Asthma USMLE Step 1 Practice Question
A 48-year-old woman with systemic sclerosis presents with progressive dyspnea, tight shiny skin over her fingers, and positive anti-topoisomerase I antibodies. Vital signs show BP 128/82, HR 98, RR 22, SpO2 92% on room air. High-resolution CT chest reveals early interstitial lung fibrosis. She denies orthopnea. Recent PFTs demonstrate reduced DLCO at 65% predicted. Pulmonary function testing is most likely to show which of the following?
Answer choices
- ADecreased FEV1 FVC ratio and increased TLC
- BDecreased TLC and decreased DLCOCorrect answer
- CNormal DLCO with isolated obesity pattern
- DIncreased residual volume with normal diffusion
- ENormal spirometry with elevated DLCO
- FPreserved FEV1/FVC ratio with decreased DLCO and normal TLC
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