Shakeetha woke up one morning and couldn’t hear anything from her left ear. She felt a little better when the doctor took her phone call and told her not to worry, it was probably nothing. A week later there was no improvement so she called again and spoke to the nurse. Shakeetha had a hearing test and her ear specialist diagnosed sudden deafness in the left ear. Treatment resulted in a partial return of hearing.
Sudden Deafness
Sudden deafness (SD) is a loss of hearing that occurs over a short period of time, no more than three days. Its cause is often unknown and it affects only one ear in most cases. The audiogram (see chapter 26) shows a loss of at least 30 dB in three consecutive frequencies. Thirty decibels is a mild sensorineural hearing loss, but many times the loss is much worse.
Sudden deafness is considered a medical emergency because it requires immediate attention if the hearing is to be restored. Many people notice sudden deafness when they wake up one morning or try to use the telephone in the deaf ear. Occasionally a pop is heard preceding the hearing loss and symptoms of vertigo and tinnitus are often present. Sudden deafness occurs mainly in middle age and affects an estimated five thousand Americans each year. Fifty percent of people recover some hearing without treatment, but this success rate goes up to 85 percent with early treatment.
Table 23.1.
Characteristics of Sudden Deafness
• Develops quickly (over about three days)
• Usually occurs in only one ear
• Is considered a medical emergency
• Audiogram shows a loss of at least 30 dB in three consecutive frequencies
• Often responds well to early treatment
Causes
The technical name of sudden deafness is idiopathic (cause unknown) sudden sensorineural hearing loss. Most of the time, as the technical name implies, the cause of sudden deafness is unknown. However, some conditions are known to cause sudden hearing loss, in which case it is not idiopathic. These include:
• Ménière’s disease
• Ear infections
• Tumors
• Head injury or diving injury
• Medications
• Exposure to loud noise or a blast
• Neurologic diseases
• Autoimmune inner ear disease
• Sickle cell disease, leukemia
For most people with sudden deafness, no cause is found and viral infection or vascular disorders are suspected. Unfortunately the cochlea cannot be cultured or biopsied for a definitive diagnosis; these standard diagnostic methods have a high chance of making things worse, so the true cause is usually unknown at the time of treatment.
Making the Diagnosis
The history you give the doctor is important, so be thinking about the time you first noticed hearing loss, what you were doing then, and what you had been doing for the preceding several days. Had you gone snorkeling or diving, flown in an airplane, had difficulty clearing the pressure in your ears, heard a pop in your ear, had a head injury, or lifted heavy weights? Have you had a recent viral infection or cold sore? Do you have a history of vascular obstruction such as a prior stroke, loss of vision, atrial fibrillation, or blood clots? Were you dizzy or did you notice ringing in the ear when you first lost hearing? Do you have Ménière’s disease or have you experienced a prior hearing loss?
Your doctor will perform a careful examination to be sure you don’t have a wax impaction, middle ear infection, neurologic abnormality, or rash. An audiogram will show the extent of the hearing loss and an MRI is often necessary to rule out hearing loss caused by a tumor. This occurs in up to 10 percent of patients with sudden deafness. Blood tests for infectious disorders such as Lyme disease and syphilis as well as autoimmune inner ear disease will also be obtained when indicated.
Treatment
Since sudden deafness may be caused by a number of different disorders, no single treatment works for everyone. If a specific cause can be identified, then treatment is aimed at that cause. Otherwise, steroids are considered the treatment of choice.
Steroids
Steroids such as prednisone and dexamethasone are thought to work by reducing inflammation, edema, and programmed cell death (apoptosis). Because short-term use is indicated, steroid complications are usually not a problem. Be sure to tell your doctor if you have diabetes, chronic infection, peptic ulcers, or a disorder of your immune system.
Once administered only by mouth, steroids are now frequently used orally in combination with injections through the eardrum. These injections are usually nearly painless and increase hearing recovery. Middle ear injection of Decadron (dexamethasone) alone is used in patients with diabetes or others who should avoid oral prednisone.
