OBSTRUCTIVE LUNG DISEASE Flashcards
In simple terms, what is the difference between obstructive and restrictive lung disease?
- obstructive: hindered ability to fully exhale
- restrictive: difficulty fully expanding lungs
think: “restricted access”
In terms of respiratory function tests, what is the hallmark of obstructive lung disease?
explain why
Reduced FEV1/FVC
FEV1 falls more than FVC
Why is there increased lung capacity in obstructive lung disease? Why is the opposite true in restrictive disease?
Air trapping, abnormal retention of air in lungs, difficult to exhale completely
- observed in obstructive lung diseases such as asthma, bronchiolitis obliterans syndrome and chronic obstructive pulmonary diseases such as emphysema and chronic bronchitis
restrictve disease: lungs can’t fill as much = reduced total lung volume
What are the 4 key obstructive lung diseases? How do you differentiate between them?
- Chronic bronchitis
- emphysema
- asthma
- bronchiectasis
Asthma respond to bronchodilators
Why do you get shunting in chronic bronchitis (COPD)? What does this cause? How does it affect response to 100% oxygen?
Mucus plug blocks some alveoli and not others to varying degrees of severity
- Capillaries supplying blocked alveoli will not be oxygenated
- Other capillaries will be maximally oxygenated
⇒ more shunt physiology they have, the less responsive to oxygen administration
Why are alveoli destroying in emphysema?
- Too many proteases vs anti-proteases
- Reduces elastic recoil = lung collapse in exhalation
A patient with typical COPD symptoms who has never smoked and has panacinar involvement is likely to have which condition?
a1 anti-trypsin deficiency
What is aspirin exacerbated respiratory disease? What triad is it associated with? Best treatment?
Samter’s Triad: asthma, sinus disease with nasal polyps, sensitivity to aspirin / NSAIDs
dysgegulation of arachadonic acid metabolism = overproduction of leukotrienes
Tx of choice: montelukast
What is pulsus paradoxus? What are two non-cardiac causes?
Pulsus paradoxus refers to exaggerated fall in BP during inspiration by greater than 10 mmHg
Asthma, COPD
Recurrent RTIs can lead to which obstructive lung disease? Why is it obstructive?
Bronchiectasis - bronchial tubes permanently damaged, widened, thickened. The small and medium bronchioles are narrowed due to thickening of walls which is why this is obstructive
Which lobes of the lung are most likely to be affected by smoking?
Upper lobes (smoke rises)
Centrilobular (centriacinar): primarily upper lobes. Occurs with loss of respiratory bronchioles in proximal portion of acinus, with sparing of distal alveoli: most typical for smokers.
Panlobular (panacinar): involves all lung fields, particularly bases.
What should you consider in somebody with COPD who presents with red hands and feet and itching after going in the bath?
Polycythaemia: chronic hypoxaemia causing production of EPO
