COPD Flashcards
What is COPD
Chronic obstructive pulmonary disease
Characterised by airflow obstruction which is usually progressive, not reversible and does not change markedly over several months
Encompases emphysema and chronic bronchitis
What is emphysema
Destruction of terminal bronchioles and distal airspaces leading to loss of alveolar SA and impingement of gas exchange
Often progresses to development of large redundant airspaces: bullae
Airways collapse during expiration
Have loss of elastic tissue -> hyperinflation as lungs are unable to resist natural tendency of rib cage to expand outwards
What is chronic bronchitis
Chronic mucus hypersecretion caused by inflammation of large airways leading to proliferation of goblet cells
Frequently occurs in smokers
Results in chronic productive couhg and frequent resp infections
Have airway obstruction due to remodelling and narrowing of airways
What pathological changes are seen in COPD
Enlargement of mucus-secreting glands of central airways
Increased goblet cell number
Ciliary dysfunction
Breakdown of elastin and loss of elastic recoil
Formation of larger air spaces
Pulmonary hypertension due to vascular bed changes
What are the causes of COPD
Smoking
Alpha-1-antitrypsin disease
Occupational exposure
Pollution
What are the symptoms of COPD
Cough and sputum production
Breathlessness
Exacerbations assocaited with increased breathlessness, sputum and cough
Difficulty eating, drinking, walking and talking
What is the MRC dyspnoea score
Score used to grade breathlessness related to activities:
- Not troubled by breathlessness except on strenuous exercise
- Short of breath when hurrying or walking up slight hill
- Walks slower than contemporaries on level ground due to breathlessenss
- Stops for breath after walkling 100m or after few minutes on level ground
- Too breathless to leave house or breathless when dressing/undressing
What are the signs of COPD
Somes no signs
Purse lip breathing
Accessory muscle use
Tachypnoea
Hyperinflation/Barrel chest
Hyper-resonance on percussion
Wheeze or quiet breath sounds on ausculation
Decreased intensity breath sounds
Cyanosis, CO2 retention, cor pulmonale
Flapping tremors
Complications of COPD
Recurrent pneumonia
Pneumothorax
Resp failure
Cor pulmonale
What investigations are done to diagnose COPD
Spirometry - FEV1 <80% predicted and FEV1/FVC ratio <70% predicted
CXR - hyperinflated lungs show flattened diaphragm, hyperlucent lungs, increased antero-posterior diameter of chest, complications of COPD
CT - assessment of degree of alveolar destruction in emphysema
ABG and/or pulse oximetry
Alpha-1-antitrypsin blood test
What features suggest COPD
Smoker or ex-smoker
Older patient
Onset of symptoms in later life
Chronic productive cough
Breathlessness
How is stable COPD managed
Smoking cessation
Pulmonary rehabilitation
Bronchodilators
Antimuscarinics/anticholinergics
Steroids
Mucolytics
Diet
Supportive
Long term O2 therapy
Lung volume reduction
Name a bronchodilator and how it works
Beta-2 agonist (e.g. salbutamol)
Ligand binds receptor -> activates adenyl cyclase -> increases cAMP and activity of PKA -> phosphorylates MLCK leading to relaxation of smooth muscle in airway and bronchodilation
What are some adverse effects of beta-2 agonists
Tachycardia
Tremor
Anxiety
Palpitations
Hypokalaemia
What do steriods do and what are adverse effects of using them
Steriods help reduce inflammatory pathways
Adverse effects include: thin skin, bruising, cataracts, adrenal insufficiency, osteoporosis, diabetes, GI symptoms, mental disturbance
