FLUID IN THE MIDDLE EAR -- (SEROUS OTITIS MEDIA)

By Mark J. Levenson, MD, FACS

Serous otitis media, better known as middle ear fluid, is the most common condition causing hearing loss in children. Normally, the space behind the eardrum which contains the bones of hearing is filled with air. This allows the normal transmission of sound. This space can become filled with fluid during colds or upper respiratory infections. Once the cold clears, the fluid will generally drain out of the ear through a tube that connects the middle ear to the nose: the Eustachian tube. The Eustachian tube does not drain well in children. Fluid which has accumulated in the middle ear space often remains blocked.

Sound transmission is slowed by the fluid and hearing is diminished. Parents may notice that their child has the sound on the television turned up too loud; they might notice their child often asking, "What?" in response to a question. In many children, there may be no noticeable complaints. This is especially true when a child is less than 2 years old. Fluid can be present for months in children, only to be detected by a routine visit to the pediatrician's office. Fluid often produces few symptoms, but can have significant consequences if not recognized.

Because children need hearing to learn speech, hearing loss from fluid in the middle ear can result in speech delay. Children begin to speak some words by 18 months. Children with fluid in both ears can show significant delay in their use of language. In addition, young children learn to pronounce words by hearing them spoken. When there is a hearing loss, even a mild one, the spoken words of parents and siblings are distorted to the child with fluid in the ears.

Since the words sound distorted to the child, pronunciation of these words by the child will also be distorted. The extreme case of this distortion is the deaf child whose speech is very difficult to understand because the child does not hear at all. If a child has fluid for many months during the formative years, there may be noticeable mispronunciation which will require speech therapy. Identification of fluid in the middle ear is important, not only to prevent future speech problems, but to avoid permanent damage to the eardrum and the middle ear.

Most children will have at least one ear infection before the age of four. With treatment, the ear infections clear up promptly. A follow-up visit to the pediatrician or family doctor is essential, in order to be certain that the ear infection has cleared, and fluid no longer remains in the middle ear. Most primary care doctors recommend a revisit during the week after completing the antibiotic. Without the follow-up visit, fluid may still be present, even though the child has no complaints or symptoms. Therefore, it is essential that ear infections be rechecked after initial treatment.

Additional antibiotics may be prescribed, if fluid is still present at the follow-up visit. If fluid has not cleared over an eight to ten week period after an infection, referral to an ear, nose and throat specialist is advisable. A complete examination of the ear, nose and throat should be performed. Hearing tests should also be obtained to assess the degree of hearing loss from the fluid accumulation. Usually, the presence of fluid results in a "mild conductive hearing loss." This could be as much as 30% hearing loss overall. In very young children (less than 2 years old), it may be very difficult to obtain accurate hearing tests, particularly for the individual ears. A general hearing level can usually be obtained, however. If the child is younger than 6 months old and does not seem to respond normally to environmental sounds, such as the doorbell, telephone ringing, or calling, a brainstem evoked response audiometry hearing test may be advisable to rule out a more severe hearing loss.

Other tests should be taken in addition to the hearing tests: impedance tympanometry, better known as a tympanogram, should be obtained to measure the movement of the eardrum when pressure is applied to it. When fluid is present in the middle ear, the motion of the eardrum will be markedly restricted. Sounds that would easily transmit are reduced in strength. As a comparison, when you strike a crystal glass gently with a spoon, you will hear a nice ring. If the glass is filled with water, the ring sounds much duller. This is precisely what happens when the middle ear is filled with fluid.

After the specialist confirms that fluid is present behind both eardrums, further medical treatment is often advised. This may consist of additional antibiotics, decongestants, and in some cases, nasal sprays. If fluid has been present for over 12 weeks, surgical drainage of the fluid is often indicated. The decision to perform surgery should be based on the response to medical treatment, the degree of hearing loss and the appearance of the eardum itself under the surgical microscope.

Surgery which drains fluid involves a small incision in the eardrum,

so that the fluid can be gently removed

and a tube can be inserted.

The procedure, medically termed a myringotomy and tubes, or tympanostomy and tubes, is performed on children under general anesthesia. Surgery is performed on an ambulatory or same day surgery basis. Within an hour or two after surgery, the child can be discharged home, to be followed up by a visit to the specialist in approximately one week.

