Question

Discuss the difference between restrictive and obstructive lung disease, In your answer include any diagnostic criteria used to differentiate between the two and any alterations in lung volumes.

Answer 1

The lung diseases are main categorised into restrictive and obstructive lung disease. The difference in between this two type of lung diseases are as follows.

i) First of all restrictive lung disease is kind of lung disease where the lungs are not fully capable to expand with air during inspiration, so in this type the expanding capabilities of lungs are restricted due to some intrinsic effect ti parenchyma tissue of the lungs. But in case of obstructive lung disease, there are some obstruction in the airways passage of the respiratory tract. Due to this high airway resistance the air flow through the respiratory tract is obstructed. This situation is called obstructive lung disease.

ii) kyphoscoliosis is a condition where the rib cage has some deformities, this deformities in thoracic rib cages restrict the lungs to expand property and lead to restrictive lung disease. In other side emphysema is a type of obstructive lung disease where the air sacs are weakened due to some clinical conditions and this situation obstruct the air flow through the airways of respiratory tract and increases the airways resistance. This develope obstructive lung disease.

iii)Diagnostic criteria: In case of restrictive lung disease the forced vital capacity (FVC) is reduced, but in this condition lungs can maintain high air flow rates so the percentage of FEV1( forced expiratory volume in 1second) or FEV% exceeds 80%. But in case of obstructive lung disease, the FVC and FEV1% both are reduced so the lungs couldn't maintain the high air flow through the respiratory tract of lungs. The FEV1% is case of obstructive lung disease is almost near 25%.

FEV1% is the ratio if FEV1 and FVC (FEV1/FVC * 100).

SO, by calculating FEV1%, we can easily differentiate restrictive and obstructive lung disease.

[FVC is the forced vital capacity that means the volume of air that can be expired rapidly with maximum force and followed by a maximum inspiration.] This volume of air is reduced in both restrictive and obstructive lung disease. But the reduction of FVC is much more in restrictive lubg diseases than obstructive lung diseases.