Obstructive vs restrictive lung disorders - comparison, causes, manifestations seen in spirometry

Introduction

Obstructive lung disorders are denoted by an increased airflow resistance. Obstructive lung disorders include COPD, emphysema and chronic bronchitis. Restrictive lung diseases are denoted by decreased total lung capacity and decreased expansion of the lung parenchyma. Restrictive lung diseases include, chronic infiltrative and interstitial diseases like pneumoconioses and interstitial fibrosis of unknown origin, and chest wall disorders. Restrictive and obstructive lung diseases can be distinguished based on pulmonary function tests.

Comparison

When comparing obstructive and restrictive lung diseases, both manifest with dyspnea at exertion. The cause behind that dyspnea is different, in obstructive lung disease it's due to difficulty in exhalation due to the lung damage and airway narrowing. In restrictive lung disease, the cause behind dyspnea is reduced lung expansion. This could be due to weak respiratory muscles, nerve damage, lung stiffness. The treatment for these lung disorders also differs as treatment for obstructive lung disease requires bronchodilators, corticosteroids for inflammation, and even a lung transplant if severe. Treatment for restrictive lung disease can also be corticosteroids for inflammation, however treatment is specific, for example, pirfenidone can be used to treat idiopathic pulmonary fibrosis.

Causes

In obstructive lung disease, the most common causes are COPD, asthma, cystic fibrosis and bronchiectasis. In restrictive lung disease, conditions like sarcoidosis, obesity, scoliosis, neuromuscular disease like ALS or muscular dystrophy, and interstitial lung disease can be the cause.

Manifestations in Spirometry

When identifying obstructive or restrictive lung disease, a pulmonary function test is used where the patient forcefully blows air through a mouthpiece and the machine will measure the flow and volume of air through the lungs. In pulmonary function tests, those with obstructive lung disorder have lower maximal airflow rates in forced expiration. This means that the ratio of Forced Expiratory Volume at 1 second (FEV1) over Forced Vital Capacity (FVC) < 0.7. Those with restrictive lung disease have a proportionate decrease in both total lung capacity and in FEV1, but a normal FEV1/FVC ratio.

Sources

Kumar, V., Abbas, A. K., & Aster, J. C. (Eds.). (2018). Robbins basic pathology (10th ed.). Elsevier.

Pulmonary Practice Associates. “Lung Disease,” Pulmonary Practice Associates, https://pulmonarypracticeassociates.com/lung-disease/ (accessed December 19, 2025).