Parents often ask why the fluid cannot be drained without inserting a tube. The need for the tube insertion is because the eardrum incision generally heals very rapidly (within a few days), which is not long enough for the swollen membranes in the middle ear to return to normal. As soon as the eardrum heals, fluid will reaccumulate. Tubes were first introduced because of this very problem.

There are many types of tubes, but all tubes serve the same function. They keep the eardrum open, allow air to enter the middle ear space, and permit fluid in the middle ear to drain. Most tubes will gradually be rejected by the ear and work their way out of the eardrum. As they come out, the eardrum seals behind the tube. Tubes will last four to six months in the eardrum before they come out. Occasionally, the eardrum does not heal completely when the tube comes out.

The majority of children treated with tubes do not require further surgery. They may have ear infections in the future, but most will clear up with medical treatment. Some children are very prone to ear infections and have a tendency to accumulate fluid after each infection. Children tend to outgrow this cycle by age 7 or 8. In an ear, nose and throat specialty practice, this group comprises 10 to 15% of all children who have required tubes.

Another set of tubes can be required, if there is a recurrence of fluid. The specialist may recommend tubes with flanged arms. When these are opened behind the eardrum, they function much like a "butterfly bolt." These so called "T tubes" are most often made of a non-reactive material called silastic. This type of tube rarely clogs with blood or secretions and is held back within the eardrum by arms that are spread behind the drum. When inserted, T tubes can generally remain in the ear for prolonged periods of time. They are not commonly rejected. In most children, they can be removed in the office without anesthesia.

In addition to the insertion of a longer lasting tube, a careful search for underlying causes of Eustachian tube function should be sought, particularly in a child who has recurrent infections and requires a second set of tubes.

ADENOIDS AND FLUID

The adenoids are lymph tissue, similar to the tonsils. The adenoids are located behind the nose and soft palate; they are normally present in all children. With frequent infections of the nose and throat, the adenoids may become enlarged, obstructing nasal breathing. Since the adenoids are next to the area of the Eustachian tube, their enlargement or infection may contribute to recurring ear problems.

One way of estimating the size of the adenoids is to obtain a soft tissue X-ray of the back of the nose, called a nasopharyngeal X-ray. This X-ray is very useful in assessing whether the adenoids are obstructing the Eustachian area. A rough estimate of the adenoidal size can also generally be obtained by noting the size of the tonsils. If the tonsils are very large, the adenoids are usually enlarged. The adenoids themselves, however, may be enlarged without significant tonsil enlargement.

Research indicates that, in children with persistent ear infections and fluid problems, an adenoidectomy at the time of tube insertion may improve Eustachian tube function. This can help to prevent ear problems in the future. Studies indicate that removing tonsils may not be helpful in clearing ear problems, unless the tonsils are chronically infected (four to five infections per year). If the tonsils are diseased, their removal is also advisable.

Most children will eventually outgrow their problems with fluid by late adolescence or the early teens. This is thought to be due to the growth of the head relative to the position of the Eustachian tube. The muscles which pull on the Eustachian tube change with head growth. This can facilitate and improve Eustachian tube function. Some children, despite their growth, continue to have poor function of the Eustachian tubes. As adults, some of these children will have chronic ear problems.

COMPLICATIONS

Short term complications from the insertion of tubes, such as a minor ear infection, can generally be cleared up with antibiotics and drops. If the ears had been infected for a long period of time prior to the insertion of tubes, they may also drain continuously for several weeks after insertion of the tubes. This allows the mastoid (the reservoir behind the ear which connects to the middle ear), to drain and dry out. In some cases, the ear will continuously drain for over one month. If this occurs, then a CT scan of the mastoid bone is necessary in order to evaluate whether disease is persisting within the mastoid itself.

If a child has had tubes in place for six months, and suddenly the ear begins to drain, this may indicate a cold, or entry of water in the ear. Usually, this type of infection will resolve rapidly with antibiotics and drops. If the ear does not dry up, further investigation is called for.

If there appears to be a polyp around the base of the tube, it should be removed if possible, or the tube itself should be taken out. Most tubes can be removed easily in the office, under a surgical microscope without anesthesia. Polyps can also occur within the middle ear space, underneath the tube. Generally, the ear will dry after the tube is removed. If fluid reoccurs after the eardrum heals, re-insertion of the tubes may be indicated.

