is often the most common cause of fluid behind eardrum, adults group especially. The Eustachian tube delivers three essential physiological functions within the body, which is the equilibration of pressure between the external and middle ears, secretion and cleansing, and protection of the middle ear. Abnormalities can occur in the region due to blockage, trauma, inflammation, or infection, among other things. The condition often develops after sever upper respiratory infection, allergic reactions, or rapid changes in air pressure (barotrauma).
The Eustachian tube connects the ear to the throat, and it helps to drain fluid from the ear and into the throat where it can be swallowed, this helps to prevent the accumulation of fluid within the ear
This condition is connected with ear infection in two ways:
After the treatment of many ear infections, fluid will remain in the middle ear for several days. When the Eustachian tube becomes partially blocked, fluid begins to accumulate in the middle ear. Bacteria can then begin to accumulate within the liquid, which can result in an infection.