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Hearing Problems
By peace | November 20, 2006
Ears not only let us hear, but they also play a role in maintaining our balance, which is vital to our ability to function in daily life. Yet, we ignore them. We can’t even see our ears, except in a mirror. We take for granted what they do for us day in and day out — until we notice something’s wrong, such as when an earache strikes or when we start having to ask people to repeat what they say.
1. Acoustic Neuroma (Vestibular Schwannoma)
This is a slow-growing, benign tumor on the 8th cranial nerve, which consists of the auditory and vestibular nerves twined together. The tumor develops as a result of overproduction of Schwann cells that cover and insulate the nerves. What stimulates these cells to overproduce is not known. The tumor usually develops at the point where the nerves exit the bony canal and enter the brain cavity.
Because an acoustic neuroma affects both the auditory and vestibular nerves, hearing loss in one ear, tinnitus and dizziness are common signs and symptoms. As the tumor grows, it can affect other nerves, especially the facial nerve, causing facial numbness and weakness or paralysis. It may also eventually press against nearby brain structures and become life-threatening.
Usually removed surgically, the tumor may also be treated with radiation therapy. To remove an acoustic neuroma surgically, the surgeon will make an incision behind or above the ear and remove a segment of the skull about the size of a silver dollar to get at the tumor. Once the tumor is removed, the bony segment or a permanent acrylic patch is used to cover the opening in the skull to prevent infection and protect the brain. If the tumor is small, it can be removed without injuring the auditory nerve and hearing will be preserved. The larger the tumor, however, the greater are the risk that facial nerves and hearing will be affected.
Radiation treatment, called gamma-knife radiation, involves shrinking or stabalizing small or medium-sized tumors. This is a closed-skull procedure that requires the use of a machine that treats the tumors with highly focused radiation beams. The main benefit is that the skull is not opened, thus reducing the chances of infection. As a result, recovery time is shorter. A serious drawback is that it offers less certainty of long-term tumor control.
2. Autoimmune Inner Ear Disease (AIED)
This occurs when the body’s immune system mistakes normal cells in the inner ear for a virus, bacteria, or other pathogen and begins attacking it, producing an inflammatory reaction in the inner ear which can lead to problems with both hearing and balance. AIED is rare, accounting for less than 1% of all cases of hearing loss.
Signs and symptoms include:
* hearing loss that usually begins in one ear and moves to the other;
* tinnitus;
* a feeling that the ear is plugged;
* dizziness.
Because these signs and symptoms are similar to those of other ear disorders, diagnosis is difficult since it is often associated with other autoimmune disorders of the body including:
* ankylosing spondylitis (a disease that affects the spine);
* Sjögren’s syndrome (a dry eye syndrome);
* Cogan’s syndrome (affects both eyes and ears);
* ulcerative colitis (affects the intestinal tract);
* Wegener’s granulomatosis (inflames blood vessels);
* rheumatoid arthritis (inflames the joints);
* scleroderma (hardens and scars the skin and other connective tissue);
* systemic lupus erythematosus (SLE) and Behcet’s syndrome (both affecting multiple systems of the body).
3. Cholesteatoma
This is a growth of normal skin tissue in the wrong place. It often occurs when skin from the ear canal grows through a hole in the eardrum and extends into the cavity of the middle ear. It may also happen when a blocked eustachian tube creates a vacuum in the middle ear, drawing the membrane of the eardrum inward to form a pocket. Old skin cells caught in the eardrum pocket contribute to the formation of a cholesteatoma. Occasionally, during fetal development, skin cells become trapped behind the eardrum so that a baby may be born with congenital cholesteatoma. This type may grow quickly.
Signs and symptoms include pus draining from the ear, hearing loss, ear pain or numbness, headaches, dizziness, and weakness of the facial muscles. The degree of hearing loss depends on where the tissue grows. Frequently, it encroaches on the ossicles, impeding the sound vibrations and causing significant conductive hearing loss.
The development of a cholesteatoma can erode bone, which makes this a potentially serious condition. It may invade the mastoid bone behind the ear and if left untreated, a cholesteatoma will continue to grow. This will eventually destroy the bony structures of the middle and inner ear, damaging the cochlea and the vestibular labyrinth and resulting in sensorineural hearing loss along with balance problems. Uncontrolled growths can also damage the facial nerve and in severe cases, may penetrate the brain causing an infection.
