Current Pediatric Reviews - Volume 6, Issue 2, 2010

Asthma remains one of the most common chronic childhood conditions in the Western world and is becoming more prevalent in the developing world. Mercifully, asthma deaths are rare in children but the burden of morbidity remains high. Thirty eight percent of children with asthma report symptoms at least once as week by day and 28% report symptoms at least once a week by night and 30% have symptoms on exercising [1]. There are several implications for childhood asthma symptoms. Children with asthma are at increased risk for developmental, emotional, and behavioral problems [2]. Nocturnal asthma symptoms in children have been linked to increased absenteeism from school for the child and from work for the parent [3]. There are concerns that children with asthma fail to attain their educational potential [3] despite historical evidence that children with asthma have a higher than average IQ [4]. The financial implications to the nation of childhood asthma have been quantified and it is estimated that the healthcare costs for a child with asthma are approximately three times greater that those for a child without asthma [5]. The heavy burden that asthma symptoms place on the individual, their family and the wider community clearly needs to be addressed but at present there is no prospect of a cure for childhood asthma. Fortunately, chronic asthma symptoms are responsive to treatment with inhaled corticosteroids in the vast majority of children and this treatment is known to be safe. Guidelines have been developed to assist clinicians in the diagnosis and management of childhood asthma [6, 7] and goals for acceptable symptoms control have been set [7]. Despite the guidelines and goals, childhood asthma still remains a clinical challenge for a number of reasons. First, there is no diagnostic test nor is there consensus on a definition of childhood asthma. Second, currently there is no reliable biomarker against which to titrate treatment. Third, asthma remains an unpredictable condition which can spontaneously remit or relapse over periods of weeks, months or even years. Whilst clinicians caring for children with many chronic conditions including cancer, diabetes, renal failure and hypertension can apply objectivity to many of their clinical decisions, the diagnosis and management of childhood asthma remains a subjective question of balancing the probabilities. The present series has been complied to provide the reader with an up-to-date review to assist in the decision-making process. The authors of the articles have been tasked to answer the following questions: 1. Why do some children develop asthma? 2. How do I diagnose childhood asthma? 3. How do I treat a child with asthma? 4. How should I monitor a child with asthma? 5. What should be my approach to the adolescent with asthma? 6. What should be my approach to the child with troublesome asthma?

Childhood asthma is an enigmatic condition which can develop in early or late childhood and thereafter persist or remit. Asthma has a complex phenotype whose aetiology is far from straight forward and many factors have been implicated. Genetic influences are widely accepted as important and thought to contribute towards as much as 50% of the risk for developing asthma. Environmental factors are also important and include antenatal and postnatal exposures to tobacco smoke, dietary factors and infective agents (including bacterial lipopolysaccharide). Large studies have demonstrated how pairings of several gene-environment combinations produce asthma; the heterogeneity of asthma may be explained by interactions between different combinations of genes and environmental factors each of which has a small-moderate influence on the outcome. The important gene environment interactions almost certainly occur in early life. A model is emerging where antenatal programming is followed by postnatal airway remodelling, driven by environmental exposures in genetically-susceptible individuals during critical stages of development. Intervention studies have confirmed the complexities of asthma pathogenesis. Future intervention studies will lead to better understanding of asthma pathogenesis and more importantly, to prevent this common condition.

Asthma is amongst the commonest chronic illnesses of childhood yet there is no single objective test that results in a definitive diagnosis. Diagnosis remains clinical, especially in young children. At present, asthma diagnosis in children is best viewed as a process. The initial steps include a clinical assessment focusing on recognising characteristic clinical features from a detailed history and examination combined with a careful review of possible alternative diagnoses. Since there is no gold standard for diagnosis, clinical evaluation can only give a probability that a given child has a diagnosis of asthma. If the probability of asthma is high, the next step is frequently a trial of anti-asthma treatment, usually a low-dose of an inhaled corticosteroid and a bronchodilator. Fairly to respond to a properly taken anti-asthma treatment suggests an alternative diagnosis. If the probability is low, a diagnosis other than asthma may be suspected. Then further investigation and specialist referral may be indicated. In those with an intermediate probability tests of lung function (expiratory airway obstruction, bronchial reversibility and occasionally bronchial hyperreactivity), and tests for atopy may be helpful.

