Pleural effusion, or fluid accumulation in the lungs, compresses the lungs, restricting respiratory function and leading to various symptoms. This condition has many different etiologies (causes). Some of these causes stem directly from lung pathologies, while others arise from systemic diseases outside the lungs.
Among lung-related causes, pneumonia stands out. Pneumonia is an infection commonly seen, especially in children, which can impede normal lung function and lead to fluid accumulation. Furthermore, various lung pathologies such as lung cancer, lung abscess, and interstitial lung diseases can also contribute to the development of pleural effusion.