Airways disease Flashcards
(65 cards)
What are the two pathophysiological features of the airway in asthma?
- reversible airflow obstruction
- airway inflammation
What is airway hyper- responsiveness?
this is where the airway goes twitchy and into spasm
What are the histological signs of asthma?
- thickening of the basement membrane
- collagen deposition in the submucosa
- hypertrophy in the smooth muscle
What are the extra histological signs in severe asthma?
- epithelial shedding
- mucus plugging
What are the presenting symptoms and signs in asthma?
- diurnal variability
- a non-productive cough
- associated atopy so increased IgE levels
- responsiveness to steroids or beta-agonists
- family history
- wheezing due to turbulent airflow
How is the diagnosis of asthma achieved and what tests are carried out?
- history taking
- examination
- diurnal variation of peak flow rate
- reversibility to inhaled salbutamol
- reduced FEV1/FVC ratio (below 75%)
- provocation testing to bronchospasm with exercise and histamine
What are the histological signs of COPD?
- tissue damage
- mucociliary dysfunction
- inflammation
What are the histological signs of chronic bronchitis?
- neutrophilic inflammation
- mucus hyper secretion
- mucociliary dysfunction
- altered lung microbiome
- smooth muscle spasm
- hypertrophy
What are the effects of emphysema?
- alveolar destruction
- impaired gas exchange
- loss of bronchial support
Are emphysema and chronic bronchitis reversible or irreversible?
chronic bronchitis is partially reversible
emphysema is irreversible
What is the chemical factor that determines the severity of COPD and what is it affected by?
- protease levels
- antiprotenase levels are genetic
- protease comes from alveolar destruction and emphysema from smoking
What are the signs and symptoms of COPD?
- chronic symptoms
- non-atopic
- productive cough
- breathlessness
- exacerbations
- wheezing from chronic bronchitis
- reduced breath sounds from emphysema
What are the features of the chronic cascade in COPD?
- fixed airflow obstruction
- impaired alveolar gas exchange
- respiratory failure
- pulmonary hypertension
- death
What happens to the FVC and TLCO in asthma?
it is preserved
What happens to FVC and TLCO in COPD?
it is reduced
What do ILDs usually present with?
- progressive breathlessness
- restrictive lung function
- reduced transfer factor
How do you diagnose ILDs?
CT scan and sometimes a lung biopsy
What is the pathophysiology of DPLD?
- impaired alveolar gas exchange (alveolar barrier to O2)
- CO2 exchange is unimpaired because alveolar ventilation is normal
- therefore, low PaO2 and normal PaCO2
What are the common causes of DPLD?
consolidation of the alveolar ai spaces from infective pneumonia or infarction
What is the treatment for DPLD?
remove trigger factor
- 1st line is systemic steroids
- 2nd line is oral azathioprine and O2 if hypoxaemic
treat secondary so pulmonary hypertension or lung transplant
What is pulmonary challenge testing?
methacholine is inhaled
the challenge will cause a >20% decrease in FEV1 in patients with asthma
What are examples of the causes of the extrinsic or intrinsic inflammatory cascades in asthma?
- extrinsic causes are pollen, dust mite faeces, animal dander or mould
- intrinsic causes are unknown
What is the pathophysiology of the asthma cascade?
- Th2 CD4 cell-mediated immunity for allergenic or Th17 CD4 for non-allergenic
- eosinophilic or neutrophilic airways inflammation
- eosinophil and mast cell activation
- nerve activation
- smooth muscle cholinergic response
What is the result of the inflammatory cascade from asthma on the airways?
- bronchoconstriction
- mucus hyper secretion
- vasodilation and oedema
- airway remodelling
