Week 2 - COPD Flashcards
What are the main causes of COPD?
Smoking, but also dust, occupational factors, pollutants
What other factors are associated with COPD?
Age, females, lower socioeconomic status, recurring childhood infection, small lung size
Why does smoking cause COPD?
Chemicals in smoke release elastase which breaks down elastin in alveolar tissue so less elastic tissue to push air out of lungs
What deficiency can lead to emphysema and how?
Alpha 1 antitrypsin. Antitrypsin fixes imbalance between protease-antiprotease, otherwise known as elastase-antielastase. If you have a deficiency, the balance remains and elastase will break down elastic tissue. Smoking + this is disastrous
What are the symptoms of COPD? (5)
Cough, sputum, wheezing, breathlessness, frequent chest infections
What should you expect upon examination of a COPD exacerbation patient?
Cyanosis, breathless, wheeze, pursed lip breathing, chest wall deformities/hyperinflation, raised JVP, cachexia, or peripheral oedema
What is cachexia?
Wasting of the body muscle and fat due to chronic disease. May be able to see ribs easily through skin
What are some of the less common symptoms of COPD?
Weight loss, fatigue, swollen ankles (peripheral oedema)
Why does weight loss occur in COPD?
Increased metabolic activity. Cachexia. Often seen in cancer
What chest wall deformity may be seen in COPD?
Barrel chest - looks like barrel is inside as its hyper-inflated, so anterior posterior distance is greater than expected
What is the mMRC dyspnoea scale?
Modified medical research council. From 0-4, stages to represent how breathless a patient is. 0 is only breathless upon strenuous exercise. 4 is breathless when dressing or too breathless to leave the house
What is the criteria for COPD diagnosis? (4)
When patient meets criteria - over 35, has risk factor of smoking/occupational, absence of asthma features and confirmed airflow obstruction after b2 agonist using spirometry
What are the 4 stages of COPD?
Mild - FEV1 80%
Moderate - FEV1 50-79%
Severe - FEV1 30-49%
Very severe - FEV1 <30%
What is the purpose of a chest X-ray in diagnosis of COPD?
Eliminated alternative pathology, like tumour or oedema that may be causing same symptoms
What test can differentiate between asthma and COPD and (maybe) confirm COPD diagnosis?
CO gas transfer test. Should decrease in COPD as less gas exchange and transfer is occurring
What is a high res CT scan used for?
Can see alveoli size in emphysema to determine if a patient has it and which type
What are the 4 types of emphysema?
Centriacinar, panacinar, periacinar and bullous emphysema
How does an acute exacerbation present?
Usually to a GP with change in cough or sputum, and general worsening symptoms
What can cause an acute exacerbation?
Infection, change in medication, pneumothorax, blood clots, change in air quality
What are features of severe COPD?
Spirometry, history of exacerbations, presence of co-morbidity like heart disease, cor pulmonae or secondary polycythaemia
What is the difference between type 1 and type 2 respiratory failure?
Type 1 - individual is hypoxic only. Reduced pO2 in arterial blood
Type 2 - individual has reduced pO2 and increased pCO2 as difficult to exhale. Seen in very severe COPD
When do we see flapping tremor and what is it caused by?
In type 2 respiratory failure due to increased pCO2 - hypercapnia. Acidosis in the blood causes central chemoreceptors to be desensitised to changes in H+ and thus pH, so ventilators drive must come from peripheral chemoreceptors.
What causes cor pulmonale?
Thickening of muscle on right side of heart and increased pressure on left of heart, due to abnormalities of the lung or pulmonary vessels
What is secondary polycythaemia? What can it lead to?
Increase haemoglobin level due to body tissues detecting hypoxia and releasing erythropoietin, causing more RBC’s to be formed. This causes increased haematocrit and blood viscosity
Can lead to strokes and many vascular issues due to viscosity and haematocrit
What happens as COPD progresses?
It’s progressive and terminal, so at end stage you’ll see a rapid decline with many exacerbations and worsening symptoms. Lung function reclines and then is slightly regained after exacerbations, until death