A cholesteatoma is removed surgically, generally in one operation if the growth is small. However, larger or more advanced cholesteatoma may require a series of operations to correct any damage to the bones of the middle ear, including the possibility of rebuilding them. If all of the growth is not removed, it will grow back. In severe cases, a radical mastoidectomy may be necessary. This leaves a cavity that can be cleaned out periodically, but does not restore damaged bones or lost hearing. Attempts to reconstruct the ossicular bones with an artificial replacement (prosthesis) or cartilage is done during a modified radical mastoidectomy.
4. Congenital Hearing Problems
These exist from birth. They can be hereditary in nature or may have developed in the womb or during the birthing process. It is estimated that genetic factors are responsible for more than 50% of all incidents of congenital hearing loss. A child whose hearing loss may be inherited usually has parents who each carry a recessive gene for hearing loss (autosomal recessive hearing loss). This gene is not expressed in the parents, who may have normal hearing, but is expressed in a child who inherits both recessive genes. To date, more than 15 genes have been identified that cause recessive hearing loss not related to any other illness.
Often, congenital hearing loss is part of a collection of symptoms (syndrome) caused by such genetic defect, as Down syndrome, Usher’s syndrome, Treacher Collins syndrome, Crouzon’s disease, and Alport’s syndrome.
Congenital hearing problems are typically sensorineural and such factors that may cause hearing loss in an infant include:
* such infection present in the mother as rubella, cytomegalovirus, herpes, or syphilis;
* premature birth;
* a lack of oxygen during or shortly after birth;
* blood incompatibilities between the mother and child;
* diabetes in the mother;
* fetal alcohol syndrome;
* abnormal development of ear, face, or neck structures.
Most newborns are screened for hearing loss before they leave the hospital. It is important to continue monitoring the child’s hearing since a hearing impairment that goes unnoticed will significantly interfere with speech and language development, socialization, and learning.
5. Cysts and Tumors
These may develop in the middle ear or surrounding tissues, as the temporal bone of the skull, although these types of growth are less common. Most middle ear tumors are benign but some, as squamous cell carcinoma, are malignant and capable of spreading to other parts of the body (metastasize). Benign tumors usually grow slowly, whereas malignant ones tend to grow at a faster rate.
A sensation of the affected ear being plugged may indicate a tumor. But, so can hearing loss or tinnitus (noise in the ears), drainage from the ear, facial paralysis, dizziness, and loss of balance. In which case, a doctor must be consulted. A CT scan or MRI can help determine if a tumor is present.
Tumors of the ear are usually surgically removed; a delicate and complex procedure that may involve removing some, or all parts of the ear, depending on the nature and size of the tumor. Needless to say, this can result in permanent hearing loss as well as the function in the nerves leading to the face and shoulder. Radiation may be used as a primary treatment or in combination with surgery.
The more common tumors include:
- Glomus tympanicum and Glomus jugulare consist of masses of cells that can grow in the middle ear, interfering with vibration of the ossicles and leading to significant hearing loss. Often a glomus tumor will cause a pulsing sound in the ear that accompanies each heartbeat. Most are benign, but in rare instances, they can spread to the lymph nodes in the neck and become a more serious problem.
- Squamous cell carcinoma is a malignant tumor. While malignant tumors of the ear are rare, of those that do occur, squamous cell carcinoma is the most common. This type of tumor usually develops in skin cells of the pinna and ear canal or in the middle ear and mastoid. Their cause is not known, but it has been associated with chronic inflammations of the ear. Ear pain, periodic draining of fluid from the ear, and extended periods of bleeding from the ear are signs and symptoms of squamous cell carcinoma. This type of cancer is fatal if left untreated.
6. Medications
They can cause hearing loss, tinnitus, and balance problems. Medications, and other chemicals, can also aggravate an existing inner ear or hearing problem. Such medications are considered ototoxic and their effects can range from mild to severe, depending on the dose, length of time on the medication, as well as such factors as heredity.
Hearing problems caused by some ototoxic drugs usually go away when the medication is discontinued. Those drugs known to cause permanent hearing loss are given only when there is no other alternative for treating a life-threatening disease.
