Helen Bedford, PhD, RN, RHV.
Senior Research Fellow, Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, London
Although relatively rare, meningitis is feared by both parents and health professionals. Concerns about the disease are fuelled by the occasional high-profile story in the press about a child who was well, or who had only mild symptoms, but within a short period of time became critically ill.
This paper provides background information for nurses in acute and community settings on the causes, treatment, outcome and prevention of meningitis in childhood.
Meningitis refers to inflammation of the meninges (the membranes that enclose the brain and spinal cord). An attack of meningitis is more likely in childhood than at any other age, and there are an estimated 1600 cases per year in England and Wales in children under the age of five years.
The cause may be viral, fungal or bacterial. Viral causes are thought to account for the largest number of cases. However, it is bacterial meningitis that attracts most attention, since this form of the disease is generally associated with a relatively high death rate and significant long-term sequelae.
The peak incidence of meningitis occurs during the neonatal period (up to 28 days after birth). There were about 300 cases in England and Wales in 1996-1997 (Holt et al, 2001). The most common causes of the disease in this age group are group B streptococci and Escherichia coli. Low birthweight and prematurity are risk factors for an attack of neonatal meningitis.
Until recently, the most common causes of bacterial meningitis following the neonatal period were, in order of importance: Haemophilus influenzae Type B (Hib), Neisseria meningitidis (meningococcus), Types B and C and Streptococcus pneumoniae. However, the introduction during the last decade of two highly effective vaccines to protect against Hib and meningococcal C infection dramatically reduced the incidence of these infections.
In the UK, meningococcal disease is almost always caused by groups B and C, in a ratio of about 60:40. While Group B disease accounts for most of the infections in the under-fives age group (particularly in children aged under two years), group C disease is more common in older children and adolescents (Ramsay et al, 1997).
Development of meningitis
The organisms that cause bacterial meningitis are often harmless commensals of the nose and throat. For example, at any one time, about 10% of individuals will be carrying one of a number of meningococcal strains, many of which are not virulent (Cartwright et al, 1987). However, these rates may be much higher in particular age groups. for example, one study found a rapid increase in carriage rates during the first week of term in university students - from 6.9% on day one to 23.1% on day four. By the end of the first term this had increased to 34.2% (Neal et al, 1999). Other risk factors are listed in Box 1. Organisms are spread by coughing, sneezing and intimate kissing.
The majority of people, despite carrying these bacteria, remain asymptomatic. However, occasionally the organisms may cause minor infections such as a sore throat or earache. In a few people the organisms break through the lining of the nasopharynx or the middle ear and enter the bloodstream. They may then overwhelm the body’s defences and multiply rapidly, crossing the blood-brain barrier and causing inflammation of the meninges.
Why some people carrying the bacteria develop the disease while others do not is not entirely clear, but certain risk factors have been identified, and these are listed in Box 2. Breastfeeding appears to offer some degree of protection against an attack of Hib disease (Takala et al, 1989).
Genetic make-up may play a significant role in determining the development of the disease and may even influence the severity of an attack.
Signs and symptoms
Meningitis may present with either relatively mild nonspecific symptoms or it may rapidly progress, causing convulsions, collapse and coma. The signs and symptoms of meningitis in young children usually include fever, vomiting and lethargy. A stiff neck may not be present in young children. In older children, headache, aversion to light and vomiting are common and neck stiffness is characteristic (Davies et al, 2001).
The classic purpuric rash seen in cases of meningococcal sepsis may also occur in meningococcal meningitis and occasionally in cases of meningitis caused by other organisms.
Because it is potentially so serious, it has been recommended that a diagnosis of meningitis should be considered in any child with the following symptoms:
- High fever (>38°C) with no obvious focus for infection
- Irritability or lethargy and fever
- Abdominal pain, vomiting, poor feeding and fever
- Persistent febrile symptoms in any child already taking antibiotics (Heyderman et al, 1993).
Diagnosis and treatment
In cases of suspected meningitis, antibiotic therapy should be given immediately, even before the results of culture are known. For some years it has been recommended that benzylpenicillin should be given before transfer to hospital to a child in whom meningococcal infection is suspected.
However, although evidence suggests that this can reduce mortality considerably, it appears that many individuals do not receive antibiotics before hospital admission (Cartwright et al, 1992; Begg, 1992).
Diagnosis is usually made by performing a lumbar puncture and examining the cerebrospinal fluid (CSF). However, in a minority of children who are showing signs of increased intracranial pressure, the procedure will not be carried out as it may result in serious complications. Lumbar puncture is a distressing procedure for both the child and the parents who will need support and information about what is happening. The causative organism can be cultured from the blood, CSF or both. The treatments of choice for bacterial meningitis in children older than three months are the third generation cephalosporins, such as ceftriaxone or cefotaxime (Davies et al, 2001). Administration of dexamethasone has been shown to reduce the incidence of neurological sequelae in Hib meningitis among children older than one month, although its effectiveness as a treatment in other types of meningitis is not proven (McIntyre et al, 1997).
Most cases of meningitis are not life threatening. Routine care is outlined in Box 3. Children may be nursed in isolation to prevent spread, for the first 24-48 hours until the antibiotics have taken effect. A small proportion of critically ill children require further attention in intensive care.
