The respiratory distress that accompanies emphysema is caused by:
chronic stretching of the alveolar walls
massive constriction of the bronchiole
sacute fluid accumulation in the alveoli
repeated exposure to cigarette smoke
The Correct Answer and Explanation is :
Correct Answer:
Chronic stretching of the alveolar walls
Explanation:
Emphysema is a chronic lung condition that falls under chronic obstructive pulmonary disease (COPD). It primarily results from prolonged exposure to irritants, with cigarette smoke being the most common cause. However, the hallmark physiological change that leads to respiratory distress in emphysema is chronic stretching of the alveolar walls.
Pathophysiology of Emphysema:
- Destruction of Alveolar Walls
- In a healthy lung, alveoli are small air sacs where gas exchange occurs.
- In emphysema, harmful substances (like cigarette smoke) trigger an inflammatory response, releasing enzymes such as elastase.
- Elastase breaks down elastin, a protein that maintains the structural integrity of alveolar walls.
- Loss of Elastic Recoil
- Normal lungs have elastic fibers that allow alveoli to expand and contract efficiently during breathing.
- With emphysema, the destruction of these fibers causes the alveoli to become permanently enlarged and lose their elasticity.
- This leads to air trapping, making it difficult for a person to exhale completely.
- Impaired Gas Exchange
- Since alveoli are stretched and damaged, their surface area is reduced, leading to less oxygen absorption and inefficient carbon dioxide removal.
- This results in hypoxemia (low oxygen levels) and hypercapnia (high carbon dioxide levels), contributing to respiratory distress.
Why the Other Options Are Incorrect:
- Massive constriction of the bronchiole → More common in asthma or chronic bronchitis, not emphysema.
- Acute fluid accumulation in the alveoli → Seen in conditions like pneumonia or pulmonary edema, not emphysema.
- Repeated exposure to cigarette smoke → A major cause but not the direct reason for respiratory distress in emphysema.
Thus, the primary cause of respiratory distress in emphysema is chronic stretching of the alveolar walls, leading to inefficient lung function and difficulty in breathing.