Longer Term Sequelae of Prematurity: The Adolescent and Young Adult

Pathophysiological Mechanisms of Asthma

The recent Lancet commission has highlighted that "asthma" should be used to describe a clinical syndrome of wheeze, breathlessness, chest tightness, and sometimes cough. The next step is to deconstruct the airway into components of fixed and variable airflow obstruction, inflammation, infection and altered cough reflex, setting the airway disease in the context of extra-pulmonary co-morbidities and social and environmental factors. The emphasis is always on delineating treatable traits, including variable airflow obstruction caused by airway smooth muscle constriction (treated with short- and long-acting β-2 agonists), eosinophilic airway inflammation (treated with inhaled corticosteroids) and chronic bacterial infection (treated with antibiotics with benefit if it is driving the disease). It is also important not to over-treat the untreatable, such as fixed airflow obstruction. These can all be determined using simple, non-invasive tests such as spirometry before and after acute administration of a bronchodilator (reversible airflow obstruction); peripheral blood eosinophil count, induced sputum, exhaled nitric oxide (airway eosinophilia); and sputum or cough swab culture (bacterial infection). Additionally, the pathophysiology of risk domains must be considered: these are risk of an asthma attack, risk of poor airway growth, and in pre-school children, risk of progression to eosinophilic school age asthma. Phenotyping the airway will allow more precise diagnosis and targeted treatment, but it is important to move to endotypes, especially in the era of increasing numbers of biologicals. Advances in -omics technology allow delineation of pathways, which will be particularly important in TH2 low eosinophilic asthma, and also pauci-inflammatory disease. It is very important to appreciate the difficulties of cluster analysis; a patient may have eosinophilic airway disease because of a steroid resistant endotype, because of non-adherence to basic treatment, and a surge in environmental allergen burden. Sophisticated -omics approaches will be reviewed in this manuscript, but currently they are not being used in clinical practice. However, even while they are being evaluated, management of the asthmas can and should be improved by considering the pathophysiologies of the different airway diseases lumped under that umbrella term, using simple, non-invasive tests which are readily available, and treating accordingly.

Management of asthma in children

This manuscript takes a challenging look at the management of asthma in childhood, in particular in the light of the recent Lancet commission. One of the central pillars of the Commission is the need to deliver personalized medicine for airway disease by deconstructing the airway into components of fixed and variable airflow obstruction, inflammation and infection. Before any treatment for asthma, a diagnostic workup is essential to exclude other conditions. A diagnosis of asthma needs to be based on objective evidence of bronchodilator sensitive variable airflow obstruction, eosinophilic airway inflammation and atopy. Most children with atopic asthma respond to low dose inhaled corticosteroids, sometimes requiring a long acting β-agonist. If the response is unsatisfactory, then, rather than escalate treatment, an approach for which there is little evidence, a full review of the child should be undertaken, including extrapulmonary comorbidities, adherence and adverse environmental influences. If these cannot or will not be addressed by the family, then further treatment including biologicals may be indicated. Asthma attacks are an important warning sign and should always be taken seriously, including a focused reassessment of all aspects of the management of the child. Finally, preschool children with wheeze can also be evaluated for eosinophilic airway inflammation using peripheral blood eosinophil count as a surrogate. It is essential that we start to deliver personalized medicine to children with airway disease.