Understanding COPD: Symptoms, Diagnosis, and Treatment
Chronic Obstructive Pulmonary Disease (COPD)
COPD involves reduced expiratory flow and decreased maximum voluntary ventilation, essentially dropping the lung’s capacity. It often stems from chronic bronchitis or emphysema, developing slowly, progressively, and usually irreversibly. This chronic airflow limitation or obstruction is linked to an abnormal inflammatory response to harmful particles and noxious gases.
Chronic Bronchitis
Chronic bronchitis is characterized by a cough and expectoration lasting for three months per year for at least two consecutive years, not attributable to other causes.
Emphysema
Emphysema involves the destruction of alveolar walls and damage extending beyond the terminal bronchioles.
Epidemiology
COPD has a prevalence of 9% in individuals aged 40-69. In men, the smoking prevalence is between 40% and 78%. Many patients remain undiagnosed initially because they don’t experience noticeable symptoms early on. Most patients seek consultation when the disease is already advanced. COPD is a leading cause of death, with a high rate of hospitalizations due to exacerbations.
Risk Factors
Smoking is a major risk factor (20%), with the impact depending on pack-years and current smoking status. Age is also a factor, and genetic predisposition plays a role. Other contributing factors include previous smoking, gender, socioeconomic status, occupational exposures, alpha-1 antitrypsin deficiency, and air pollution.
Natural History
Smoking triggers an aggressive respiratory response, leading to inflammation, cough, and expectoration. This damages the bronchioles and alveolar walls, reducing FEV1 (forced expiratory volume in one second). A healthy individual’s FEV1 peaks at 20-25 years of age and then declines by about 30ml per year. A smoker may experience a loss of 50-80ml/year.
Prognostic Factors
- FEV1 and age: Symptomatic COPD is indicated by FEV1 < 1.5L. With FEV1 < 1L, the 5-year survival rate is around 50%.
- Nutritional status: BMI < 25kg/m² is a negative prognostic factor.
- Chronic respiratory insufficiency: PaO2 < 60mmHg and PaCO2 > 45mmHg indicate a worse prognosis.
- Superinfections and hypersecretion: These do not significantly alter the prognosis.
- Cor pulmonale: The impact on prognosis is uncertain.
Spirometry
Spirometry is a pulmonary function test used to confirm COPD diagnosis. It measures the volume of exhaled air. FVC stands for forced vital capacity, and FEV1 represents the maximum expiratory volume in one second.
COPD Diagnosis with Spirometry
COPD is diagnosed when FEV1 is less than 80% of the predicted value and the FEV1/FVC ratio is less than 70% of the predicted value.
Clinical Presentation
Dyspnea is often the only initial symptom, progressively worsening from exercise-induced to occurring with moderate exertion and eventually even at rest. Morning cough may also be present and can worsen during superinfections.
Physical Examination
Auscultation may reveal wheezing. Sputum production and hemoptysis (always investigate for neoplasia) can also be observed.
Differential Diagnosis
- Asthma: Spirometry results in COPD can be similar to asthma. To differentiate, inhaled salbutamol is administered, and spirometry is repeated. An increase in FEV1 of more than 12% from the initial value suggests a positive bronchodilator response, pointing towards asthma. Other features favoring asthma include atopy, family history of asthma, wheezing, absence of chronic cough, any age of onset, positive bronchodilator test, and good response to corticosteroids.
- Bronchiectasis: This involves permanent dilation of the airways. Symptoms include chronic cough and bronchorrhea. A CT scan can confirm the diagnosis.
- Other conditions: Congestive heart failure, pulmonary neoplasm, pulmonary tuberculosis, pneumoconiosis, sarcoidosis, and cystic fibrosis should also be considered.
Severity Classification
- Mild: FEV1 80-60% of predicted
- Moderate: FEV1 60-40% of predicted
- Severe: FEV1 < 30% of predicted
Treatment Objectives
- Smoking cessation
- Symptom improvement
- Exacerbation prevention
- Quality of life improvement
- Preservation of lung function
- Increased survival
- Immunization
- Prevention of complications
Individualized Treatment
Treatment is tailored to the individual’s condition, ranging from smoking cessation and vaccination for asymptomatic patients to continuous bronchodilator therapy for symptomatic individuals and oxygen therapy for those with chronic respiratory insufficiency.
Treatment Options
- Smoking cessation: This is crucial.
- Bronchodilators: Short-acting bronchodilators (e.g., salbutamol, ipratropium bromide) are used as needed for symptom relief. Long-acting bronchodilators (e.g., salmeterol, formoterol, tiotropium bromide) are used for daily control in symptomatic patients.
- Glucocorticoids: Inhaled corticosteroids (e.g., budesonide, fluticasone) are considered if FEV1 is < 50%.
- Other treatments: Mucolytics, expectorants, and vaccinations are also used.
- Antibiotics: The choice of antibiotic depends on the severity of COPD, age, and the presence of comorbidities.
- Oxygen therapy: This is beneficial for patients with advanced disease and chronic respiratory insufficiency.
Hygienic and Dietary Measures
These include respiratory physiotherapy, maintaining a healthy weight, ensuring adequate protein intake, avoiding flatulent foods, and moderating alcohol consumption.