Ranking	Diagnosis
1	Respiratory tract infections
2	Chronic diseases of tonsils and adenoids
3	Asthma
4	Abdominal and pelvic pain
5	Viral infection (unspecified site)
6	Non-suppurative otitis media
7	Inguinal hernia
8	Unspecified head injury
9	Gastroenteritis/colitis
10	Undescended testicle

Congenital anomalies

Congenital anomalies remain an important cause of infant and child mortality in England and Wales, and account for an increasing proportion of infant deaths. The National Congenital Anomaly System (NCAS), established in 1964 in the wake of the thalidomide tragedy, has monitored congenital anomalies nationally in England and Wales. Registers such as NCAS are important in planning service delivery and alerting specialists to conditions where research is required. However, it relies on voluntary notifications and collaborates with local registers to improve the quality and quantity of data (see Useful Paediatric Websites at end of chapter).

Data for 2008 are available but there is ongoing discussion about the future direction of the recording service, given the wide variability in reporting between areas with and without regional congenital anomaly registers. In 2007, a new classification of congenital anomalies was introduced to include tighter rules for deciding which congenital anomalies should be included in the Office for National Statistics report making year on year comparisons more difficult.

In 2008, there were 175 central nervous system (CNS) anomalies, for example, hydrocephalus, 282 cleft lip/palate, 932 heart and circulatory, 258 hypospadias and 225 Down’s syndrome reported to NCAS.

Neural tube defects (spina bifida) are one example of devastating congenital malformations that have been influenced by public health intervention programmes. The results of a long-term study (MRC Vitamin Study Research Group, 1991) showed that folate supplementation prevented 72% of neural tube defects when given to women at high risk of having a child with a neural tube defect. Hence, folate supplementation is now part of the routine advice given in antenatal clinics.

Cancer

Cancer is very rare in childhood; around 1700 new cases are diagnosed in children less than 15 years old in the UK each year. About one-third of all childhood cancers are leukaemias and of these, about 80% are of the acute lymphoblastic type (ALL). Although rare, childhood cancer is the most common cause of death from illness in children aged between 1 and 15 years of age.

As a consequence of the technical advances in treatment and the centralisation of services in specialist centres, a much greater number of childhood cancer sufferers are surviving to adulthood.

Asthma, eczema and hay fever

Asthma, eczema and hay fever (allergic rhinitis) are among the most common chronic diseases of childhood and most of the affected children are managed in primary care. During the 1970s and 1980s there was considerable expansion of epidemiological research into these disorders, prompted mainly by concern about the increase in hospital admissions for childhood asthma despite the availability of effective anti-asthma medication. These studies failed to identify any demographic, perinatal or environmental factor which could explain more than a small proportion of the large changes in prevalence of asthma, hay fever or eczema. Incidence rates of acute asthma in children under 5 years old were reported to be 1.5 per 1000 per week in 1991; the rates for children aged 5–14 years old were 0.9 per 1000 per week. Between 1993 and 2000 the incidence rates for both groups declined, but asthma continues to be an important childhood illness placing a burden on the health service.

Infections

Despite a dramatic decline in the incidence of childhood infectious diseases during the twentieth century, they remain an important cause of ill health in childhood. Major advances in the prevention of infections have been achieved through the national childhood vaccination programme.

The importance of maintaining high vaccine uptake has been demonstrated by the resurgence of vaccine-preventable diseases where children have not been vaccinated. Adverse publicity surrounding the MMR (measles, mumps and rubella) vaccine, involving a possible association with Crohn’s disease and autism, resulted in a loss of public confidence in the vaccine and a decrease in MMR coverage. This occurred in spite of rigorous scientific investigation and evidence refuting the claims. The annual coverage for MMR for 2-year olds declined from 92% in 1992 to 87% in 2000 and data for 2004 show that it dropped to 81.5%. Although this decline is far less than that seen for pertussis in the 1970s, if MMR coverage remains at this level or declines further, resurgences of MMR in primary schoolchildren will become more common. NHS information centre data revealed 85% of children in England had received the MMR vaccine in 2007/8. However, to achieve herd immunity, 95% of children need to be immunised; unless this figure is improved a measles epidemic still remains a possibility.

