Obstructive Airway Diseases Flashcards
A. What is an obstructive airway disease?
A disease in the airways that has an impact on respiration
A. What is a restrictive airway disease?
A disease in the lungs that leads to problem with respiration.
A. Give some examples of obstructive airway disease
Asthma, chronic bronchitis and emphysema. The latter being part of COPD.
ACO - Asthma and COPD overlap syndrome.
A. What are the causes of airway obstruction within a COPD or asthma patient?
Muscle constriction of smooth muscle can lead to lumen shrinkage of the airways.
Alveolar walls can be lost.
A. What is emphysema?
A lung condition in which the alveoli are damaged, resulting in large air spaces when the alveoli rupture
A. What are the three points of the asthma triad?
T2 airway inflammation (eosinophil is usually the effector)
Airway hyper responsiveness
Reversible airflow obstruction
A. Describe the way in which asthma symptoms progress.
- Broncho-constriction - brief symptoms
- Chronic airway inflammation - exacerbations of airway hyper-responsiveness.
- Airway remodelling - fixed airway obstruction with laying down of collagen tissue
A. What are the hallmarks of remodelling in asthma?
- Thickening of the basement membrane.
- Collagen deposition in the submucosa
- Hypertrophy of the smooth muscle.
A. Describe the process of type 2 inflammation in asthma.
- Allergen comes into contact with airway epithelium.
- Thymic stromal lymphoproteins are released and bind to dendritic cells.
- This complex then moves to the lymph node.
- This leads to the differentiation of T cells into TH2 cells which produces the cytokine, IL-5, which is chemotactic for eosinophils.
- It also interacts with B cells to produce cytokines IL-4 and IL-13, and release IgE which interacts with mast cells (to release histamine) and basophils (to release leukotriene D4)
- The leukotriene D4 will attract eosinophils and cause goblet cells to produce mucous.
A. Name factors that, if present, will lead to type 2 inflammation in asthma.
Presence of cytokines (IL4/5/13)
Raised total or specific IgE
Blood/sputum eosinophilia
Raised FeNO
A. Describe the inflammatory cascade in asthma.
We would treat the top of the cascade first.
- Inherited or acquired factors e.g. allergens such as pets.
- Eosinophilic inflammation e.g. anti inflammatory medication such as corticosteroids.
- Mediators and Th2 cytokines e.g. antihistamines, monoclonal antibodies
- Twitchy smooth muscle e.g. bronchodilators
A. Name some triggers for asthma exacerbations.
Allergens - animal dander, pollens etc. Exercise Viral infection Smoke Cold Chemicals Drugs - NSAIDs, beta blockers
A. Describe the clinical syndrome of asthma.
Episodic symptoms Diurnal variability. Non-productive cough/wheeze Triggers - allergens, exercise etc. Associated T2 comorbitities Reversible Family history
A. What are some associtated T2 comorbidities of asthma?
Allergic rhino conjunctivitis Chronic rhino sinusitis with nasal polyps Atopic dermatitis Eosinophilic esophagitis Urticaria
A. How will asthma be diagnosed?
History and examination