Philadelphia Ear, Nose and Throat Associates: PENTA

Middle Ear Problems

 What kind of middle ear problems cause hearing loss?

Temporary hearing loss is commonly caused by ear infections. Middle ear infections cause swelling of the mucosal lining in the middle ear, and often an accumulation of fluid (such as pus). When there is fluid behind the eardrum surrounding the ossicles, these structures cannot work properly; and hearing loss results. Infections are usually treated with antibiotics, sometimes with decongestants, and occasionally with drainage by lancing the eardrum (a procedure called myringotomy). If infections are severe or inadequately treated, they may cause permanent hearing loss by damaging the ossicles (incus, malleus or stapes), causing fixation or stiffness of the ossicle, or perforating the eardrum. Most perforations (holes) heal spontaneously. When one does not, it can nearly always be repaired surgically. The procedure is usually relatively fast, and is generally performed under local anesthesia.

Ear fluid not caused by infection accumulates commonly in children, and sometimes in adults. The condition is known as serous otitis media. This is the condition that leads to myringotomy and tube placement, one of the most common operations performed in the United States. It is useful to understand the mechanism behind serous otitis media. Usually it is due to malfunction of the eustachian tube which connects the ear with the back of the throat. The eustachian tube’s job is to keep the pressure in the middle ear approximately the same as that in the ear canal and otuside world. The eustachian tube does so by opening momentarily when we swallow or yawn. If it fails to open because of swelling, allergy, structural developmental reasons, the air already in the middle ear becomes trapped. Gradually, this air is resorbed into the blood stream. The middle ear space is bony except for the eardrum. As resorption occurs and less and less air is present, its disappearance creates a vacuum (negative pressure) which sucks the eardrum into the middle ear (retracted ear drum). When the negative pressure is great enough, it causes fluid to seep out of the blood vessels in the mucosa lining of the middle ear. This is the serous fluid that constitutes serous otitis media. The condition causes hearing loss, and sometimes frequently recurring ear infections. In some cases, the eustachian tube starts to work again spontaneously and the condition resolves. In others, decongestants may be helpful. When allergy is the cause, allergy treatments may improve the problem. When serious otitis media causes frequent infections (recurrent acute otitis media) some physicians recommend the long-term use of antibiotics although this treatment is currently controversial. The most widely accepted treatment for persistent middle ear fluid especially in children is myringotomy and tube placement. This ordinarily eliminates the hearing loss almost instantly, decreases the incidence of recurring infections and prevents the reformation of fluid. The tine tubes placed in the eardrum to keep the ear drainage hole open are not drainage tubes. They are ventilating tubes.

They act in lieu of a functioning eustachian tube to maintain normal pressures within the middle ear. Hence, no vacuum forms, and the fluid is not created in the first place. This is why children with tubes don’t have constant problems with fluid draining out of their ears. Treatment of this condition is important for many reasons. In addition to eliminating disturbing hearing loss and frequent infections, there is evidence to suggest that such hearing loss in children interferes with learning, perhaps more than we might expect it to from the mild to moderate severity of the hearing loss in most cases. Middle ear effusion in adults deserves special mention, too. It is not an uncommon consequence following barotraumas, such as a poorly pressurized airplane descent. However, occasionally we find unexplained middle ear effusion in one ear of an adult. It is essential to determine the cause of this problem, and especially to rule out the presence of a mass (such as a cancer) in the nasopharynx occluding the opening of the eustachian tube.

Otosclerosis is a common hereditary disease that deposits one around the footplate of the stapes. This prevents normal bone transmission of sound from the eardrum to the inner ear, and consequently conductive hearing loss. This hereditary condition is present in about 10 percent of white Americans, and it causes significant hearing loss in about 1 percent. It occurs less commonly in black and Asian people. Otosclerosis generally becomes apparently during early life, and the severity of hearing loss is accelerated by pregnancy. The hearing loss can be cured by an operation called stapedectomy, in which the stapes bone is replaced by an artificial bone. In good hands of the surgeon, this procedure usually only takes fifteen or twenty minutes, and it is performed under local anesthesia. When all goes well, hearing may return to normal.

Various birth defects may also involve the middle ear and cause hearing loss. Some are major and cause obvious external defects. Many involve only the inner ear structures and CT scan or even surgery may be necessary to establish the diagnosis. In any case, most conductive forms or hearing loss are surgically treatable.

It is also important to recognize that the tumors of the middle ear may be responsible for hearing loss. They may be malignant, such as rhabdomyosarcoma in children or squamous cell carcinoma in adults. It may also be benign, such as glomous tumors (which can also cause pulsating ear noises) or neuromas of the facial or acoustic (hearing and balance) nerves. Cholesteatoma is a common benign skin cyst that grows slowly and dissolves adjacent bone as it grows. It is a fairly common problem, especially in people who have had repeated ear infections; but it may also occur from birth in the absence of infections. It generally requires mastoid surgery.