Module 5
5.1: Introduction to Pulmonology
The main function of the respiratory system is two-fold: (1) to deliver oxygen to the cells of the body and (2) remove
carbon dioxide from the body. This is accomplished through the combination of the upper respiratory tract working in
communication with the lower respiratory tract. A diagram of the anatomy of the respiratory tract is shown in Figure 5.1.
The upper respiratory tract (URT) is outside the chest cavity and includes the nose, and nasopharynx (down to the
larynx). The lower respiratory tract (LRT) includes the organs within the chest including the trachea, bronchial tree, and
lungs. When a person breathes in air, oxygen diffuses across the alveoli (microscopic sacs) in the lungs where it is
exchanged for carbon dioxide. The diffused oxygen is then taken to the rest of the body through the circulatory system.
Figure 5.1 Anatomy of the Respiratory Tract. Above is a diagram of the anatomy of the respiratory tract broken down between the
Upper Respiratory Tract (URT) and the Lower Respiratory Tract (LRT).
There are several common diseases that affect the airways and this exchange of gas, the most common of which are
asthma and chronic obstructive pulmonary disease (COPD).
Asthma is the general term for recurrent and reversible shortness of breath resulting from the narrowing of the bronchi
and bronchioles.
COPD consists of both emphysema and chronic bronchitis.
Emphysema is a disease process involving inflammation of the alveoli.
Chronic Bronchitis is characterized by chronic inflammation or irritation on the lower respiratory tract, specifically the
bronchi.
The primary drugs used in the treatment of both asthma and COPD include bronchodilators and a variety of anti-
inflammatory and antiallergic agents.
Pathophysiology
All three of these diseases have one primary similarity in that they all involve obstruction of airflow through the airways.
Chemical Mediators are defined as a substance released from mast cells and white blood cells during inflammation and
allergic reactions. As such, chemical mediators are responsible for most of the symptoms and complications associated
with asthma and COPD. The only chemical mediator with a known involvement where drug therapy has been shown to
This study source was downloaded by 100000836551366 from CourseHero.com on 02-16-2022 08:52:08 GMT -06:00
https://www.coursehero.com/file/78909088/Pharmacology-Module-5docx/
, help patient symptoms is leukotrienes. Leukotrienes are potent bronchoconstrictors with a long duration of action. They
stimulate receptors responsible for bronchoconstriction, edema and other inflammatory actions. There is a class of drugs
called leukotriene inhibitors that inhibit these actions and have an important role in treating asthma specifically.
Asthma
The narrowing of the bronchioles can be caused by bronchospasm, inflammation, edema and the production of mucus.
This ultimately obstructs airflow meaning that the carbon dioxide cannot get out and the oxygen cannot get in.
There are different types of asthma. Some asthma is caused by outside factors such as allergens; this is often referred to
as allergic asthma. Conversely, intrinsic asthma is caused by unknown factors. In some cases, certain factors have
precipitated the asthma attack such as respiratory infections, stress, or cold weather. It is not fully understood why some
people seem to be predisposed to asthma attacks.
Emphysema
Emphysema occurs when the air spaces within the bronchioles enlarge as a result of the destruction of the alveolar
walls. As the alveolar walls are destroyed, there is less surface area available for oxygen and carbon dioxide exchange.
The cause of this appears to be enzymes that are released in response to inflammation. These enzymes are increased by
air pollution, tobacco smoke, and other irritants to the respiratory tract. Hyperinflation is the result of the air spaces
being enlarged. These patients have difficulty expelling air from the lungs. This results in a reduction in gas exchange and
the feeling of shortness of breath. Emphysema causes irreversible lung damage over time.
Chronic Bronchitis
Chronic irritation, usually from cigarette smoke or other environmental pollutants, can lead to chronic bronchitis. The
irritants cause mucus secretions to increase and thicken which can then begin to interfere with gas exchange within the
lungs. These patients often present with a chronic cough, difficulty breathing, and increased respiratory infections. Drug
therapy can provide relief, but it cannot reverse the damage.
Drug Therapy
Historically, the treatment of both asthma and COPD has centered around bronchodilation. Recently, there has been a
shift in focus to the anti-inflammatory component of treatment. Treatment still includes bronchodilators, so we will cover
both types of treatment since they are often used in combination. Table 5.1 provides a summary of the most common
treatment options used in asthma and COPD management.
Table 5.1 Asthma and COPD Treatment Options
Drug Class Select Examples Common Administration Use
Beta2 adrenergic agonist Short Acting Beta agonist Inhalation- inhaler or SABA- Rescue medication
(bronchodilators) (SABA)- albuterol, nebulizer LABA- long term controller
levalbuterol Asthma and COPD
Long acting Beta Agonists
(LABA)- salmeterol,
formoterol
Anticholinergic Ipratropium (Atrovent)- Inhalation- inhaler or Prevention of
(bronchodilators) short acting nebulizer bronchospasm associated
Tiotropium (Spiriva)- long with COPD
acting Can also be used when
additional bronchodilation
in asthma is needed
Xanthine derived Theophylline Tablet Asthma and COPD
bronchodilator
This study source was downloaded by 100000836551366 from CourseHero.com on 02-16-2022 08:52:08 GMT -06:00
https://www.coursehero.com/file/78909088/Pharmacology-Module-5docx/
5.1: Introduction to Pulmonology
The main function of the respiratory system is two-fold: (1) to deliver oxygen to the cells of the body and (2) remove
carbon dioxide from the body. This is accomplished through the combination of the upper respiratory tract working in
communication with the lower respiratory tract. A diagram of the anatomy of the respiratory tract is shown in Figure 5.1.
