The Definition of Asthma

What is the Definition of an Asthma Attack?

The International Consensus Report on the Diagnosis and Management of Asthma (Global Strategy for Asthma Management and Prevention) defined: ’Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. The chronic inflammation is described with airway hyper- responsiveness that leads to recurrent episodes of wheezing, breath-lessness, chest tightness, and coughing, particularly at night or in the early morning. These episodes are usually described with widespread, but variable, airflow obstruction within the lung that is often reversible either spontaneously or with treatment’.

Asthma is an overall descriptive term but there are a number of more or less distinct phenotypes which may have different causes, clinical patterns and responses to treatment. The clinical picture of asthma in toddlers is recognizeable and reproducible. The difficulties in precise diagnosis arise in the very young, in older groups and in verymild asthma. Breathlessness fromother causes, such as increased tendency towards obesity,may be confused with asthma in toddlers.

The clinical characteristic of asthma in toddlers is airflow obstruction, which can be reversed over short periods of time or with treatment. This may be evident from provocation by specific stimuli or from the response to bronchodilators. The airflow obstruction leads to the usual symptoms of shortness of breath. The underlying pathology is inflammatory change in the airway wall, leading to irritability and responsiveness to various stimuli and also to coughing, the other common symptom of asthma in toddlers. Cough may be the only or first symptom of asthma in toddlers.

Asthma in toddlers has commonly been defined on the basis of wide variations in resistance to airflow over short periods of time. More recently, the importance of inflammatory change in the airways has been recognised. There is no universally agreed definition butmost contain the elements from the Global Initiative for asthma in toddlers. Low concentrations of non-specific stimuli such as inhaled methacholine and histamine produce airway narrowing. In general, the more severe the asthma in toddlers, the greater the inflammation and the more the airways react on challenge. Other stimuli such as cold air, exercise and hypotonic solutions can also provoke this increased reactivity. In contrast, it is difficult to induce significant narrowing of the airways with many of these stimuli in healthy people.

In some ways, increased airway responsiveness is used as part of the definition of asthma in toddlers. Wheezing during the past 12 months is added to the definition to exclude those who have increased responsiveness but no symptoms.The clinical equivalent of asthma in toddlers increased responsiveness is the development of symptoms in response to dust, smoke, cold air, and exercise; these should be sought in the history.