What are the key features of restrictive lung diseases?

The key features of restrictive lung diseases primarily include reduced lung volumes and increased work of breathing. In restrictive lung conditions, the ability of the lungs to expand is diminished, resulting in a decrease in lung capacity. This could be due to several factors, including stiffness of the lung tissue, pleural disease, or neuromuscular disorders that impair the chest wall's ability to expand properly.

Patients with restrictive lung disease often experience an increased work of breathing as they use more muscular effort to help expand the lungs against the reduced compliance. The overall reduction in lung volumes means that less air can be inhaled, which contributes to breathing difficulties and often leads patients to exhibit symptoms such as shortness of breath, especially during exertion.

The other response options do not accurately reflect the nature of restrictive lung diseases, as increased lung volumes and normal lung function tests are more indicative of obstructive lung diseases, while increased lung compliance would suggest a different pathological condition entirely. Therefore, the combination of reduced lung volumes along with the increased effort required for breathing epitomizes the challenges faced in restrictive lung diseases.