Week 2 - Respiratory - Obstructive Airways Disease Flashcards
Define Obstructive Airway Disease
- Airflow obstruction or limitation, causing difficulty during expiration
- Examples:
- Chronic obstructive pulmonary disease
(COPD) - Asthma
List the common symptoms of Obstructive Airway Disease
- Dyspnoea
- Increased work of breathing (use of
the accessory muscles) - A decreased forced expiratory volume in one second (FEV1)
- Decreased FEV1/forced vital capacity (FVC) ration
Define the Pathophysiology of Asthma
Hypersensitivity reaction (immunological processes), leading to inflammation
What are the principal characteristics of Asthma
- Airway inflammation (oedema)
- Airway hyper-responsiveness (bronchial smooth muscle spasm, thickening of airway walls)
- Mucus hypersecretion (thick mucus, impaired mucociliary function)
What happens to the airways in Asthma
- Thick mucus
- Mucosal oedema (inflammation)
- Smooth muscle spasm causing obstruction of small airways occurs in asthma
- Breathing becomes laboured and expiration is difficult due to the airway restrictions
Define Exacerbations
Events that require urgent action to prevent a serious outcome, such as hospitalization or death from asthma.
What triggers acute exacerbations
- Allergens
- Infections
- Occupational exposures
- Tobacco smoke or from treatment non-adherence.
What are the symptoms of exacerbations of Asthma
- Bronchoconstriction
- Expiratory wheezing
- Dyspnoea
- Cough
- Prolonged expiration
- Tachycardia and tachypnoea (increased ventilatory rate)
- The accessory muscles of ventilation
What is the first long term goals for Asthma management
- Maintain asthma control & maintain lung function
- The most important element of regular asthma management > reduction of inflammation
- A stepwise approach recommended:
- Education, avoidance of triggers
- Pharmacotherapy
- Inhaled corticosteroids and
- Bronchodilator therapy
What is the second long term goals for Asthma management
- Prevent morbidity & mortality
- Acute asthma episodes > life threatening
- Maintain a patent (open) airway
- Administration of oxygen
- Rapid-acting bronchodilators E.g. salbutamol
- Systemic steroids for moderate to severe attacks > decrease inflammatory responses in the lungs
Define Sympathetic Nervous System
- Autonomic nervous system responsible for “fight or flight” responses.
- It increases heart rate, dilates airways, and prepares the body for action in stressful situations.
Define Parasympathetic Nervous System
- Autonomic nervous system responsible for “rest and digest” functions.
- It slows the heart rate, increases digestion, and promotes relaxation.
What receptors has sympathetics effects
- Adrenergic Receptors
- Alpha and Beta
- Beta 1 - Increase heart rate
- Beta 2 - Brochodilation
- Alpha 1 - Urinary Retantion
- Beta 1 - Increases Contractility
- Beta 1 - Atrioventricular conduction
What receptors has parasympathetics effects
Cholinergic Receptors
- M3 and M2 - Mucus Secretion
- M2 - Brochoconstriction
- M2 - Decrease Heart Rate
Explain the mechanism of action of Brochodilators
- β2 -adrenergic receptors control bronchial smooth muscle of the airway.
- When these receptors are stimulated by sympathomimetic agents (e.g. salbutamol) > leads to
bronchodilation (smooth muscle relaxation)
What receptor is Salbutamol and what is it for?
- Short-acting β2 receptor agonists
- Act very quickly, last for a short duration in the lungs
- Used for quick relief of bronchospasm
What receptor is Salmeterol and what is it for?
- Long-acting β2 receptor agonists
- A longer duration of action/used to control symptom
What is an example of non-selective adrenergic agonist
- Ephedrine
- Stimulate the β2 recpetors in the lung but can also stimulate the β1-receptors in the heart
- May be dangerous to use in a client with COPD who also suffers from heart disease.
What are reliever medications of Asthma
- Relax bronchial smooth muscle
- Rapid bronchodilation
- Acute relief of symptoms
- Administered on an as-needed basis.
- E.g. Salbutamol ad Iprotropium (Combivent)
What are preventer medication of Asthma
- Treat inflammation + overall asthma control
- Examples:
- Inhaled corticosteroids such as budesonide
Define Chronic Obstructive Pulmonary Disease (COPD)
- A preventable, progressive, chronic disease characterised by irreversible
obstruction of the airways - Immunological processes leads to the airway inflammation and lung damage
What is the cause of COPD
- Exposure to noxious particles or gases
- Most common = cigarette smoke
- Other risks: inhaled noxious particles
E.g. occupational exposure and air pollution.
Define COPD Pathophysiology
COPD is Pathophysiologically characterised by:
Chronic bronchitis:
- airway inflammation and remodelling
Emphysema:
- destruction of alveolar tissue, and a decrease in elastic recoil
- Commonly the coexistence of both
What is Emphysema
Destruction of alveolar tissue, and a decrease in elastic recoil
What causes Emphysema
Inhaled irritants stimulate inflammation which over time causes:
- Loss of the normal elastic recoil of the bronchi
- Expiration becomes difficult because loss of elastic recoil > air trapped in the lungs > increase in expansion of the chest
What is Alveolar Destruction
- Produces large air spaces within the lung tissue > not effective in gas exchange.
- Obstruction results from changes in lung tissues, rather than mucus production as in chronic bronchitis.
What are the goals of COPD management
- Reduce the risk of exacerbation &
- Minimise symptoms.
What are the treatments of COPD
Reduction of risk by:
- Stop smoking
- Influenza vaccinations
Pharmacotherapy including:
- Inhaled glucocorticosteroids
- Short-acting bronchodilators
- long-term oxygen therapy
Pulmonary rehabilitation:
- When symptomatic regardless of severity.
Define Brchoiectasis
Abnormal permanent dilation and distortion of the bronchi and bronchioles, resulting from chronic inflammation of the airways, and leading to progressive destruction of the bronchial walls and lung tissue
What is Brochiectasis associated with?
- Recurrent lower respiratory tract infections
- Bronchitis
What is the treatment for Bronchiectasis
- Avoidance/management of chest infections
- Antibiotics
- Airway clearance techniques
- Mucolytic agents
- Pulmonary rehabilitation if experience dyspnoea during
ADLs
