COPD Flashcards
Definition of COPD
- a disease predominantly caused by smoking ans is characterised by airflow obstruction that is not fully reversible
- AFO does not change markedly over several months, long term deterioration
- Exacerbation often occurs
Where are the sites of Airflow obstruction (AFO)
- large away damage: bronchitis
- small airway damage: the silent zone, airways narrowing due to bronchoconstriction and inflammation
- Alveolar damage: emphysema,
Define the pathology of emphysema
- destruction of alveoli distal to terminal bronchiole
- loss of elastic supporting tissue
- gas exchange affected as well as AFO
What are some causes of COPD?
- Smoking (anything)
- Second hand smoke: especially in childhood
- Alpha-1 antitrypsin deficiency
- Occupational: rail workers, coal miners, welders, painters, cleaners
What is Alpha-1-antitrypsin?
- AAT is a protein that is largely produced in the liver
- protects lungs from neutrophil elastase
- neutrophil elastase, digests damaged or aging cells and bacteria to promote healing in the lungs
What is Alpha-1-antitrypsin deficiency?
- Autosomal recessive inheritance
- homozygous PIZZ
- smoking is a co-factor esp. >40s
- accounts for 2% of all emphysema in the UK
- minority also have liver disease
Typical symptoms of COPD
- Exertional breathlessness
- chronic cough
- regular sputum
- frequent winter bronchitis
- wheeze
- post bronchodilator FEV1:FVC < 60%
Make some distinctions between Asthma as COPD
- onset between 35-55yrs in COPD vs as a child in Asthma
- Flat PEFR chart in COPD
- Constant symptoms vs daily variation
- progressive SOB vs Beta-2 reversibility
- No steroid reversibility vs reversibility
- significant smoking Hx vs Atopy/Family Hx
- spirometry confirms AFO, spirometry may be normal
Mangement of COPD
- stop smoking, pneumococcal and flu vaccinations
- self-management plan, pulmonary rehabilitation
- inhaled therapies, inhaled therapies are needed to relieve breathlessness or exercise limitation
- LABA + LAMA: no asthmatic features
- LABA +ICS: asthmatic features, suggesting steroid responsiveness –> later add LAMA if still breathless
What is Pulmonary Rehabilitation
- supervised exercise training
- comprehensive educational; programme
- psychosocial support
- improvements Dyspnoea
- reduced SOB
- increased exercise capacity
Other Interventions for COPD
- transplant
- volume reduction
What is Chronic Bronchitis?
Airway narrowing due to chronic irritation of the bronchi –> chronic cough
- sputum production for 3 months per year
- for at least two consecutive years
- hyperplasia of mucus glands
- squamous metaplasia
What does a flow-volume curve look like in obstructive and severe obstructive disorder?
- lower peak expiratory flow rate
- more flattened as there is a lower volume
- in severe conditions, this is more significant with an immediate drop in expiratory flow rate after its peak
What determines the severity of the lung obstruction?
- must have an FEV1/FVC < 0.7
- the lower the FEV1% predicted the more severe the obstruction
- <30% is very severe stage 4
What are the physiological effects of COPD?
- Increased work breathing
- Reduced Exercise Tolerance
- Impaired gas exchange: Hypoxia, Hypercapnia, raised pulmonary artery pressure, salt and water retention, RV dilatation
- Loss of Fat-Free Mass
What are the benefits of inhaled therapy?
- Reduce airflow obstruction
- Reduce dynamic hyperinflation
- Reduce symptoms
- Reduce the rate of exacerbations
What are the three main types of Inhaled therapies for COPD?
- Beta-agonists: SABA; LABA
- Anti-Muscarinics: SAMA; LAMA
- Inhaled Corticosteroids (ICS): low dose, medium dose, high dose
can be used in combination: LABA/LAMA, ICS/LABA, LAMA/ICS/LABA
What is Long Term Oxygen Therapy (LTOT), and when should it be used?
- used in Chronically hypoxaemic patients
- when pO2 is < 7.3 kPA when stable
- pO2 between 7.3-8 kPA with: 2y polycythaemia (increased red blood cell production); nocturnal hypoxemia; peripheral oedema; pulmonary hypertension
