What is the Eustachian tube?
The Eustachian tube originates in the rear of the nose adjacent to the soft palate, runs a slightly uphill course, and ends in the middle ear space. The middle ear space is the hollowed out portion of the skull bone that contains the hearing apparatus and is covered on one side by the eardrum. In adults, the Eustachian tube is approximately 35 mm long (1.3 inches) and approximately 3 mm in diameter (less than 1/10 inch). Cartilage provides the supporting structure for the first two-thirds of the Eustachian tube, with the last third (the part closest to the middle ear space) being made of bone.
The tissue that lines the Eustachian tube is similar to that inside the nasal cavity and may respond the same way (swelling) when presented with similar stimuli. The Eustachian tube was named in honor of the 16th century Italian anatomist Eustachius. Sources credit Almaceon of Sparta as the first to describe the structure in approximately 400 BC.
What are the functions of the Eustachian tube?
The primary function of the Eustachian tube is to ventilate the middle ear space, ensuring that its pressure remains at near normal environmental air pressure. The secondary function of the Eustachian tube is to drain any accumulated secretions, infection, or debris from the middle ear space. Several small muscles located in the back of the throat and palate control the opening and closing of the tube. Swallowing and yawning cause contractions of these muscles located in the back of the throat and help regulate Eustachian tube function. If it were not for the Eustachian tube, the middle ear cavity would be an isolated air pocket inside the head that would be vulnerable to every change in air pressure and lead to unhealthy middle ear space function.
Normally, the Eustachian tube is closed, which helps prevent the inadvertent contamination of the middle ear space by the normal secretions found in the back of the nose. A dysfunctional Eustachian tube that is always open is called a "patulous" Eustachian tube. Patients with this rare condition are plagued by chronic ear infections. A much more common problem is a failure of the Eustachian tube to effectively regulate air pressure. Partial or complete blockage of the Eustachian tube can cause sensations of popping, clicking, and ear fullness and occasionally moderate to severe ear pain. Such intense pain is most frequently experienced during sudden air pressure changes during airplane travel, particularly during take-off and landing. Young children may describe the popping sensation as "a tickle in my ear."
As Eustachian tube function worsens, air pressure in the middle ear falls, and the ear feels full and sounds are perceived as muffled. Eventually, a vacuum is created which can then cause fluid to be drawn into the middle ear space (termed serous otitis media). If the fluid becomes infected, the common ear infection (suppurative otitis media) develops.
Picture of the Stuctures of the Inner EarWhat can cause Eustachian tube blockage?
The Eustachian tube can be blocked, or obstructed, for a variety of reasons.:
Eustachian tube problems and the associated ear infections are among the most common problems seen by doctors. Many people have chronic problems regulating middle ear pressure. Causes range from allergies to excessively small Eustachian tubes (as may afflict children with Down Syndrome). These patients often notice intermittent ear fullness, ear popping or cracking, mild hearing loss (an attenuation of sound), ringing in the ears (tinnitus), and/or occasional poor balance. Smoking is associated with damage to the cilia that sweep along mucus and debris from the middle ear space to the back of the nose where it may be expelled.
How do changes in altitude or air travel affect Eustachian tube problems?
A rapid change in altitude, and thus air pressure is equalized across the eardrum by a normally functioning Eustachian tube. A healthy tube opens frequently and widely enough to equalize these changes in air pressure. With altitude changes during the descent of an airplane, air pressure increases as the plane lowers. The air pressure change pushes the eardrum inward (retraction). Persons with Eustachian tube blockage can develop fullness of the ear, dulled hearing, and possibly pain when this occurs. Those with poorly functioning Eustachian tubes may experience similar symptoms when riding in elevators, driving through the mountains, or diving to the bottom of a swimming pool. Scuba divers learn tricks to equalize their ear pressures.
How is Eustachian tube blockage treated?
Several maneuvers may be done to improve Eustachian tube function and thus aid in equalization of air pressure.
Many individuals who travel with Eustachian tube problems use a decongestant pill or nasal spray an hour prior to takeoff, and if necessary, prior to descent. The decongestant acts to shrink the membranes lining the nose and throat, allowing the ears to equalize more easily. Similarly, patients experiencing chronic daily problems with Eustachian tube dysfunction can benefit by aggressive control of allergies (with antihistamines, decongestants, and prescription nasal sprays). Allergy evaluation can be helpful. In severe situations, a "pressure equalization tube" (PET) can be surgically placed in the eardrum, replacing the role of a functioning Eustachian tube, and thus guaranteeing equalization of middle ear pressure.
What can cause Eustachian tube blockage?
The Eustachian tube can be blocked, or obstructed, for a variety of reasons.:
Eustachian tube problems and the associated ear infections are among the most common problems seen by doctors. Many people have chronic problems regulating middle ear pressure. Causes range from allergies to excessively small Eustachian tubes (as may afflict children with Down Syndrome). These patients often notice intermittent ear fullness, ear popping or cracking, mild hearing loss (an attenuation of sound), ringing in the ears (tinnitus), and/or occasional poor balance. Smoking is associated with damage to the cilia that sweep along mucus and debris from the middle ear space to the back of the nose where it may be expelled.
How do changes in altitude or air travel affect Eustachian tube problems?
A rapid change in altitude, and thus air pressure is equalized across the eardrum by a normally functioning Eustachian tube. A healthy tube opens frequently and widely enough to equalize these changes in air pressure. With altitude changes during the descent of an airplane, air pressure increases as the plane lowers. The air pressure change pushes the eardrum inward (retraction). Persons with Eustachian tube blockage can develop fullness of the ear, dulled hearing, and possibly pain when this occurs. Those with poorly functioning Eustachian tubes may experience similar symptoms when riding in elevators, driving through the mountains, or diving to the bottom of a swimming pool. Scuba divers learn tricks to equalize their ear pressures.
How is Eustachian tube blockage treated?
Several maneuvers may be done to improve Eustachian tube function and thus aid in equalization of air pressure.
Many individuals who travel with Eustachian tube problems use a decongestant pill or nasal spray an hour prior to takeoff, and if necessary, prior to descent. The decongestant acts to shrink the membranes lining the nose and throat, allowing the ears to equalize more easily. Similarly, patients experiencing chronic daily problems with Eustachian tube dysfunction can benefit by aggressive control of allergies (with antihistamines, decongestants, and prescription nasal sprays). Allergy evaluation can be helpful. In severe situations, a "pressure equalization tube" (PET) can be surgically placed in the eardrum, replacing the role of a functioning Eustachian tube, and thus guaranteeing equalization of middle ear pressure.
Source: http://www.rxlist.com
Many individuals who travel with Eustachian tube problems use a decongestant pill or nasal spray an hour prior to takeoff, and if necessary, prior to descent. The decongestant acts to shrink the membranes lining the nose and throat, allowing the ears to equalize more easily. Similarly, patients experiencing chronic daily problems with Eustachian tube dysfunction can benefit by aggressive control of allergies (with antihistamines, decongestants, and prescription nasal sprays). Allergy evaluation can be helpful. In severe situations, a "pressure equalization tube" (PET) can be surgically placed in the eardrum, replacing the role of a functioning Eustachian tube, and thus guaranteeing equalization of middle ear pressure.
Source: http://www.rxlist.com
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