What Is Sudden Hearing Loss?

“Sudden hearing loss” usually refers to sudden sensorineural hearing loss (SSNHL) – damage to the inner ear or hearing nerve that develops over minutes to up to 72 hours. It is commonly defined as a loss of at least 30 dB affecting three or more neighboring frequencies on a hearing test.:contentReference[oaicite:0]{index=0}

Most people describe it as:

• “My ear suddenly went dead”
• “It feels like cotton or water in my ear, but nothing comes out”
• Ringing (tinnitus), fullness, or distortion in one ear

SSNHL is an ENT emergency: early treatment improves the chance of recovery.:contentReference[oaicite:1]{index=1}

Common Causes

Many cases of SSNHL are “idiopathic,” meaning no clear cause is found even after testing. But some important causes include:

• Viral or inflammatory injury to the inner ear
• Vascular problems that briefly reduce blood flow to the cochlea
• Autoimmune inner ear disease
• Tumors on the hearing nerve (e.g., vestibular schwannoma)
• Head trauma or acoustic trauma (very loud blasts)
• Pressure-related injuries such as barotrauma or decompression sickness (DCS) in divers or after rapid decompression

Sudden Hearing Loss from Barotrauma and Decompression Sickness

Barotrauma: When Pressure Changes Damage the Ear

Barotrauma is damage from rapid changes in pressure, such as during scuba diving, flying, riding in elevators, or blast exposure. It can affect:

• Middle ear: “airplane ear,” eardrum stretching or rupture, fluid or blood behind the eardrum
• Inner ear: tears around the oval or round window, perilymph fistula, or inner ear bleeding, which may cause sudden sensorineural hearing loss and vertigo

Ear barotrauma happens when the pressure in the middle ear cannot equalize quickly with the environment (for example, blocked Eustachian tube during descent or ascent).:contentReference[oaicite:2]{index=2}

Symptoms can include:

• Sharp ear pain during descent or ascent
• A “pop,” followed by sudden muffled hearing or complete loss in one ear
• Ringing, fullness, or fluid/blood in the ear
• Vertigo, imbalance, or nausea (if the inner ear is involved)

Significant barotrauma can sometimes cause permanent hearing and balance problems if not recognized and treated promptly.:contentReference[oaicite:3]{index=3}

Inner Ear Decompression Sickness (DCS) and Gas Bubbles

Decompression sickness (DCS) occurs when dissolved inert gas (usually nitrogen) forms bubbles in the body as pressure decreases too quickly (rapid ascent from a dive, decompression incidents in aircraft, problems in hyperbaric chambers).:contentReference[oaicite:4]{index=4}

When these bubbles affect the inner ear (called inner ear decompression sickness – IEDCS), people can develop:​:contentReference[oaicite:5]{index=5}

• Sudden or rapidly progressive hearing loss (usually one-sided)
• Severe vertigo and imbalance
• Nausea and vomiting
• Nystagmus (rapid, uncontrollable eye movements)
• Loud ringing in the affected ear

Gas bubbles are thought to form in the inner ear’s fluid spaces and blood vessels, reducing blood flow and directly injuring the delicate hair cells and nerve fibers. Without quick treatment, this can lead to permanent hearing loss and chronic dizziness.:contentReference[oaicite:6]{index=6}

Dangers of Rapid Decompression

Rapid decompression (for example, a fast ascent from depth or sudden loss of cabin pressure) is risky because:

• It greatly increases the amount and size of gas bubbles forming in blood and tissues.
• It stresses the middle and inner ear with sudden pressure changes, making barotrauma and DCS more likely.
• Inner ear structures are particularly vulnerable to both pressure changes and microbubbles.

In divers or compressed-gas workers, inner ear involvement (vertigo, hearing loss, tinnitus) after a rapid ascent or missed decompression stop is an emergency that should be treated as possible DCS until proven otherwise.:contentReference[oaicite:7]{index=7}

What To Do If You Suddenly Lose Hearing

1. Seek urgent medical care.
   • Emergency department or urgent care if severe symptoms (vertigo, trouble walking, neurological signs, recent dive or rapid decompression).
   • Ask to be evaluated by an ENT (ear, nose, and throat) specialist as soon as possible.
2. Get a hearing test (audiogram).
   • Confirms the degree and type of hearing loss (sensorineural vs. conductive).
   • Helps guide treatment and track recovery over time.
3. Tell your doctor about any diving, flying, trauma, or decompression events.
   • This helps differentiate idiopathic SSNHL, barotrauma, and inner ear DCS, which are treated differently.
4. Act quickly. Best outcomes are seen when treatment (especially steroids and, when appropriate, HBO) starts within days, not weeks.:contentReference[oaicite:8]{index=8}