Some ear, nose and throat specialists advocate removing the tubes in the operating room, and patching the eardrum at the time of removal. The patch is generally made out of a gelatin sponge (Gel-foam), or a small paper patch. This may be worthwhile when a tube has been in place for a prolonged period of time, especially in a child who does not allow cleaning of the ear in the office. Patching does not seem to be necessary in most children. Usually, after the tubes are removed the drum will heal spontaneously without patching.

When tubes fall out or are rejected spontaneously, the eardrum almost always heals behind the tube. T tubes do not extrude by themselves. These have to be physically removed. After removal, over 90% of the defects in the eardrum will heal within one month. If the T tube has been in place for a prolonged period of time (over two years), the drum may be slower to heal. In most cases, the drum will eventually heal itself over a period of months. In some children (less than 1% of all who have had tubes inserted), the eardrum may not heal.

The proportion of permanent perforations increases directly with the number of tubes inserted in the past and the length that the current tube is left in position. High risk cases for permanent perforations include those who have needed multiple sets of tubes in the past. This small subset of children and adults may have permanent changes in the strength, thickness and blood supply of the eardrum.

There are instances, after the tube has fallen out or is removed, when the drum may not heal without surgical intervention. These permanent changes in the eardrum are largely due to the disease process itself. The eardrum with chronic fluid and recurring infections tends to become thin and atrophied with time. Surgical repair of the perforation is recommended in these cases.

Before performing surgery, there should be reasonable expectation that the fluid problems have been cleared and that the patient is beyond the age of having Eustachian tube problems: the so- called maturity of Eustachian tube function. Since there is no reliable way to measure Eustchian tube function directly, the status of the opposite ear may be the only indicator of what can happen to the ear with the perforation, if it is repaired.

If the opposite ear has persistent infections and fluid problems, it may be advisable to deter the repair of the perforated eardrum until the opposite ear clears fluid and appears to have matured its Eustachian tube function.

One significant exception to this situation would be if the perforation is marginal, at the edge of the eardrum. In this case, prompt closure of the perforation may be necessary to prevent the formation of a cholesteatoma (cross reference). Repair of the eardrum may also be deferred in children who have undergone cleft palate repair, or who have other cranio-facial anomalies that are associated with prolonged poor Eustachian tube function.

ADULTS

Fluid in the middle ear can also occur in adults. Most often, fluid problems in adults follow a severe upper respiratory infection: sinusitis, severe allergies, or flying with a cold. Symptoms include a muffled, blocked feeling in one or both ears, and pain if there is an infection.

A combination of decongestants and antibiotics will usually clear up the infection and allow the fluid to drain. In some adults, especially those with underlying nasal or sinus conditions, the fluid may not clear. Additional treatment is necessary with these patients. Cortisone containing medications, such as Prednisone or Medrol, may be given for six or seven days. They are often effective in clearing fluid when other medication has failed.

If fluid is still not cleared after medical treatment has been completed, surgical drainage and the insertion of a ventilating tube is often indicated. In adults, this procedure can be performed in the office of an ear, nose and throat specialist equipped with an operating microscope. The drum is anesthesized with an injection of Xylocaine, topical drops of phenol or iontophoresis (a method of inducing anesthesia without the injection by electrical current).

Once the eardrum is anesthesized, the eardrum is opened, and the fluid is removed with aspiration and suction. A tube is then inserted. The tube may be left in the ear for a shorter period of time than in children (usually four to six weeks in adults). Unless there is active sinusitis or severe allergies, the tube is removed as an office procedure. The tube site opening will heal rapidly within several weeks after the tube is removed.

During the time the tube is in the ear, and pending confirmation that the drum itself has healed, water precautions are necessary. Swimming is not advisable.

When fluid develops in one ear only, without the patient having a prior history of ear problems and no evident cause, such as a recent severe cold, the implications may be more serious. Examination must be performed by the ear, nose and throat specialist to ascertain that a growth is not compressing the Eustachian tube. These growths can either be benign or cancerous. This is certainly not the only cause of fluid in one ear. However, if there is no prior history of upper respiratory infection, colds, sinusitis, or severe allergies, it is extremely important to investigate the other possible causes of the fluid accumulation.

The opening of the Eustachian tube is at the back of the nose. A flexible or rigid fiberoptic instrument is generally passed into the nasal passage to examine the opening of the Eustachian tube. X-ray studies, such as CT scan or an MRI scan, may also be ordered to rule out a growth or tumor of the skull base. Nasopharyngeal tumors are uncommon, but they can cause symptoms of fluid in one ear alone.

