Pathophysiology of COPD Flashcards
What is COPD?
Persistent airflow limitation associated with enhanced chronic inflammatory response
What is COPD predominantly caused by?
Smoking
What are the symptoms of COPD?
Dyspnoea
Chronic cough
Chronic sputum production
What is a lung?
Each bronchus with is bronchioles + alveoli
What is chronic bronchitis?
COPD classification
Chronic cough with sputum production for at least 3 months for 2 years
What happens in chronic bronchitis?
Bronchioles lose their shape + become clogged with mucus
What is emphysema?
COPD classification
Chronic cough
Shortness of breath
Limited activity level
What happens in emphysema?
Enlargement of distal air passages in terminal bronchioles = alveolar wall destruction
What is the main risk factor of COPD?
Smoking
What accumulates in alveoli in COPD?
Neutrophils + macrophages
What happens to accumulated neutrophils + macrophages?
Activated + release their granules containing elastase + MMP
= elastic tissue destruction
What are contained in cigarettes?
Reactive oxygen species (ROS)
What does ROS in cigarettes do in COPD?
Stimulate NK-KB, cytokines, TNF + IL-8
= activate neutrophils + macrophages
+ elastase + MMP
= tissue destruction
What does the tissue destruction do in COPD?
Destroys wall of alveoli
What does congenital/functional alpha1 anti-trypsin deficiency cause?
Imbalance between destructive effects of protease activity + productive effects
What are the consequences of tissue damage in the lung?
Thickening of bronchiolar wall
Respiratory bronchioles collapse
Mucus accumulating
= AIRFLOW OBSTRUCTION
Why is air trapped in COPD?
Due to loss of elasticity
= can’t fully get air out in expiration
What is an exacerbation of COPD?
Acute event worsening the respiratory symptoms beyond normal day-to-day
What is the most common cause of COPD exacerbations?
Viral upper respiratory tract infections
What are COPD patients at increased risk for?
Cardiovascular diseases
Osteoporosis
Respiratory infections
Anxiety + depression
Diabetes
Lung cancer
When should spirometry be performed?
After administration of adequate dose of short acting bronchodilator to minimise variability
What will the FEV1 be under if COPD?
<0.70
What is the difference between COPD + asthmatic patient?
FEV1 return to normal with drug therapy in asthmatic patient
What is uncommon in COPD but common in asthma?
Night-time waking
Significant day to day variability of symptoms
What are the therapeutic option?
Nicotine replacement
Regular physical activity
Pharmacologic therapy
What do short-acting bronchodilators do?
Ease COPD symptoms
What are included in short-acting bronchodilators?
Anticholinergics
Beta-2 agonists
What do long-acting bronchodilators?
Prevent breathing problems
What are included in long-acting bronchodilators?
Anticholinergics
Beta-2 agonists
Combo of 2
OR beta-2 + corticosteroid
When is a corticosteroid used in combo with beta-2?
Presence of asthmatic features
How do anticholinergics work?
Muscarinic antagonists
Prevent Ach from binding to smooth muscle
+ prevent signal transduction of Gq mediated
What do anticholinergic do?
Dilate airways, prevent bronchospasm + reduce mucus
How do beta-2 agonists work?
Bind to beta-2 adreno receptor
Adenyl cyclase activated via signal transducing GS protein
= increase cAMP
= activate PKA
PKA mediates smooth muscle relaxation
