Chronic Obstructive Pulmonary Disease Overview

Chronic Obstructive Pulmonary Disease (COPD)

• COPD is a group of diseases characterized by airway obstruction, where the lungs don't fully empty and air gets trapped.
• This leads to a decrease in the volume of air that can be forcefully expired (decreased FVC), especially in the first second (decreased FEV1), resulting in a reduced FEV1/FVC ratio.
• Total lung capacity (TLC) is usually increased due to air trapping.

Chronic Bronchitis

• Chronic bronchitis is characterized by a productive cough lasting at least 3 months over 2 years, strongly associated with smoking.
• It's marked by an enlargement of the bronchial mucus glands.

Emphysema

• Emphysema involves the destruction of alveolar air sacs.
• It results from an imbalance of proteases and antiproteases, where inflammation in the lungs releases proteases and antiproteases neutralize these proteases.
• Excessive inflammation or a shortage of a₁-antitrypsin (AAT) can lead to alveolar destruction.
• Smoking is the most common cause, leading to excessive inflammation and protease-mediated damage.
• AAT deficiency is a rare cause, resulting in centriacinar emphysema affecting upper lungs, and panacinar emphysema affecting lower lungs. Liver cirrhosis may occur.
• Emphysema presents with increased thickness of mucus glands, productive cough with mucus plugs leading to increasing carbon dioxide and decreasing oxygen, and an increased risk of infection and cor pulmonale.

Asthma

• Asthma involves reversible airway bronchoconstriction, often triggered by allergic stimuli (atopic asthma).
• It frequently begins in childhood and may be linked to allergic rhinitis, eczema, and a family history of allergies (atopic history).
• Asthma's pathogenesis involves type I hypersensitivity- allergens trigger TH2 cells that secrete cytokines (IL-4, IL-5, IL-10).
• Re-exposure to the allergen triggers mast cell activation, releasing pre-formed mediators (histamine), and leukotrienes.
• This results in bronchoconstriction, inflammation, and edema (early-phase reaction), and inflammation can lead to damage and bronchoconstriction (late-phase reaction).
• Asthma symptoms include dyspnea, wheezing, productive cough with mucus plugs (Curschmann spirals, Charcot-Leyden crystals).
• Asthma can be triggered by different factors.

Bronchiectasis

• Bronchiectasis involves permanent dilation of the bronchi, often due to inflammatory damage to the airway walls, leading to air trapping.
• Potential causes include cystic fibrosis, primary ciliary dyskinesia, necrotizing infection, or allergic bronchopulmonary aspergillosis.
• Symptoms include a chronic cough, dyspnea, and possibly foul-smelling sputum.
• Complications may include hypoxemia (low blood oxygen levels) with cor pulmonale and secondary diseases like amyloidosis.

This quiz covers key aspects of Chronic Obstructive Pulmonary Disease (COPD), including chronic bronchitis and emphysema. Learn about the characteristics, symptoms, and mechanisms behind these respiratory conditions. Test your knowledge on airway obstruction, lung capacity, and the impact of smoking.