Otitis media with effusion is fluid in the space behind the eardrum (middle ear). This condition occurs when a blockage of the tube that connects the throat and middle ear (eustachian tube) prevents fluid from draining normally out of the middle ear space and prevents air from entering the middle ear.
Fluid in the middle ear may:
The body usually reabsorbs the fluid 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, or is accompanied by prolonged fever and other symptoms, antibiotic treatment may be necessary.
WebMD Medical Reference from Healthwise