COPD Flashcards
What is COPD?
Chronic Obstructive Pulmonary Disease
• C - smoking related lung disease, chronic bronchitis, emphysema
• O - asthma
• P - bronchiectasis
• D - rarities: obliterative bronchiolitis, Langhans cells hystiocytosis
Characterised by airflow obstruction and are diseases of the lung - this is usually progressive, NOT fully reversible, and does NOT change markedly over several months
What host/genetic susceptibility may cause COPD?
E.g. alpha 1 - anti-trypsin deficiency -> makes lungs especially sensitive to tobacco smoke
Other gene polymorphisms e.g. matrix metalloproteinases, TNF-alpha, glutathione S transferase
What environmental factors may cause COPD?
Tobacco smoke exposure
Cannabis
Other smokes - biomass fuels important in non-industrialised countries
Mineral dusts e.g. coal, cadmium
What leads to the signs and symptoms seen in COPD?
COPD is mediated through the inflammatory response due the toxins inhaled from tobacco smoke
Difference in mucosa - in COPD there are lots of lymphocytes and inflammatory cells which mediate tissue damage
Goblet cell hyperplasia - increased mucus production
Airway narrowing - due to inflammation, fibrosis and scarring of bronchial wall and excess mucous production
Alveolar destruction - breathlessness
What symptoms are seen in COPD?
- Exertion breathlessness
- SOB
- Chronic cough
- Regular sputum production
- Winter exacerbations
- Wheeze
What physical signs are seen in COPD?
- Tar-staining of fingers
- Central cyanosis (if hypoxic or polycythaemic - increased conc. of haemoglobin)
- Tachypnoea
- Chest hyper-expansion ‘barrel-shaped’
- Reduced lateral and increased vertical chest expansion
- Paradoxical lower chest motion (lower chest moves inwards, instead of outwards) reduced breath sounds
- Wheeze
- Palpable liver edge
How is COPD diagnosed?
Based on clinical presentation + spirometry
Spirometry will show an “obstructive picture”. This means that the overall lung capacity is not as bad as their ability to quickly blow air out of their lungs
- The overall lung capacity is measured by forced vital capacity (FVC) and their ability to quickly blow air out is measured by the forced expiratory volume in 1 second (FEV1)
- Being able to blow air out is limited by the damage to their airways causing airway obstruction
What is the FEV1/FVC ratio seen in COPD?
Airflow obstruction = post-bronchodilator FEV1/FVC ratio such that FEV1/FVC is less than 0.7
What causes air trapping?
Gas gets trapped due to pre-mature airway collapse - air is breathed in but can’t be exhaled causing barrel shape
In COPD airway integrity is NOT maintained due to damage to airway and the alveoli around the airways, so they are no longer supported
- When an expiratory manoeuvre is performed there is a pinch point, due to pressure outside airway being greater than inside
What are the stages of GOLD Staging?
- Stage 1: FEV1 ≥ 80% predicted
- Stage II: FEV1 50% tp 79% predicted
- Stage III: FEV1 30% to 49%
- Stage IV: FEV1 ≤ 30% predicted
What is the Dyspnoea Scale?
This is a 5 point scale that NICE recommend for assessing the impact of their breathlessness:
Grades:
- Grade 1 – Breathless on strenuous exercise
- Grade 2 – Breathless on walking up hill
- Grade 3 – Breathless that slows walking on the flat
- Grade 4 – Stop to catch their breath after walking 100 meters on the flat
- Grade 5 – Unable to leave the house due to breathlessness
What may be seen on an x-ray of COPD?
- Often normal
- Hyper expansion
- LOW, FLAT diaphragms
What may be seen on a CT scan of COPD?
- ‘Holes’ or bullae - due to alveolar destruction/emphysema
* Bronchial wall thickening
What investigations may be done for COPD?
Chest xray to exclude other pathology such as lung cancer
Full blood count for polycythaemia or anaemia. Polycythaemia (raised haemoglobin) is a response to chronic hypoxia
Body mass index (BMI) as a baseline to later assess weight loss (e.g. cancer or severe COPD) or weight gain (e.g. steroids)
Sputum culture to assess for chronic infections such as pseudomonas
ECG and echocardiogram to assess heart function
CT thorax for alternative diagnoses such as fibrosis, cancer or bronchiectasis
Serum alpha-1 antitrypsin to look for alpha-1 antitrypsin deficiency. Deficiency leads to early onset and more severe disease
Transfer factor for carbon monoxide (TLCO) is decreased in COPD
- It can give an indication about the severity of the disease and may be increased in other conditions such as asthma
What is type I respiratory failure?
