Based on pulmonary function testing, what condition is indicated by low FVC, high FEV1/FVC ratio, and low DLCO?

The combination of low forced vital capacity (FVC), a high forced expiratory volume in one second to forced vital capacity (FEV1/FVC) ratio, and low diffusing capacity for carbon monoxide (DLCO) is indicative of a restrictive lung disease, particularly idiopathic pulmonary fibrosis.

In idiopathic pulmonary fibrosis, the lung tissue becomes thickened and scarred, limiting the ability of the lungs to expand fully. This results in a decreased FVC, as the maximum volume of air that can be exhaled after a deep breath is reduced due to the stiffness of the lungs. The high FEV1/FVC ratio typically indicates that, although the total lung capacity is low, the airways remain open and can expel the air effectively during the forced expiratory maneuver.

The low DLCO is particularly significant in identifying pulmonary fibrosis because it points to impaired gas exchange in the alveoli, which is a hallmark of restrictive lung disease characterized by interstitial lung processes. In patients with idiopathic pulmonary fibrosis, the thickening of the alveolar walls interferes with the diffusion of gases, resulting in a significantly diminished DLCO.

Other conditions, such as chronic bronchitis and emphysema, tend to exhibit different pulmonary function test patterns,