In contrast to the adult population, many medicines used in children with asthma have been inadequately studied with the result that evidence for their usage is lacking. Short-acting bronchodilators and inhaled corticosteroids have been available for over 40 years and thankfully, evidence for their usage in children is now relatively good. This is not the case for long-acting bronchodilators, leukotriene receptor antagonists and omalizumab. This article discusses currently available evidence on all aspects of treatment relevant to children and offers comments on possible future trends. The development of national and international children's research networks throughout Europe and beyond should enable robust studies to be undertaken to fill our evidence gap and improve control of asthma in all ages of children.

Current monitoring of childhood asthma focuses on the level of asthma control and reduction of future risk to the patient. However, guidelines are not clear in their recommendations on the best strategy to monitor asthmatic children. As asthma is a heterogeneous disease with symptoms, airways obstruction, airways hyperresponsiveness and chronic inflammation as the principal components, no single outcome measure can be expected to adequately assess asthma control. To determine the level of control, standardized questionnaires like the asthma control test (ACT), asthma control questionnaire (ACQ) and asthma therapy assessment questionnaire (ATAQ) may be used. Whether the use of such questionnaires actually improves asthma control remains to be shown. Spirometry and measurement of reversibility are recommended at least once per year to assess control and future risk. There is no need for bronchoprovocation testing as a routine monitoring tool in childhood asthma, but airway hyperresponsiveness might be important in estimating future risk. The fraction of nitric oxide in exhaled air (FENO) reflects eosinophilic airway inflammation. Recent studies only showed modest effects on asthma outcomes as a result of FENO monitoring in children.

This review is divided into two parts. The first part discusses an approach to the management of adolescents with asthma and provides practical tips for health professionals to enable them to work more effectively with this group. The second part focuses more specifically on the latest literature relating to asthma in adolescence, highlighting relevant articles which address the epidemiology, diagnosis and management of adolescent asthma. Key points: • It is important to spend time with adolescents to develop rapport and to find out how asthma fits in with the rest of their life. • Time should be spent seeing adolescents on their own, separate from their parents, with some assurance of confidentiality given. • Consultations should include discussions of adherence to treatment, self-management, health risk behaviours and mood. • Paediatricians should help adolescents to prepare for the transition from paediatric to adult care.

Children with problematic asthma represent about 0.5% of the population but consume a disproportionate amount of healthcare staff time and resources. The most important step in managing children with problematic asthma is differentiating those with genuine severe, therapy resistant disease from those who have difficult to treat asthma for a variety of other remediable factors. The most common causes of poor symptom control are poor adherence to therapy, ongoing exposure to sensitized allergens or co-morbid psychosocial problems. In up to half of the children with problematic asthma, addressing these simple factors can avoid further escalation of treatment or more invasive investigation. All asthmatic children with poor control despite treatment with ≥ 800μg of inhaled budesonide (or equivalent) should be referred to a paediatric respiratory specialist for evaluation. Management of children with problematic asthma, and particularly those with genuine severe therapy resistant disease, requires a stepwise multidisciplinary approach.

When initiating oral feedings, many preterm infants, compared to term newborns, have difficulty coordinating swallowing and breathing, making them at increased risk for aspiration. These are major clinical challenges that may prolong the Neonatal Intensive Care Unit (NICU) stay for otherwise healthy preterm infants. This review explores the impact of preterm birth on oral feeding and the development of a functional swallowing pump consisting of the brain, the multifunctional tongue and pharynx, and other oral structures. It also further examines the challenges preterm infants face coordinating swallowing with respiration. These issues present clinicians with assessment and treatment challenges.