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Ear Barotrauma
ALTERNATIVE NAMES: Barotitis.
DEFINITION: Trauma to the eardrum, middle ear, or inner ear structures as a result of changes in barometric pressure.
WHAT IS GOING ON IN MY BODY? With a normally functioning eustachian tube that opens every time an individual swallows, there is equalization of air pressure across the eardrum. Normal atmospheric pressure is placed on all surfaces of the body, including the outer surface of the eardrum. The eustachian tube, which allows air to move from the back part of the nasal cavity into the space behind the eardrum, also allows the same atmospheric pressure to be behind the eardrum. As long as equal pressure is on either side of the eardrum, it stays in its normal position. When you fly or descend from any altitude, such as being in the mountains, it is normal to have the ear with descent start to feel plugged up and with swallowing or yawing to feel the ear pop, with restoration of hearing. Barometric pressure changes are always more difficult going from a low-pressure to high-pressure environment. The higher in elevation, the lower the atmospheric pressure. Most individuals are not aware of the normal equalization that occurs on ascent in elevation. This is because when an individual begins to ascend, the pressure decreases on the outside of the eardrum with increasing ascent. If the individual does not swallow, then the atmospheric pressure behind the eardrum will be the same as that at the lower elevation. When you swallow and the eustachian tube opens up, since the air is under higher pressure, it jets out of the eustachian tube with an equalization of pressure. The real problem with equalization occurs on descent. If a person starts at a higher elevation and then begins to descend without swallowing, as the lower barometric pressure behind the eardrum stays the same, then the pressure on the outside of the eardrum is increasing. This creates a relative vacuum behind the eardrum. This becomes equivalent to sucking on a straw, with collapse of the straw side wall. If swallowing occurs before this relative vacuum becomes too great, then the collapsed eustachian tube will then open, with equalization of pressure across the eardrum. However, if swallowing occurs too late, then the vacuum behind the eardrum will keep the eustachian tube walls collapsed and in touch with each other; and as descent continues, this wall-to-wall contact becomes more and more firm. If the vacuum continues to increase, then ear pain can occur, and fluid can be sucked out of the membrane lining the middle ear, with the result that bloody plasma fluid then fills the space behind the eardrum. This can be severe enough that membrane structures inside the inner ear can rupture, with resultant deafness or vertigo, both of which may be permanent. This same sequence of events occurs in individuals diving under water. The changes, however, occur much more rapidly because of the water pressure that is exerted. At sea level, one atmosphere is equivalent to the entire weight of a vertical column of atmosphere, which can extend up to about 80,000 feet. That same pressure is obtained by descending 33 feet in water. Just to give an example, the same pressure difference between the top of Mt. Everest and sea level is obtained by descending approximately 10 feet in water. Equalization of ear pressure during descent under water occurs in a manner identical to that occurring in descent from high altitude. Obviously, the more rapid the descent, the greater the change in pressure across the eardrum and the greater need to equalize more frequently. This same process can occur with any air-filled space in the body, particularly with the air-filled cavities in the facial skeleton, the paranasal sinuses. Any process that narrows the eustachian tube makes equalization more difficult. That is why individuals with acute or chronic allergies or upper respiratory infections have a greater difficulty equalizing their ear pressure as compared to when they are not ill. Also, since children's and infants' eustachian tubes are of a smaller diameter, they are much more likely to have equalization problems as compared to adults.
WHAT ARE THE SIGNS AND SYMPTOMS? The earliest symptom is a sensation of ear plugging and diminished hearing. As the pressure difference increases, the hearing and plugging worsen, followed by progressive pain. A popping sensation occurring in the ears is actually an indication that equalization of pressure is occurring. When the vacuum behind the drum gets to a certain point, fluid with a small bit of blood is then sucked into the middle ear space, with resultant hearing loss, a sensation of bubbling, pain, and popping. On occasions the eardrum may rupture, with sudden resolution of the ear pressure and pain. If there is fluid behind the drum, then honey-colored, slightly blood-tinged fluid may appear coming out of the ear canal. If the eardrum perforates, with subsequent discharge of fluid or equalization of pressure, there still may be a hearing loss, depending upon the size and location of the perforation. Severe barotrauma with rupture of inner ear membranes can result in acute vertigo that usually lasts several days and then gradually subsides. Whereas the hearing loss occurring from fluid or severe negative pressure behind the eardrum is conductive (meaning that sound is not conducted well across the eardrum or the bones for hearing), severe baro pressure trauma can occur to the inner ear, with injury to the nerve component of hearing, with possible resultant permanent nerve deafness.
