Fluid in the space behind the eardrum (middle ear) is called otitis media with effusion. It occurs when a eustachian tube (which connects the throat and middle ear) is blocked. This keeps fluid from draining normally out of the middle ear space and prevents air from entering the middle ear.

Fluid in the middle ear may:

• Cause sounds to be muffled.
• Cause mild discomfort. The pain usually increases with changes in atmospheric pressure, such as increasing cabin pressure when an airplane is coming down to land.
• Create an environment for the growth of viruses or bacteria, which may cause infection. But fluid in the middle ear does not always mean that an infection is present.

The body usually reabsorbs the fluid that is behind the eardrum within weeks. As the fluid is reabsorbed, hearing gradually returns to normal. If fluid is still present in the middle ear after a few months, you and your doctor may talk about having ear tubes placed to help drain the fluid.