Hyperbaric Oxygen
Hyperbaric oxygen therapy (HBO) is a method that uses a pressure chamber to increase oxygen levels in the blood. Higher oxygen levels are thought to help damaged tissue recover. In sudden deafness, HBO has been claimed to increase the recovery of hearing when added to steroid therapy. However HBO is not widely accepted as a treatment for sudden deafness.
Antiviral Medication
The herpes family of viruses has been associated with SD and is susceptible to antiviral medication. However, antivirals such as acyclovir may not be effective in treating SD.
Vasodilators
Vasodilators are medications that are intended to increase circulation in order to provide more oxygen and nutrients to injured tissue. However, at this time, studies have not demonstrated conclusively that vasodilators improve recovery from SD.
Autoimmune Inner Ear Disease
Autoimmune inner ear disease (AIED) is a rare disorder resulting in progressive nerve deafness of both ears. It is caused by the immune system mistakenly attacking the tissues of the inner ear. The immune system usually attacks bacteria, viruses, and cancer cells using antibodies and immune cells. But in autoimmune diseases, our immune system attacks one or more of our own healthy tissues by mistake. There are over eighty types of autoimmune disorders, including rheumatoid arthritis, lupus, Type 1 diabetes, and multiple sclerosis. Autoimmune inner ear disease accounts for less than 1 percent of all hearing impairment or dizziness. The causes of mistaken immune attacks are unknown.
Making the Diagnosis
Autoimmune inner ear disease symptoms are a result of inflammation caused by the autoimmune attack. They may be limited to the ear (hearing loss, tinnitus, and vertigo) or may occur in association with other autoimmune disorders such as those mentioned above. When combined with attacks on other organs, ear symptoms may be accompanied by fever, joint pain, eye pain, neurological symptoms, rash, and fatigue. The typical onset is sudden hearing loss in one ear that involves the opposite ear over a period of weeks to months.
The first symptoms of autoimmune inner ear disease may resemble sudden deafness. However, after the initial loss of hearing, it usually progresses and involves the other ear over a few weeks to a few months. The finding of progressive, bilateral nerve deafness is the primary diagnostic criterion for AIED. Other hearing tests may also be performed, but generally do not help make the diagnosis.
Testing
There are also a large number of blood tests available to help in diagnosis. However, none of these are specific to AIED or sensitive enough to direct treatment. Tests may be performed to rule out concomitant autoimmune disorders such as lupus as well as infections such as Lyme disease or syphilis. MRI with contrast is sometimes used to identify inflammation of the inner ear or to rule out bilateral tumors (very rare in this context).
Treatment
The initial treatment of autoimmune inner ear disease is the same as that for sudden deafness: steroid therapy that may be administered orally or by injection through the eardrum. Steroids are effective, so much so that a response in both ears to steroids is considered by some ear specialists to confirm the diagnosis.
Steroid treatment for AIED is usually continued for one month, owing to the high rate of recurrence when it is used for shorter periods. Unfortunately, complications from steroids become more likely the longer they are used. Systemic steroids (oral medications that are spread through the blood) are usually not prescribed for patients with peptic ulcers, diabetes, glaucoma, tuberculosis, and high blood pressure. People with these disorders should be treated with injections through the eardrum because that confines the steroid exposure to the ears.
Even when treatment is continued for one month, hearing loss may recur after steroids are stopped, requiring ongoing use of steroids to prevent nerve deafness. This condition is called steroid dependency. In such cases, as soon as the steroids are stopped, the hearing loss returns. After a period of time, steroids may stop working adequately. This is called steroid resistance.
When dependency or resistance occur, other medications can be used to slow down or prevent further hearing loss. Methotrexate, a mild anti-immune and anti-cancer agent, has been used to treat steroid-dependent AIED, but with little success. Cytoxan (cyclophosphamide) is a similar, but stronger drug that has also been used with sporadic reports of success. However, it has not been adequately studied and sometimes causes serious complications.
A new group of drugs, biologics or biological therapy agents, are created by fusing parts of two or more genes together. They are designed to block the inflammatory process. Preliminary studies of biologics for treatment of autoimmune inner ear disease show some promise, but require replication and larger studies.