What causes fluid in the middle ear?
Otitis media with effusion (OME) is inflammation and fluid buildup (effusion) in the middle ear without bacterial or viral infection. This may occur because the fluid buildup persists after an ear infection has resolved. It may also occur because of some dysfunction or noninfectious blockage of the eustachian tubes.
What causes OME?
Children are more likely to experience OME due to the shape of their eustachian tubes. Their tubes are shorter and have smaller openings. This increases the risk of clogging and infection. Children's eustachian tubes are also oriented more horizontally than in adults. This makes it more difficult for fluid to drain from the middle ear. And children have more frequent colds and other viral illnesses that can set them up for more fluid in the middle ear and more ear infections.
OME isn't an ear infection, but they can be related. For example, an ear infection can affect how well fluid flows through the middle ear. Even after the infection is gone, fluid may remain.
Also, a blocked tube and excess fluid can provide the ideal environment for bacteria to grow. This can lead to an ear infection.
Allergies, air irritants, and respiratory infections can all cause OME. Changes in air pressure can close the eustachian tube and affect fluid flow. These causes might be due to flying in an airplane or by drinking while lying down.
A common misconception is that water in the ear can cause OME. This is untrue.
What are the symptoms of OME?
OME isn't the result of an infection. Symptoms are often mild or minimal, and can vary based on a child's age. But not all children with OME have symptoms or act or feel sick.
One common symptom of OME is hearing problems. In younger children, behavior changes can be a symptom of hearing problems. For example, a child may turn the television up louder than usual. They may also tug or pull on their ears.
Older children and adults who have OME often describe sound as muffled. And they may have the feeling that the ear is full of fluid.
How is OME diagnosed?
A doctor will examine the ear using an otoscope, which is a magnifying glass with a lighted end used for looking inside the ear. The doctor will be looking for:
- air bubbles on the eardrum's surface
- an eardrum that appears dull instead of smooth and shiny
- visible fluid behind the eardrum
- an eardrum that doesn't move when a small amount of air is blown into it
More sophisticated testing methods are available. One example is tympanometry. For this test, a doctor inserts a probe into the ear. The probe determines how much fluid is behind the eardrum and how thick it is. An acoustic otoscope can also detect fluid in the middle ear.