnesses such as heart disease, diabetes or sickle cell anemia, and for those who don't have a spleen.

Meningococcal conjugate vaccine:

The Centers for Disease Control and Prevention recommends that a single dose be given to children ages 11 to 12, with a booster shot given at age 16. If the vaccine is first given between ages 13 and 15, the booster shot is recommended between ages 16 and 18 and no booster is necessary if the first shot is given at age 16 or older.
This vaccine can also be given to younger children who are at high risk of bacterial meningitis or who have been exposed to someone with the disease. It is also approved for use in children of 9 months old.