SPECIAL SELECTED TOPICS- RESPIRATORY SYSTEM DISORDERS-SSTRSDO-QAA 005
1. What
are the main differences between obstructive and restrictive lung disease?
Obstructive lung diseases are characterized by increased
resistance to airflow due to narrowing or obstruction of the airways. Examples
include COPD, emphysema, chronic bronchitis, bronchial asthma, and
bronchiectasis.
Expiration is prolonged, and the FEV₁/FVC ratio is reduced.
Restrictive lung diseases are characterized by reduced lung expansion because
of decreased lung compliance or chest wall abnormalities. Examples include
interstitial lung disease, pulmonary fibrosis, sarcoidosis, and pneumoconiosis.
Total lung capacity and vital capacity are reduced, while the
FEV₁/FVC ratio is usually normal or increased. Obstructive diseases mainly
impair airflow, whereas restrictive diseases mainly reduce lung volume.
Dyspnea occurs in both conditions, but hyperinflation is
typical of obstructive disease. Pulmonary fibrosis is characteristic of
restrictive disorders.
2. Define
Chronic Obstructive Pulmonary Disease (COPD).
Chronic Obstructive Pulmonary Disease (COPD) is a chronic,
progressive respiratory disorder characterized by persistent airflow limitation
that is not fully reversible. It results from chronic inflammation of the
airways and destruction of lung parenchyma.
The major components are chronic bronchitis and emphysema.
Cigarette smoking is the principal risk factor worldwide. Other causes include
biomass fuel exposure, air pollution, occupational dust, and alpha-1
antitrypsin deficiency. Patients present with chronic cough, sputum production,
exertional dyspnea, and wheezing.
Airflow obstruction gradually worsens over time.
Exacerbations accelerate disease progression and reduce quality of life. COPD
is a leading cause of disability and death globally.
3. What
are the main differences between various types of COPD?
COPD mainly includes chronic bronchitis and emphysema,
although many patients have features of both. Chronic bronchitis is
characterized by chronic productive cough due to mucus hypersecretion and
airway inflammation.
Emphysema is characterized by permanent enlargement of
airspaces with destruction of alveolar walls. Chronic bronchitis predominantly
affects the bronchi, whereas emphysema primarily affects the alveoli. Airway
obstruction in bronchitis results mainly from mucus plugging and inflammation.
In emphysema, airflow limitation results from loss of elastic recoil and airway
collapse.
Cyanosis is more common in chronic bronchitis, while marked
dyspnea is typical of emphysema. Pulmonary hypertension develops earlier in
chronic bronchitis. Mixed clinical features are frequently encountered in
advanced COPD.
DR.C.GANESAN M.D
PROFESSOR OF MEDICINE
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