The child and parents will require continued support and, after the initial shock of the diagnosis, information about the disease. The fear of meningitis means that friends and relatives may be concerned that they or their children may also contract the infection. They should be reassured that, while there is an increased risk of an attack in close contacts, the risk is low. It is advisable, however, to provide prophylaxis for household contacts (people who have prolonged close contact).
The aim of prophylaxis is to eliminate nasopharyngeal carriage of the organisms. In the case of Hib disease in a child, the immunisation status of all children under the age of four years in the household should be checked, and any who are not fully immunised should be offered the vaccine as soon as possible. If any children are not fully immunised, rifampicin should be given to eliminate nasopharyngeal carriage. In the case of meningococcal disease, rifampicin is the drug of choice for household contacts. Unless the child has been treated with ceftriaxone, he or she will also require treatment to eliminate carriage (Davies et al, 2001).
Recovery and outcome
The majority of children eventually make a full recovery but there is often a long period of convalescence. Young children may show changes in behaviour such as clinginess, temper tantrums, sleep disturbance and loss of recently acquired skills simply because they have been hospitalised with a serious illness. However, there is a significant death rate associated with bacterial meningitis and a proportion of survivors will have significant permanent problems. Reported death rates range from 4% for Hib meningitis to 15% for pneumococcal meningitis (Baraff et al, 1993). Rates of severe or moderate disability reported in one large study of long-term effects in infants ranged from 9% for meningococcal meningitis to 24% for pneumococcal meningitis (Bedford et al, 2001).
Recognised sequelae include cerebral palsy, learning disabilities, epilepsy, visual problems and sensorineural hearing loss. These may occur following meningitis due to any bacterial cause. More subtle deficits have also been shown to persist many years after an attack, including reductions in IQ, poorer academic abilities and behavioural problems (Grimwood et al, 2000).
Following an attack of meningitis it is important that children are followed up and that all have their hearing tested. Some children have been found to have progressive hearing loss following meningitis. Risk factors for poor outcome include acute neurological complications such as seizures, coma and hydrocephalus at the time of the illness and a delay in initiation of treatment.
Support after meningitis
After discharge from hospital many families will benefit from continued support. In addition to routine health, social and educational services, two registered charities, the National Meningitis Trust and the Meningitis Research Foundation, provide information and support for families who have experienced meningitis. This may mean simply providing relevant information about the disease and outcome or, in cases where a child has been left with disabilities, grants may be available for aids and equipment. See further information, left.
Prevention of meningitis
Despite improvements in treatment, the best route to reducing death and disability associated with bacterial meningitis is still primary prevention.
For some years vaccines have been available to provide protection against bacterial meningitis. These vaccines were produced by purifying the outer polysaccharide (sugar) coat of the organism. Although polysaccharide vaccines were effective in children over the age of 18 months, they were not effective in treating the youngest, most at risk children. However, by attaching the outer coat to a carrier protein and producing a conjugate vaccine, its efficacy is increased.
Trials showed conjugate Hib vaccines to be highly effective in all age groups. In 1992, a Hib conjugate vaccine, which had already been used widely in the USA, was introduced to the UK. It was well received and produced a 97% reduction in cases of the disease compared with the period before the vaccine was introduced (Department of Health, 1999). This reduction has occurred throughout the population, not only among those who are vaccinated, suggesting that carriage of the organism is also reduced. Hib vaccine is offered routinely to infants with their primary course of diphtheria, tetanus and pertussis and polio at two, three and four months. Redness and swelling occurs in 10-15% of children, usually after the first injection; no more serious reactions have been reported.
Using the same principles of conjugation, an effective vaccine against meningococcal C infection was also produced. In November 1999, the UK became the first country in the world to introduce this vaccine into the routine vaccine schedule. In order to protect older children, a campaign was launched to offer the vaccine to all children below age 17 years. The frequency of reported side-effects following meningococcal C vaccine depended on the age of the recipient: about a quarter of children aged from four to 18 years reporting redness and swelling and about one in 10 children in this age group experienced headache (Health Promotion England, 1999). During the winter of 2000/2001, there was a 90% reduction in the incidence of meningococcal diseases in infants and young people aged between 15 and 17 years - the two groups who were targeted to receive the vaccine first (Department of Health, 2001).
Work is underway to develop a vaccine against meningococcal B infection, although it is likely to be some years before the vaccine is available for general use. The first pneumococcal conjugate vaccine was licensed in the UK in 2001 and recommendations for its use are still under consideration.
The prospects for the future prevention of bacterial meningitis look very good, although strategies for neonatal meningitis may be more difficult to implement. In the meantime, meningitis should be recognised as a potentially life-threatening infection that is perceived by parents as the most serious childhood disease and possible cases should be dealt with accordingly.
- The National Meningitis Trust, Fern House, Bath Road, Stroud, Gloucestershire GL5 3TJ. Tel: 01453-768000. www.meningitis-trust.org.uk
- Meningitis Research Foundation, Midland Way, Thornbury, Bristol BS35 2BS. Tel: 01454 281811. www.meningitis.org.uk
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