Sudden Sensorineural Hearing Loss (SSHL)

Sudden Deafness - Unilateral Hearing Loss - Idiopathic Inner Ear Disorder

Sudden Sensorineural Hearing Loss (SSHL)
Sudden hearing loss (or Idiopathic Sudden Sensory Hearing Loss (ISSHL)) is the occurrence of at least 30 dB of hearing loss at 3 sounds in a row, occurring in less than 3 days. Generally, hearing loss occurs unilaterally and concurrent bilateral involvement is very rare. Viruses are cited as the most important cause in the development of sudden hearing loss whose cause is unknown and cannot be found. Herpes virus, also known as herpes virus, can cause damage to the hearing cells in the inner ear with the infection it creates.

In the United States of America, 5-20 cases per 100,000 people are reported. However, the annual incidence estimates of sudden hearing loss may not be accurate (many cases are likely underreported and the incidence may be high).

Sudden Sensorineural Hearing Loss Definition

Sudden hearing loss is defined as hearing loss with more than 30 dB at least 3 frequencies that started within 3 days. As the name suggests, it occurs in a short period of time. There are no external and middle ear causes. The cause of sudden hearing loss is not well known. However, viruses, autoimmune causes, and occlusion of the small-diameter vessel feeding the inner ear are among the possible causes. In addition, similar hearing losses may rarely be encountered in tumors involving the inner ear canal and brainstem. Consulting an ENT specialist without spending time in sudden hearing loss is very important for the success of the treatment. Steroids, drugs that increase blood flow to the inner ear, antivirals and hyperbaric oxygen therapy, which were initiated in a short time, provide successful results in a significant number of patients. However, the success of the treatment decreases in cases that are late.

Sudden Sensorineural Hearing Loss Etiology

Sudden hearing loss is usually seen between the ages of 30-60, 90% of them are unilateral. Bilateral sudden hearing loss is seen in about 2-8% of the patients and indicates a poor prognosis. It is more common in men and its incidence increases with age. Patients present with complaints such as unilateral hearing loss, ear fullness, and a feeling of obstruction in the ear. Approximately 30-40% of the patients have vertigo and 70% of them have tinnitus.

In 88% of the patients, the etiology cannot be determined by diagnostic tests, it is thought that viral cocleitis, microvascular events and autoimmune diseases are among the reasons in these cases evaluated as idiopathic. Approximately 1% of the cases were associated with retro-cochlear pathologies such as schwannoma or demyelinating disease, while infectious and inflammatory processes or primary middle ear disease were responsible for 10-15%.

We can cite viral infections, trauma, exposure to very loud sounds, vascular problems, pressure change, inner ear disease, occult brainstem tumors (acoustic neuroma), some systemic diseases and some drugs used in cancer treatment as the cause of sudden hearing loss. However, many causes of sudden hearing loss are unknown.

Causes of Sudden Hearing Loss

Sudden hearing loss can be caused by any trauma, exposure to very loud sounds, pressure change, inner ear disease that the patient is experiencing, hidden brainstem tumors, some systemic diseases, tuberculosis, malaria, lung and kidney diseases, and cancer drugs. .

It is thought that the following 4 pathophysiological mechanisms may cause sudden hearing loss:

- Viral infection (such as mumps, measles, rubella)

- Labyrinthine vascular occlusion (such as hypercholesterolemia and hypoalphalipoproteinemia ... but controversial)

- Intracochlear membrane rupture

- Immune-mediated inner ear disease (as in Cogan's syndrome, systemic lupus erythematosus and other autoimmune rheumatologic diseases)

The following diseases and conditions have been associated with sudden hearing loss:

- Infection

Viral infections such as mumps, cytomegalovirus, chickenpox / herpes zoster and bacterial infections such as meningitis, syphilis

- Inflammation

Sarcoidosis, Wegener granulomatosis, Cogan syndrome

- Vascular (Vascular) Factors

Hypercoagulable conditions (e.g. Waldenström's macroglobulinemia), embolism (e.g., after coronary artery bypass surgery), after radiotherapy

- Tumor

Vestibular schwannoma, temporal bone metastases, carcinomatous meningitis

- Trauma

Temporal bone fracture, acoustic trauma, penetrating temporal bone injuries

- Toxins

Aminoglycoside antimicrobials, cisplatin

Sudden hearing loss can occur as a symptom of any disease process involving any that could lead to these theoretical possibilities. Each theory can explain some of the episodes with sudden hearing loss, there is no theory that can fully explain all sudden episodes of hearing loss. Sudden hearing loss in all age groups; this is an indication of the multifactorial nature of the clinical problem.

