Chronic Obstructive Pulmonary Disease (COPD) PDF

CHRONIC OBSTRUCTIVE PULMONARY DISEASE “COPD” Mohamad Osama Aloukda Professor of Pathology April 10th 2023  Objectives Generally understand the nature of obstructive airway disease (bronchitis, bronchiolitis & emphysema) and differentiate from relate...

CHRONIC OBSTRUCTIVE PULMONARY DISEASE “COPD” Mohamad Osama Aloukda Professor of Pathology April 10th 2023  Objectives Generally understand the nature of obstructive airway disease (bronchitis, bronchiolitis & emphysema) and differentiate from related bronchial disorders namely, asthma & bronchiectasis Specifically: 1. Define COPD, explain the role of smoking in relation to COPD 2. Define chronic bronchitis & characterize its pathologic changes 3. Define emphysema & describe its etiology & structural changes 4. Define bronchiectasis & outline its pathologic features 5. Explain mechanism of bronchial asthma & describe the characteristic pathological features, how it differs from COPD 6. List the clinico-pathological differences between the main types of bronchial asthma (extrinsic & intrinsic) 7. Outline the complications of each of the above mentioned conditions 2  Definition COPD is a common prolonged morbid respiratory condition characterized by persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways and the lung in response to irritation by smoke or noxious particles and gases.  Clinical Picture of COPD Productive Cough Wheezes Chest pain Difficult breathing (dyspnoea) Cyanosis Hypoxia Easy fatigability Bouts of acute respiratory infections COPD includes the following diseases: Chronic bronchitis, emphysema, bronchiectasis, and “some” bronchial asthma patients They are characterized by reduced air flow especially during expiration and with entrapment of air in distal lung passages, resulting in hypoxemia, and hypercapnia , reduced forced expiratory volume to less than 30% and reduced FEV1/FVC to < 75% and reduced vital capacity ‘VC’. 5  Characteristics of COPD prolonged course partial or complete obstruction to the airflow at any level from trachea Expiratory difficulty Diffuse affection of both lungs Inflammatory “irritative” component Link to smoking  Two groups of Pulmonary Diseases affecting air flow & leading to dyspnoea  Chronic bronchitis common & prevalent condition defined clinically as persistent cough with expectoration on most days for at least three months of the year for two or more consecutive years  CLINICAL FEATURES Some important features of ‘predominant bronchitis’ are : 1. Persistent cough with copious expectoration of long duration; initially beginning in a heavy smoker with ‘morning catarrh’ or ‘throat clearing’ which worsens in winter. 2. Recurrent respiratory infections are common. 3. Dyspnoea is generally not prominent at rest but is more on exertion.  Causes of Chronic bronchitis 1. Recurring Infection: Pneumococci “Strept. Pneumoniae” Viruses Ricketssia Mycoplasma 2. Smoking 3. Fumes (gases, dust, etc), urban contamination 4. Occupational irritants 10  Pathogenesis of Chronic Bronchitis Epithelial damage with or without infection (on top of smoking injury) release of cytokines  polymorphnuclear & mononuclear cellular infiltrate (inc. CD8+ cells) Inflammation, fibrosis, mucous glandular hyperplasia & hypersecretion & smooth muscle changes 11  Morphology Grossly: - Thickened hyperaemic edematous bronchial walls - Lumina of the bronchi & bronchioles may contain mucus plugs & purulent exudate - Mucosal focal necrosis & hemorrhages - Pearly whitish fibrous bands around bronchioles (peribronchioloitis) with prolonged course 13 Microscopically: 1. Hyperemia & edema of mucus membranes 2. Mucinous secretions filling airways. 3. Increase in size of mucous glands (hyperplasia) 4. Bronchial or bronchiolar mucous plugging, inflammation & fibrosis in “prolonged course” 5. Loss of epithelial cilia, squamous metaplasia or dysplasia or carcinoma in situ of bronchial epithelium (acc. to duration & severity) 6. Smokers with both symptoms of chronic bronchitis and chronic airflow limitation have an increased number of goblet cells and inflammatory cells in the epithelium of peripheral airways. 7. Smooth muscle hyperplasia Chronic bronchitis: microscopic features 15  Reid Index Ratio of the thickness of mucous gland layer to thickness of the wall between the epithelium and cartilage is known as the Reid Index. Normal Reid index is