Marked decreased FVC and FEV1/FVC ratio are seen in –
**Core Concept**
The question tests the understanding of pulmonary function tests, specifically the Forced Vital Capacity (FVC) and the Forced Expiratory Volume in one second to FVC ratio (FEV1/FVC). This ratio is crucial in differentiating between obstructive and restrictive lung diseases.
**Why the Correct Answer is Right**
A marked decrease in both FVC and FEV1/FVC ratio indicates an obstructive lung disease. In such conditions, the airways are narrowed, making it difficult to exhale quickly, thus reducing FEV1 more significantly than FVC. However, without the specific answer choices, we focus on the principle that obstructive diseases like COPD or asthma characteristically show a decreased FEV1/FVC ratio due to airway obstruction.
**Why Each Wrong Option is Incorrect**
**Option A:** Would be incorrect if it suggested a restrictive pattern, which typically presents with a normal or increased FEV1/FVC ratio.
**Option B:** Might be incorrect if it represented a condition not associated with the described pulmonary function test abnormalities.
**Option C:** Could be incorrect if it indicated a normal pulmonary function test result or a different lung condition altogether.
**Option D:** Would likely be the correct choice if it represented an obstructive lung disease, given the decreased FEV1/FVC ratio.
**Clinical Pearl / High-Yield Fact**
Remember, obstructive lung diseases are characterized by a decreased FEV1/FVC ratio, whereas restrictive lung diseases typically show a normal or increased ratio. This distinction is key in interpreting pulmonary function tests.
**Correct Answer:** D. Obstructive lung disease.