Flashcards in *Obstructive Airway Disease Deck (26)
What is obstructive airway disease?
Any respiratory disease characterised by air trapping caused by either decrease airway diameter or increased airway secretions, or both
what are 3 obstructive airway disease?
What is asthma/ COPD overlap syndrome?
Not clearly defined but patients with features of asthma and COPD (e.g. atopic smoker with partially reversible airway obstruction) - COPD with reversibility and eosinophilia who are steroid responsivE
What causes the turbulent airflow in asthma and COPD?
Mucosa and sub-mucosa become inflamed and invaginate and therefore obstruct airflow
what type of leukocytes are involved in COPD and asthma?
COPD = neutrophil
Asthma = eosinophil
How can the tone of the smooth muscle be described in COPD and asthma?
COPD = hypertrophic
Asthma = twitchy
What 3 sets of words can be used to describe asthma?
Early onset/ late onset
Atopic (allergic)/ non-atopic
Extrinsic (external factor)/ intrinsic (internal factor)
What is the asthma triad?
Reversible airflow obstruction
Airway hyperresponsivenes (hyperreactivity)
What is the evolution of asthma?
Bronchoconstriction (brief symtpoms)
Chronic airway inflammation (exacerbations airway hyperresponsiveness)
Airway remodelling (fixed airway obstruction = COPD like symptoms)
What are the hallmarks of asthma remodelling? (3)
Basement membrane = thickened
Submucosa = collagen deposition
Smooth muscle = hypertrophy
What is the inflammatory cascade in asthma? + treatment?
Genetic predisposition + triggers (viruses, allergen, chemical, nutrition) - avoidance
Eosinophilic inflammation - anti-inflamatory (corticosteroid)
TH2 cells release mediators (Interleukins e.g. IL-12, IL-4, IL-5) - anti-leukotriene/ histamine, anti-IgE, anti-IL5)
Twitchy smooth muscle (hyper-reactivity) - bronchodilators (beta-2 agonists, muscarinic antagonists)
What are examples of the environmental factors that can affect asthma?
Age, gender, obesity, infeciton, atopic status, allergin exposure
Genetic = Epithelial-specific asthma gene signature
Examples of some asthma triggers?
drugs (NSAIDs, beta-blockers)
What are the clinical signs of asthma?
Episodic symptoms and signs
diurnal variability (nocturnal/ early morning)
non-productive cough, wheeze
What can be used to help diagnose asthma?
History and examination
diurnal variation of peak flow rate
Reduced forced expiator rate (FEV1/FVC 15%)
Provocation testing leads to bronchospasm
What can be used to provoke asthma in the clinical setting?
Histamine/ metacholine/ mannitol
What are the 3 components of COPD caused by noxious particles or gases?
(these lead to the development of obstruction and ongoing disease progression)
What are the characteristics of COPD? (2)
Reduced lung fucntion
What is the disease process in COPD?
Inhaled noxious chemicals causes inflammation of the lungs (if normal protective mechanisms aren't working properly)
Cigarette smoke activated macrophages and airway epithelial cells which release neutrophili chemotaxis factor
Neutrophils and macrophages then releases proteases that break down lung parenchyma (emphysema)and stimulate mucous hyper secretion (chronic bronchitis)
Cytotoxic T cells may also be involved
In COPD, what is there an imbalance of?
Proteases and anti-proteases (e.g. alpha1-antitrypsin)
What are the features of chronic bronchitis?
Chronic neutrophilic inflamation
altered lung biome
smooth muscle spasm and hypertrophy
What are the features of emphysema?
Impaired gas exchange
Loss of bronchial support
What are indicative of high risk COPD?
2 exacerbations or more within the past year or FEV2 less than 50%
Clinical features of COPD?
Chronic symptoms (not episodic)
Daily productive cough
Frequent infective exacerbations
Chronic bronchitis = wheezing
Emphysema = reduced breath sounds
What is the chronic cascade in COPD?
Progressive fixed airflow obstruction
Imparied alveolar gas exchange
Respiratory failure (decrease PaO2, increased PaCO2)
Right ventricular hypertrophy/ failure (for pulmonale)
(stopping smoking arrests further decline in lung volume)