The Eustachian tube (ET) connects the air filled middle ear space to the throat. It’s function is mainly to keep the pressure in the middle ear equalized with pressure in the outside.
When the pressure becomes negative with respect to the outside world, the ear drum gets pulled inward. When pressure is positive, the ear drum bows outward.
A valve near the opening into the middle ear allows controls this process. The valve is usually closed, which keeps bacteria and various other things in the mouth and nose from getting into the middle ear.
It may be important to keep acid from the stomach from getting into the middle ear (Brunworth et al, 2014). It opens naturally when there is a big pressure difference between the middle ear and nose (such as when you blow your nose).
It often can be opened by yawning, opening the mouth widely, and swallowing. Some talented people can open it voluntarily.
When it cannot be opened easily, pressure differentials build up. Usually this results in a “full” feeling — whether the ear is over or under-pressurized with respect to the outside world.
There are other causes of “full” feelings — such as Meniere’s disease, but this is the only one that responds to “popping” of the ear.
Inability to pop the ears can be a problem in persons who fly on airplanes and who Scuba dive. In many cases, however, this may be alleviated by use of special ear plugs.
Fullness in the ears can be a very troublesome symptom that can also arise from TMJ (jaw joint) disturbances, migraine, and Meniere’s disease.
Function of the eustachian tube
The eustachian tube is a narrow, one and a half inch long channel connecting the middle ear with the nasopharynx, the upper throat area just above the palate, in the back of the nose.
The eustachian tube functions as a pressure equalizing valve for the middle ear which is normally filled with air. When functioning properly the eustachian tube opens for a fraction of a second periodically (about once every three minutes) in response to swallowing or yawning.
In so doing it allows air into the middle ear to replace air that has been absorbed by the middle ear lining (mucous membrane) or to equalize pressure changes occurring on altitude changes.
Anything that interferes with this periodic opening and closing of the eustachian tube may result in hearing impairment or other ear symptoms.
Obstruction or blockage of the eustachian tube results in a negative middle ear pressure, with retraction (sucking in) of the eardrum membrane.
In the adult this is usually accompanied by some ear discomfort, a fullness or pressure feeling and may result in a mild hearing impairment and head noise (tinnitus). There may be no symptoms in children.
If the obstruction is prolonged, fluid may be drawn from the mucous membrane of the middle ear creating a condition we call serous otitis media (fluid in the middle ear).
This occurs frequently in children in connection with an upper respiratory infection and accounts for the hearing impairment associated with this condition.
Occasionally pain or middle ear fluid develops when landing in an aircraft. This is due to failure of the eustachian tube to properly equalize the middle ear air pressure and the condition is called aerotitis.
It is temporary and often can be avoided by taking precautions.
On occasions just the opposite from blockage occurs: the tube remains open for prolonged periods. This is called abnormal patency of the eustachian tube. This condition is less common than serous otitis media and occurs primarily in adults.
Because the tube is constantly open the patient may hear himself breathe and hears his voice reverberate. Fullness and a blocked feeling are not uncommon. Abnormal patency of the eustachian tube is annoying but does not produce hearing impairment.
How people change the pressure (pop)their ears.
You may have noticed that your ear pops when you blow your nose. Sometimes people learn or are taught how to blow pressure up into the middle ear. This is generally done by basically the same technique as blowing the nose, but the nose is pinched completely shut.
Pressure created by blowing will often go upward into the ET, open the valve, and overpressurize the middle ear (notice that we didn’t say that it normalizes pressure)
This is called “Self Politzerisation”, after it’s inventor, Dr. Adam Politzer. Dr. Politzer devoted most of his career to the ET. Amazingly enough, there is presently a society named after Dr. Politzer.
How pressure changes can (rarely) damage the ear.
While generally, blowing the nose forcefully with the nostrils pinched shut or using the fancier name — self-Politzerisation — does not cause any harm, people who do this very frequently or use very high pressure can damage their ear drum.
This can cause the ear drum to “sag”, which reduces hearing and also alters ear test results (tympanometry).
Extremely rarely, people who create very high pressure differentials in their middle ear, perhaps by Scuba diving, can damage the inner ear by causing a fistula.
Usually, ETD is diagnosed by talking to the patient, and identifying symptoms that clear with manipulation of the ET, such as by “popping” the ear. A ETD questionnaire was developed in 2014 called the EDTQ-7 (Schroder et al, 2014). We are dubious that a questionnaire is needed for this simple diagnosis.
Formal measurement of ET function
Eustachian tube function can be evaluated formally by the process of measuring pressure in the ear using tympanometry, documenting that it is different than 0, then having the person attempt to open up their ET, and then measuring it again.
If pressure changes, then the ET opened. If it didn’t, either the pressure was normal to start with, or the tube didn’t open.
Eustachian tube disorders (ETD)
Eustachian tube function changes with age, and some disorders may derive from this (Suzuki et al, 2003).
Allergies are common causes of ETD.
Eustachian tube function may be poor for several months after a bout of otitis media (Caye-Thomasen and Tos 2004).
ETD may be in some way related to gastric reflux (Brunworth et al, 2014)
The Eustachian tube may be open too much (“patulous”), close too much resulting in negative pressure in the ear, or open/close too much (popping).
The patulous (open too much) eustachian tube is also diagnosed by noting that people have autophony (hear their own voice in their ear), an abnormal resonance to the voice (due to the tube being open), or the simple expedient of watching the ear drum move while the person breathes.
The Japanese recently described another method involving testing hearing with masking noises inserted into the nose (Hori et al, 2006). While clever, diagnosis is generally so easy that procedures are unnecessary.
There are rare disorders where the ET opens regularly and periodically — mainly palatal myoclonus. This is a fascinating condition where the palate moves up and down rhythmically, and is often accompanied by rhythmical oscillation of the ET too.
A ventilation tube being placed in the ear drum.
Treatment of ETD is not very sophisticated or effective.
For the usual type of ETD (closed), medications for allergy such as decongestants, systemic or local antihistamines and nasal topical steroids are commonly tried. We are particularly fond of using “Astelin”, which is a prescription antihistamine nasal spray, as well as kits that involve irrigation of the nose with salt water.
Occasionally, people with severe symptoms due to ET dysfunction may have a ventilation tube placed in their ear drum. This relieves the symptoms of ET dysfunction but creates a perforation in the eardrum which reduces hearing to a small extent as well as provides a potential entry point for infection.
However, in most cases, it is worth it to find out if symptoms respond to ventilation of the ear.
Methods of treatment aimed at “patulous” (abnormally open) eustachian tubes include Premarin nose drops or nasal spray (compounded 25 mg in 30 cc NS), and insufflation of boric acid and salicylate powder as described by Bezold.
These agents are intended to close eustachian tubes, and would not be appropriate for persons who have plugged eustachian tubes rather than abnormally open ones.
As a last resort, a patulous eustachian tube may be closed surgically (Rotenberg et al, 2012) and a perforation created in the eardrum. However, it is difficult to imagine a situation where this would be desirable.