MENINGITIS

Meningitis is one of the most terrifying diseases. It can be fatal in hours yet its early symptoms resemble self-limiting conditions like flu and colds…..
Meningitis is an infection of the fluid in the spinal cord and the fluid that surrounds the brain. Meningitis is usually caused by an infection with a virus, with a bacterium or even with fungi.
Common pathogens:
Meningococcus:
common organisms that cause meningitis in children.
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.
Haemophilus Influenzae type B (Hib)
is caused by haemophilus bacteria. It was once the most common form of bacterial meningitis,
one of the deadliest childhood diseases.
Pneumococcus
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.
How do people get it?
The most frequent cause of meningitis is the entry of microorganisms from an infection elsewhere in the body through the blood into the cerebrospinal fluid. 

Luckily, it's not easy to get meningitis. The body has natural defenses against infections - and usually even if someone comes across a virus or bacteria that can cause meningitis, the body can fight it off.

However, certain germs may outsmart the body's defenses and spread inside of the body. Some of these germs might then have the ability to infect the central nervous system, invading the meninges and causing meningitis.
Symptoms of meningitis can come on very quickly or take a couple of days to appear. Most cases of meningitis occur in the first 5 years of life, with the peak incidence between 3 and 5 months of age.
This varies with the organism and the underlying cause of the meningitis, but once the organisms have entered the cerebrospinal fluid, the body defenses cannot control their rapid growth as well as they could when the organisms were only in the bloodstream.

Once bacteria have entered the spinal fluid, the child usually shows symptoms fairly rapidly.
Complications Young children:
Babyish behavior
Forgetting recently learned skills
Reverting to bed-wetting
Babyish behavior
of MOne of the most common problems resulting from meningitis is hearing loss. Anyone who has had meningitis should take a hearing test.
Older people:
Lethargy
Recurring headaches
Difficulty in concentration
Short-term memory loss
Clumsiness
Balance problems
Depression
Other serious complications can include:

Brain damage

Epilepsy 
Changes in eye sight
Bacterial meningitis can be treated with a number of effective antibiotics. It is important, however, that treatment be started early in the course of the disease. Appropriate antibiotic treatment of most common types of bacterial meningitis should reduce the risk of dying from meningitis to below 15%, although the risk is higher among the elderly.

Knowing whether meningitis is caused by a virus or a bacterium is important because of differences in the seriousness of the illness and the treatment needed.
Investigations:
Examinations of CSF by lumber puncture
blood cultures
neuroimaging studies (CT or MRI)
detection of bacterial nucleic acid by polymerase chain reaction (PCR) assay.