WHAT ARE THE CAUSES AND RISKS? The causes are declines in elevation, and the more rapid decline in elevation, the more rapid development of symptoms. Descent in water is also a cause. Acute or chronic allergy or poor eustachian tube function are risk factors for the development of this disease process.
HOW TO PREVENT THE DISEASE: Frequent swallowing and yawning promote eustachian tube opening and pressure equalization. Plugging the nose and trying to blow out while letting just the slightest bit of air escape out of the nose increases the air pressure around the eustachian tube opening, which can then open the eustachian tube and equalize the pressure. Individuals who have difficulty equalizing the pressure can take oral and topical nasal spray decongestants prior to the descent to improve eustachian tube function. Certainly if there is ongoing nasal or sinus inflammation, those illnesses need to be treated to minimize their impact upon the eustachian tube function. If an individual is going to use oral decongestants, they will need to take them at least an hour prior to the descent. Since the nasal decongestant sprays work more rapidly, they can be taken 15 to 20 minutes before descent occurs. Individuals with acute upper respiratory illness may need to postpone snorkeling, scuba diving, or airplane flights if there is a concern about severe barotrauma occurring.
HOW IS IT DIAGNOSED? With mild barotrauma the eardrum may be tugged in. If air is blown into the ear canal while the eardrum is examined, the drum will not move well when air pressure is applied through the ear canal to the outer surface of the eardrum but will move outward when a vacuum is applied to it. A tympanogram (which is a measure of the pressure behind the eardrum) will often show that there is a vacuum occurring behind the eardrum and that it is pulled in; and on a hearing test there may even be a small, low-frequency conductive hearing loss. With more extensive barotrauma, there may be a yellow, pink, or frankly bloody fluid behind the eardrum. In an individual who is dizzy, examination of the eyes will disclose nystagmus, which is an indication of acute inner ear balance injury. If there is some concern about an acute injury to the nerve component of hearing, then this can be diagnosed with a hearing test.
WHAT ARE THE LONG-TERM EFFECTS: As most individuals are able to equalize the pressure, there are no long-term effects. If a tympanic membrane rupture occurs, over 95% of these close spontaneously. Those that do not close may require surgical repair in order to create a safe ear and also to restore hearing. If there is a hearing nerve injury, most of those will have some recovery, but some of them may be permanent. Lastly, if there is an inner ear injury, most individuals will recover completely, except for some mild dizziness noted with rapid head or body movement.
AM I PUTTING OTHERS AT RISK? No.
WHAT ARE THE TREATMENTS? As mentioned above, avoiding significant pressure changes during acute illness may be required. Using oral decongestants at least an hour prior to the planned descent and spray nasal decongestants approximately 15 to 30 minutes before the descent can be beneficial. Nasal or oral steroids may be useful in those individuals who are having acute allergy or upper respiratory tract infection. The ultimate way to prevent barotrauma is by placing a pressure equalization tube in the eardrum. For those individuals who develop fluid behind the eardrum from barotrauma injury, the fluid usually resolves spontaneously. If it has not resolved by several months, then an incision can be made in the eardrum and the fluid removed.
WHAT ARE THE SIDE EFFECTS TO THE TREATMENTS? Use of any oral decongestant may cause sleeplessness, increased heart rate, dry mouth, or at times a sensation of anxiousness. Use of nasal spray decongestants may give rise to a sensation of burning inside the nose. There are little, if any, system-wide effects from the use of sprays, but continued usage can actually begin to create problems with nasal stuffiness and bleeding. Brief courses of oral steroids cause very few, if any, side effects. The most common side effects identified are stomach upset, appetite stimulation, fluid retention, sleeplessness, and anxiousness. The main side effect that could occur from placement of a tube in the eardrum is a perforation, which is a permanent hole remaining in the eardrum that can occur in up to 3% of individuals.
WHAT HAPPENS AFTER TREATMENT? The use of decongestants prior to descent is quite successful in preventing ear barotrauma. Fluid usually resolves spontaneously. Vertigo or nerve hearing loss may not completely resolve.
HOW DO I MONITOR THE DISEASE? Being aware of increasing sensation of plugging, progressive hearing loss, and inability to pop the ear are signs that barotrauma may be imminent. Pain is a sign that the eustachian tube is not able to equalize. If possible, it would be wise to prevent any further descent at this point.
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