Which of the following is NOT an example of a restrictive lung disease?

Restrictive lung diseases are characterized by a reduced ability of the lungs to expand, leading to decreased lung volume and difficulty in fully filling the lungs with air. These conditions often result from structural lung changes or parenchymal disease, which limit lung expansion.

Asthma, while it presents challenges in airflow, is primarily classified as an obstructive lung disease because it involves narrowing of the airways and difficulty in exhaling air, rather than a restriction in lung volume. Patients with asthma experience bronchoconstriction, inflammation, and increased mucus production, all of which lead to airflow limitation. This differentiates it from restrictive diseases.

On the other hand, both sarcoidosis and histoplasmosis can cause lung restriction by causing pulmonary fibrosis, inflammation, or granuloma formation, which hinder lung capacity. Toxoplasmosis can potentially affect lung function but is generally associated with immunocompromised states and may not directly classify under the restrictive category as clearly as the others. Thus, identifying asthma as the option that does not align with restrictive lung disease characteristics is correct.