Which spirometry pattern characterizes restrictive lung disease?

Which spirometry pattern characterizes restrictive lung disease?

• A. Reduced FVC with normal or increased FEV1/FVC ratio; decreased total lung capacity
• B. Increased FVC and TLC
• C. Decreased FEV1 with decreased FVC and decreased TLC
• D. Normal FEV1, FVC, and TLC

Answer: (A)

Restrictive lung disease limits how much the lungs can expand, so overall lung volumes drop. In spirometry, this shows up as a reduced FVC and a reduced total lung capacity, while the FEV1/FVC ratio stays normal or may be higher because FEV1 decreases in step with FVC. So the pattern of a lower FVC with a normal or increased FEV1/FVC ratio and a decreased TLC best matches restriction. The other scenarios don’t fit: increasing FVC and TLC would not indicate restriction; a pattern with both FEV1 and FVC decreased and TLC decreased would not have a preserved or raised FEV1/FVC ratio; and normal values show no restriction.

Restrictive lung disease limits how much the lungs can expand, so overall lung volumes drop. In spirometry, this shows up as a reduced FVC and a reduced total lung capacity, while the FEV1/FVC ratio stays normal or may be higher because FEV1 decreases in step with FVC. So the pattern of a lower FVC with a normal or increased FEV1/FVC ratio and a decreased TLC best matches restriction. The other scenarios don’t fit: increasing FVC and TLC would not indicate restriction; a pattern with both FEV1 and FVC decreased and TLC decreased would not have a preserved or raised FEV1/FVC ratio; and normal values show no restriction.