pathology of obstructive airway diseases Flashcards
What are the main obstructive airway diseases
Asthma and COPD
COPD - chronic bronchitis and emphysema
What is the normal FEV1 and FVC
FEV1 - 3.5-4L
FVC - 5L
FEV1/FVC = 0.7-0.8
What happens to the FEV1 and FVC in obstructive lung disease
Airflow limitation therefore:
Peak expiratory flow rate is reduced
FEV1 reduced
FVC may be reduced but not significantly
FEV1/FVC will decrease as FEV1 will decrease more than FVC will
What is bronchial asthma
Bronchial smooth muscle contraction and inflammation which is reversible, either spontaneously or by medical intervention
What is the clinical diagnosis for chronic bronchitis
Cough productive of sputum often for at least 3 consecutive months for 2 or more consecutive years
What is complicated chronic bronchitis
Sputum turns mucopurulent (acute infective exacerbation) or the FEV1 drops
What does chronic bronchitis do to large airways
Mucous gland and goblet cell hyperplasia
Inflammation and fibrosis is a small component
What does chronic bronchitis do to small airways
inflammation and fibrosis
What is the definition of emphysema
Pathological increase in the airspace distal to the terminal bronchiole from dilatation or from destruction of their walls
What happens in centri-acinar emphysema
It begins with bronchiolar dilatation and then alveoli tissue begins to be lost
What is a bulla
Emphysematous space >1cm
What happens to the inflation of the lung in emphysema
Hyperinflation but the lung loses its capabilty to stretch
Why does COPD cause hypoxaemia
Airway obstruction which reduced respiratory drive and reduced the alveolar surface area.
What happens to pulmonary vessels when there is hypoxaemia
They constrict to make for a shunt
This can lead to pulmonary hypertension
What is chronic cor pulmonale
Hypertrophy of the right ventricle resulting from disease affecting the structure or function of the lung
