PULMONARY FUNCTION TEST-PATHOLOGY

SUMMARY

RESTRICTIVE DISEASE
1. Restrictive disease decreases TLC due to extra-thoracic or intra-thoracic restriction.

2. In intra-thoracic disease (e.g. parenchymal disease, ILD), the RV is decreased unless there is concomitant obstructive disease. In extra-thoracic disease (e.g. obesity, kyphosis), the RV can be normal.

OBSTRUCTIVE DISEASE
3. Obstructive disease decreases expiratory flow rate due to increased expiratory airways resistance. Normal FEV₁/FVC = 80% and < 70% is abnormal.

4. Obstructive disease of the upper airway can be fixed (due to compressive tumors & tracheal stenosis) or dynamic (extra-throacic or intra-thoracic).

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].