Question

question 30
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which of the following is an example of an obstructive lung disease that would have a normal tlc but a reduced fev1/fvc ratio?
pulmonary fibrosis
pneumonia
tuberculosis
asthma

Explanation:

• Pulmonary fibrosis: It is a restrictive lung disease. In restrictive lung diseases, TLC (Total Lung Capacity) is reduced, not normal. So this option is incorrect.
• Pneumonia: It can cause various changes in lung function. But it is not a typical obstructive lung disease. Obstructive lung diseases are mainly about airway obstruction. So this option is incorrect.
• Tuberculosis: It can affect the lungs in multiple ways (e.g., causing granulomas). But it is not a classic obstructive lung disease with the described FEV1/FVC ratio and normal TLC pattern. So this option is incorrect.
• Asthma: It is an obstructive lung disease. In asthma (especially in some stable or less - severe chronic cases), the airways are narrowed (obstructed). The TLC may be normal (as the lung tissue itself is not fibrotic or destroyed in a way that reduces the total volume in the early - stage or non - fibrotic cases). The FEV1 (Forced Expiratory Volume in 1 second) is reduced more than FVC (Forced Vital Capacity) because of the airway obstruction, leading to a reduced FEV1/FVC ratio.

Answer:

Asthma