• Emphysema is defined pathologically as Dilatation and destruction of the lung tissue distal to the terminal bronchioles
Emphysema classified according to site of damage : • Centri-acinar emphysema :Distension and damage of lung tissue is concentrated around the respiratory bronchioles,whilst the more distal alveolar ducts and alveoli tend to be well preserved.This form of emphysema is extremely common;when of modest extent,it is not necessarily associated with disability.
• Pan-acinar emphysema :. This is less common.Here,distension and destruction appear to involve the whole of the acinus,and in the extreme form the lung becomes a mass of bullae. Severe airflow limitation and VA/Q mismatch occur. • Occurs in alpha1-antitrypsin deficiency
Irregular emphysema :There is scarring and damage affecting the lung parenchyma patchily without particular regard for acinar structure.
Clinical observations led to suggestions that there were two distinct type of patients
TYPE-A fighter is pink and puffing. Although the person is breathless,arterial tensions of oxygen and carbon dioxide are normal and there is no cor pulmonale .These individuals were thought to be suffering predominantly from emphysema with little emphysema.
TYPE-B non-fighter,on the other hand,is blue and bloated . The person does not appear to be breathless but has marked arterial hypoxemia,carbon dioxide retention,secondary polycythemia and cor pulmonale.these patients were thought to be suffering predominantly from chronic bronchitis.
LUNG FNCTION TESTS : show evidence of airflow limitation. The ratio of FEV 1 to FVC is reduced and PEFR is low. Lung volumes may be normal or increased, and the gas transfer coefficient of CO is low when significant emphysema is present.
Classification and diagnosis of copd Breathlessness, wheeze, cough prominent, swollen legs FEV 1 40% Severe exertional breathlessness+_wheeze, cough+_ sputum FEV 1 40-59% Moderate Smoker’s cough +_ exertional breathlessness FEV 1 60-90% Mild symptoms spirometry severity
CHEST X-RAY is often normal, even when the disease is advanced. Classic features are presence of bullae, severe overinflation of lungs with low, flattened diaphragms, a large retrosternal airspace on the lateral film.
Hb-LEVEL AND PCV can be elevated as a result of persistent hypoxemia.
BLOOD GASES are often normal. In the advanced case there is evidence of hypoxemia and hypercapnia .
SPUTUM examination unnecessary in ordinary cases.
ECG: In corpulmonale the P-wave is taller (P-pulmonale)