Episodic or chronic symptoms of airflow obstruction: breathlessness, cough, wheezing and chest tightness. Asthma symptoms frequently get worse at night or in the early morning. Prolonged expiration and diffuse wheezes on physical examination. There is limitation of airflow on pulmonary function testing or positive bronchoprovacation challenge. There is Complete or partial reversibility of airflow obstruction, either spontaneously or following the bronchodilator therapy. Some Asthma patients have infrequent brief attacks of asthma and others may suffer nearly continuous breathing difficulty. Asthma symptoms may occur spontaneously or may be precipitated or exacerbated by many different asthma triggers. Occupational Asthma is triggered by various agents in the workplace and may occur weeks to years after initial exposure and sensitization.
This may be normal between the exacerbations in patients with mild asthma. Wheezing during normal breathing or a prolonged force expiratory phase correlates well with the presence of airflow obstruction.
Pulmonary Function Testing:
The evaluation of asthma includes spirometry before and after the administration of the short acting bronchodilator. Peak expiratory flow (PEF) meters are handheld devices designed as home monitoring tools. PEF monitoring can establish peak flow variability, quantify asthma severity, and provide both the asthma patients and the physician with objective measurements on which to base asthma treatment decisions. Bronchial Provocation testing with histamine or metheacholine-or exercise challenge testing may be useful when asthma is suspected and spirometry is non-diagnostic.
Biologic Asthma markers of inflammation such as cell counts and mediator titers in blood and sputum are being investigated. Skin testing or in vitro testing to assess sensitivity to relevant environmental allergens may be useful in patients with persistent asthma. Arterial blood gas measurements may be normal during a mild asthma exacerbation.
Lower airway disorders that mimic Asthma include non-asthmatic chronic obstructive pulmonary disease, chronic bronchitis or emphysema.