Sudden hearing loss

Sudden hearing loss is the term for hearing loss that occurs all of a sudden, or over the course of just a few days.

About one out of every 5,000 adults experiences sudden-onset hearing loss annually, though that number could be much higher due to the number of cases that go unreported and undiagnosed. Medically, this condition is known as sudden sensorineural hearing loss (SSHL or SSNHL).

Aside from its rapid onset, it is often “idiopathic,” meaning the cause is usually unknown. A cause can be identified in only 10 to 15 percent of diagnosed cases.

Sudden hearing loss is a medical emergency

If you or a loved one has suddenly developed hearing loss, see your doctor right away. While often downplayed as not serious, any new or sudden hearing loss should be taken seriously by you and your healthcare providers. Why? The sooner you get a thorough audiological workup, the better your chances are for a full recovery.

Symptoms of sudden hearing loss

Sudden hearing loss usually only affects one ear. Some people notice sudden hearing loss when they wake up first thing in the morning and realize their hearing is different. Others don’t notice a difference until they hold the phone up to the affected ear or try to listen to headphones. In some cases SSHL is preceded by a very noticeable “pop," which can be quite alarming.

Afterward, some patients report a feeling of fullness in the affected ear or a strange feeling on that side of the head, possibly accompanied by sudden ringing in the ear (tinnitus) and dizziness. This is sometimes called "aural fullness."

Sudden hearing loss usually only affects one ear. Some people notice sudden hearing loss when they wake up first thing in the morning and realize their hearing is different. Others don’t notice a difference until they hold the phone up to the affected ear or try to listen to headphones. In some cases the hearing loss is preceded by a very noticeable “pop," which can be quite alarming.

Testing for sudden hearing loss

See a medical provider right away. They will check your ears, go over your symptoms, check for impacted earwax and possibly run blood and imaging tests, including a hearing test. SSHL will be diagnosed in the case of a hearing loss of at least 30 decibels in at least three connected frequencies. 

More: Degrees of hearing loss

If any of your healthcare providers are unwilling to thoroughly investigate your sudden hearing loss, seek a second opinion. As audiologist Dennis Colucci stated, healthcare providers must "understand that sudden hearing loss is a medical emergency. Without immediate action, there is likely to be less benefit and more burden to patients, their families, and the healthcare system."

Steroids are the standard treatment

The drugs used to treat sudden hearing loss are steroids called prednisone, which suppress inflammation. They work by decreasing swelling and reducing inflammation. Usually administered in pill form, steroids also can be given through an injection behind the eardrum, or intravenously (into a vein).

While sometimes doctors give high doses of steroids, the latest research indicates that standard doses are likely just as effective and cause fewer side effects.

Emerging evidence also indicates that hyperbaric oxygen therapy may restore hearing, too.

Additional treatments may be necessary to treat the underlying cause, for example, taking antibiotics for an infection.

Don't delay getting help

The window to restore hearing closes two to four weeks after the onset of the hearing loss, meaning the hearing loss will then become permanent and irreversible.

The good news? About 50 percent of people who experience SSHL will spontaneously recover all or some of their hearing within one to two weeks.

Still, it is vital to seek treatment as soon as possible, in case your hearing does not come back. After that short window, without treatment, the hearing loss will likely become permanent and irreversible.

What if my hearing doesn't come back?

In about 15% of cases, permanent single-sided deafness is the outcome, even with treatment.

Treatments will focus on amplifying any remaining sound a person has, via hearing aids or similar devices. CROS hearing aids are also an option if the hearing loss is profound or severe.

Potential causes

Most people will not have a clear cause for their sudden hearing loss. However, risk factors include:

• Bacterial and viral infections
• Inner ear disorders, especially Meniere's disease
• Migraines
• Tumors (e.g. acoustic neuroma)
• Some drugs can cause hearing loss as a side effect, known as ototoxic medications, especially if taken in high doses
• Neurologic diseases or disorders (e.g. multiple sclerosis)
• Head injury or trauma
• Autoimmune inner ear disorder and other autoimmune diseases
• Low thyroid hormones, such as from autoimmune hypothyroidism
• Circulation issues (e.g. vasculitis)

Researchers suspect a link to viral infections

Researchers think that in cases of sudden hearing loss where no obvious cause can be identified, a mild viral infection may have been to blame. This is because people often report having a head cold or respiratory infection in the days and weeks before they lost their hearing.

How would it do this? The virus itself—or the resulting inflammation—somehow damages the inner ear's delicate hair cells and/or the blood supply. Any number of viruses may be responsible, including some that may not produce many symptoms, meaning a person is unaware they're sick until they experience hearing loss. This is an area of emerging research.

More: I lost my hearing suddenly due to Ramsay Hunt syndrome. Here’s what I learned.

Quite a few more serious viruses, some of them life-threatening, can cause hearing loss, either gradual or sudden. Many of them are vaccine-preventable, such as measles, mumps and rubella, and chickenpox (varicella). Because these often produce widespread severe symptoms, these cases are easier to catch and treat earlier.

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^Source:

^{Challenges in Diagnosing Sudden Sensorineural Hearing Loss, The Hearing Journal, DOI: 10.1097/01.HJ.0000833456.10864.09}