Flashcards in Obstructive Airway Disease 1 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 = neutrophilAsthma = eosinophil
How can the tone of the smooth muscle be described in COPD and asthma?
COPD = hypertrophicAsthma = twitchy
What 3 sets of words can be used to describe asthma?
Early onset/ late onsetAtopic (allergic)/ non-atopicExtrinsic (external factor)/ intrinsic (internal factor)
What is the asthma triad?
Airway inflammationReversible airflow obstructionAirway 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 = thickenedSubmucosa = collagen depositionSmooth muscle = hypertrophy
What is the inflammatory cascade in asthma? + treatment?
Genetic predisposition + triggers (viruses, allergen, chemical, nutrition) - avoidanceEosinophilic 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?Genetic factors?
Age, gender, obesity, infeciton, atopic status, allergin exposureGenetic = Epithelial-specific asthma gene signature
Examples of some asthma triggers?
Animal danderDust mitesPollensFungiExercise Viral infectionSmokeColdChemicalsdrugs (NSAIDs, beta-blockers)
What are the clinical signs of asthma?
Episodic symptoms and signsdiurnal variability (nocturnal/ early morning)non-productive cough, wheezetriggersassocaited atopyfamily history
What can be used to help diagnose asthma?
History and examinationdiurnal variation of peak flow rateReduced forced expiator rate (FEV1/FVC 15%)Provocation testing leads to bronchospasm
What can be used to provoke asthma in the clinical setting?
ExerciseHistamine/ metacholine/ mannitol
What are the 3 components of COPD caused by noxious particles or gases?
Mucociliary dysfunctionNeutrophilic inflammationTissue damage(these lead to the development of obstruction and ongoing disease progression)
What are the characteristics of COPD? (2)
ExacerbationsReduced 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 factorNeutrophils 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 inflamationmucus hypersecretionmucociliary dysfunctionaltered lung biomesmooth muscle spasm and hypertrophyPartially reversible
What are the features of emphysema?
Alveolar destructionImpaired gas exchangeLoss of bronchial supportIrreversible
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)SmokingNon-atopicDaily productive coughProgressive breathlessnessFrequent infective exacerbationsChronic bronchitis = wheezingEmphysema = reduced breath sounds
What is the chronic cascade in COPD?
Progressive fixed airflow obstructionImparied alveolar gas exchangeRespiratory failure (decrease PaO2, increased PaCO2)Pulmonary hypertensionRight ventricular hypertrophy/ failure (for pulmonale)Death (stopping smoking arrests further decline in lung volume)