COPD Flashcards
What is COPD?
- COPD is a common, preventable and treatable disease
- characterized by the presence of persistent respiratory symptoms and airflow limitation
- secondary to airway and alveolar abnormalities resulting from exposure to noxious particles or gases
- influenced by host factors including abnormal lung development
Airflow obstruction and COPD?
not fully reversible
COPD spectrum of abnormalities?
- emphysema
- chronic bronchitis
What is emphysema?
Permanent dilatation and wall destruction of airspaces distal to the terminal respiratory bronchioles
What is chronic bronchitis?
- Inflammation of the airways
- large airway involvement leads to mucosal thickening and mucus hypersecretion
- smaller bronchioles involvement produces airflow obstruction
- Chronic productive cough for at least 3 months of two consecutive years
- absence of other diseases causing sputum production.
Modifiable Risk factors for COPD?
cigarette smoking
- most common risk factor worldwide, representing the principal cause in up to 90% of patients
- Effects of smoking on lung function decline are dose dependent (airflow obstruction is directly proportional to the smoking pack years)
Genetic risk factors for COPD?
α1-Antitrypsin Deficiency
- Autosomal dominant mutations of SERPINA1 gene on chromosome 14
Non-modifiable risk factors for COPD?
- Occupational exposure
- mining and chronic dust e.g. silica, cotton - Biomass Fuel
- HIV infection in smokers
- Second Hand Cigarette Smoking
- Ambient air pollution
- Airway hyperresponsiveness
- Preterm birth
- Respiratory infections e.g. PNA, TB and Bronchiectasis
- Children born to smoking mothers
Pathogenesis of COPD?
- Chronic exposure to cigarette smoke in genetically susceptible individuals triggers inflammatory and immune cell recruitment within large and small airways and in the terminal air spaces of the lung
- Inflammatory cells release proteinases that damage the extracellular matrix supporting airways, vasculature, and gas exchange surfaces of the lung
- Structural cell death occurs through oxidant-induced damage, cellular senescence, and proteolytic loss of cellular-matrix attachments leading to extensive loss of smaller airways, vascular pruning, and alveolar destruction
- Disordered repair of elastin and other extracellular matrix components contributes to air space enlargement and emphysema
Pathological changes in COPD?
In Emphysema
- Panacinar emphysema is characteristic of AAT deficiency and is typically more severe in the lower Lobes
- Centriacinar emphysema is common in cigarette smokers and rare in nonsmokers
Clinical features?
- Dyspnea on exertion (or at rest) that is progressively worsening over time.
- Chronic cough
- Sputum production
- Weight loss with end-stage COPD.
- Morning headaches
Important things to note in history of COPD?
- Past Medical Hx
- Other underlying lung pathology - Social hx:
- Cigarette smoking (Active/ passive)
- Environmental exposures (home/ occupational)
- Biomass fuel - Family history
- Genetic predisposition
General exam findings?
- Cyanosis
- Nicotine staining fingers
- Wasting
Respiratory exam findings?
- Inspection:
- Hyper inflated ‘barrel chest’
- Accessory muscle use and tachypnoea - Palpation:
- Reduced chest expansion
- Hoover’s sign: Drawing in of the lower intercostal muscles with inspiration. - Percussion: Hyperresonance
- Auscultation:
- expiratory wheeze
- Prolonged expiration
- Reduced breath sounds
- crackles
Complications of COPD?
CVS changes
1. Tachycardia
2. Loud P2 in pulmonary HTN
3. Elevated JVP
4. Peripheral edema
Chest imaging findings?
- Increased lung volumes
- Relatively depressed diaphragms
- Straightened left heart border
- Tear drop heart shadow
- an increased AP chest diameter
Pulmonary function test results in COPD?
COPD shows obstructive airway disease pattern, FEV1/FVC < 0.7, which is not reversible
- FEV1 determines the severity of obstruction.
Note: If FEV1 and FVC are partially reversible, then an asthmatic component is present
GOLD classification of severity of COPD?
- mild COPD
- FEV1/FVC <0.7
- FEV1 >80% predicted - moderate COPD
- FEV1/FVC <0.7
- FEV1 <80 but >50% of predicted - severe COPD
- FEV1/FVC <0.7
- FEV1 <50% but >30% of predicted - very severe COPD
- FEV1/FVC <0.7
- FEV1 <30% of predicted or
- FEV1< 50% with respiratory failure or right sided heart failure
What other investigations can you do in COPD?
- Arterial blood gases
- hypercapnia
- respiratory acidosis
- hypoxemia - FBC (polycythaemia)
- EPO mediated rise in HCT in response to prolonged hypoxia
Modified medical research council dyspnea scale?
0 - not troubled by breathlessness except on strenuous exercise
1 - short of breath when hurrying or walking up a slight hill
2 - walks slower than contemporaries on the level because of breathlessness or has to stop for breath when walking at own pace
3 - stops for breath after walking 100m or after a few minutes on the level
4 - too breathless to leave the house or breathless when dressing or undressing
Long term treatment of COPD?
- bronchodilators
- inhaled corticosteroids - reduce exacerbations
- theophylline e.g. aminophylline
- phosphodiesterase 4 inhibitors e.g. roflumilast
- prophylactic antibiotics e.g. azithromycin in frequent exacerbations
- A1AT augmentation therapy
Bronchodilator drugs?
- Beta agonists e.g. salbutamol, formoterol
- Anticholinergics e.g. ipratropium, tiotropium
Non-pharmacotherapy long term treatment?
- Pulmonary rehabilitation
- Lung volume reduction surgery
- Lung transplant
- Vaccination (Pneumococcal, COVID, Influenza)
- Nutritional support and counselling
What interventions can improve survival?
- Smoking Cessation
- oxygen therapy in chronically hypoxemic patients
- lung volume reduction surgery (LVRS) in selected patients with emphysema
