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What is meningitis? |
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Viral meningitis |
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Bacterial Meningitis |
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Symptoms and detection |
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Disease development and treatment |
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Useful links |
The term meningitis refers to a symptom rather than a causal agent. It is an inflammation of the meninges which is the lining surrounding the brain and the spinal cord. Meningitis can be caused by bacteria, viruses, fungi, malignant cells or blood (following a haemorrhage). In common usage, the term is usually restricted to cases of viral or bacterial inflammation. Fungal meningitis (Cyptococcus), is caused by a fungus called Cyptococcus neofermans, which is found in soil containing bird droppings. Although dangerous, it is rare and only affects people with a suppressed immune system. It is however, of concern for patients suffering from diseases such as AIDS.
Viral meningitis is the more common and tends to occur in late summer and early autumn. Last year approximately 3000 cases were reported in the U.K., however doctors suspect that the real figure is much higher as many people would not distinguish its symptoms from a severe flu. These symptoms include fever, fatigue, disorientation, stiffness and a rash. In some cases, patients exhibit neurological disturbances: temporary paralysis or changes in consciousness. These more severe symptoms are fortunately rare, normally only occurring in those patients whose immune systems are weakened, such as the very old or the very young. It is only in these extreme cases, that permanent damage to the brain is done. Since this is a virus (like the common cold) antibiotics are not effective. However most cases run a short, uneventful course: most patients recovering within 7-14 days of the onset of symptoms. Nevertheless, people suspecting viral meningitis should consult a doctor, so as to eliminate the possibility of bacterial meningitis.
Bacterial meningitis is a rare disease (2000 cases were reported last year in the U.K) but is very serious. It is the bacterial form of this disease that makes newspaper headlines. 70 per cent of acute bacterial meningitis are caused by three bacteria: Neisseria meninitidis (meningococcus), Haemophilus influenza and Streptococcus pneumonia (pneumococcus). Other bacteria include Esherichia coli, Mcycobacterium tuberculosis and Treponema pallindum. The later two are the bacteria responsible for tuberculosis and syphilis, respectively. These are not a problem in the U.K. However, both tuberculosis and syphilis are widespread in the developing world and meningitis is a common complication in these diseases.
Symptoms of bacterial meningitis are similar to those of viral meningitis but are more severe and their onset tends to be more sudden. A patient with a fever greater than 101 degrees, and a severe sudden headache accompanied by mental disturbances, rashes and neck/back stiffness should consult their doctor immediately. The rash is a result a septicaemia and occurs in 60% of patients. Unlike most other rashes, it will not turn white under pressure. This has lead to the standard tumbler test for meningitis. The rashes' appearance is variable. They may be as small as 1-2mm across and appear as tiny red or purple spots or they may be large, resembling purple bruises.
If meningitis is suspected various clinical tests are performed. The cerebrospinal fluid (the fluid surrounding the brain) is analysed by taking a lumber puncture sample from the spinal cord. Diagnostic information can also be gained from cell counts and the bio-chemical make-up of the cerebrospinal fluid. Tests may be performed to rule out the syphilis bacteria; however this is now very rare in Britain.
Although these clinical tests are conclusive, detection prior to clinical tests is problematic for a number of reasons.
Meningitis is a very rare condition and many of its
symptoms are common to other illness e.g. a migraine or severe flu. Moreover, not all the
symptoms need be exhibited.
Speed of onset can vary rapidly. Both extremes can cause problems. At one
end, a patient may be in a potentially fatal condition within 24 hours of the symptoms
developing. In such cases, if a patient postponed seeking medical aid until say the
morning., the consequences may be dire. In contrast, the condition may remain at a fairly
low level for a period of a week or longer, and then deteriorate rapidly. This may lull
the patient into believing that they are not suffering from meningitis.
Although an extremely useful tool, the tumbler test should not be seen as
a conclusive test: 25% of sufferers do not have a rash at all. Even doctors have sometimes
been guilty of missing the symptoms because the sufferer does not have a rash. However,
this relates to our first point; in the absence of an epidemic, meningitis is very hard
for even doctors to detect without expensive clinical tests, therefore we can see how an
over-reliance on the tumbler test might develop.
Between 5%-10% of the population carry the bacteria responsible for meningitis in the back of their throat or nose, in a harmless state. This carrier state may last for many months, with bacteria spread from person to person via close contact i.e. coughing, kissing, sharing utensils etc. Meningitis spreads rapidly when there is a large number of people in close contact, for example in schools, university halls of residences, prisons. In an epidemic, the percentage of carriers in the population may rise to over 95%; however the infection rate will be under 1%. This indicates that a carrier's general state of health is an important factor in determining whether they will contract this disease. These bacteria reach the meninges either via the blood stream or less commonly via the sinuses then into the skull's bone marrow. Researchers are not certain about how these bacteria reach the blood stream; however the present consensus suspects that this occurs via the lungs.
Bacterial meningitis can be treated using anti-biotics. If these are started soon enough, most patients make a full recovery. However, in approximately 5% of cases the onset of the disease is too sudden and the result is fatal. If an individual is diagnosed with meningitis, family members and close friends should be started on a course of anti-biotics irrespective of whether they are exhibiting symptoms. Doctors now offer a vaccination against certain strains of meningitis. This is recommended for children under the age of five.
Yahoo: Meningitis by category.
Meningitis Foundation of America Forum Discussions,bulletins and message postings.
Meningitis Research Foundation A U.K charity which funds research and provides information about Meningitis.
National Meningitis Trust Another U.K. based charity researching into meningitis.