Symptoms of Sudden Sensorineural Hearing Loss (SSHL)

Sudden hearing loss can occur as a loss of unilateral or bilateral hearing, sometimes noticed by the patient. However, initially your hearing loss may not be noticeable. Often, patients feel an incipient ringing or humming noise. Sometimes there is a feeling of fullness or congestion in the ear. In cases such as new ear congestion, hearing loss, buzzing or ringing, an ear-nose-throat specialist should be consulted immediately. The most important point in the treatment of sudden hearing loss is early diagnosis and early initiation of treatment. The possibility of hearing loss returning increases with early treatment.

Sudden Hearing Loss is an "Emergency" Situation Related to the Ear

Sudden Hearing Loss – SSHL

If you don't hear when you wake up one morning for no reason, you may have sudden hearing loss. Do not say "wait a while, maybe it will pass", consult a doctor immediately! Sudden hearing loss is referred to as an otological emergency. Patient assessment should be continued immediately and expeditiously. Early diagnosis and treatment improves prognosis. Current guidelines of the American Academy of Otorhinolaryngology and Head and Neck Surgery Foundation (AAO-HNSF) especially recommend that physicians who examine patients with sudden hearing loss should distinguish between conductive hearing loss and sensorineural (neural type) hearing loss. (For example, after flu infection, the patient with a collapse or fluid in the eardrum should be distinguished from the patient with hearing loss without any abnormal findings in the eardrum; early diagnosis of this condition with inner ear disease should be provided). Patients should also be questioned about the onset of hearing loss, other underlying diseases, whether they have had similar complaints before, and whether they use drugs such as aspirin that can damage the inner ear.

In the clinical examination, tuning fork tests are very important. Thanks to the tuning fork test, in a patient who gave an anamnesis as "my ear started to hear less after the flu", while the examination was normal; It can be understood roughly that there is a problem in the inner ear of the deaf ear. Fistula testing with a pneumatic otoscope can also be helpful.

Sudden Hearing Loss Diagnosis

After a detailed physical examination, audiometry testing is mandatory, including pure voice and speech tests and imitans (tympanometry, acoustic reflex) tests. Test history and physical examination can be guided by the information gathered. Blood tests for viral infection antibodies may be desired.

How to diagnose sudden hearing loss?

The most striking feature is that hearing loss develops in less than 3 days. In some patients, dizziness can be observed as well as hearing loss.

• The main test for diagnosis of sudden hearing loss; audiometry (hearing test). In the hearing test, at least 30 dB (decibel) hearing loss should be detected at three consecutive frequencies.

• In the blood test, metabolic and etiological factors are screened.

• If the hearing loss does not improve in three weeks, detailed examination is made with MRI and tomography.

Sudden Sensorineural Hearing Loss (SSHL)
The auditory brainstem response test and the otoacoustic emission (OAE) test can provide additional information regarding the functional integrity of the auditory system. OAE tests can provide information about cochlear function, and auditory brainstem responses can be used to evaluate auditory nerve function. Auditory brainstem response and OAE results can also be helpful in diagnosing a functional hearing loss.

Vestibular tests are not mandatory and are available when the history and physical examination findings show.

Approximately 1-2% of the patients with sudden hearing loss have a tumor of the internal acoustic canal (IAC) or cerebellopontine corner. In contrast, 3-12% of patients with vestibular schwannoma present with sudden hearing loss. Gadolinium diethylenetriamine-pentaacetic acid (DPTA) -li Magnetic resonance imaging (MRI) is the gold standard imaging method in these tumors.

According to the American Academy of Otorhinolaryngology and Head and Neck Surgery Foundation (AAO-HNSF) 2012 guidelines, computed tomography (CT) scans are not beneficial in patients with sudden hearing loss and cause ionizing radiation exposure. Therefore, CT is not recommended for the initial evaluation of patients with a pre-diagnosis of sudden hearing loss.

Sudden Hearing Loss Treatment

Sudden hearing loss can occur as a loss of unilateral or bilateral hearing, sometimes noticed by the patient. However, initially your hearing loss may not be noticeable. Often, patients feel an incipient ringing or humming noise. Sometimes there is a feeling of fullness or congestion in the ear.

In cases such as new ear congestion, hearing loss, buzzing or ringing, an ear-nose-throat specialist should be consulted immediately. The most important point in the treatment of sudden hearing loss is early diagnosis and early initiation of treatment. The possibility of hearing loss returning increases with early treatment.

