Chronic obstructive pulmonary disorder (COPD)
Objectives
At the end of this PDF Notes, student will be able to
• Define COPD
• Explain the pathophysiology of COPD
• Describe the symptoms of COPD
Chronic Obstructive Pulmonary Disease (COPD)
“A chronic slowly progressing disorder characterized by air flow obstruction leading to reduced pulmonary inspiratory & expiratory capacity”
• Disease may co-exist with asthma
Two major forms of COPD
• Chronic bronchitis
• Emphysema
Chronic bronchitis
• Characterized by excessive mucus production by the tracheo-bronchial followed by edema & bronchial inflammation leading to airway obstruction
• It is associated with cigarette smoking & air pollution
Pathogenesis of chronic bronchitis
Two pathological processes underlining the development of chronic bronchitis include
1. Hypersecretory disorder
• Characterized by expectoration with increased susceptibility to respiratory infections
• Normally, cilia & mucus in the bronchi protect against inhaled irritants which are trapped and expectorated
• Persistent irritation causes proliferation of mucus secreting glands & goblet cells in the bronchial epithelium leading to hypersecretion of thick & viscous mucus
• Accumulation of mucus inturn causes inflammation and recurrent viral & bacterial infections
2. Chronic inflammation & edema causes thickening of bronchio & alveolar walls
• Alveoli gets distorted, affects blood vessels closely associated with them, leading to vasoconstriction and pulmonary hypertension
• Reduction of gas exchange across alveolar epithelium – hypoxemia
• Sustained pulmonary hypertension – increased right ventricular pressure within heart, right ventricular hypertrophy and failure
• Pulmonary edema results followed by activation of renin angiotensin, aldosterone system, salt & water retention – reduction in renal blood flow
Emphysema
• Condition of permanent destructive enlargement of respiratory bronchioles, alveolar ducts & alveolar sac
• Adjacent alveoli becomes indistinguishable from one another
2 main consequence of emphysema
• Loss of available gas space & impaired gas exchange
• Loss of elastic recoil in the small airways leading them to collapse during expiration
Pathogenesis of emphysema
Arise as a consequence of 2 critical imbalances
- Protease – antiprotease imbalance
- Oxidant – antioxidant imbalance
Protease – anti protease theory
• Emphysema results from gradual progressive loss of elastic tissue in lungs due to an imbalance between proteolytic enzymes & protective factors
• Macrophages & neutrophills releases lysosomal enzymes (elastase) – capable of destroying connective tissue in the lungs
• Normal condition – protective mechanism called α1 – anti trypsin or α1 – protease inhibitor inhibits proteolytic enzyme and prevent damage
• α1 – anti trypsin is present in serum, tissue fluids & macrophages
• Deficiency of α1 – anti trypsin causes destruction of elastic tissue leading to emphysema
Oxidant – antioxidant imbalance
• Normally lungs contains anti oxidants like SOD, glutathione – reduces oxidative damage
• Tobacco smoke, activated neutrophills – increases oxygen free radicals – depletes antioxidant mechanism – tissue damage
• Inactivation of antiproteases, functional deficiency without enzyme deficiency
Symptoms of COPD
• Chronic cough ( after 20 or > cigarettes/day)
• Dyspnea (during physical activity and rest)
• Frequent respiratory infections
• Production of purulent sputum
• Bluish discoloration of lips and nail beds
• Morning headaches
• Wheezing
• Weight loss
• Pulmonary hypertension
• Peripheral oedema
• Hemoptysis
Summary
• COPD is the most prevalent manifestation of obstructive lung disease, mainly comprises chronic bronchitis and emphysema
• Reduction of overall personal exposure to tobacco smoke, occupational dusts, chemicals and pollutants is an important goal to prevent the onset and progression of COPD
• Risk factors for COPD include host factors (a, -antitrypsin deficiency and airway hyperresponsiveness) and exposures (tobacco smoke, occupational dusts and chemicals, indoor and outdoor pollutants, infections) and socio-economic status
COPD FAQ
Q1: What is COPD? COPD, or Chronic Obstructive Pulmonary Disorder, is a chronic lung disease characterized by persistent airflow limitation that makes it difficult to breathe. It typically includes chronic bronchitis and emphysema.
Q2: What are the main causes of COPD? COPD is primarily caused by long-term exposure to irritants, with cigarette smoke being the leading cause. Other factors can include occupational dust and chemicals, air pollution, and genetic predisposition.
Q3: What are the common symptoms of COPD? Common symptoms include chronic cough, excessive mucus production, shortness of breath (especially during physical activity), wheezing, and chest tightness.
Q4: Is COPD a progressive disease, and how does it progress? Yes, COPD is generally a progressive disease. Over time, the airways become more obstructed, and lung function declines, leading to increased symptoms and decreased lung capacity.
Q5: How is COPD diagnosed? COPD is diagnosed through a combination of medical history, physical examination, lung function tests (spirometry), and imaging studies (chest X-rays or CT scans).
Q6: What are the stages of COPD, and how are they determined? COPD is typically categorized into stages (I to IV) based on the severity of airflow limitation, as measured by spirometry. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) provides guidelines for staging.
Q7: What is the main treatment for COPD? The mainstays of COPD treatment include lifestyle changes (smoking cessation, exercise, and a healthy diet), bronchodilator medications, inhaled corticosteroids, oxygen therapy, and, in severe cases, surgery (such as lung volume reduction or lung transplantation).
Q8: Can COPD be prevented or its progression slowed down? While COPD is not entirely preventable, lifestyle changes, especially quitting smoking, can help prevent the disease from developing. Early diagnosis and appropriate management can also slow down its progression.
Q9: Are there any complications associated with COPD? COPD can lead to various complications, including respiratory infections, pulmonary hypertension, heart problems, and a higher risk of lung cancer. It can also impact a person’s quality of life and daily activities.
Q10: How can individuals with COPD manage their condition effectively? Managing COPD involves adherence to prescribed medications, regular exercise, a healthy diet, and avoiding exacerbating factors like smoking and exposure to pollutants. Support from healthcare providers and support groups can also be valuable.
Q11: Can individuals with COPD lead a normal life? With proper management and lifestyle adjustments, many individuals with COPD can lead fulfilling lives. Early diagnosis and timely interventions can significantly improve the quality of life for those with COPD.
Q12: Is oxygen therapy always necessary for COPD patients? Oxygen therapy is typically prescribed for individuals with severe COPD when their blood oxygen levels are low. It can help improve breathing and overall health, but it’s not necessary for all COPD patients.
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