Benign respiratory pathology Flashcards
Asthma definition
Chronic inflammatory disorder of the airways, with paroxysmal bronchospasm causing: wheeze, cough, variable bronchoconstriction that is at least partially reversible
Asthma epidemiology
- Extrinsic (atopic)
- Children and young adults = 33.9% children with wheeze (1 in 10 UK children diagnosed asthma)
- Adults = 9-15% occupational cause - commonest occupational lung disease
Asthma pathogenesis
- Mucosal inflammation and oedema
- Mucus plugs in bronchi
- Hyperinflated lungs
Atopic asthma
- Type 1 hypersensitivity reaction
- Caused by allergen
- Can cause centrilobular emphysema when exacerbated
- Mucous lands hyperplasia
- Bronchiolar wall smooth muscle hypertrophy
COPD definition
two distinct pathological entities
Chronic bronchitis =
Cough with sputum for 3 months in 2 consecutive years
Emphysema =
caused by chronic bronchitis - abnormal enlargement of alveolar airspaces
COPD epidemiology
- Smokers
- 1 in 20 of >65yrs consult GP per year
Bronchitis pathogenesis
- Cell damage = inflammation = scar, mucus, infection
- Bronchiole wall thickened or lumen blocked/damaged
- Mucus gland hyperplasia
Emphysema pathogenesis
- Increased elastase causes alveolar wall loss and decreased contractility = decreased gas exchange
Classification of emphysema
- Centrilobular (centiacinar) – most associated with smoking and coal dust
- Panlobular (panacinar) - severest lower lobe bases
- Paraseptal (distal acinar) – can rupture pneumothorax
Key clinical features of COPD
- Dyspnoea
- Cough: mucus and irritation of lining
- Sputum: hyperproduction of mucus
- Infection
- Right heart signs: increased workload as increased resistance pulmonary HTN and right ventricular hypertrophy
Bronchiectasis definition
- Permanent dilation of bronchi and bronchioles caused by destruction of the muscle and elastic tissue (usually with inflammation)
Bronchiectasis pathogenesis
bronchiole damage due to infection or autoimmune conditions = inflammation = wall pulled open by adjacent scar/collapse
- Scars cause a major abscess complication
- Bronchiole wall thickened but lumen dilated
Aetiology of Bronchiectasis
- Cystic fibrosis,
- Primary ciliary dyskinesia,
- Kartagener syndrome
- Bronchial obstruction (tumour, foreign body)
Key clinical features of Bronchiectasis
- Cough, fever, copious foul smelling and yellow/green sputum, abscesses
- Complications = pneumonia, septicaemia, metastatic infection, amyloid (deposits of amyloid in lungs)
Interstitial Lung Disease (ILD) definition
group of diffuse and chronic diseases of pulmonary connective tissue – may affect alveolar walls/air spaces and bronchioles
ILD pathogenesis
- Trigger causes inflammation and fibrosis in bronchioles
- Leads to thickening = decreased lung compliance
Key clinical features of acute ILD
- Damage to lung parenchyma causing acute respiratory distress syndrome = respiratory alkalosis
Key clinical features of chronic ILD
- Can affect a lot of alveolar tissue before symptoms arise (dyspnoea increasing for months to years), clubbing, fine crackles, dry cough.
- End stages = honeycomb lung
Cystic fibrosis definition
- Inherited multiorgan disorder of epithelial cells affecting fluid secretion in exocrine glands and the epithelial lining of the respiratory, GI and reproductive organs.
Cystic fibrosis epidemiology
- Mostly Caucasians; common: 1/25 carrier
Cystic fibrosis aetiology
- Mutation in CFTR gene on chromosome 7
Cystic fibrosis pathogenesis
- defective CFTR protein means chloride ions can’t be transported out of cells
- Water can’t follow so mucous becomes sticky and causes bronchioles to become blocked
- Hyperplasia of mucus secreting glands, severe chronic bronchitis and bronchiectasis, atrophy and fibrosis of exocrine ducts
Key clinical features of CF
- Pancreatic problems = atrophy + fibrosis
- GI problems = meconium ileus
- Liver problems = plugging of bile canalucili = cirrhosis
- 95% of males are infertile
Treatment of CF
- 41 years median survival in UK – physio, mucolytics, transplants, vitamins
