Fluid behind the eardrum is a common cause of conductive hearing loss. The fluid in the middle ear behind the eardrum is usually caused by bacteria (or viruses) that enter from the nose or throat and ascend the Eustachian tube to reach the middle ear. This occurs when the Eustachian tube is not functioning properly often because the Eustachian tube is inflamed from a cold, sinus or throat infection, or an allergy attack. The opening of the Eustachian tube is in the naospharynx so it is easy for the bacteria or virus to find its way into the Eustachian tube and then into the middle ear.
The middle ear is lined with mucous membrane and it absorbs oxygen from the middle ear space. If fresh oxygen cannot travel through the Eustachian tube to replace the oxygen that has been absorbed, then negative pressure can develop in the middle ear. The negative pressure can be quite severe and that causes the eardrum to be retracted inward toward the middle ear space. The retracted ear drum does not transmit sound waves coming into the ear canal because the eardrum is “rigid” and the sound wave energy bounces off the eardrum rather than being transferred on to the inner ear. This of course leads to hearing loss.
If the fluid in the middle ear is not infected then it is called serous otitis media. However, if the fluid is infected with bacteria that has travelled through the Eustachian tube, then matters can get much worse. Infection in the middle ear causes earache, a red inflamed eardrum, and a build up of pus and mucus behind the eardrum. If the pressure builds enough, the eardrum will actually rupture. You may find drainage on your pillow or feel it running out of your ear. A ruptured eardrum is nature’s way of relieving the pressure. However, you want to receive treatment for this long before it reaches that point if you can.
If you are suspicious of a problem with your middle ear, then you should communicate with your primary care physician quickly. Your physician may recommend you to an audiologist for a hearing exam including a tympanogram. The tympanogram will measure not only the movement of the eardrum but also the pressure in the middle ear. Obtaining a tympanogram is usually a painless procedure and can usually be obtained on children without too much difficulty. If you child is constantly pulling at their ears it is possible that they may have fluid or significant negative pressure in their middle ear. Again, early detection is important since these conditions can cause hearing loss and can result in significant pain.