Meningitis

Meningitis is inflammation of the meninges (membranes covering the brain and spinal cord), usually due to infection.

Causes

Viral meningitis tends to occur in epidemics in winter; it is usually relatively mild. Bacterial meningitis, however, is life-threatening. It is mainly caused by Haemophilus influenzae,Streptococcus pneumoniae, or Meningococcus types B and C. The infection usually reaches the meninges via the bloodstream from an infection elsewhere in the body, often in the nose or throat. Less commonly, it passes through skull cavities from an infected ear or sinus, or from the air following a skull fracture.

Symptoms

The main symptoms are fever, severe headache, nausea and vomiting, dislike of light, and a stiff neck. In viral meningitis, the symptoms are mild and may resemble influenza. In bacterial meningitis, the main symptoms may develop over only a few hours, followed by drowsiness and, occasionally, loss of consciousness. In about half the cases of meningococcal meningitis, there is also meningococcaemia (a potentially life-threatening condition in which bacteria multiply rapidly in the blood). This condition causes a reddish-purple rash under the skin, which does not fade with pressure. The rash starts as pin-prick spots that can expand to give a bruiselike appearance.

Diagnosis and treatment

To make a diagnosis, a lumbar puncture is performed to remove a small sample of cerebrospinal fluid. Viral meningitis needs no treatment and usually clears up in a week or two with no after-effects. Bacterial meningitis is a medical emergency. It is treated with intravenous antibiotic drugs. With prompt treatment, a full recovery is usually made; the earlier treatment is given, the better the outlook. In some cases, however, deafness or brain damage may occur, or the person may lose an area of skin, or fingers or toes, as a result of the rash.

Prevention

Vaccines are now given to protect children and teenagers against two of the major types of bacterial meningitis: those caused by Haemophilus influenzae and by Meningococcus type C.

There is now a vaccine againist "Meningitis B" caused by Meningococcus type  B. This vaccine is called Bexsero. 

Antibiotic drugs may be given as a protective measure to people who have come into contact with these infections. Immunization against some forms of meningitis is recommended for Muslims travelling to Saudi Arabia for the Hajj and Umrah pilgrimages, and for people travelling to Nepal and some parts of sub-Saharan Africa.

Bacterial Meningitis 

Viral Infections of the Central Nervous System - includes viral meningitis and encephalitis