What is Meningitis ?

Some days ago, my friend of my friend was diagnosed infected by a dangerous bacteria, and it called maningitis. I didn't really understand what is it. So, I tried to gather some information about it. And maybe it will more useful if I share here.

From wikipedia, I got the short explanation about this diseases.

Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges.[1] The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs. Meningitis can be life-threatening because of the inflammation's proximity to the brain and spinal cord; therefore the condition is classified as a medical emergency.

The most common symptoms of meningitis are headache and neck stiffness associated with fever, confusion or altered consciousness, vomiting, and an inability to tolerate light (photophobia) or loud noises (phonophobia). Sometimes, especially in small children, only nonspecific symptoms may be present, such as irritability and drowsiness. If a rash is present, it may indicate a particular cause of meningitis; for instance, meningitis caused by meningococcal bacteria may be accompanied by a characteristic rash.

A lumbar puncture may be used to diagnose or exclude meningitis. This involves inserting a needle into the spinal canal to extract a sample of cerebrospinal fluid (CSF), the fluid that envelops the brain and spinal cord. The CSF is then examined in a medical laboratory. The usual treatment for meningitis is the prompt application of antibiotics and sometimes antiviral drugs. In some situations, corticosteroid drugs can also be used to prevent complications from overactive inflammation. Meningitis can lead to serious long-term consequences such as deafness, epilepsy, hydrocephalus and cognitive deficits, especially if not treated quickly. Some forms of meningitis (such as those associated with meningococci, Haemophilus influenzae type B, pneumococci or mumps virus infections) may be prevented by immunization.



We can understood it better with these question and answer.


WHAT IS MENINGITIS ?


Meningitis is an inflammation of the meninges, the lining that protects the brain and spinal cord.
It is almost always caused by an infection, usually by a bacteria (bacterial meningitis) or a virus (viral meningitis). In rare cases it can be triggered by a fungus or parasite.
Meningitis occurs most commonly in young children under 5, those aged 17-25 (who often live in close quarters like dormitories and barracks), and people over age 55. People with compromised immune systems, such as people with HIV or AIDS, are also at increased risk.

What Are The Meninges?


The meninges are composed of three layers of membranes enclosing the brain and spinal cord.

• Pia mater is the innermost layer. It is akin to a tissue paper that closely adheres to the brain and spinal cord, dipping into the various folds and crevices.
• Arachnoid mater is the middle layer. It is a filmy membrane that is joined to the pia mater by fine threads resembling a cobweb.
• The dura mater, a parchment-like membrane, lies on the outermost part of the meninges and adheres to the skull and spinal canal.
• The cerebral spinal fluid (CSF) is the fluid that circulates in the spaces in and around the brain and spinal cord.



What Happens When The Meninges Swell?


The most frequent cause of meningitis is the entry of a microorganism-such as a bacterium or a virus-from an infection elsewhere in the body. The microorganisms travel through the blood and into the meninges and cerebral spinal fluid.

In the bloodstream, infection-causing microorganisms are fought off by white blood cells, an important part of the immune system. However, there are no white blood cells in the cerebral spinal fluid to fight infectious agents.
Once infectious organisms have entered the cerebrospinal fluid, the body's defenses cannot control their rapid growth and the disease races through the delicate surfaces and fluids of the central nervous system.

As the immune system gears up to fight off the microorganisms, it sends out chemical signals that produce inflammation and interfere with the normal functioning of the central nervous system. That, in turn, causes swelling and increased pressure inside the skull, and disrupts the brain's normal functioning.


What Causes Meningitis?


There are two main forms of meningitis:

* Bacterial Meningitis, and


* Viral Meningitis.


Bacterial Meningitis

Bacterial meningitis affects fewer people than the viral form, but it often results in more serious health consequences. Bacterial meningitis is fatal in 1 in 10 cases and leaves 1 in 7 survivors with a severe disability caused by brain injury.

There are several types of bacterial meningitis. Two types represent the majority of bacterial meningitis cases:

1. meningococcal

2. pneumococcal

The bacteria that cause these cases are common and live in the back of the nose and throat, or in the upper respiratory tract.

The bacteria are spread among people by coughing, sneezing and kissing. These bacteria cannot live outside the body for long, so they cannot be picked up from water supplies, swimming pools, or a building's air-conditioning system.

Individuals can carry these bacteria for days, weeks, or months without becoming ill. In fact, about 25 percent of the population carries the bacteria. Only rarely do the bacteria overcome the body's defenses and invade the cerebra spinal fluid, causing meningitis.

Meningococcal meningitis accounts for more than half of all cases of bacterial meningitis in the United States. Meningococcal disease is caused by bacteria called Neisseria meningitidis. There are several strains of Neisseria meningitidis. Strain B causes about 75 percent of the meningococcal cases and has the highest fatality rate.

Pneumococcal meningitis is caused by pneumococcus bacteria, which also cause several diseases of the respiratory system, including pneumonia. It has a fatality rate of about 20 percent. It also results in a higher incidence of brain damage than other forms of the disease.

Other types of bacterial meningitis include:


Neonatal meningitis



This form affects mostly newborn babies and is caused by Group B streptococcus bacteria, commonly found in the intestines.


Staphylococcal meningitis



This is a rare, but deadly form caused by staphylococcus bacteria. It usually develops as a complication of a diagnostic or surgical procedure.

Haemophilus influenza type B (Hib) is caused by haemophilus bacteria. It was once the most common form of bacterial meningitis, and one of the deadliest childhood diseases. However, in 1985, an Hib vaccine was introduced into the routine immunization program for U.S. children and virtually eliminated Hib meningitis in the United States.


Viral meningitis


Viral meningitis is far more common than the bacterial form and, in most cases, much less debilitating. Most people exposed to viruses that cause meningitis experience mild or no symptoms and fully recover without complications. '

The disease can be caused by many different viruses. Some of the viruses are transmitted by coughing or sneezing or through poor hygiene. Other viruses can be found in sewage polluted waters.

Occasionally, viral meningitis will develop following the mumps or chicken pox. Mosquito-born viruses also account for a few cases each year.

Approximately half of the viral cases in the United States are due to common intestinal viruses, or enteroviruses Viruses that live in the gut and are usually shed in the feces and in discharges from the mouth and nose.. These viruses are shed in the feces and in discharges from the mouth and nose. Most people who become infected with the virus contract it through hand-to-mouth contact.


source :
http://neuropathology.neoucom.edu
http://www.ehealthmd.com
http://wikipedia.com
http://textbookofbacteriology.net
http://bioweb.uwlax.edu
http://textbookofbacteriology.net
What is Meningitis ? What is Meningitis ? Reviewed by skyoko7@gmail.com on Thursday, December 02, 2010 Rating: 5

1 comment:

  1. It's a nice article. Everyone should read. Thanks for sharing. For more amazing info you can find it from this link What Is Meningitis

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