The upper respiratory tract (URT) is outside the chest cavity and includes the nose, and nasopharynx (down to the
larynx). The lower respiratory tract (LRT) includes the organs within the chest including the trachea, bronchial tree, and
lungs. When a person breathes in air, oxygen diffuses across the alveoli (microscopic sacs) in the lungs where it is
exchanged for carbon dioxide. The diffused oxygen is then taken to the rest of the body through the circulatory system.
Figure 5.1 Anatomy of the Respiratory Tract. Above is a diagram of the anatomy of the respiratory tract broken down between the
Upper Respiratory Tract (URT) and the Lower Respiratory Tract (LRT).
There are several common diseases that affect the airways and this exchange of gas, the most common of which are
asthma and chronic obstructive pulmonary disease (COPD).
Asthma is the general term for recurrent and reversible shortness of breath resulting from the narrowing of the bronchi
and bronchioles.
COPD consists of both emphysema and chronic bronchitis.
Emphysema is a disease process involving inflammation of the alveoli.
Chronic Bronchitis is characterized by chronic inflammation or irritation on the lower respiratory tract, specifically the
bronchi.
The primary drugs used in the treatment of both asthma and COPD include bronchodilators and a variety of anti-
inflammatory and antiallergic agents.
Pathophysiology
All three of these diseases have one primary similarity in that they all involve obstruction of airflow through the airways.
Chemical Mediators are defined as a substance released from mast cells and white blood cells during inflammation and
allergic reactions. As such, chemical mediators are responsible for most of the symptoms and complications associated
with asthma and COPD. The only chemical mediator with a known involvement where drug therapy has been shown to
This study source was downloaded by 100000836551366 from CourseHero.com on 02-16-2022 08:52:08 GMT -06:00
https://www.coursehero.com/file/78909088/Pharmacology-Module-5docx/
, help patient symptoms is leukotrienes. Leukotrienes are potent bronchoconstrictors with a long duration of action. They
stimulate receptors responsible for bronchoconstriction, edema and other inflammatory actions. There is a class of drugs
called leukotriene inhibitors that inhibit these actions and have an important role in treating asthma specifically.
Asthma
The narrowing of the bronchioles can be caused by bronchospasm, inflammation, edema and the production of mucus.
This ultimately obstructs airflow meaning that the carbon dioxide cannot get out and the oxygen cannot get in.
There are different types of asthma. Some asthma is caused by outside factors such as allergens; this is often referred to
as allergic asthma. Conversely, intrinsic asthma is caused by unknown factors. In some cases, certain factors have
precipitated the asthma attack such as respiratory infections, stress, or cold weather. It is not fully understood why some
people seem to be predisposed to asthma attacks.
Emphysema
Emphysema occurs when the air spaces within the bronchioles enlarge as a result of the destruction of the alveolar
walls. As the alveolar walls are destroyed, there is less surface area available for oxygen and carbon dioxide exchange.
The cause of this appears to be enzymes that are released in response to inflammation. These enzymes are increased by
air pollution, tobacco smoke, and other irritants to the respiratory tract. Hyperinflation is the result of the air spaces
being enlarged. These patients have difficulty expelling air from the lungs. This results in a reduction in gas exchange and
the feeling of shortness of breath. Emphysema causes irreversible lung damage over time.
Chronic Bronchitis
Chronic irritation, usually from cigarette smoke or other environmental pollutants, can lead to chronic bronchitis. The
irritants cause mucus secretions to increase and thicken which can then begin to interfere with gas exchange within the
lungs. These patients often present with a chronic cough, difficulty breathing, and increased respiratory infections. Drug
therapy can provide relief, but it cannot reverse the damage.
Drug Therapy
Historically, the treatment of both asthma and COPD has centered around bronchodilation. Recently, there has been a
shift in focus to the anti-inflammatory component of treatment. Treatment still includes bronchodilators, so we will cover
both types of treatment since they are often used in combination. Table 5.1 provides a summary of the most common
treatment options used in asthma and COPD management.
Table 5.1 Asthma and COPD Treatment Options
Drug Class Select Examples Common Administration Use
Beta2 adrenergic agonist Short Acting Beta agonist Inhalation- inhaler or SABA- Rescue medication
(bronchodilators) (SABA)- albuterol, nebulizer LABA- long term controller
levalbuterol Asthma and COPD
Long acting Beta Agonists
(LABA)- salmeterol,
formoterol
Anticholinergic Ipratropium (Atrovent)- Inhalation- inhaler or Prevention of
(bronchodilators) short acting nebulizer bronchospasm associated
Tiotropium (Spiriva)- long with COPD
acting Can also be used when
additional bronchodilation
in asthma is needed
Xanthine derived Theophylline Tablet Asthma and COPD
bronchodilator
This study source was downloaded by 100000836551366 from CourseHero.com on 02-16-2022 08:52:08 GMT -06:00
https://www.coursehero.com/file/78909088/Pharmacology-Module-5docx/
