Asthma is a respiratory disease caused by narrowing and inflammation of airways in the lung. It impedes air flow especially during expiration thus make a person to breathe difficultly.
It has symptoms such as shortness of breath, cough, and wheezes. In rare cases such as severe crisis, the patient may also present with chest tightness. It is difficult to provide a definition of asthma that distinguishes it from similar and overlapping conditions. It does not have a definitive laboratory test neither bio-marker.
Some experts sat down and proposed a more precise definition of being “a common chronic airway disorder that is complex and characterized by airway obstruction, bronchial hyper responsiveness and underlying inflammation” This definition encompasses descriptive key features of the disease though it lacks utility for patients and clinicians, as long as it fails to differentiate it from other airway inflammatory disorders such as chronic bronchitis and bronchiolitis.
Clinical symptoms in a patient with asthma are cough especially at night, wheeze and shortness of breath. Some triggers such as allergens, exercise and viral infection may be reported through patient’s history. These symptoms are recurring and variable in severity from one person to another as it is from one time to another in the same individual. Because symptoms of asthma can be present in other diseases, it is somehow difficult to be certain about a diagnosis hence it is advised to go deeper in history of the disease to unveil some key features of symptoms and triggers. For instance, asthma has episodic symptoms which come and go for hours to days, resolving spontaneously after removing trigger stimulus or administration of anti-histaminic medications. Most common cases have triggering agents that are too rare to miss such as cold air, exercise, dust, stress, inhaled allergens and all are suggestive of asthma. Some allergens may be mites, molds, furry animals, cockroaches, and pollens. Food allergens in asthmatic cases are very rare in absence of simultaneous presentation of angioedema, urticaria, hypotension or gastrointestinal distress. There are some types of asthma called occupational asthma which is mainly work-related exposure where 10% of new-onset asthmatic cases in adult are due workplace related exposure. A positive family history for asthma is also a key that favors a diagnosis of the latter. Globally there is no age limit for asthma, it can start in childhood as it can in adulthood.
In clinic, physical findings of asthmatic patient may include widespread, high-pitched and musical wheezes on expiration. In severe cases, rapid heart rate, rapid respiratory rate, prolonged expiratory phase compared to inspiration phase, use of the accessory muscles of breathing (eg: muscles of the neck). Importantly the absence of wheeze in asthma is a poor predictor of severe airflow obstruction. Laboratory evaluation predominantly focuses on testing pulmonary functions by using spirometry. A patient has to give one forceful and complete exhalation in a spirometer which will give information on forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). The measurement will help in the diagnosis of asthma. Some other laboratory tests such as chest radiography, full blood count, allergy tests are useful in selected patients for asthma diagnosis.
Prevention of asthma is to avoid triggers and to increase intakes of fresh fruit and vegetables have been shown to be protective, possibly owing to the increased intake of antioxidants. Genetic variation in antioxidant enzymes is associated with more severe asthma, no vaccine has ever been used. Treatment of asthma depends on severity of the disease but in acute asthmatic attack, the management should include: Putting a patient in a semi-sitting position, administration of oxygen in case O2 Saturation is less than 90 %, bronchodilators ( eg: Salbutamol inhalers) and Steroids ( eg: intravenous hydrocortisone ). Avoidance of triggering agent if known is a cornerstone in management of asthmatic attack. Patient should be educated on medication and other strategies. In current practice sedatives and aminophylline are not recommended.
Dos and Don’ts in asthmatic patient
Non-steroidal anti-inflammatory drugs such as aspirin, indomethacin and some others induce precipitation of new asthmatic attacks so they are contraindicated
Beta-blockers (eg: Atenolol, labetalol...) are contra-indicated because they cause bronchoconstriction in an already bronchoconstriced airways
Avoid cold air, dusts, excessive exercise, air pollution, vapors and fumes
Kumar & Clark, clinical medicine 6th Edition
Harrison’s internal medicine 17th Edition
Authored by Dr Felix MUSABIREMA, MD Deputy Medical officer at United Nations in North America, Port-au-Prince, HAITI.
Wilson04 March 2019 18:20