Marked decreased FEV1 and FEV1/ FVC ratio are seen in
**Core Concept**
A marked decreased FEV1 and FEV1/FVC ratio are indicative of obstructive lung disease, characterized by airway narrowing or obstruction, leading to difficulty in exhaling air. This is often associated with conditions such as COPD, asthma, or bronchiectasis.
**Why the Correct Answer is Right**
The FEV1 (Forced Expiratory Volume in 1 second) measures the amount of air exhaled in the first second of a forced exhalation, while the FVC (Forced Vital Capacity) measures the total amount of air exhaled. In obstructive lung disease, the airways are narrowed, making it harder to exhale air quickly, resulting in a decreased FEV1. Additionally, the FEV1/FVC ratio is also decreased, as the airways obstruction affects the ability to exhale air efficiently, leading to a prolonged exhalation time.
**Why Each Wrong Option is Incorrect**
**Option A:** This option would be incorrect as it does not specify a condition that affects the lung parenchyma or airways directly.
**Option B:** This option would be incorrect as it does not specifically describe a condition that affects the lung function, particularly the FEV1 and FVC ratio.
**Option C:** This option would be incorrect as it describes restrictive lung disease, which is characterized by a decreased FVC with a relatively preserved FEV1/FVC ratio.
**Clinical Pearl / High-Yield Fact**
A mnemonic to remember the key features of obstructive vs. restrictive lung disease is: "Obstructive: FEV1/FVC ratio 0.7, FVC decreased."
**Correct Answer: C. Restrictive lung disease**