Eustachian tube dysfunction (ETD): Description, Causes and Risk Factors:
Eustachian tube: A tube leading from the tympanic cavity to the nasopharynx; it consists of an osseous (posterolateral) portion at the tympanic end, and a fibrocartilaginous (anteromedial) portion at the pharyngeal end; where the two portions join, in the region of the sphenopetrosal fissure, is the narrowest portion of the tube (isthmus); the auditory tube enables equalization of pressure within the tympanic cavity with ambient air pressure, referred to commonly as “popping of the ears.”
The eustachian tube connects the middle ear (the main cavity of the ear; between the eardrum and the inner ear) to the throat. Its purpose is to equalize middle ear pressure with environmental pressure. When your ear "pops" on a high-speed elevator or in an airplane, the reason is that the eustachian tube has opened and equalized pressure. Occasionally people develop symptoms when the eustachian tube does not equalize pressure. In other words, it is closed when it should be opened. This may involve pain or fullness. It may be a particular problem and source of severe pain when flying on airplanes, ascending tall buildings, or diving. 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.
Another variant of eustachian tube dysfunction is when the eustachian tube is chronically open, called a "patulous" eustachaian tube. This causes a "man in a barrel" sensation when one talks.
Finally, sometimes the eustachian tubes opens and closes rhythmically, causing a clicking noise. This is usually due to palatal myoclonus, which is discussed elsewhere. Colds and other nose, sinus, ear or throat infections.
This is the common cause of ETD. The blocked nose, or thick mucus that develops during a cold or other infections, may block the Eustachian tube. An infection may also cause the lining of the Eustachian tube to become inflamed and swollen. Most people will have had one or more episodes in their life when they have had a cold and find that they cannot hear so well due to ETD. The symptoms of ETD may persist for up to a week or so (sometimes longer) after the other symptoms of the infection have gone. This is because the trapped mucus and swelling may take a while to clear even when the infecting germ has long gone.
• Sometimes the infection is very mild. Perhaps a mild cold with a mild bunged up nose. However, ETD may still develop in some people for a while.
• Glue ear: Glue ear is a condition where the middle ear fills with glue-like fluid. The eustachian tube becomes congested and prevents the free flow of air into the middle ear, causing the difference in air pressure mentioned above. The eardrum becomes tight, reducing its ability to vibrate, resulting in dulled hearing. The situation is made worse by the glue-like fluid damping down the vibrations of the drum even further. It is a common condition in children. It clears by itself in most cases but some children need an operation to solve the problem.
• Allergies: Allergies that affect the nose, such as perennial rhinitis and hay fever, can cause extra mucus and inflammation in and around the eustachian tube and lead to ETD.
• Blockages: Anything that causes a blockage to the eustachian tube can cause ETD. For example, enlarged adenoids. Rarely, ETD can be a symptom of rare tumours that sometimes develop at the back of the nose. These will usually cause other symptoms in addition to ETD.
The main symptom is muffled or dulled hearing. You may also have ear pain because the eardrum is tensed and stretched.
Other symptoms that may also develop include:
• A feeling of fullness in the ear.
(ringing or buzzing in the ear).
Symptoms can last from a few hours to several weeks or more. It depends on the cause. In most cases due to a cold (the common cause) the symptoms are likely to go within a week or so. As symptoms are easing, you may get popping sensations or noises in the ear. Also, the dulled hearing may come and go for a short time before getting fully back to normal.
Diagnosis is generally made from history. Someone who reports that they have fullness in their ears, which clears when they swallow or "pop" them, has ETD of the most common kind -- the ET is not opening when it should. One can prove that the ET opens or not, using tympanometry. This is simply a method of recording pressure in the ear. 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 expediant 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.
Treatment of eustachian tube dysfunction (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 ETD may have a ventilation tube placed in their eardrum (the membrane in the ear that vibrates to sound). This relieves the symptoms of ETD 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 and insufflation of boric acid and salicylate powder as described by Bezold. These agents are intended to close eustachaian 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 and a perforation created in the eardrum. However, it is difficult to imagine a situation where this would be desirable.
NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.