Obstructive & Restrictive Lung Disease Flashcards
What are the shared characteristics of obstructive and restrictive lung diseases?
Not infectious, diffuse, chronic
What are the obstructive lung diseases?
Asthma, COPD, bronchiectasis
What is the obstructive pattern of spirometry?
Marked decrease in FEV1 and not much decrease in FVC
What is the restrictive pattern of spirometry?
FEV1 is a bit low and FVC is markedly decreased
What are the 3 aspects of COPD?
emphysema, chronic bronchitis and small airway disease
What is asthma?
The increased responsiveness of airways to various stimuli which causes bronchoconstriction and is partly reversible
What are the two types of asthma?
Allergic type (type 1 hypersensitvity) and non allergic
What is the pathophysiological mechanism of asthma?
A trigger causes the release of inflammatory mediators from mast cells, there is an immediate response of oedema, mucous production and bronchospasm and a late phase of inflammation where the epithelium starts to become damaged
What are the short term complications of asthma?
Death, collapse of lungs, rupture of lungs
What are the long term complications of asthma?
airway remodelling, chronic hypoxia leading to cor pulmonale
What is emphysema?
abnormal, permanent enlargement of air spaces distal to the terminal bronchiole from destruction of the alveolar wall without fibrosis
What are the types of emphysema?
centriacinar, panacinar, distal acinar, irregular
How does smoking cause emphysema?
Cigarette smoking attracts inflammatory cells, neutrophils release elastase, elastase damages elastic tissue. Cigarette smoking also impairs function of anti proteases
How is emphysema inherited?
Through a deficiency in alpha-1 antitrypsin - an anti protease
How does emphysema cause airway obstruction?
The loss of elastic tissue makes the airway floppy and so it is difficult to open
Which is more important in emphysema - airway obstruction or loss of gas exchange?
Airway obstruction
What are the complications of emphysema?
Hypoxia caused by airway obstruction and also loss of gas exchange surfaces, pulmonary hypertension leading to cor pulmonale, pneumothorax
What is bullous emphysema?
A localised area of emphysema which is fragile and may lead to a pneumothorax
What is chronic bronchitis?
A persistent cough with sputum for at least 3 months in 2 consecutive years
What is the pathogenesis of chronic bronchitis?
Inhaled substance causes chronic irritation which leads to increased mucous procution in the larger airways and airway inflammation, scarring and narrowing in the smaller airways
What happens at a cellular level in chronic bronchitis?
Hypetrophy of mucus secreting glands, increased goblet cells, increase in inflammatory cells, fibrosis around small airways, squamous metaplasia
What causes lung cancer?
Squamous metaplasia
What are the complications of chronic bronchitis?
Infections, hypoxia leading to cor pulmonale, lung cancer
What is small airways disease?
Chronic inflammation, fibrosis and obstruction of terminal bronchioles
How does smoking predispose to pulmonary infection?
inhibition of the much-cilary escalator, increased mucus, inhibition of leukocyte function, direct damage to epithelium
What is bronchiecstasis?
An irreversible, abnormal dilation of bronchi/bronchioles
What is idiopathic pulmonary fibrosis?
A common restrictive lung disease with unknown cause leading to interstitial fibrosis and inflammation
