SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS – SSTRSDO-QAA 006
1. What is emphysema?
Emphysema is a chronic lung disease characterized by
permanent enlargement of airspaces distal to the terminal bronchioles with
destruction of alveolar walls and minimal fibrosis. It results in loss of
elastic recoil and impaired expiration.
Cigarette smoking is the commonest cause. Alpha-1 antitrypsin
deficiency causes hereditary emphysema, especially in younger individuals.
Destruction of alveolar septa reduces the surface area
available for gas exchange. Small airways collapse during expiration, causing
airflow obstruction and air trapping.
The lungs become hyperinflated and less efficient. Patients
experience progressive exertional dyspnea. Emphysema is a major component of
COPD.
2. What
are the main characteristics of different types of emphysema?
The Centriacinar emphysema mainly involves the respiratory
bronchioles and predominantly affects the upper lobes. It is strongly
associated with cigarette smoking. Panacinar emphysema involves the entire
acinus uniformly and mainly affects the lower lobes.
It is commonly associated with alpha-1 antitrypsin
deficiency. Distal acinar (paraseptal) emphysema affects the distal acinus near
the pleura and interlobular septa. It predisposes to spontaneous pneumothorax
in young adults. Irregular emphysema is associated with scarring from previous
lung injury.
Centriacinar emphysema is the commonest type encountered clinically. The extent of alveolar destruction determines the severity of respiratory impairment.
3. Describe the main clinical symptoms of emphysema.
Progressive exertional dyspnea is the most prominent symptom
of emphysema. Patients often have minimal cough with scanty sputum production.
Expiration becomes prolonged because of airflow obstruction. The chest becomes
barrel-shaped due to lung hyperinflation. Accessory respiratory muscles are
used during breathing. Patients frequently breathe through pursed lips to
prevent airway collapse.
Breath sounds are diminished, and wheezing may be present.
Weight loss and muscle wasting occur in advanced disease.
Hypoxemia develops late, while carbon dioxide retention
appears in severe stages. Respiratory failure may eventually occur.
PROFESSOR OF MEDICINE
No comments:
Post a Comment