After all potentially serious causes for fluid in one ear have been eliminated, a tube is placed in the ear. It is left in place for several months and then removed. If fluid reoccurs in the same ear, especially in a middle aged adult, further evaluation including direct exam of the nasopharynx under anesthesia and/or a biopsy may be indicated. Tumors of the nasopharynx are more common in Asian adults who have lived part of their lives in China. Indications of more serious problems would include bleeding from the nose or nasal obstruction on the side of the fluid problem.

PERMANENT EUSTACHIAN TUBE PROBLEMS

Some adults will have ear problems their entire lives. These individuals will experience fluid reoccuring on a regular basis and lasting for prolonged periods. These individuals have undergone multiple insertions of temporary tubes. Despite investigation for other causes of their condition, they have continued ear fluid problems. Permanent tubes made of silastic or synthetic bone (called hydroxyapatite) are indicated in these cases.

The objective of permanent tubes is to bypass the poorly functioning Eustachian tube completey. Determination of permanent tube implantation is based on a history of lifelong or very long term Eustachian tube problems with recurring fluid. Most patients who have undergone permanent tube placement have experienced the return of fluid almost immediately after their regular tubes fall out.

These individuals should be very carefully examined for all other treatable underlying problems, such as chronic sinusitis, nasal obstruction from a deviated septum or chronic allergies. If a significant problem is identified, it should be aggressively treated medically or surgically, in order to improve Eustachian tube function. In some individuals, despite treatment of all possible related problems, poor Eustachian tube function may continue. The insertion of permanent tubes is indicated in these cases.

Permanent tubes are generally made with a very large flange. The flange is often too large to place through the eardrum itself, or it would require an incision in the eardrum that would be damaging to the ear. In order to place most types of permanent tubes, an operation is required. An incision is the ear canal is made and the entire eardrum is lifted. A small trough is drilled into the posterior bony canal wall in order to accommodate the tube which is two to three times the size of a standard tube. The flange is then placed partially behind the bony middle ear wall in order to anchor it into position.

The drum is then rolled back around the tube. In most patients who undergo this operation, the tubes are successful in preventing recurrent fluid. They do require maintenance, however, as well as cleaning and permanent protection from water, including swimming and bathing. Custom ear molds can be made that will fit the ear canal tightly and protect the ear from water.

SPECIAL PROBLEMS:

  • FLUID IN THE EARS AFTER RADIATION FOR HEAD AND NECK TUMORS

    Patients who have had cancer of the nasopharynx, or other areas of the head and neck, may require radiation as part of their treatment. Radiation has become much more sophisticated as a method of treatment in the last decade. The beam of radiation is more accurate, and more limited to the tumor itself. However, a tumor of the nasopharynx is usually located next to the Eustachian tube, and radiation of this type of tumor will certainly encompass the treatment zone.

    After radiation, fluid often builds up in one or both ears, due to the radiation-induced swelling and inflammation of the Eustachian tube.

    It may be prudent after radiation to wait several months for all inflammation to subside before inserting tubes. In some cases, the fluid may be resolved without the insertion of tubes. When the decision is made to insert tubes, they should be implanted in as sterile a manner as possible. Strict water precautions are also necessary. Infection in a patient who has had radiation therapy is much more difficult to treat. Another option is to obtain a hearing aid and leave the fluid.

  • FLUID IN THE EARS FOLLOWING RADICAL HEAD AND NECK SURGERY FOR MAXILLARY AND OTHER TUMORS OF THE HEAD AND NECK

    Fluid in the ear can occur after surgery of the head and neck, particularly radical operations on the maxillary sinus and palate for cancer. Portions of the Eustachian tube in the involved side may be completely transected. Clearly, in this instance, Eustachian tube function will be permanently limited. Permanent ventilation of the ear may be necessary. If only one ear contains fluid, it may be prudent to delay insertion of a ventilating tube until a later date. When a ventilating tube is inserted, it should be inserted in a sterile setting.

    Consultation between the surgeon and the radiologist is often useful in determining the appropriate post-operative timing for the insertion of tubes. Some studies have indicated that a greater percentage of patients in this group will develop infections from their tubes. In the head and neck cancer patient, fitting of hearing aids may be the preferred alternative.

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