COPD Flashcards
What kind of airway disease is COPD?
Obstructive
What makes up COPD?
Chronic bronchitis
Emphysema
What are the histopathological features of COPD?
Mucociliary dysfunction
Inflammation
Tissue damage
How does COPD change over time?
Progressive condition
What causes COPD?
Smoking and exposure to inhaled noxious particles and gases
How does cigarette smoke or another irritant lead to progressive airflow limitation?
Activates macrophages and cells which release neutrophil chemotactic factors (IL-8), mediators (LTB4) and oxygen radicals
Neutrophils and macrophages release proteases that break down connective tissues in parenchyma and cause mucous hypersecretion
= Progressive airflow limitation
Connective tissue in the parenchyma breaks down because of an imbalance between?
Proteases and anti-proteases
What is emphysema?
Irreversible alveolar wall destruction resulting in impaired gas exchange and loss of bronchial support
Alpha-1-anti-trypsin is an inhibitor of?
Proteases
What is the chronic cascade?
Progressive fixed airflow obstruction Impaired gas exchange Respiratory failure (decreased PaO2, increased PaCO2) Pulmonary hypertension RVH Right Ventricular Heart failure Cor pulmonale Death
What are chronic symptoms of COPD?
Smoking Non-atopic Daily productive cough (progressive) Breathlessness Wheezing (bronchitis) Reduced breath sounds (emphysema) Worsening quality of life Exacerbation (frequent/infective) Reduced lung function
What are acute symptoms of COPD?
Respiratory distress
Wheeze
Coarse crackles
Possible cyanosis
How do you assess someone at high risk?
Spirometry
FEV1 less than 50% predicted
2 or more exacerbates within past year
Co-morbidities - IHF / HF
What are the features of COPD on spirometry?
Reduced FVC and total lung capacity
Reduced FEV1
FEV1/FVC ratio <75%
<15% FEV1 response to salbutamol
What are non-pharmacological management options for COPD?
Stop smoking (stop further decrease in lung function)
Physical activity
Oxygen
Lung volume reduction surgery
Which drug can reduce parasympathetic activity to improve symptoms in COPD?
Muscarinic Acetylcholine Receptor Antagonists
What is the mechanism of action of a Muscarinic Acetylcholine Receptor antagonist?
Block activation by muscarinic receptor antagonists
M3 receptor = parasympathetic fibres
What are examples of a SAMA?
Ipratropium
Oxitropium
What receptors does Ipratropium act on?
Non-selective blocker of M1, M2 and M3
What is an example of a LAMA?
Tiotropium
Aclidinium
What feature of Tiotroprium and Ipratroprium reduces adverse effects by reducing absorption and system exposure?
Quaternary ammonium group
How are muscarinic receptor antagonists administered?
Inhalation
Why is blocking of the M2 receptor not desireable?
Because release of ACh from parasympathetic post-ganglionic neurone is increased
What are examples of LABAs?
Salmeterol
Formeterol
What are examples of combination inhalers used in COPD?
LAMA-LABA
LABA-ICS
What is an example of a PDE4 inhibitor?
Rofumilast
What are side effects of Rofumilast?
Nausea
Diarrhoea
Headache
Weight loss
Where PDE expressed?
Neutrophils
T-cells
Macrophages
Inhibition of PDE4 may have inhibitory effects on?
Inflammatory / Immune cells
What is the effect of PDE4 inhibitors?
Suppress inflammation and emphysema
What is an example of a mucolytic?
Carbocisteine
What is the effect of carbocisteine?
Reduce sputum viscosity and aide septum expectoration
How is an acute exacerbation of COPD treated?
(iSOAP - BUZZ) Ipratroprium Salbutamol (nebulised, high-dose) Oxygen (24-28% - titrated against PaO2/PaCO2) Amoxicillin/Doxycycline (if infection) Prednisolone (oral)
Normally non-invasive ventilation for a higher FiO2 is used; when would ITU intubated assisted ventilation be used?
Only if reversible component, i.e. pneumonia