Known as hypoxaemic failure and is defined by PaO2 of less than 8 kPa
- Indicates a serious underlying pathology with the lungs e.g. infection, oedema or a shunt
What is type II respiratory failure?
Aka ventilatory failure, occurs when PaCO2 is MORE than 7 kPa
Reduced ventilatory effort can be a result of gas trapping, such as in COPD and severe asthma due to chest wall deformities, muscle weakness or central causes of respiratory depression
What are the clinical features of hypercapnia?
Dilated pupils Bounding pulse Hand flap Myoclonus Confusion Drowsiness Coma
What should all COPD patients stop doing?
STOP SMOKING
- Professional advice, nicotine replacement, anti-depressants (e.g. bupropion) and nicotine receptor blockers (e.g. varenicline)
What vaccinations should COPD patients be given?
Influenza, pneumococcal
What medications can be given in COPD?
Inhaled bronchodilators:
- SHORT-acting ß-agonists: e.g. salbutamol, terbutaline
- LONG-acting ß-agonists: e.g. salmeterol, formoterol
- Anti-muscarinics: e.g. ipratropium, tioptropium
Inhaled corticosteroids:
- E.g. beclomethasone, budesonide, fluticasone
Oral theophylline: e.g. aminophylline
Mucolytics: e.g. carbocysteine
Why are bronchodilators and corticosteroids given in COPD?
Bronchodilator - symptom relief
LABAs also reduce exacerbation frequency
Inhaled corticosteroids:
- Reduce exacerbation frequency (if > 2 per year)
- Slow disease progression
- Only for severe or frequent exacerbators
What does O2 therapy involve in COPD?
Long-term O2 therapy (LTOT): if PaO2 was maintained ≥8.0kPa for 15h a day, 3yr survival improved by 50%
What is the first medication to be started in COPD?
SABA (ß2-agonist) or SAMA (anti-muscarinic)
How should COPD be managed and treatment escalated?
If still breathless (after SABA/SAMA) add LABA OR long acting anti-muscarinic (LAMA e.g. tiotropium)
Add inhaled corticosteroids if frequent exacerbations (and already on LABA)
Final escalation: LAMA + LABA/ICS combination inhaler
What are complications of COPD?
- Exacerbations
- Pneumonia
- Pneumothorax
- Right ventricular failure
- Peripheral neuropathy
- Cachexia
What symptoms are seen in an exacerbation of COPD?
- Preceding coryzal (inflammation of nose) symptoms
- Increased breathlessness
- Increased cough
- Increased sputum
- Sputum purulence
- Ankle swelling
How is a COPD exacerbation managed?
Oxygen to give SaO2 88-92% (less in selected cases)
- Via Venturi mask
- Repeat ABG to check they’re NOT retaining CO2
High dose SABAs, usually nebulised
High dose corticosteroids (usually prednisolone 30mg/day – 7 days)
(Antibiotic only if purulent sputum or very severe illness)
Reassess after 1 hour
If after 1 hour still respiratory acidosis consider all of:
• IV bronchodilator (salbutamol or theophylline)
• Urgent intensive care opinion
• Non-invasive ventilation
• Intubation and assisted ventilation
Why is a nasal cannula used?
- Readily available
- Minimal discomfort to pt- can eat and drink
- Max flow rate 5l/min
- Cannot control the amount of inspired oxygen (cranial sinuses act as an oxygen reservoir)
Why is a non-rebreathe mask used?
- Can give high concentrations of oxygen very quickly (15l/min ~85% FiO2)
- Always use when initially assessing an unwell patient
- Cannot regulate amount of inspired oxygen - once initial assessment of patient completed, reduce oxygen to appropriate target saturations (94-98% or 88-92%)
Why is a Venturi mask used?
• Can give a define concentration of inspired oxygen
• Venturi masks are often used in COPD, where it is important not to over-oxygenate the patient
◦ BLUE = 2-4 L/min = 24% O2
◦ YELLOW = 4-6 L/min = 28% O2
◦ RED = 10-12 L/min = 40% O2
◦ GREEN = 12-15 L/min = 60% O2
• Indicated when correct target oxygen saturations are essentials
• Patients don’t like them as much
What is Cor pulmonale?
Due to chronic lung disease
• Hypoxia -> pulmonary arterial vasoconstriction -> increased pulmonary artery pressure -> right ventricular hypertrophy -> right ventricular failure