Some signs and symptoms of ototoxic reactions to medications include:
* onset of tinnitus or worsening of existing tinnitus;
* a feeling of plugged ear(s);
* loss of hearing or worsening of existing hearing loss;
* dizziness that is sometimes accompanied by nausea.
7. Ossicular Chain Disruption
This can be the result of a traumatic head injury that displaces or breaks the small bones of the middle ear. These bones (the hammer, anvil, and stirrup) are referred to as the ossicular chain. The most common site of displacement from a trauma is at the joint where the anvil connects to the stirrup and frequently, the anvil itself is partially broken.
The disruption of the ossicular chain causes a breakdown in the passage of sound waves from the eardrum to the inner ear, resulting in significant hearing loss. Surgery involves a procedure called ossiculoplasty, which attempts to rebuild the displaced ossicles or to replace them either with a prosthesis or with small pieces of bone or cartilage. Because ossicles are so small, the operation is very delicate and not all of the hearing may be restored. If head trauma has caused damage to the cochlea, resulting in sensorineural hearing loss, a hearing aid may be the best option as surgery will not resolve cochlear damage.
Although complications are rare, some of the risks involved may be:
* total deafness in the affected ear;
* tinnitus;
* dizziness and loss of balance;
* damage to the facial nerves, resulting in changes to the sense of taste or facial paralysis on the affected side.
8. Otosclerosis
This develops when an abnormal growth of spongy bone forms at the entrance to the inner ear (oval window). Because of this growth, the stirrup (stapes) gradually becomes fixed to the oval window and loses its ability to vibrate. In some cases, the cochlea of the inner ear becomes involved, causing greater hearing loss.
Otosclerosis is the most frequent cause of the middle ear hearing loss in young adults. It is twice as common in women as men and affects whites more often than people of other races. Signs and symptoms usually appear between the ages of 15 and 35. The development of the disease is slow and can affect one or both ears. In women with otosclerosis, the rate of hearing loss may increase during pregnancy.
An increasing amount of evidence suggests that genetic defects may predispose a person to the disease, since about half have a family history of the disease. Other recent studies indicate that the measles virus may also be a contributing factor.
Treatment generally consists of hearing aids if the hearing loss remains mild to moderate. Surgery is another option used to remove the fixed stirrup from the ear and insert a tiny wire or prosthesis made of platinum, titanium, teflon, or stainless steel – a procedure known as a stapedotomy. The prosthesis can help most people with otosclerosis, but in a few cases it may cause total loss of hearing. The prosthesis may also become displaced, a growth of spongy bone may recur over the oval window, or the incus (to which the prothesis is attached) may erode. If the disease continues to progress after surgery, the ability of the prosthesis to function may be greatly reduced.
9. Perilymph Fistula
This is the medical term for a tear in the membrane covering either the oval window or round window, which are situated between the middle ear and the inner ear. It most commonly results from trauma to the head, but may also be caused by rapid changes in atmospheric pressure (scuba diving or airplane maneuvers) and extreme exertion (weightlifting or childbirth).
Signs and symptoms of a perilymph fistula include vertigo, imbalance, nausea, and vomiting. A fistula may also lead to tinnitus and hearing loss. Bed rest and avoiding sudden movements often allow the rupture to heal on its own otherwise, surgery is required.
10. Superior Semicircular Canal Dehiscence (SSCD)
This is similar to perilymph fistula in that both involve an abnormal opening in the inner ear. With SSCD the abnormal opening is at the top of one of the semicircular canals of the vestibular labyrinth, where there is a lack of bone covering the canal. The primary symptom associated with SSCD is dizziness when straining. Treatment may involve surgery.
11. Sudden Sensorineural Hearing Loss (SSNHL)
This is a medical emergency and may be caused by a viral inner ear infection, an abrupt loss of blood flow to the cochlea, a tear in the membrane within the cochlea, or from an acoustic neuroma. Most times, the cause is unknown. Sudden deafness may not always come as a result of a loud noise. It may come all at once or within only a few days, a condition known as sudden sensorineural hearing loss (SSNHL). When this happens, a popping sound is noticed, or it may be detected upon awakening or try to use the impaired ear. SSNHL is almost always confined to one ear and dizziness or tinnitus may also accompany the hearing loss. More common in young or middle-aged adults, about 4,000 new cases occur each year in the US.
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