An important gastro-intestinal infection that appears to be increasing is infection with verotoxin-producing Escherichia coli (VTEC). This is important because it is the main cause of haemolytic uraemic syndrome, a severe condition which can lead to acute renal failure in children. VTEC is an example of an emerging infection. Before the 1980s it was unknown and during the 1990s reports of infection with VTEC in children in the UK tripled from 172 in 1991 to 531 in 1999. In 2009 the rates of VTEC 0157 decreased as age increased, with significantly higher rates in the 0–4 year age group (8 per 100,000) than in 5–9 year olds (4 per 100,000) and a further decrease (2 per 100,000) in the 10–19 year age group. It is a public health priority to improve VTEC 0157 surveillance and improve diagnostic testing.

Respiratory syncytial virus (RSV) is the most important cause of lower respiratory tract infection in infants and young children in the UK, in whom it causes bronchiolitis, tracheobronchitis and pneumonia. It is responsible for seasonal outbreaks of respiratory tract infection most commonly between October and April. The main burden of disease is borne by children under 2 years and there are around 7000–10000 confirmed laboratory reports of RSV in children in England and Wales each year. During the winter months, RSV is the single greatest cause of admission to hospital in children.

Mental health disorders

Mental health disorders are another emerging concern in the child health arena. In 2004, 1 in 10 children and young people aged 5–16 years old had a clinically diagnosed mental health disorder. These included 4% with an emotional disorder such as depression or anxiety, 6% with a conduct disorder, 2% with a hyperkinetic disorder and 1% with less common disorders, for example, autism, tics.

Groups at particular high risk of psychiatric disorder include children in the care system, young people who are homeless and young offenders. Longitudinal evidence has confirmed that many child psychiatric disorders persist well into adult life. Biological, psychological and social factors all seem likely to contribute to the risk of psychiatric disorders, and may act in combination.

Drugs, smoking and alcohol

The harm that drugs, smoking and drinking can do to the health of children and young people is recognised and a number of targets have been set in an attempt to reduce prevalence. Recent figures on smoking, alcohol and drug use among young people have been provided by the NHS Information Centre in their 2008 report.

In 2008, 6% of schoolchildren smoked regularly (at least once a week). Girls are more likely to smoke than boys and the prevalence increases with age. Around 14% of 15-year olds smoke regularly compared to 0.5% of 11-year olds. However, the prevalence of smoking amongst children has halved since its peak in the mid-1990s (13% in 1996), suggesting a decline in prevalence to below government targets. In 2007, the minimum age for buying tobacco was increased from 16 years old to 18 years old.

More than half of pupils (52%) aged 11–15 years have drunk alcohol in their lifetime. In 2008, a national survey identified that the mean amount of alcohol consumed by pupils who had drunk in the last week was 14.6 units. Boys drink more than girls and older pupils drink more than younger pupils. In one large survey, 17% of pupils aged 11–15 years old admitted to being drunk in the last 4 weeks.

The prevalence of drug use has declined since 2001. In 2008, 22% of pupils said that they had ever used drugs with 33% reporting that they had ever been offered drugs. Pupils were most likely to have taken cannabis (9%). Five percent of pupils had sniffed glue or other volatile substances in the last year and 2.9% had sniffed poppers. Overall, 3.6% of pupils had taken class A drugs in the last year.

Nutrition and exercise

Health during childhood can impact upon well-being in later life. Good nutrition and physical exercise are vital both for growth and development and for preventing health complications in later life. In addition, dietary patterns in childhood and adolescence have an influence on dietary preferences and eating patterns in adulthood.

In 2000, an international definition of overweight and obesity in childhood and adolescence was proposed to help calculate internationally comparable prevalence rates of overweight and obesity in children and adolescents. The definition interprets overweight and obesity in terms of reference points for body mass index (BMI, in kg/m²) by age and sex, and is linked to the widely used adult overweight cut-off point of 25 and adult obesity cut-off point of 30.

In 2004, it was estimated that 14% of boys and 17% of girls aged 2–15 years of age were obese. Probable reasons for a rise in overweight and obesity in children are changes in diets and an inactive lifestyle. There is evidence that obesity at an early age tends to continue to adulthood.

