What is a common cause of chronic serous otitis media?

Chronic serous otitis media is often characterized by the presence of fluid in the middle ear that is typically not infected. One of the most common causes of chronic serous otitis media is the enlargement of adenoids. When adenoids become enlarged, they can obstruct the Eustachian tubes, which connect the middle ear to the nasopharynx. This obstruction prevents normal ventilation and drainage of the middle ear, leading to a buildup of fluid and resulting in serous otitis media.

Mucus accumulation can also occur as a result of chronic inflammation or irritation in the middle ear, further contributing to the condition. In certain cases, lymphatic fluid may also accumulate, particularly in situations where there are underlying anatomical or functional issues affecting the middle ear and Eustachian tube.

Thus, all these factors—enlargement of adenoids, mucus, and lymph in the middle ear—can contribute to the development of chronic serous otitis media, making the option that includes all of them the most comprehensive and correct answer.