COPD Flashcards
Mechanisms of Airflow limitation in COPD
- Mucus hypersecretion: luminal obstruction.
- Disrupted alveolar attachments: emphysema.
- Mucosal & peribronchial inflammation & fibrosis (obliterative bronchiolitis).
Disease process in COPD
Cigarette Smoke => Alveolar macrophage <=> Neutrophil => Proteases => Emphysema & Chronic Bronchitis => Progressive airflow limitation.
Two aspects of COPD
Chronic Bronchitis & Emphysema
Chronic Bronchitis
- Chronic Neutrophilic inflammation.
- Mucus hypersecretion.
- Mucociliary dysfunction.
- Altered lung biome.
- Smooth muscle spasm & hypertrophy.
- Partially reversible.
Emphysema
- Alveolar destruction.
- Impaired gas exchange.
- Loss of bronchial support.
- Irreversible.
Symptoms of COPD
- Productive cough.
- Progressive dyspnoea (SOB)
- Frequent infections.
- Wheezing (Chronic Bronchitis)
Signs of COPD
- Reduced Breath sounds (Emphysema)
Complications of COPD
Pulmonary hypertension & RV hypertrophy/failure (cor pulmonale)
Chronic cascade in COPD
Progressive fixed airflow obstruction => impaired alveolar gas exchange => Resp failure (decreased PaO2, increased PaCO2)
COPD History
Smoking
Corticosteroids in COPD
May cause pneumonia due to local immune suppression & impaired Mucociliary clearance (especially fluticasone due to prolonged lung retention).
Reduces exacerbations in Eosinophilic COPD (ACO)
Oral steroids
Prednisolone used for acute exacerbations.
Inhaled steroids
Beclomethasone used for maintenance monotherapy in asthma.
Bronchodilators: B2 agonists
Stimulate bronchial smooth muscle B2 receptors: Increased cAMP.
SABA or LAMA.
LAMA/LABA or ICS/LABA/LAMA used.
Bronchodilators: Muscarinic Antagonists (anti-cholinergics)
Block post-junctional end plate M3 receptors.
SAMA (Ipratropium) & LAMA (Tiotropium)
Chronic: LAMA or LAMA/LABA or ICS/LAMA/LABA. To reduce exacerbations.
Acute: High Nebulised doses of ipratropium.
Route of Administration of SAMA & LAMA
Inhalation
Bronchodilator/Anti-inflammatory: Methylxanthines
Non-selective phosphodiesterase inhibitor (increased cAMP). Also acts as adenosine antagonist.
Chronic:
- Oral (theophylline).
- Used as add-on with ICS.
Acute:
- IV (aminophylline)
Anti-inflammatory: PDE4 inhibitors
Anti-inflammatory action & reduces exacerbations.
E.g. Oral roflumilast.
Used as add-on to LABA or LAMA/
Adverse effects of Roflumilast (PDE4 inhibitor)
Nausea, diarrhoea, headache, weight loss.
Mucolytics
Reduce sputum viscosity. aid sputum expectoration & reduce exacerbations.
E.g. Oral carbocisteine & erdosteine.
Non-pharmacological treatment for Chronic COPD
- Smoking cessation.
- Influenza/pneumococcal immunisation.
- Physical activity.
- Domicilary oxygen.
Pharmacological treatment of Chronic COPD
- LABA/LAMA combo.
- ICS/LABA/LAMA combo (if high eosinophil count).
- Roflumilast.
- Carbocisteine.
- Antibiotics for infections - Azithromycin.
Treatment of Acute COPD
- Nebulised high dose SABA (Salbutamol) + SAMA (Ipratropium).
- Oral prednisolone.
- Antibiotic (amoxicillin/doxycycline) if infection.
- Oxygen: 24-28% titrated against PaO2/PaCO2.
- Physio to aid sputum expectoration.
- Non-invasive ventilations.
- ITU assisted ventilation if reversible component (e.g. pneumonia)