Being overweight is linked to the development of type 2 diabetes, high blood pressure, heart disease, stroke, certain cancers and other types of illnesses. Therefore, healthy eating is not only important in relation to weight but also contributes to reducing the risk of heart disease, stroke and some cancers in later life. It is recommended that a well-balanced diet providing all the nutrients required should include at least five portions of fruit and vegetables a day. It is now practice in many areas for infant children (aged 4–7 years) each day to be provided with a piece of free fruit during school break time.

The normal child

Growth and development are important indicators of a child’s general well-being and paediatric practitioners should be aware of the normal development milestones in childhood. In the UK, development surveillance and screening of babies and children is well established through child health clinics.

Weight is one of the most widely used and obvious indicators of growth, and progress is assessed by recording weights on a percentile chart (Fig. 10.1). A weight curve for a child which deviates from the usual pattern requires further investigation. Separate recording charts are used for boys and girls and since percentile charts are usually based on observations of the white British population, adjustments may be necessary for some ethnic groups. The World Health Organization (WHO) has challenged the widely used growth charts, based on growth rates of infants fed on formula milk. In 2006, it published new growth standards based on a study of more than 8000 breast-fed babies from six countries around the world. The optimum size is now that of a breast-fed baby. Recently, new growth charts have been introduced for children from birth to 4 years of age. These combine the UK and WHO data. Copies can be accessed at http://www.rcpch.ac.uk/Research/UK-WHO-Growth-Charts.

Fig. 10.1 Example of a centile chart (Child Growth Foundation).

Height (or length in children less than 2 years of age) is another important tool in developmental assessment. In a similar way to weight, height or length should follow a percentile line. If this is not the case or if growth stops completely, then further investigation is required. The normal rate of growth is taken to be 5 cm or more per year and any alteration in this growth velocity should be investigated.

For infants up to 2 years of age, head circumference is also a useful parameter to monitor. In addition to the above, assessments of hearing, vision, motor development and speech are undertaken at the child health clinics. A summary of age-related development is shown in Fig. 10.2.

Fig. 10.2 A summary of the various stages of development.

Child health clinics play a vital role in the national childhood immunisation programme, which commences at 2 months of age. Immunisation is a major success story for preventive medicine, preventing diseases that have the potential to cause serious damage to a child’s health, or even death. An example of the impact that immunisation can have on the profile of infectious diseases is demonstrated by the meningitis C immunisation campaign, which began in November 1999. The UK was the first country to introduce the meningitis C conjugate (MenC) vaccine and uptake levels have been close to 90%. The programme was targeted at under-20 year olds and has been a huge success, with a 90% reduction in cases in that age group. Authorities were hoping to mirror the success of the meningitis C campaign with the introduction of the seven valent pneumococcal vaccine into the routine UK childhood immunisation schedule in April 2006. Post-licensing surveillance has shown a large reduction in both invasive and non-invasive disease incidence due to vaccine serotypes in vaccinated individuals. However, during the same period, the UK has seen an increase in invasive disease due to the non-vaccine serotypes, caused for a large part by the six serotypes not covered by the seven valent vaccine, but present in a new 13 valent vaccine. In April 2010, the 13 valent pneumoccocal vaccine replaced the seven valent vaccine in the standard immunisation schedule. Human papilloma virus vaccine has also recently been introduced to the immunisation programme in the UK for females aged 12–13 years of age, to reduce the risk of cervical cancer.

Advice on the current immunisation schedule can be found in the current edition of the British National Formulary for Children.

Drug disposition

Pharmacokinetic factors

An understanding of the variability in drug disposition is essential if children are to receive rational and appropriate drug therapy (Anderson and Holford, 2008, 2009). For convenience, the factors that affect drug disposition will be dealt with separately. However, when treating a patient all the factors have a dynamic relationship and none should be considered in isolation.

Absorption

As a percentage of total body weight, the total body water and extracellular fluid volume decrease with age (Table 10.2). Thus, for water-soluble drugs such as aminoglycosides, larger doses on a milligram per kilogram of body weight basis are required in the neonate than in the older child to achieve similar plasma concentrations.

Table 10.2 Extracellular fluid volume and total body water as a percentage of body weight at different life stages