Serous otitis media is the most common cause of hearing loss in children. Fortunately, the hearing loss associated with this condition usually is not permanent . Proper treatment restores the hearing to a normal level and prevents secondary complications which can give rise to a more serious problem. In order to better understand serous otitis media an explanation of the normal function of the ear is helpful.
THE NORMAL EAR
To facilitate understanding of its normal function, the ear can be divided into three portions: the outer, middle and inner ear.
The outer ear is made up of the auricle (the part external to the head) and the external ear canal.
The middle ear is composed of the tympanic membrane (ear drum) and three little ear bones: the malleus (hammer), the incus (anvil), and the stapes (stirrup). The air space surrounding these three little bones is known as the middle ear space. This space is normally filled with air which passes through the eustachian tube from the throat to the middle ear. Immediately behind the middle ear space is a bony honeycomb of air pockets within the mastoid bone.
The third portion, the inner ear, is composed of two segments: the cochlea (the hearing canal) and the labyrinth (the balance canal). Both are normally filled with a watery solution which bathes the delicate nerve endings of the hearing and balance nerves.
HOW WE HEAR
Sound waves travel through the ear and pass into the external ear canal. They strike the tympanic membrane causing it to vibrate. These vibrations are then transmitted through the chain of little ear bones to the fluid of the inner ear. A fluid wave is created and passes through the snail-like cochlea and stimulates the delicate endings of the hearing nerve. These nerve endings then generate a nerve impulse which travels along the hearing nerve to the brain where it is interpreted as sound.
HOW SEROUS OTITIS DEVELOPS
In serous otitis media, the external ear, inner ear, and hearing nerve are normal. The problem stems from inadequate function of the eustachian tube. The tube becomes blocked and does not allow air to fill the middle ear space. Subsequently, fluid forms from the middle ear lining and collects in the space. The presence of this serous fluid limits, or Adampens,@ the vibration of the ear drum and causes a mild to moderate hearing impairment. This fluid makes the ear more susceptible to recurrent ear infections in many children. The trapped fluid is an ideal place for bacteria to grow and reproduce rapidly. Therefore, bacteria entering the middle ear space can easily cause an infection: the pus produced then exerts pressure on the ear drum with resultant pain.
However, serous otitis media may be present without recurrent ear infections, and a mild hearing loss may be the only sign of it=s presence.
In children below 15 months of age the most common cause of blockage of the eustachian tube is an immature eustachian tube. In children older than 15 months, the most common cause of blockage of the eustachian tube is enlarged adenoidal tissue (a tonsil-like tissue found in the upper part of the throat near the opening of the eustachian tube). Among other causes are: nasal allergies, cleft palate, and recurrent upper respiratory tract infections.
After the diagnosis of serous otitis media, medical treatment should be initiated. This includes the use of steroid nasal sprays to decrease swelling in the adenoid area, oral decongestants, and maneuvers to inflate the eustachian tube. Forced air inflations through the eustachian tube are frequently employed by blowing the nose with the nose blocked off completely. Do not do this more than three times per day. Antibiotics can also be used in some cases. Recent studies show that medical treatment is not any more effective, however, than simply waiting for the fluid to resolve without treatment. If medical treatment is not effective, then surgical treatment is advised.
Surgical treatment is directed towards the removal of the serous fluid, aeration of the middle ear space via the placement of pressure equalization tubes, and removal of the adenoid tissue, if indicated. Surgical treatment is usually recommended if the fluid has been present in the middle ear for three consecutive months, especially if a hearing loss is confirmed by a hearing test. The operation is done under general anesthesia. The adenoid tissue is removed (adenoidectomy) if it is enlarged and causing problems. The ear drum is viewed through the operating microscope and a small incision (myringotomy) is made.
The serous fluid is then removed. A small silicone rubber tube is placed in this opening. The patient usually leaves the hospital the same day. The pressure equalization tube usually remains in place until the ear drum pushes the tube out and heals. This usually takes from six months to two years. In 20 percent of children who had tubes placed only, the condition recurs after the tubes fall out. At this point additional pressure equalization tubes may be necessary as well as an adenoidectomy.
We enjoy teaching our patients about their medical problems and the treatment plan that we have recommended. We believe that with this education, our patients are more likely to get better and to stay better.
These information sheets are intended for use by our patients in conjunction with regular care from Drs. Siegel and Bosworth. Use of these sheets by others can lead to a delay in diagnosis with potential worsening of health. If you are not one of our patients, please schedule an appointment so that we can help you to feel better as soon as possible.