Asthma is a common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath.Classification
Asthma is clinically classified according to the frequency of symptoms, forced expiratory volume in 1 second (FEV), and peak expiratory flow rate. Asthma may also be classified as atopic (extrinsic) or non-atopic (intrinsic), based on whether symptoms are precipitated by allergens (atopic) or not (non-atopic).
While asthma is classified based on severity, at the moment there is no clear method for classifying different subgroups of asthma beyond this system. Within the classifications described above, although the cases of asthma respond to the same treatment differs, thus it is clear that the cases within a classification have significant differences. Finding ways to identify subgroups that respond well to different types of treatments is a current critical goal of asthma research.
Signs and symptoms
Common symptoms of asthma include wheezing, shortness of breath, chest tightness and coughing. Symptoms are often worse at night or in the early morning, or in response to exercise or cold air. Some people with asthma only rarely experience symptoms, usually in response to triggers, where as other may have marked persistent airflow obstruction.
Gastro-esophageal reflux disease
Gastro-esophageal reflux disease coexists with asthma in 80% of people with asthma, with similar symptoms. This is due to increased lung pressures, promoting bronchoconstriction, and through chronic aspiration.
Sleep Disorders
Due to altered anatomy of the respiratory tract: increased upper airway adipose deposition, altered pharynx skeletal morphology, and extension of the pharyngeal airway; leading to upper airway collapse.
Cause
Asthma is caused by environmental and genetic factors. These factors influence how severe asthma is and how well it responds to medication. The interaction is complex and not fully understood.
Diagnosis
There is currently not a precise physiologic, immunologic, or histologic test for diagnosing asthma. The diagnosis is usually made based on the pattern of symptoms (airways obstruction and hyper responsiveness) and/or response to therapy (partial or complete reversibility) over time.
Treatment
Treatment of acute symptoms is usually with an inhaled short-acting beta-2 agonist (such as salbutamol). Symptoms can be prevented by avoiding triggers, such as allergens and irritants, and by inhaling corticosteroids. Leukotriene antagonists are less effective than corticosteroids and thus less preferred. Prevention
The evidence for the effectiveness of measures to prevent the development of asthma is weak. Ones which show some promise include: limiting smoke exposure both in uterus and after delivery, breastfeeding, increased exposure to respiratory infection per the hygiene hypothesis (such as in those who attend daycare or are from large families).
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