VOL: 98, ISSUE: 38, PAGE NO: 54
Sarah Booker, RGN, BSc, is education and research coordinator, Meningitis Trust, Stroud
Bev Hart, RGN, MSc, is education and training manager, Meningitis Trust, StroudMeningitis is an important health issue that can cause great concern for nurses who read about it or manage it first hand.
Meningitis is an important health issue that can cause great concern for nurses who read about it or manage it first hand.
It is a term used to describe inflammation of the meninges, which are the membranous tissues that surround the brain and part of the spinal cord. The major organisms that cause meningitis are bacteria, viruses and fungi.
Causes of meningitis
Bacterial meningitis is usually caused by infection with one of the following organisms: Neisseria meningitidis (meningococcal), Streptococcus pneumoniae (pneumococcal) or Haemophilus influenzae B (Hib). There are around 3,000-3,500 reported cases of bacterial meningitis in the UK each year, and a high percentage of these occur in children and young adults.
Viral meningitis is more common than bacterial meningitis, although the true burden of disease caused by viruses is unknown. It is commonly caused by infection with enteroviruses, namely echoviruses and coxsackie. Many other viruses, including herpes simplex, can also cause meningitis. Viral meningitis is more commonly reported in adults, although it also occurs in infants and children.
Early recognition and rapid clinical diagnosis are required to reduce mortality and morbidity due to meningitis. The initial diagnosis of meningitis is often based on clinical features for which patient history and examination are crucial.
In the early stages the symptoms of meningitis may be ambiguous or appear similar to other febrile illnesses. For example, infants may be drowsy and off their feeds, and adults may have joint pain and vomiting or diarrhoea.
However, there are characteristic features of meningitis that are easier to recognise. Infants may display neck retraction, have a tense or bulging fontanelle, a high-pitched cry and impaired consciousness, while adults may complain of neck stiffness, photophobia and a severe headache. They may also be confused or have impaired consciousness.
Where septicaemia is present, both infants and adults will have signs of circulatory failure, such as cool peripheries and delayed capillary refill.
The septicaemic rash occurs primarily with meningococcal septicaemia. It may begin as a maculopapular rash (blanching) and progress to a petechial rash with areas of purpura (non-blanching). The above picture shows an infant with a maculopapular rash, among which there is one non-blanching petechiae (indicated by the arrow). Where a rash is present with other signs of a febrile illness in a child or an adult it is important to make a thorough examination, as it is easy to miss one petechiae among a widespread maculopapular rash.
The onset of disease can be rapid. Not all the symptoms appear at one time, and the rash may appear very late or not at all. Therefore, it is important to have a high degree of suspicion and to be aware of the potential rapid deterioration that can occur in patients who present with non-specific signs and symptoms.
Microbiological confirmation can be provided by isolating the organism from blood, cerebrospinal fluid (CSF), throat swabs or rash aspirates. Due to early treatment of bacterial meningitis with antibiotics the number of patients with culture-positive disease has reduced over recent years.
CSF removed during a lumbar puncture (LP) can be investigated biochemically to confirm a diagnosis of meningitis. Although there has been a move away from LP, in the absence of specific contraindications it can provide valuable information for optimal management and disease surveillance.
Other diagnostic tests include rapid antigen detection and polymerase chain reaction. The latter is an advanced microbiological test used to detect microbial DNA and can be particularly useful in patients already receiving antibiotics.
Treatment and nursing care
Where bacterial meningitis or septicaemia is suspected antibiotics should be administered as soon as possible (if possible by the GP). First-line treatment with benzylpenicillin is recommended where meningococcal meningitis or septicaemia is suspected. There is some debate regarding the use of chloramphenicol. However, current recommendations state that it should be given where there is known anaphylaxis in response to penicillin. Penicillin-resistant strains of the meningococcus are very rare in the UK. The meningococcus is also sensitive to third-generation cephalosporins. These may also be given where bacterial infection is suspected and will cover disease caused by an organism other than Neisseria meningitidis.
Treatment for shock and raised intracranial pressure should also be instigated. In sepsis circulatory shock should be treated with volume replacement, oxygen therapy and, in severe cases, inotropic support. Where there are signs of raised intracranial pressure a lumbar puncture is contraindicated and diagnosis should be made on clinical features and blood assays. Raised intracranial pressure can be treated with steroids, such as dexamethasone, and in severe cases mannitol.
Viral meningitis can be severe enough to cause raised intracranial pressure and decreased consciousness. Otherwise treatment is primarily symptomatic.
The global picture
Meningitis and meningococcal disease are a global problem. With regard to meningococcal disease, different serogroups of the bacteria are prevalent in different areas of the world. For example, the majority of meningococcal disease in the UK is caused by serogroups B and C. The sub-Saharan meningitis belt often has year-round epidemics. Meningococcal disease in this area is commonly caused by serogroup A.
Serogroup W135 of the meningococcus was rare in Europe and the UK, but incidences of this serogroup of the bacteria have increased over the last few years. The evidence indicates that W135 is being carried into Europe by pilgrims returning from their annual pilgrimage to Mecca. This year prospective pilgrims were subject to a mass vaccination campaign aimed to protect them against W135, Y, A, and C.
In 1999 and 2000, 25 European countries reported over 8,100 cases of laboratory-confirmed cases of meningococcal disease, with an overall fatality rate of 6.9% (Noah and Henderson, 2001). Therefore, meningitis and meningococcal disease remain a comparatively rare disease but a significant cause of mortality among infectious diseases.