Types and causes
Meningitis is mostly bacterial or viral, but some rare cases are caused by fungus. Bacterial meningitis is usually more serious than other forms.
Bacterial meningitis
At least 50 kinds of bacteria can cause meningitis.
Here are the main types. Click on the name of the type of meningitis for more information.
Meningococcal infection causes most cases of bacterial meningitis in the UK and Republic of Ireland. Meningococcal bacteria cause both meningitis (inflammation of the lining around the brain) and septicaemia (blood-poisoning). These two forms of meningococcal disease have different sets of symptoms, but most people who are infected have symptoms of both. When septicaemia occurs without meningitis it is more life-threatening.
Pneumococcal meningitis is the second biggest type of bacterial meningitis in the UK and Ireland, and in some countries it is the main type of meningitis. The bacteria are quite commonly carried, and are more likely to cause earache, pneumonia and less serious illnesses than meningitis. Pneumococcal meningitis is not considered to be contagious. Septicaemia does not often accompany meningitis. The rash typical of meningococcal disease is not normally seen.
Most cases of pneumococcal meningitis are in children under two years old and adults with specific problems (head injuries, diseases of the blood or circulation, or immune deficiency).
This used to be the most common type of meningitis in children under 5 in many countries. Since the introduction of the Hib vaccine in 1992, cases have dropped by over 90%. Symptoms of Hib meningitis are the same as for other bacterial meningitis.
This is the main cause of meningitis in newborn babies. GBS bacteria can cause septicaemia, meningitis and pneumonia. Up to 90% of babies who get this disease survive and a recent study found that half of those who recovered from GBS disease had no significant after effects. GBS bacteria are carried by at least 30% of people and are usually harmless.
Certain strains of these bacteria can cause meningitis, especially in newborn babies, and people of any age who have particular health problems. It is a much more important cause of meningitis in developing countries. Many other similar bacteria cause meningitis in the same way, but these are more rare.
This form of meningitis occurs mainly in babies, elderly people and those with weakened immune systems. It can be passed from mother to foetus during pregnancy or labour. When illness occurs very soon after birth, the most common problem is pneumonia and respiratory distress. Meningitis mainly occurs in babies who develop illness 2 or 3 days after birth. Late-onset infection may also occur through contact with other infected infants or adults who handle the baby. Very few cases now occur each year in the UK and Ireland, largely due to successful education campaigns about the dangers of eating unpasteurised milk products or contaminated pate, poultry or shellfish in pregnancy. The disease can be very serious, with a death rate of about 30%.
This is a rare form of meningitis due to the tuberculosis bacteria. It is 3 times more common in children under 6 than in adults. Most patients who have got TB meningitis have tuberculosis of the lungs or elsewhere. It occurs when tuberculous lesions that have spread to the brain area rupture. Diagnosis can be difficult because the onset is not sudden as in other forms of bacterial meningitis. People with tubercular meningitis often lack classic meningitic symptoms, become increasingly unwell, tired and drowsy with muscle aches, low grade fever and gradually worsening headache. After several weeks, when the disease is well-advanced, vomiting, neck stiffness and fits may occur. In the elderly, symptoms are sometimes limited to feeling drowsy and unwell until coma eventually results. The disease is fatal in up to 30% of cases, especially if treatment is delayed, and 10-30% of survivors have permanent after effects.
This is a very rare form of meningitis caused by salmonella bacteria.
This type of meningitis is usually relatively mild, with symptoms of headache, fever and general ill feeling, although some serious features of meningitis may occur. Since people with viral meningitis often recover without medical treatment, it is difficult to be certain how common it actually is, but it is probably more common than bacterial meningitis.
Fungal meningitis is quite rare. It mainly affects people with immune deficiencies.
There are other rarer types of meningitis.
In the UK and Ireland, all clinically diagnosed cases of meningitis and meningococcal septicaemia must be reported to the local public health doctor.
The public health doctor responsible in England and Wales and Northern Ireland is the CCDC (Consultant in Communicable Disease Control), CPHM (Consultant in Public Health Medicine) in Scotland, and in the Republic of Ireland the area medical officer and the specialist in public health fulfils the role.
Page last updated 10.08.07