There are many different treatment regimens available for sudden hearing loss. Treatment of sudden hearing loss; Good results were obtained if started as early as possible. It is the most preferred way to plan treatment for the condition where the underlying possible cause is thought for each patient. The exact underlying cause can be determined in only 10-15% of the diseases. The American Academy of Otorhinolaryngology Head and Neck Surgery Foundation (AAO-HNSF) recommends treatment protocols containing corticosteroids as the initial treatment for patients with sudden hearing loss. Apart from corticosteroids, vasodilators (vasodilators), anticoagulants, dextrans, antiviral agents, diuretics, Triiodobenzoic acid derivatives can also be given to patients. Hyperbaric oxygen therapy has been evaluated as a treatment for sudden hearing loss. The effect of hyperbaric oxygen therapy on tinnitus and hearing loss in late-presenting patients is limited.

Apart from these, vitamin tablets (containing vitamin B6, vitamin C or ascorbic acid, vitamin B2, vitamin B3, vitamin B5, lecithin, vitamin B1, vitamin B12, bioflavonoids, choline bitartrate and inositol) created for the treatment of Meniere's Disease and sudden hearing loss in our country. available (such as "Lipo-Flavonoid Plus 60 Tablets" and "Ote Flavonoid Plus 100 Tablets").

In patients with oval and round window perilymph fistula (PLF) after trauma or barotrauma, if there is a positive fistula test, surgical closure of the fistula can be applied in the treatment of sudden hearing loss.

Intervention in the first 48 hours is important for effective treatment

Sudden hearing losses of unknown cause can lead to permanent hearing loss if not intervened immediately in the first days. However, with the right treatment, it is possible to return to normal hearing. The first 48 hours of intervention and correct treatment are of great importance in sudden hearing loss.

Sudden hearing loss is considered a medical emergency in the practice of ear-nose-throat medicine. Patients should seek help from an ear-nose-throat physician immediately in the presence of conditions such as buzzing, ringing, congestion in the ear, and fullness. For ear health, necessary examinations and treatments should be initiated without wasting time.

When one month is late, the chance of drug treatment decreases

The definitive diagnosis of sudden hearing loss is made by performing a hearing test (audiological examination). It also uses audiological tests to monitor the response to treatment and recovery. Sometimes, if it is thought that tumors in the inner ear canal may cause hearing loss suddenly, evaluation of the auditory and balance nerves with MRI is one of the primary examination methods.

The treatment of sudden hearing loss is medication. In order for drug therapy to be effective, it is important to diagnose the disease and start treatment as soon as possible. After a month after the development of sudden hearing loss, drug treatment is not applied because it will not be useful.

The most effective drug in sudden hearing loss is corticosteroids, popularly known as cortisone. Corticosteroids are administered in high doses and for a short time in case of sudden hearing loss. In addition, if sudden hearing loss is detected in the first three days, antiviral drugs effective against viruses are also added to the treatment. However, they are not given because they are not effective after the first three days. If adequate improvement is not observed in audiological test follow-ups after drug therapy is initiated, corticosteroid injection is applied through the eardrum to the middle ear.

You can find the latest guideline (with update) of the American Academy of Otolaryngology and Head and Neck Surgery Foundation (AAO-HNSF) about SSHL >> Clinical Practice Guideline: Sudden Hearing Loss (Update)Clinical practice guideline: sudden hearing loss

Prognostic Factors in Sudden Hearing Loss

Positive Prognostic Factors (Recovery Means High Probability)

  • Early admission of the patient and starting treatment immediately (first 10 days are very important)
  • No hearing loss in low and medium frequencies and severe hearing test
  • Detection of rising curve type hearing loss in the audiogram
  • Young patient 
  • Unilateral hearing loss
  • Lack of risk factors such as smoking, stress, atherosclerosis, alcohol
  • Less or no dizziness

Negative Prognostic Factors (Improvement Means Low Probability)

  • Elderly patient
  • Bilateral and total hearing loss
  • Vestibular symptoms and presence of facial paralysis
  • Presence of more than one vascular risk factor
  • Late application of the patient and late initiation of treatment
  • The curve in the audiogram is in the form of a descending curve

Even if an improvement is observed in the hearing thresholds of the patient; There may be no change in tinnitus. Prognostic tinnitus is considered a good indicator of response to treatment.

Sources I can recommend to you on the subject:

Murat Enoz, MD, Otorhinolaryngology, Head and Neck Surgeon - ENT Doctor in Istanbul

Private Office:
Address: İncirli Cad. No:41, Kat:4 (Dilek Patisserie Building), Postal code: 34147, Bakırköy - İstanbul
Appointment Phone: +90 212 561 00 52
Mobile phone: +90 533 6550199
Fax: +90 212 542 74 47




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