ear audioSudden Hearing Loss

by , last modified on 10/16/14
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Introduction

This webpage describes an alarming situation where your hearing suddenly decreases inexplicably without any other symptoms (perhaps ringing or fullness may be present). One day your hearing fine, and the next, it suddenly has gotten worse... and doesn't seem to be getting better.

This situation is known as Sudden Sensorineural Hearing Loss and is considered an emergency for which you should see an ENT as soon as possible!!! Read a story about this condition in the Washington Post.

Why is this an Emergency?

Because there is a window of opportunity where treatment can be administered which increases the chance that your hearing can be restored back to normal. Beyond that window of opportunity, NOTHING can be done other than time and hope. This time period of ideal treatment is within 14 days of hearing loss. After about 30 days, treatment has not been found to significantly improve hearing.

Why Does This Occur?

It is not precisely known why this occurs, but there are several theories.

When you consider the fact that there is only one single artery (cochlear artery) that supplies the hearing organ, it is not surprsing that one theory states that sudden hearing loss may be due to a compromise in the blood flow. Think of it as a heart attack of the ear. However, studies report that this is likely not the case.

Rather, the most common and accepted theory is a viral infection of the hearing nerve (cranial nerve number 8). This situation is akin to the loss of smell when the smell nerve is infected during a cold or Bell's Palsy leading to facial paralysis.

When a nerve becomes infected, it tends to swell. Unfortunately, the hearing nerve (along with the facial nerve) goes through a bony canal called the Internal Auditory Canal (arrow in picture) which is a passageway for the nerve to go through the skull to get to the ear. This bony passage does not enlarge to accomodate the nerve as it swells leading to the nerve becoming "strangulated" and therefore becoming non-functional leading to hearing loss.

skull zoomed
Arrow pointing to the hole where the hearing nerve passes thru to get to the ear.
skull
Close-up view of the bony canal thru which the hearing nerve goes thru to get to the ear.


To use an analogy, if your foot is the nerve and your shoe is the bony canal, imagine what would happen to your foot if it starts to swell, but you keep wearing the same size shoe. Ouch!

In this swollen and entrapped state, the nerve only has so much time before it potentially starts to die. As such, the only medication found to be helpful is steroids... lots of it and at high doses. Just as steroids decreases swelling of an inflamed arthritic knee, it seems to decrease sweling of the hearing nerve allowing it to recover more quickly before permanent damage settles in.

That's why the window of opportunity. The nerve only has so much time of being strangulated inside its bony canal before it starts to die.

Erectile Dysfunction Medication

Of note, if you are taking cialis, viagra, or any other erectile dysfunction medication, stop it immediately as these drugs are associated with sudden hearing loss. Read the FDA warning here. Hypothetically, it is felt that the sudden hearing loss in this one specific situation is due to a sudden decrease in blood flow to the inner ear resulting in a "hearing stroke" rather than nerve swelling. Earlier treatment with hyperbaric oxygen may be warranted though studies are lacking.

Is there dizziness present?

If dizziness or vertigo is associated with your hearing loss, you may have a condition called Meniere's disease. This situation is different from Sudden Sensorineural Hearing Loss described on this webpage. Treatment is also different. Click here for more information.

Treatment

If no treatment is pursued, there is a ~50% chance that hearing WILL improve back to normal without any intervention. However, the chance of improvement back to normal is higher and faster if treatment is pursued. But there is a caveat... there is only a short window of time when such treatment is effective, typically the sooner the better (ideally within 10 days of hearing loss onset). Starting treatment after 30 days, the chance of significant improvement becomes nominal if any.

So what is the treatment???

High doses of prednisone is the treatment of choice, typically tapered over a 2 week course (start at 20mg 3X per day for 5 days than taper the dose slowly every 3 days). Depending on severity of loss, the dosage may be adjusted down.

Depending on timing, intra-tympanic steroid injection is also offered (dexamethasone 10-24mg/cc). Intra-typmpanic steroid injection is performed by inserting a needle through the eardrum and injecting about 1.5cc of highly concentrated steroids directly into the middle ear space. The patient is than instructed to keep the affected ear up for 30 minutes without swallowing, yawning, or popping the ear. After injection, the patient is allowed to immediately resume normal activities. This steroid injection has also been used to treat Meniere's Disease flare-ups.


videoWatch Video on Intra-Tympanic Steroid Injections

Anti-viral antibiotics such as valtrex (valacyclovir) or acyclovir has NOT been shown to be helpful and is no longer recommended.

Hyperbaric oxygen has been shown to be of possible benefit and should be administered within 3 months of hearing loss onset.

SO, to summarize, the following treatment course is expected ideally:

  • Visit #1 (ideally within 5-10 days of hearing loss)
  • Visit #2 (2-3 weeks later)
    • Repeat audiogram to see if there is any improvement. If no or minimal improvement, recommend Intra-Tympanic Steroid Injection to be done if not already done.
    • If hearing almost back to normal, no further intervention recommended.
  • Visit #3 (2-3 weeks later)
    • Repeat audiogram. If significant improvement, no further intervention recommended.
    • If still no or minimal improvement, recommend MRI scan of the head if not already done. Why? To make sure there is no tumor that is causing the hearing loss.
  • Visit #4 (after MRI)
    • Review of MRI results. Only in less than 10% of cases does it actually show anything abnormal
    • At this point, assuming normal MRI, hyperbaric oxygen can be considered if hearing without significant improvement. Hypothetically, if hearing loss associated with taking an erectile dysfunction medication, hyperbaric oxygen can be started earlier to reverse any ischemia that may have occurred.
    • Return visit in 3-6 months is recommended.
    • If no hearing improvement after 1 year, the hearing loss is considered permanent.


Patients should be aware that once sudden sensorineural hearing loss has occurred, there IS a slightly higher risk of this occurring again in the future [link].

If you have suffered a sudden hearing loss, call for an appointment sooner rather than later!

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References:

Clinical practice guideline: sudden hearing loss. Otolaryngol Head Neck Surg. 2012 Mar;146(3 Suppl):S1-35.

Intratympanic dexamethasone is an effective method as a salvage treatment in refractory sudden hearing loss. Otol Neurotol. 2011 Dec;32(9):1432-6.

Intratympanic steroids for sudden sensorineural hearing loss: a systematic review. Otolaryngol Head Neck Surg. 2011 Oct;145(4):534-43. Epub 2011 Aug 26.

Efficacy of 3 different steroid treatments for sudden sensorineural hearing loss: a prospective, randomized trial. Otolaryngol Head Neck Surg. 2013 Jan;148(1):121-7. doi: 10.1177/0194599812464475. Epub 2012 Oct 16.

Simultaneous versus subsequent intratympanic dexamethasone for idiopathic sudden sensorineural hearing loss. Otolaryngol Head Neck Surg. 2011 Dec;145(6):1016-21. Epub 2011 Aug 4.

Intratympanic Dexamethasone as a Symptomatic Treatment for Ménière's Disease. Otol Neurotol. 2014 Jul 16. [Epub ahead of print]

Recurrence of Idiopathic Sudden Sensorineural Hearing Loss: A Retrospective Cohort Study. Otol Neurotol. 2014 Oct 9. [Epub ahead of print]

 

Any information provided on this website should not be considered medical advice or a substitute for a consultation with a physician. If you have a medical problem, contact your local physician for diagnosis and treatment. Advertisements present are clearly labelled and in no way support the website or influence the contents.

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