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Chronic Obstructive Pulmonary Disease (COPD) and Emphysema

Basics

  • COPD is a heterogenous condition with chronic respiratory symptoms due to airway (bronchitis/bronchiolitis) and/or alveolar (emphysema) abnormalities.
  • Causes persistent, often progressive airflow obstruction.
  • Major cause of morbidity and mortality globally with ~3 million annual deaths.

Epidemiology

  • Incidence: 8.9 per 1,000 person-years.
  • Global prevalence: ~10.3%.

Etiology and Pathophysiology

  • Exposure to noxious gases or particles → airway and lung parenchymal damage.
  • Impaired gas exchange, persistent airflow obstruction, parenchymal destruction.
  • α1-Antitrypsin deficiency: rare inherited cause (autosomal codominant).

Risk Factors

  • Tobacco smoking (including marijuana, passive smoking, water pipe).
  • Severe childhood respiratory infections.
  • Aging and cumulative lung damage.
  • Low socioeconomic status and education.
  • Asthma and airway hyperreactivity.
  • Indoor biomass and occupational exposures.

Prevention

  • Smoking cessation and avoidance of noxious exposures are key.

Commonly Associated Conditions

  • Pulmonary: lung cancer, chronic respiratory failure, sleep apnea, pulmonary hypertension, asthma.
  • Cardiac: coronary artery disease, arrhythmias.
  • ENT: chronic sinusitis, laryngeal carcinoma.

Diagnosis

Diagnostic Criteria

  • Post-bronchodilator FEV1/FVC <0.7 confirms persistent airflow limitation.
  • Symptoms: dyspnea, chronic cough, sputum, wheezing.
  • History of exposure to risk factors (e.g., smoking).

History and Exam

  • Detailed tobacco and environmental exposure history.
  • Exacerbation triggers: infections, pollution, medication noncompliance.
  • Physical exam: prolonged expiration, wheezing, barrel chest, accessory muscle use, cyanosis.
  • Clubbing suggests alternative diagnoses (lung cancer, bronchiectasis).

Differential Diagnosis

  • Asthma, RADS, TB, ILD, bronchiectasis, lung cancer, chronic pulmonary embolism, sleep apnea, CHF, GERD, cystic fibrosis, vasculitis.

Tests

  • Spirometry: confirms airflow obstruction (FEV1/FVC <0.7), staging by GOLD criteria.
  • ABGs: hypercapnia, hypoxia.
  • CBC: eosinophilia, polycythemia.
  • Chest imaging: CXR shows hyperinflation, flat diaphragm; CT may show bullae and destruction.
  • α1-antitrypsin screening in selected patients.

GOLD Staging (FEV1 % predicted)

  • Grade 1: ≥80%
  • Grade 2: 50-80%
  • Grade 3: 30-50%
  • Grade 4: <30%

Symptom Assessment

  • COPD Assessment Test (CAT) score (0-40).
  • Modified Medical Research Council (mMRC) Dyspnea Scale (0-4).
  • GOLD ABE grouping by symptoms and exacerbation risk.

Treatment

General Measures

  • Smoking cessation (most important).
  • Home oxygen for severe hypoxemia (PaO2 ≤55 mm Hg or ≤60 mm Hg with cor pulmonale/polycythemia).
  • Vaccinations: COVID-19, pneumococcal, influenza, pertussis, varicella zoster (>50 years).
  • Regular inhaler technique assessment.
  • Pulmonary rehabilitation.
  • Noninvasive positive-pressure ventilation (NPPV) reduces mortality and rehospitalization.

Pharmacotherapy

  • Group A: Short- or long-acting bronchodilator (e.g., albuterol).
  • Group B: LABA + LAMA preferred over ICS.
  • Group E: LABA + LAMA, add ICS if blood eosinophils ≥100 cells/μL; consider macrolides or roflumilast if exacerbations persist.
  • Acute exacerbations: short-acting bronchodilators, corticosteroids, antibiotics (5-7 days).

Precautions

  • β-agonists: tachycardia, arrhythmias.
  • Anticholinergics: minimal systemic absorption, possible urinary retention.
  • ICS: increased pneumonia risk, oral candidiasis.
  • Corticosteroids: metabolic side effects.
  • Macrolides: risk of bacterial resistance, hearing loss.

Referral

  • Severe exacerbations, frequent hospitalizations, rapid disease progression, or surgical evaluation.

Additional Therapies

  • Pulmonary rehab for high symptom burden.
  • Surgical: lung volume reduction surgery, bronchoscopic lung volume reduction, bullectomy, lung transplant.

Inpatient Care

  • Manage acute exacerbations with oxygen, bronchodilators, systemic steroids, antibiotics, NPPV.
  • ICU care for respiratory failure.
  • Discharge planning: inhaler education, oxygen evaluation, follow-up scheduling.
  • Advance directives discussion.

Follow-Up

  • Monitor symptoms and medications 4 and 12 weeks post-exacerbation.
  • Repeat spirometry at 12 weeks.

Patient Education

  • Refer to American Lung Association: https://www.lung.org/lung-health-diseases
  • Smoking cessation critical.
  • Vaccination adherence.

Prognosis

  • Supplemental oxygen improves survival.
  • Smoking cessation slows progression.
  • Lung volume reduction surgery for severe upper-lobe predominant disease.
  • Lung transplant for very severe refractory disease.
  • 4-year mortality: 28% (mild-moderate) to 62% (severe).

Complications

  • Malnutrition, poor sleep, infections.
  • Polycythemia, respiratory failure, pneumothorax.
  • Arrhythmias, cor pulmonale, pulmonary hypertension.

Clinical Pearls:

  • Smoking cessation remains the most important intervention.
  • Screen high-risk patients with spirometry.
  • Oxygen therapy improves mortality.
  • Regularly reassess medication regimen and disease burden.
  • Keep vaccinations up to date.
  • Discuss advance directives early.