Internal Medicine: COPD Overview

Study Notes

Internal Medicine: Chronic Obstructive Pulmonary Disease (COPD)

COPD is a preventable and treatable lung disease with extra-pulmonary effects that may contribute to its severity.
The primary cause is chronic exposure to noxious particles and gases, primarily cigarette smoke, leading to structural changes, airway inflammation, and lung tissue destruction.
Typical symptoms include a chronic cough, sputum production, and progressive shortness of breath (dyspnea) during exertion or rest.
Diagnosis is primarily made through spirometry, which measures lung function by looking at Forced Expiratory Volume in one second (FEV1) and the ratio of FEV1/FVC.
A chest X-ray or CT scan may also be required to detect structural changes such as hyperinflation, bullae, and signs of chronic bronchitis.
COPD is characterized by irreversible airflow limitation, often progressive, and an abnormal inflammatory response to noxious particles and gases in the lungs.
Chronic bronchitis is characterized by a productive cough lasting for at least three months in two consecutive years.
Emphysema involves the destruction of lung tissue (alveoli). It is characterized by the enlargement of the airspaces distal to the terminal bronchioles, accompanied by the destruction of their walls. The pattern of enlarged air spaces can be centriacinar, panacinar, or periacinar.
COPD has both pulmonary and systemic components, with changes in pulmonary and chest wall compliance that exacerbate airflow obstruction during exercise due to reduced expiratory time.
Common extrapulmonary manifestations of COPD include impaired nutrition, weight loss, skeletal muscle dysfunction, and cardiovascular disease.
The prevalence of COPD is directly linked to tobacco smoking prevalence and the use of biomass fuels in low- and middle-income countries.
In 2005, COPD contributed to over 3 million deaths globally. By 2020, it was predicted to be the third leading cause of death worldwide.
Key risk factors for COPD include smoking, biomass fuel exposure, occupational exposures (e.g., cadmium), outdoor and indoor air pollution, and low birth weight, although individual susceptibility factors are important too.
Infections, low socioeconomic status, and nutritional factors, are also implicated in the development and progression of the condition.
Genetic factors, including a₁-antitrypsin deficiency, can contribute to COPD susceptibility.
Airway hyper-reactivity is also possibly part of the problem.
The severity of COPD can be classified by the post-bronchodilator FEV1, which is expressed as a percentage of predicted value for the patient's age.
COPD exacerbations are characterized by worsening symptoms, lung function deterioration, and can be triggered by infections, change in air quality, among others. Treatment typically involves increased bronchodilator use, corticosteroids, and possible antibiotics.
Patients who exhibit severe hypoxemia require chronic long-term oxygen therapy.
Significant improvements in breathlessness and lung function may be observed through interventions like pulmonary rehabilitation.
Surgical interventions, such as bullectomy and lung volume reduction surgery, can benefit specific patient types.
Regular influenza and pneumococcal vaccinations are recommended for COPD patients.
BMI, dyspnea scale, and examination of other complications for COPD patients are important.
Additional treatment measures include bronchodilator therapies, inhaled corticosteroids, and, if necessary, oxygen therapy.
Non-invasive ventilation can be employed for patients who experience worsening tachypnea and acidosis.
Patients with COPD also should be assessed for comorbid conditions like obesity, malnutrition, depression, and social isolation for better management strategies and treatment outcomes.
The BODE index considers the body mass index, airflow obstruction, dyspnea, and exercise capacity to provide a composite score predictive of mortality.