CHAPTER 20 Respiratory Disorders
I. Asthma
A. Background
2. In people with asthma, the air passages within the lungs are constantly swollen, which restricts the amount of air that can pass through the trachea.
4. According to the American Lung Association, approximately 20 million Americans have asthma, which causes about 5000 deaths each year.
5. There is no cure for asthma, but many medications and lifestyle changes help manage the condition.
B. Classifications
1. There are various classifications of asthma. These conditions cause airway obstruction and inflammation that is partly reversible by medication. The symptoms are usually similar; however, the main difference is their cause.
a. Allergic (extrinsic) asthma
(1) An allergic reaction triggers allergic asthma, which is an immune system response that causes the airway to become inflamed.
(2) Inhaled allergens, such as dust mites, mold spores, pollen, and pet dander, may trigger allergic asthma.
C. Pathophysiology
1. Because asthma is an inflammatory process, several cells (mostly immune system–mediated cells) have been identified as playing a role in the disease process (Figure 20-1).
2. There are three major parts of the immune system response
b. Inflammatory cells
(2) Mast cells, which can be found in the lungs, mediate the inflammatory response that is triggered by IgE.
(3) The inflammatory eosinophil cells are closely associated with all types of asthma and can be found in various parts of the lungs and respiratory system.
D. Signs and symptoms
1. Asthma symptoms may appear at any time in life. Individuals who develop asthma as adults have adult-onset asthma. This condition may develop as late as age 50 or older. Unlike children, who usually experience intermittent symptoms, individuals with adult-onset asthma are more likely to experience persistent symptoms. The cause of adult-onset asthma is unknown. However, some evidence suggests that allergy and asthma may be genetically determined. In addition, obesity, which has both genetic and environmental influences, appears to significantly increase the risk of developing asthma in adulthood. The following symptoms may occur in any age group, unless otherwise noted.
a. Bronchospasm (abnormal contraction of the bronchi, which obstructs the airway), coughing (constant or intermittent)
E. Diagnosis
F. Treatment
1. Short-term relief: bronchodilation
a. Beta-2 adrenoceptor agonists
(5) Short-acting: used for quick relief of asthma symptoms
2. Long-term control: anti-inflammatory medications (asthma “controllers”)
b. Leukotriene inhibitors (Figure 20-3)
(1) Mechanism of action
(a) Inhibits leukotreine receptors by blocking 5-lipoxygenase activity. Examples: zafirlukast (Accolate), montelukast (Singulair)
II. Chronic Obstructive Pulmonary Disease
A. Background
1. Chronic obstructive pulmonary disease (COPD) is a type of lung disease that involves damage to or obstruction of the airways of the lungs, which makes it difficult to breathe. COPD is an overall term referring to a group of chronic lung conditions, including chronic bronchitis and emphysema and possibly asthma or asthmatic bronchitis. Although chronic bronchitis and emphysema may occur separately, it is common for patients to have both diseases simultaneously.
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