Obstructive & Restrictive Lung Disease Flashcards
What features to restrictive and obstructive lung diseases share?
- chronic
- diffuse (across the whole lung)
- non-infectious
What are the obstructive lung diseases?
- asthma
- COPD
- chronic bronchitis + emphysema
- small airways disease/chronic bronchiolitis
- bronchiectasis
What are the restrictive lung diseases?
- idiopathic pulmonary fibrosis
- pneumoconiosis
- asbestosis
- sarcoidosis
- honeycomb lung
What is asthma?
- increased responsiveness of airways to various stimuli leading to episodic bronchoconstriction which is at least partly reversible
- obstructive lung disease
What are the two types of asthma?
- atopic/allergic
- increased serum IgE
- specific external allergens
- non-allergic asthma
- normal serum IgE
- non-specific triggers
What are the phases of the asthma response?
- acute/immediate [tx with relievers eg ventolin/salbutamol]
- increased vascular permeability –> oedema
- increased mucous production
- bronchospasm
- late phase (4-8 hours) [tx with corticosteroids]
- chemotaxis of eosinophils, mast cells, lymphocytes, macrophages –> ongiong inflammation
- epithelila damage
What are the complications of asthma?
- short term:
- death
- atelectasis (collapse or rupture of lungs)
- spontaneous pneumothorax and/or pneumomediastinum (rare)
- long term (severe chronic)
- remodelling: fibrosis and scarring = irreversible obstruction
- chronic hypoxia –> pulmonary hypertension –> cor pulmonale
What is emphysema?
- abnormal, permanent enlargement of air spaces distal to the terminal bronchiole
- from destruction of the alveolar walls without fibrosis
What are the types of emphysema?
- centriacinar (centrilobular) – from smoking
- panacinar (panlobular)
- distal acinar (paraseptal)
- irregular
How does cigarette smoking cause emphysema?
- damages intralveolar septae
- attracts inflammatory cells into lung tissue
- neutrophils release a protease called elastase
- the body normally has anti-protease to downregulate proteases
- smoking impairs this function
- tf getting upregulation of elastase and downregulation of its inhibition
- can develop without smoking due to an inherited form of trypsin deficiency that produces non-functional anti-proteases
How does emphysema cause airway obstruction?
-
loss of elastic recoil
- loss of supporting elastic tissue around small airways leads to collapse
- dynamic airway collapse during forced expiration
- tf air moves out more slowly
- associated conditions:
- small airways disease
- chronic bronchitis
What are the complications of emphysema?
- hypoxia
- caused by airflow obstruction, loss of diffusion capacity due to IAV septum damage (late)
- pulmonary hypertension –> cor pulmonale
- pneumothorax
What is chronic bronchitis?
- **clinical **definition:
- persistent cough productive of sputum for at least 3 months in 2 consecutive years
What is the patgogenesis of chronic bronchitis?
- chronic irritation by inhaled substances
- cigarette smoke (rarely other things like grain dust, silica, etc.)
- increased mucous production in larger airways
- due to hypertrophy of mucous secreting glands and increase in goblet cells on the surface epithelium
- thickening of wall + more mucous; hypertrophy is single main contributor to the pathogenesis of chronic bronchitis
- due to hypertrophy of mucous secreting glands and increase in goblet cells on the surface epithelium
- inflammation, scarring, and narrowing of smaller airways
What are the morphological features of chronic bronchitis?
- excessive mucous
- due to hypertrophy of mucous secreting glands
- single main contributor to pathogenesis of CB
- increased goblet cells on the surface epithelium
- due to hypertrophy of mucous secreting glands
- mild increase in inflammatory cells: lymphocytes, macrophages, and plasma cells, causing edema
- peribronchial fibrosis in small airways
- +/- sqamous metaplasia
- predisposes to squamous cell carcinoma (lung cancer)
Patients with predominantly chronic bronchitis present with COPD as
blue bloaters
bluish colour of skin and lips due to hypoxia + ankle swelling
Patients with predominant emphysema present with COPD as
pink puffers
pink complexion, fast respiratory rate, pursed lips, hyperinflated lungs
What is the pathogenesis of bronchiectasis?
- severe destructive inflammation of the airways
- severe or recurrent infection +/- obstruction
- loss of surrounding elastic tissue and muscle exceeds contraction of fibrous tissue
- clearance of organisms and fluid impaired
- severe infection develops, causes damage to the bronchiolar wall causing it to dilate
- dilated airways often full of pus
- causes lots of foul smelling sputum
- fever
- SOB, cyanosis, cor pulmonale
What is the most common form of restrictive (interstitial) lung disease?
- idiopathic pulmonary fibrosis/usual intersitial pneumonitis
- interstitial inflammation, fibrosis at varying stages of development
- inevitable progression to end-stage lung disease (~3yrs survival)
- unknown cause
