COPD Flashcards
What is COPD?
Chronic obstructive pulmonary disease - progressive disorder characterised by airway obstruction with little/no reversibility (includes chronic bronchitis and emphysema).
What are the main symptoms of COPD?
- Productive cough - starts in the morning and progresses (earliest symptom)
- Sputum
- Dyspnoea - initially with exercise, then at rest
- Wheeze - infection in early stages, chronic later
- Recurrent infection, flapping tremor, weight loss
What are the main signs in COPD?
- Tachypnoea, bounding pulse (strong)
- Use of accessory muscles, barrel chest
- Hyperinflation, quiet breath sounds on auscultation
- Hyperresonant percussion
- Intercostal retraction, pursed lips
What is the underlying pathophysiology in COPD?
- Chronic inflammation causing obstruction and stenosis.
- Imbalance between proteases and anti-proteases - smoking increases macrophages and inhibits a1 antitrypsin, alveolar wall destruction.
- Abnormal inflammatory reaction, cilia paralysis = airway inflammation and goblet cell hyperplasia = increased sputum production and oedema = chronic bronchitis.
- Progressive hypoxia, VSMC thickening, pulmonary hypertension.
- Emphysema - permanent dilation of airways distal to terminal bronchiole
What are the causes of COPD?
- Tobacco smoke (40-70% of cases)
- Air pollution
- Occupational exposure (mining, textiles)
- Genetics (a1 antitrypsin deficiency)
What ae these test used for in COPD?
- Spirometry
- FBC
- ABG
- CXR
- ECG
- Measure FEV1 and its percentage of predicted FEV1.
- Used to assess severity of exacerbation and length of disease.
- Checked in acutely unwell patients with sats <90%.
- Seldom diagnostic, rules out other pathologies.
- RFs for COPD and IHD are similar, common comorbidities.
What would be found in COPD on these tests?
- Spirometry
- FBC
- ABG
- CXR
- ECG
- FEV1 <80% predicted, FEV1/FVC <0.7
- Polycythaemia, raised haematocrit >55%, high ESR, CRP, WCC (chronic infection).
- Hypercapnia, hypoxia, respiratory acidosis (metabolic compensation in chronic).
- Hyperinflated lungs, flattened diaphragm, increased AP diameter (barrel chested), bullae.
- Right atrial and ventricular hypertrophy (cor pulmonale).
What are the stages of COPD in terms of FEV1 (%of predicted)?
- Stage 1 (mild) - >80%
- Stage 2 (moderate) - 50-79%
- Stage 3 (severe) - 30-49%
- Stage 4 (very severe) - <30%
What are the aims of management in COPD?
- Slow progression
- Relieve symptoms
- Prevent exacerbation
- Prolong survival
What is the medical management of COPD?
- SABA PRN/SAMA PRN
- FEV1 >50% - LABA/LAMA
- FEV1 <50% - LABA + ICS/LAMA
- FEV1 >50% persistent SOB - LABA + ICS
- Final step - LAMA + LABA + ICS
What is the general preventative management in COPD?
- Smoking cessation
- Influenza and streptococcus pneumonia vaccines
- Mucolytics (carbocystine) in patient with chronic bronchitis phenotype.
- Pulmonary rehabilitation in early stages.
What additional medical management should you consider for COPD?
- LTOT for 16h/day reduces PPH by relieving hypoxia and and decreasing pulmonary artery tone.
- Theophylline (PDEi) in severe symptoms.
- ICS for more frequent exacerbations
What is the mechanism of action of SAMA and LAMA and what are some examples?
- Competitive inhibitor of ACh, reduces smooth muscle tone and reduces secretions.
- SAMA - ipratropium, LAMA - tiotropium
What are the side effects of SAMAs and LAMAs?
Antimuscarinic bronchodilators by inhalation have few systemic side effects. Mostly just dry mouth.
What is the mechanism of action of theophylline?
PDEi - increases cAMP and subsequent VSM relaxation.
