Restrictive Lung Disease

Restrictive lung diseases are a heterogeneous set of pulmonary disorders defined by restrictive patterns on spirometry. These disorders are characterized by a reduced distensibility of the lungs, compromising lung expansion, and, in turn, reduced lung volumes, particularly with reduced total lung capacity (TLC). These functional and other characteristics allow to differentiate them from obstructive pulmonary diseases such as chronic obstructive pulmonary disease (COPD), bronchiectasis, asthma, emphysema, and bronchiolitis characterized by increased resistance to flow due to obstruction partial or complete at any level, from the trachea to the terminal bronchioles. In numerical terms, restrictive syndromes account for about a fifth of pulmonary syndromes, while obstructive syndromes are the majority (80%).

Restrictive lung diseases may be caused by the destruction of distal lung parenchyma due to infiltrates from inflammation, toxins, and mechanisms yet to be elucidated (intrinsic conditions) as well as extra parenchymal conditions (extrinsic causes). Within the former group, there are diseases characterized by inflammatory changes involving the alveolar interstitium with possible involvement of the peripheral bronchial structures. The conditions leading to this destruction are encompassed among the interstitial lung diseases (ILDs). This term refers to an umbrella with numerous disorders that are characterized by diffuse cellular infiltrates in a periacinar location, including clinical conditions that vary from occasional self-limited inflammatory processes to severe debilitating fibrosis of the lungs. Other conditions originate from within the alveolus (e.g., edema, hemorrhage) and spread to interstitial structures. If the process starts from the interstitium or from the alveolus, in both cases, alteration of the lung architecture, which reverberates into functional impairment occurs.

On the other hand, restrictive lung diseases may also result from limitations in neuromuscular function and chest wall movements (extrinsic causes). These may be due to neuromuscular diseases, pleural disorders, obesity, costosternal or costovertebral fusion, a fusion or deviation of the thoracic vertebra, and other etiologies that result in a physical impediment to inspiration. Regardless of the intrinsic or extrinsic mechanisms, these diseases are featured by impaired ventilatory function and respiratory failure.

A brief review of the restrictive lung diseases would be discussed. Because the topic is vast, here we have prepared an overview of the disorders, including their diagnosis, treatment, and more.