Asthma is a chronic condition affecting populations around the world. Public attention has recently focused on this condition because its prevalence and the associated mortality rate have increased over the last several decades. While familial aggregation is observed, no clear pattern of segregation can be discerned. Most likely, there are multiple genetic, developmental, and environmental factors which interact to produce the overall condition.
Asthma is a complex disease characterized by bronchial hyperresponsiveness (BHR), inflammation, and intermittent airway obstruction. A person with asthma may experience wheezing, shortness of breath, chest tightness and cough particularly after exposure to an allergen, cold air, exercise, or when emotional. Asthma is treated with drugs, whether inhaled or in the form of tablets, but there are lifestyle changes which can be used to reduce exacerbations.
Signs and symptoms
The main symptom of asthma is wheezing caused by obstruction of the airways. A cough, sometimes with clear sputum, may also be present. Typically the symptoms are very variable, often with rapid onset, and associated with the triggers listed above. In severe cases, symptoms can be worse during the night or upon waking. Asthma sometimes occurs with acid indigestion, especially amongst older patients.
Signs of asthma are wheezing, rapid breathing, expiratory phase of breathing longer than inspiratory, in-drawing of tissues between ribs and above sternum & clavicles, over-inflation of the chest and rhonchi (wheezy noises heard with a stethoscope). In severe attacks the asthma sufferer may be cyanosed (blue), may have chest pain and can lose consciousness. Between attacks a person with asthma may show no signs at all.
Diagnosis
In most cases the physician can make the diagnosis on the basis of typical symptoms and signs. The typical rapid changes in airway obstruction can be demonstrated by a fall in pulmonary function tests spontaneously, after exercise or inhalation of histamine or methacholine, and subsequent improvement with an inhaled bronchodilator medication.
Many people with asthma have allergies; positive allergy tests support a diagnosis of asthma and may help in identifying avoidable triggers. Some people with asthma have been diagnosed with gastroesophageal reflux disease (GERD) and immune related disorders including atopic dermatitis. Other tests (for example chest X-ray or chest CT scan) may be required to exclude other lung disease.
Common Respiratory Tract Infections
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