COPD (+emphysema) Flashcards
Define COPD
A preventable and treatable condition characterised by airflow limitation which is not fully reversible, and encompasses both emphysema and chronic bronchitis
Epidemiological features of COPD
> 90% cases due to cigarette smoking
Development of COPD directly proportional to amount of cigarettes smoked per day
More common in older people
M:F = 1:1
5th leading cause of death and disability worldwide
What is emphysema?
Abnormal, permanent enlargement of air spaces, due to alveolar weakening and rupture, distal to the terminal bronchiole, accompanied by destruction of the walls and capillary beds
What happens to the values of pCO2, pO2 and RR in Va/Q mismatch?
pCO2 - Same or low
pO2 - Decreased
RR - Increased
What causes the ‘Blue Bloater’ presentation in COPD?
Px fails to maintain respiratory effort pCO2 increases Insensitivity occurs Px relies on hypoxic drive Causes renal hypoxia Fluid retention
Why is oxygen therapy sometimes dangerous in COPD
Blue bloaters rely on hypoxic drive so oxygenating them removes the hypoxaemia
Characteristic symptoms of COPD
Productive cough Wheeze Breathlessness Increase SOB on exertion Increases SOB in cold weather
Signs observed in COPD
Mild COPD may have no signs but a wheeze
Severe COPD: Tachypnoea Use of accessory muscles Hyperinflation Pursing of lips on expiration Reduced chest expansion Resonant/Hyper-resonant percussion
Pink puffer points
Increase in alveolar ventilation Normal pO2 Normal or low pCO2 Breathless but not cyanosed CO2 sensitive
Blue bloater points
Decreased alveolar ventilation Decrease pO2 Increase PCO2 Cyanosed but not breathless CO2 insensitive
Classification of Respiratory Failure
Type 1: Hypoxaemic
Type 2: hypercapnic
O2/CO2 results in hypoxaemic resp. failure
pO2 <8
pCO2 - normal or low
O2/CO2 results in hypercapnic resp. failure
pCO2 > 6
pO2 < 8
Which two conditions encompass COPD?
Emphysema
Chronic obstructive bronchitis
What is chronic bronchitis?
Chronic productive cough of more than 3 months duration for more than 2 consecutive years, with airflow limitation
Causes of chronic bronchitis
Chronic irritation from smoking and recurrent infections
2 causes of emphysema
- Increased elastase production - more related to smoking
2. Inherited deficiency of a1 proteinase inhibitor - accounts for 1% of cases
What breath sounds are heard in a patient with COPD
A wheeze may be heard
Crepitations if there is an infection
Prolonged expiratory time in chronic bronchitis
What is the FEV1:FVC required for a diagnosis of COPD?
<70%
Which 2 lung function tests could you do to aid diagnosis?
FEV:FVC
PEFR
What may be seen on the CXR of a COPD patient?
Can often be normal
May observe overinflation w/ low flattened diaphragm
What is the requirement for ‘overinflated lungs?’
> 6 ribs seen above diaphragm
What would the FBC findings be?
Increased Hb
Increased PCV
Both due to persistent hypoxaemia
What is cor pulmonale?
Right ventricular failure due to fluid overload secondary to lung disease. Characterised by pulmonary HTN + RV hypertrophy
What is the usual A/VBG result seen in COPD?
Often normal
More advanced conditions may show a hypoxemic picture
Advanced cases of COPD may show which characteristic feature on an ECG?
Tall P waves
What are the treatment options for COPD?
General: Lifestyle changes + a SABA (salbutamol) or Antimuscuranic (ipratropium)
Mild/Moderate: Inhaled long acting antimuscuranic (tiotropium) + SABA (salbutamol)
Severe: Combination of LABA (salmeterol or formoterol) + corticosteroid (symbicort)
Remain symptomatic: Long acting antimuscuranic (tiotropium) + inhaled steroid + laba + refer
Important complications of COPD
Nocturnal hypoxia acute respiratory failure polycythemia pneumothorax cor pulmonate lung carcinoma acute exacerbations w/wo infection
Aetiology of COPD
Smoking causes an inflammatory response, cilia dysfunction and oxidative injury
Oxidative stress + imbalance in proteinases and antiproteinases
Pathophysiology of COPD
Chronic inflammation that affects central and peripheral airways, lung parenchyma and pulmonary vasculature
Narrowing and remodelling of airways + increased number of goblet cells + changes to vascular bed = hypertension
Stages 1 to 4 of COPD all share a similar FEV1/FVC value which is
<70%
Which vaccines should patients with cardiopulmonary disease be offered?
Viral influenza
S. Pneumonia
5 Step Management of acute exacerbation of COPD
- Oxygen
- SABA + anticholinergic
- Glucocorticoids
- Abx
- Mechanical ventilatory support (if above doesn’t work)
Tests to order in COPD
ECG Spirometry Peak Flow ABG Bloods (check for infection) Plus SATS
