COPD Flashcards
What are the causes?
Smoking
Air pollution
Occupational exposure - mining, building + chemical industries
A1AD
What are the two main types of COPD? what are its with them also known as?
- Emphysema - pink puffers
2. Chronic bronchitis - blue bloaters
What is emphysema?
Dilatation and destruction of lung tissue distal to terminal bronchioles ->
loss of elastic recoil ->
premature closure of airways limiting expiratory flow while loss of alveoli decreases capacity for gas transfer
What is chronic bronchitis?
Airway narrowing -> airflow limitation due to hypertrophy + hyperplasia of mucus secreting glands (goblet cells) of the bronchial tree -> XS mucus secretion
Decreased airflow, hyper secretion + chronic cough
Explain the pathophysiology of COPD
increased airway resistance
most have both emphysema and chronic bronchitis
Explain VQ mismatch in COPD
mismatch leads to fall in PaO2 and increased work
Explain how COPD leads to pink puffers
Normal CO2 maintained by increasing alveolar ventilation in an attempt to correct their hypoxia
Explain how COPD leads to blue bloaters
when pts lead to maintain resp effort and PaCO2 levels increase
In the short term rise in CO2 leads to stimulation of respiration
In longer term pts become insensitive to CO2 + depend on hyperaemia to drive ventilation
Renal hypoxia -> fluid retention + increased erythrocyte production -> polycythaemia
Leads to bloating and cyanosis - blue bloater
What are the resp symptoms?
- Cough - productive w white or clear sputum
- Wheeze
- SOB
- Colds settle on chest w frequent infections
What things worsen sx?
cold
damp weather
air pollution
What are systemic sx of COPD?
HTN Osteoporosis Depression WL Reduced muscle mass due to generalised weakness
What is found on examination?
- Barrel chest
- Hyperresonance on percussion
- Distant breath sounds on auscultation
- Wheeze on auscultation (exacerbations)
- Coarse crackles - mucus
What tests should be done?
- Spirometry: FV1/FVC ratio <0.7, post bronchodilator
- Sats - assess need for O2 therapy if FEV1 <50% of predicted
- CXR - rule out other Dx
- FBC
- Sputum culture
Explain how spirometry should be performed to diagnose and grade COPD
Carry out S 15-20 mins after inhaling salbutamol/terbutaline
Airflow obstruction = FEV1/FVC ratio <0.7
Severity
stage 1 - mild 80% or more of predicted value
Stage 2 - mod FEV1 50-79 of predicted value
Stage 3 - severe FEV1 30-49
Stage 4 - v severe FEV1 less than 30%
What is usually sen on CXR in cOPD?
hyperinflation
What are the differentials of COPD?
Asthma CCF Bronchiectasis TB Bronchiolitis Lung cancer
How do COPD and asthma differ?
Asthma - early onset, Hx of allergy, daily variability in sx,
reversibility on spirometry w bronchodilators
How do COPD and CCF differ?
Hx of CVD present Orthopnoea Fine bibasilar inspiratory crackles NT-proBNP elevated CXR - pulmonary vascular congestion Echo confirms
How do COPD and bronchiectasis differ?
Hx of recurrent infection in childhood
large volumes of purulent sputum
Clue: Hx fo pertussis or TB
Chest CT - bronchial dilation + wall thickening
What is the conservative treatment of COPD?
Stop smoking
Pneumococcal and influenza vaccinations
Pulmonary rehabilitation
Optimise treatment for comorbidities
Give the pharmacological treatment of COPD?
- SABA (salbutamol/terbutaline) or SAMA (ipratropium bromide)
- LABA (salmeterol/formeterol) or LAMA (tiotropium)
Discontinue rx w SAMA if giving LAMA - If asthmatic features - change to LABA + ICS
- If no asthmatic feature - LABA + LAMA
What are the add on treatments?
Oral aminophylline or theophylline if still symptomatic after SABA and LABA
Mucolytic - for chronic productive cough
Oral corticosteroids + abx for exacerbations
What are complications of COPD?
- Cor pulmonale
- Recurrent pneumonia
- Pneumothorax
- Respiratory failure
- Anaemia
- Polycythaemia
How does COPD lead to cor pulmonale?
chronic hypoxia and subsequent vasoconstriction in pulmonary vasculature causing pulmonary HTN and R sided HF
What are the signs of cor pulmonale?
Engorged neck veins
Loud P2
Lower extremity oedema
Hepatomegaly
What is the management of cor pulmonale?
continuous O2 therapy
Judicious use of diuretics
How do acute exacerbations of COPD present?
increasing cough, SOB or wheeze
decreased exercise capacity
What ix would u do in an acute exacerbation of COPD?
ABG CXR - exclude pneumothorax + infection FBC, U&E, CRP ECG Sputum culture Blood culture if fever
Give the initial management of acute COPD
- Neb salbutamol 5mg/4h + ipratropium 500mcg/6hr
- Controlled O2 therapy if sats <88 or PaO2 <7
Start at 24-28, aim for sats 88-92, PaO2 >8 and rise of PaCO2 <1.5 - IV hydrocortisone 200mg + oral pred 30mg (continue for 1-2w)
- Abx if infection
- Physio to aid sputum clearance
- IV aminophylline if no response
Give the management of acute COPD if no response to initial therapy
- Non-invasive +ve pressure ventilation if RR>33 or pH <7.35 or PaCO2 rising
or - Resp stimulant drug if not suitable for ventilation
When should intubation and ventilation be considered in rx of acute COPD?
if pH <7.26 and PaCO2 rising despite NIPPV
