Sudden Hearing Loss - A Medical Emergency

Sudden hearing loss (SHL) should be treated as a medical emergency. Patient evaluation should take place immediately. The window of time for treatment is generally forty-eight hours. Early presentation to a physician or emergency room and early institution of treatment improves the prognosis for hearing recovery. Information about the onset, time course, associated symptoms, and recent activities may be helpful. Past medical history may reveal risk factors for hearing loss. All medications, including over-the-counter products, should be described.  

Many patients will awaken with a hearing loss in one ear; others notice rapid loss of hearing in one ear over the course of minutes to hours, yet others may discover the problem when they try to use the telephone, or may describe a brief period of fluctuating hearing before the loss. About 50% of patients complain of accompanying unsteadiness or vertigo. Tinnitus (head noise) is common, as is a sense of fullness in the ear.

Most studies find no seasonal, geographic, ethnic, racial or sexual tendency for SHL. The right and left ears appear equally vulnerable. In most cases only one ear is affected,;however, in a very small percentage both ears will be affected. Reported overall incidence of SHL ranges from 5% to 20% per 100,000 persons per year. The mean overall age for SHL is 46 years.

Some infections have a well-known association with SHL: syphilis, meningitis, reactivated chicken pox infection (herpes zoster oticus), congenital cytomegalovirus infection, measles, mumps, and rubella. Head trauma can certainly lead to SHL. Some antibiotics, chemotherapeutic agents and other drugs can cause SHL. Sarcoidosis and multiple sclerosis are occasionally associated with SHL.

Unfortunately, most cases of SHL remain unexplained. Possible causes of such unexplained cases include: unidentified viral infection, immunologic diseases (such as systemic lupus erythematosus), and vascular occlusion (essentially, an inner ear "stroke").

If an infectious origin is strongly suspected, the doctor will treat it accordingly. Unfortunately, for many viral infections, no drug treatments are available. For SHL of unknown origin, the only drug treatment that is supported by solid medical evidence is corticosteroid therapy. This should be started as early as possible after the onset of the hearing loss.

It is generally agreed that spontaneous recovery is common in SHL, usually occurring within two weeks of onset. Approximately 65% of all SHL patients will have spontaneous recovery of functional hearing without treatment. Others have estimated that about one-third have spontaneous return to normal hearing, and another one-third have return to functional hearing with a residual hearing deficit. The most important factors influencing recovery appear to be severity of initial loss, patient age, duration of symptoms, degree of vertigo, and time from onset to initial visit.