Treatment Options

1. Steroid Therapy

High-dose corticosteroids (by mouth or injected through the eardrum into the middle ear) are a mainstay of treatment for idiopathic SSNHL and are often used for pressure-related inner ear injuries as well.:contentReference[oaicite:9]{index=9}

Steroids aim to:

• Reduce inflammation and swelling in the inner ear
• Stabilize cell membranes
• Improve blood flow and oxygen delivery

The 2019 American Academy of Otolaryngology guideline emphasizes starting steroid therapy within 2 weeks of symptom onset for best results, with intratympanic injections used either as primary or “salvage” therapy if oral steroids fail or cannot be taken.:contentReference[oaicite:10]{index=10}

2. Hyperbaric Oxygen Therapy (HBO / HBOT)

Hyperbaric oxygen therapy (HBO or HBOT) involves breathing 100% oxygen in a pressurized chamber. For sudden hearing loss, it is used in two main settings:

1. Inner ear decompression sickness / DCS
   • Recompression with HBO is the primary treatment for DCS and inner ear DCS.:contentReference[oaicite:11]{index=11}
   • Increased pressure shrinks gas bubbles and returns them to solution.
   • High oxygen levels improve blood flow and oxygen delivery to injured inner ear tissues.
2. Adjunct therapy for idiopathic SSNHL
   • Updated AAO–HNS guidelines allow HBO as an option in combination with steroids, either as initial therapy within 2 weeks or as salvage within 1 month of onset.:contentReference[oaicite:12]{index=12}

While generally safe, HBO can have side effects such as ear or sinus barotrauma, temporary nearsightedness, lung issues, or oxygen toxicity, so it must be supervised by physicians experienced in hyperbaric medicine.:contentReference[oaicite:13]{index=13}

3. Management of Barotrauma

Treatment depends on the location and severity of injury:

• Middle ear barotrauma – Pain control, decongestants or nasal steroids, watchful waiting in many cases. Eardrum perforations often heal on their own; surgery may be needed in severe cases.:contentReference[oaicite:14]{index=14}
• Inner ear barotrauma – Strict avoidance of straining and diving, bed rest with head elevation, possible steroids, and sometimes surgical repair of a perilymph fistula.:contentReference[oaicite:15]{index=15}
• Overlap with DCS – When history and symptoms could fit both inner ear barotrauma and DCS, many diving medicine experts favor early HBO “test of pressure” because improvement with recompression supports a DCS component.:contentReference[oaicite:16]{index=16}

4. Other Testing and Treatments

• MRI of the internal auditory canals/brain to rule out tumors or other central causes:contentReference[oaicite:17]{index=17}
• Blood tests if autoimmune or infectious causes are suspected
• Vestibular (balance) testing when dizziness or vertigo is prominent
• Hearing aids or cochlear implants if permanent hearing loss remains after treatment

Prognosis – What to Expect

Recovery from sudden hearing loss is highly variable and depends on the cause, severity, and how quickly treatment begins.

• Up to half of idiopathic SSNHL patients may have at least partial spontaneous recovery, but timely steroids and, when appropriate, HBO improve the odds.:contentReference[oaicite:18]{index=18}
• Better outcomes are seen when:
  • Hearing loss is mild to moderate (not “dead ear”).
  • Treatment starts within the first 7–14 days.
  • No additional serious neurologic symptoms are present.
• Inner ear DCS can leave permanent hearing or balance deficits, especially if HBO is delayed or symptoms are very severe.:contentReference[oaicite:19]{index=19}
• Barotrauma limited to the middle ear usually resolves; inner ear barotrauma has a more guarded prognosis, depending on the degree of damage.:contentReference[oaicite:20]{index=20}

Case Studies (Illustrative Examples)

These are composite, educational examples, not real individual patients.

Prevention Tips

• Avoid diving, flying, or hyperbaric exposure with a severe cold, sinus infection, or uncontrolled allergies.
• Use gentle, frequent equalization techniques (swallowing, jaw movements, mild Valsalva) rather than forceful pressure.
• Follow dive tables and computer guidance carefully; avoid rapid ascents and respect decompression stops.
• Stay well-hydrated, rested, and avoid excess alcohol before and after diving.
• Seek early ENT and/or diving medicine evaluation for any ear pain, fullness, vertigo, or hearing changes after pressure exposure.