Chronic obstructive pulmonary disease (COPD) refers to a group of lung diseases that block airflow and make breathing difficult. Emphysema and chronic bronchitis are the two most common conditions that make up COPD. Chronic bronchitis is an inflammation of the lining of your bronchial tubes, which carry air to and from your lungs. Emphysema occurs when the air sacs (alveoli) at the end of the smallest air passages (bronchioles) in the lungs are gradually destroyed.
Here's a great animation from Nucleus Medical Media to help introduce the lungs, COPD, and how its different presentations it develop.
Here's a great animation from Nucleus Medical Media to help introduce the lungs, COPD, and how its different presentations it develop.
COPD Epidemiology & Pathophysiology:
Epidemiology: Chronic obstructive pulmonary disease (COPD) is estimated to affect 32 million persons in the United States and is the fourth leading cause of death in this country. Patients typically have symptoms of chronic bronchitis and emphysema, but the classic triad also includes asthma.
Pathophysiology: COPD is characterized by airflow limitation that is poorly reversible. Cumulative, chronic exposure to cigarette smoking is the number one cause of the disease, but repeated exposure to secondhand smoke, air pollution and occupational exposure (to coal, cotton, grain) are also important risk factors.
Chronic inflammation plays a major role in COPD pathophysiology. Smoking and other airway irritants cause neutrophils, T-lymphocytes, and other inflammatory cells to accumulate in the airways. Once activated, they trigger an inflammatory response in which an influx of molecules, known as inflammatory mediators, navigate to the site in an attempt to destroy and remove inhaled foreign debris.
Under normal circumstances, the inflammatory response is useful and leads to healing. In fact, without it, the body would never recover from injury. In COPD, repeated exposure to airway irritants perpetuates an ongoing inflammatory response that never seems to shut itself off. Over time, this process causes structural and physiological lung changes that get progressively worse.
As inflammation continues, the airways constrict, becoming excessively narrow and swollen. This leads to excess mucus production and poorly functioning cilia, a combination that makes airway clearance especially difficult. When people with COPD can't clear their secretions, they develop the hallmark symptoms of COPD, including a chronic, productive cough, wheezing and dyspnea. Finally, the build-up of mucus attracts a host of bacteria that thrive and multiply in the warm, moist environment of the airway and lungs. The end result is further inflammation, the formation of diverticula (pouch-like sacs) in the bronchial tree, and bacterial lung infection, a common cause of COPD exacerbation.
Epidemiology: Chronic obstructive pulmonary disease (COPD) is estimated to affect 32 million persons in the United States and is the fourth leading cause of death in this country. Patients typically have symptoms of chronic bronchitis and emphysema, but the classic triad also includes asthma.
Pathophysiology: COPD is characterized by airflow limitation that is poorly reversible. Cumulative, chronic exposure to cigarette smoking is the number one cause of the disease, but repeated exposure to secondhand smoke, air pollution and occupational exposure (to coal, cotton, grain) are also important risk factors.
Chronic inflammation plays a major role in COPD pathophysiology. Smoking and other airway irritants cause neutrophils, T-lymphocytes, and other inflammatory cells to accumulate in the airways. Once activated, they trigger an inflammatory response in which an influx of molecules, known as inflammatory mediators, navigate to the site in an attempt to destroy and remove inhaled foreign debris.
Under normal circumstances, the inflammatory response is useful and leads to healing. In fact, without it, the body would never recover from injury. In COPD, repeated exposure to airway irritants perpetuates an ongoing inflammatory response that never seems to shut itself off. Over time, this process causes structural and physiological lung changes that get progressively worse.
As inflammation continues, the airways constrict, becoming excessively narrow and swollen. This leads to excess mucus production and poorly functioning cilia, a combination that makes airway clearance especially difficult. When people with COPD can't clear their secretions, they develop the hallmark symptoms of COPD, including a chronic, productive cough, wheezing and dyspnea. Finally, the build-up of mucus attracts a host of bacteria that thrive and multiply in the warm, moist environment of the airway and lungs. The end result is further inflammation, the formation of diverticula (pouch-like sacs) in the bronchial tree, and bacterial lung infection, a common cause of COPD exacerbation.
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