Session 2 - Lung Diseases Flashcards
(22 cards)
What is interstitial lung disease and give an example
Stiff lungs due to fibrotic tissue in interstitial space (between alveolar cells and capillary basement membrane)
Many causes
End result tissue injury and fibrosis
What effects does fibrotic tissue in the interstium have on the lungs ( pathophysiology )
Lungs stuff , hard to expand since collagen less stretchy than elastin, lung compliance reduced
Elastic recoil incr ( both elastin and collagen fibres returning to original size , collagen not stretchy )
Small lungs due to incr elastic recoil
Reduced chest expansion on examination
Causes restrictive type of vent defect
Why are the airways normal in interstitial lung disease and what’s it called
Fibrous tissue exert outward pull ( radial traction ) on small bronchioles keep airways open
Why in interstitial disease would oxygen values decrease but co2 normal
Thickening of alveolar walls increases the distance o2 has to diffuse from alveolar air to blood
But the effect on diffusion of o2 is greater than that on Co2 which is more soluble
What are symptoms and signs of interstitial disease
Shortness of breath, reduced exercise tolerance, dry cough
Signs : incr resp rate , tachycardia
Many causes but all have same result (sometimes not even known cause) for interstitial lung disease
Do not need to know list of causes
What is respiratory distress syndrome
Occur in newborns (another stiff lung disorder(
Deficiency of surfactant in babies less than 32 weeks
Describe what happens in RDS
Without surfactant the ST in alveoli is high making lungs harder to expand so some alveoli collapse and no gas exchange occur
Stiff lungs so low compliance
More effort to breathe resulting in impaired ventilation
Signs of RDS
Grunting
Cyanosis
Intercostal recession on inspiration
Treatment of RDS
Surfactant replacement and o2 with assistant ventilation
What is emphysema and what does it cause
Loss of elastin and breakdown of alveolar walls
causes incr lung compliance and narrowing of small air ways
What is the main cause of emphysema and why
COPD - caused by smoking which breaks down elastin fibres in alveolar walls
Pathophysiology (due to loss of elastin , opp of lung fibrosis)
Lungs EASY to expand as there is LESS elastin so compliance incr
Elastic recoil reduced which cause lungs to be hyper inflated at rest
Barrel chest due to hyper inflation
Small airways narrow due to loss of elastin exerting outward force (radial traction) on small bronchioles
Obstructive type of defect
Symptoms of emphysema
Shortness of breath and reduced exercise tolerance
What is one main lung function test
Spirometry
What is asthma and what triggers it
What happens (pathophysiology)
Chronic inflam process which can be triggered by allergies
Airway narrowing due to bronchial smooth muscle contraction
Thickening of airway walls by mucosal oedema and excess mucus production can partially block lumen
Describe what a pneumothorax is
Air enters pleural space, loss of pleural seal along with lung collapse
At rest, the neg pressure is slightly less than atmospheric creating pleural seal to keep lungs adhered to chest wall but when opening created air will flow into pleural cavity down pressure gradient until pressure in pleural sanity reaches atmospheric
Breaks pleural seal which disrupts elastic recoil causing lung to collapse toward hilum cuz neg pressure and chest wall outward recoil cannot counteract it
What are others causes of lung collapse (atelectasis)
- incomplete expansion of lungs
- collapse of previously inflated lung producing areas of airless parenchyma
What are the main types of acquired atelectasis (lung collapse)
- compression occur when fluid or air acculturate in pleural cavity
- resorption from complete airway obstruction cuz overtime air is resorbed from alveoli which collapse (bronchial carcinoma)
When the term lung collapse is used on its own what is it referring to
Resorption atelectasis secondary to airway obstruction ( lung tumour etc )
What is hypoventilation
Poor expansion of thoracic cavity or lungs
Cause : resp uncle weakness , thoracic wall defects can cause this and resp failure , stiff lungs , severe airway constriction
What is required for normal ventilation
Neurones from resp center in brain to reach resp muscles via spinal nerves
Expansion of thoracic cavity and lungs
Normal bony thorax
