Which condition is associated with thick mucus accumulation in the lungs?

Cystic fibrosis is associated with thick mucus accumulation in the lungs due to a genetic defect in the CFTR gene, which leads to altered ion transport. This results in the production of concentrated, viscous mucus that obstructs the airways and creates an environment conducive to recurrent lung infections. The thick mucus can trap bacteria and particles, making it difficult for the respiratory system to clear them, which can lead to chronic inflammation and lung damage over time. This condition often presents in early childhood and is characterized by symptoms such as persistent cough, difficulty breathing, and frequent lung infections. Treatment typically focuses on managing symptoms and minimizing lung infections.

In contrast, the other conditions listed typically involve different mechanisms or characteristics. Asthma primarily involves airway constriction and inflammation, pneumonia is an infection of the lungs that usually does not involve thick mucus buildup as a primary feature, and chronic bronchitis is characterized by a cough and mucus production, but the mucus is generally not as thick and tenacious as that seen in cystic fibrosis.