Meningitis is an infection of the meninges that are membranes that cover the brain and the spinal cord.
Meninges are 3 connective tissue layers. They consist of the pia mater (closest to the central nervous system organs), the arachnoid and the dura mater (farthest from the brain and spinal cord).
They also include blood vessels and contain cerebrospinal fluid. These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain.
Meningitis is an infection of the meninges. The infection may be caused by bacteria or a virus, and it leads to the meninges becoming inflamed (swollen). This can cause serious damage to the nerves, brain and the spinal cord.
Meningitis is commonly manifested by:
Symptoms can differ in young children and babies.
Meningitis may be caused by bacteria and viruses and both types have some distinctive features. Meningococcal disease is the leading infectious cause of death in early childhood.
Bacterial meningitis is very serious and should be treated as a medical emergency. Left untreated this may lead to severe brain damage and infect the blood causing septicimeia. The most common infecting bacteria are Neisseria meningitidis bacteria.
In 2008 and 2009 in England and Wales saw 1,166 cases of meningitis due to this bacteria. However, with the successful vaccination against this bacteria also known as meningococcal bacteria the number of cases have declined. However, there is currently no vaccine to prevent meningococcal group B disease, which is the most common cause of bacterial meningitis in the UK.
Bacterial meningitis is most common in children who are under five years old and is often life threatening in infants under the age of one. It is also common among teenagers aged 15 to 19 years. Of all the cases around 15% are bacterial meningitis and 25% may manifest with septicaemia. In 60% of cases both may present together.
Viral meningitis is the more common but less severe type of meningitis. The number of cases are difficult to estimate since the symptoms are akin to a bout of flu. Viral meningitis is most common in children and is more widespread during the summer months.
Meningitis may affect people of all age groups. Infants and young children and the elderly are however more at risk. Viral meningitis is the most common cause of the condition. Every year around 2,500 cases of bacterial meningitis, and nearly 5,000 cases of viral meningitis, occur in the UK.
The people most at risk of getting meningitis include:
Crowding (e.g. schools, day care, military recruits and college students) raises risk of meningitis.
Viral meningitis usually gets better within a couple of weeks but bacterial meningitis needs aggressive treatment.
Bacterial meningitis needs to be treated with antibiotics, admission to the hospital and even admission to the intensive care units.
Meningococcal disease (the combination of meningitis and septicaemia) causes death in around one in 10 cases. In spite of cure some children may go on to develop complications, such as hearing loss, after having bacterial meningitis. Prevention is by complete vaccinations against the infection.
Meningitis is the inflammation of the membranes that cover the brain and the spinal cord. Inflammation and infection of the meninges is often a life threatening medical condition as it can lead to brain infection and infection in the blood stream or septicaemia which can be fatal.
Meningitis may be caused by bacteria or by viruses. Viral meningitis usually is more common and runs a milder course while bacterial meningitis is a medical emergency.
Bacterial meningitis is the more serious form of the condition. Symptoms begin suddenly and worsen rapidly. Meningitis commonly affects children and elderly but may affect all age groups.
Some of the initial warning symptoms include:
Early symptoms of bacterial meningitis include:
As the disease progresses the symptoms include:
Young children and infants have some different symptoms that indicate meningitis. These include:
Viral meningitis is more common than bacterial meningitis. The illness appears much like flu and may have milder symptoms.
Common symptoms of viral meningitis include:
In more severe cases of viral meningitis symptoms may be:
Meningitis can be caused by bacteria or a virus. While bacterial meningitis is more dangerous, viral meningitis is more common and runs a milder course.
There are currently a number of bacteria that can lead to meningitis. Some of these include:
According to age group of the patient the most likely bacterial causes of meningitis include:
The meningococcal bacteria that cause meningitis are usually spread through prolonged, close contact. Spread is possible by being in proximity of an infected person who passes on the bacteria by sneezing, coughing, kissing, sharing personal possessions like toothbrushes, cutlery, utensils etc.
Pneumococcal bacteria are also spread by close contact with an infected person and by coughing, sneezing etc. However, in most cases they only cause mild infection, such as a middle ear infection (otitis media). Those with a poor immune system may develop a more severe infection such as meningitis.
There are several viruses that may lead to viral meningitis. Vaccinations against many of these viruses have led to the decline in the incidence of several viral meningitis cases. For example measles, mumps and rubella (MMR) vaccine provides children with immunity against mumps, which was once a leading cause of viral meningitis in children.
Viruses that may cause meningitis include:
Viral meningitis infection may be spread by close contact with the infected person and being exposed when the person sneezes and coughs.
Hand washing after they are contaminated with the virus – for example, after touching a surface or object that has the virus on it can prevent the spread.
Other causes of meningitis include:
Risk factors of getting meningitis include:
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)