Tinnitus: Causes and Solutions for Ear Ringing - Otolaryngology

Dr. Ye Dawei reply Otolaryngology

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● Classification of Tinnitus "Tinnitus is a gradual onset of deafness," and "If tinnitus persists, it may lead to deafness." These ancient phrases highlight the serious possibility that tinnitus can cause significant hearing loss.
The English term for tinnitus is derived from the Latin word meaning "ringing." Scholars commonly classify tinnitus based on its underlying causes as follows:
○ Cochlear Tinnitus Cochlear tinnitus, as the name suggests, is tinnitus caused by inner ear disorders.
The most notable conditions include "Meniere's disease" and the increasingly common "sudden sensorineural hearing loss." I have previously discussed this in "A Discussion on Dizziness," and I will reiterate it here.

1.
Meniere's Disease When the general public thinks of dizziness, they often associate it with "Meniere's," and even general practitioners frequently diagnose it as such.
However, there are not as many cases of Meniere's disease as one might think; many patients who complain of dizziness are often overdiagnosed by physicians.
Therefore, if the number of Meniere's cases is disproportionately high among patients in a neurotology clinic, the physician's competence in managing dizziness may be called into question.
In simple terms, if a patient experiences dizziness, tinnitus, and hearing loss, the physician will consider this disease.
The renowned Japanese physician Ichiro Chikuwait even described it as "7 points disease" due to the following characteristics:
1) Severe dizziness: It feels as if the world is spinning and can last for several hours, with the first episode being the most intense.

2) Spontaneous dizziness: It occurs without any apparent trigger and can suddenly manifest.

3) Recurrent dizziness: Patients with Meniere's disease often experience repeated episodes, rarely having just one occurrence.

4) Reversible dizziness: There are periods of complete normalcy between episodes, and dizziness does not persist for several days.

5) Dizziness accompanied by cochlear nerve symptoms: Patients often experience fluctuating hearing, severe tinnitus during acute episodes, and sometimes perceive sounds at different frequencies.

6) Hearing loss is often more pronounced at low frequencies.

7) There may be a "reverberation phenomenon," where patients complain of discomfort in noisy environments, such as markets or train stations.

To date, no laboratory tests can definitively diagnose Meniere's disease, making a detailed medical history and basic physical examination crucial.
Patients often experience unforgettable episodes of severe dizziness accompanied by tinnitus, a feeling of ear fullness, and hearing loss.
These episodes do not occur daily, and their duration is not as brief as "benign paroxysmal positional vertigo," nor as prolonged as "vestibular neuritis." Most patients experience dizziness for about 3 to 4 hours before gradually improving, but episodes may recur weeks later.
Many elderly patients report having experienced recurrent dizziness since their youth, eventually leading to gradual hearing deterioration and persistent tinnitus.
This condition typically occurs between the ages of 20 and 40 and has a maternal inheritance pattern.
The underlying cause is endolymphatic hydrops in the inner ear, leading to a sensation of ear fullness.
Treatment primarily involves medical management, including neuroprotective agents, vasodilators, and mild sedatives.
If episodes occur monthly, treatment should last at least four months; if they occur every two months, treatment should last at least five months, which is the interval between episodes plus three months.
If medication is ineffective or the patient cannot tolerate long-term medication, endolymphatic sac decompression surgery may be considered.
○ Noise-Induced Tinnitus Generally, noise-induced tinnitus can be divided into chronic noise exposure and acute trauma-induced tinnitus.
The former is typically caused by long-term exposure to noisy environments, while the latter includes events such as explosions, gunfire, fireworks, or even the popular rock concerts and personal music players among today's youth.

1.
Chronic Noise-Induced Hearing Loss The modern industrialized society has brought prosperity but also created a noisy environment.
Many workplaces can lead to this occupational hazard, such as railroads, factories, airports, auto repair shops, DJs, video game store employees, and stockbrokers.
Noise levels below 80 decibels are less likely to cause hearing damage, but exposure to noise levels exceeding 100 decibels for more than 8 hours can easily lead to temporary threshold shifts.
If one avoids noisy environments promptly, hearing may recover.
However, if permanent threshold shifts occur, hearing loss becomes irreversible.
Pathologically, one may observe outer hair cell degeneration and fusion or loss of stereocilia in the inner ear, which is an irreversible tissue injury.
Labor safety regulations have established permissible noise exposure limits to protect workers' hearing, which can serve as a reference for daily life and work.
In principle, the maximum allowable industrial noise level is 90 decibels, and exposure should not exceed 8 hours per day.

2.
Acute Trauma-Induced Hearing Loss Acute trauma-induced hearing loss refers to inner ear damage caused by a sudden, intense external sound stimulus.
This is a direct physical injury from mechanical waves.
Nowadays, young people often frequent rock concerts, karaoke bars, and pubs, and may experience tinnitus, hearing loss, and a sensation of ear fullness the following day, which can be termed "disco deafness," "karaoke deafness," or "personal music player deafness." After the presidential election, several patients presented in the clinic with symptoms of ear fullness, ear pain, and tinnitus after exposure to loudspeakers at campaign headquarters, which could also be termed "election deafness." Additionally, the high-pressure shock waves from the recent explosion in Wall Street lasted more than 1.5 milliseconds, while the shock waves from gunfire typically last less than 1.5 milliseconds.
Unlike irreversible hearing loss caused by long-term exposure to noisy work environments, the aforementioned situations are due to transient acoustic trauma, and medication treatment is very effective.
It is strongly recommended to seek prompt treatment to restore hearing.
However, if noise levels exceed 130 decibels and the exposure duration is prolonged (such as continuous firecrackers commonly seen at weddings or funerals), it can also lead to a decrease in the ear's adaptability to noise, resulting in fatigue, similar to the irreversible damage caused by chronic noise exposure.
○ Metabolic Tinnitus The most common cause of metabolic tinnitus among the population is hyperlipidemia.
This is due to the economic prosperity of modern society, leading to widespread nutritional excess and a significant increase in hyperlipidemia cases.
In neurotology clinics, up to 10% of patients may have this condition.
These patients often complain of persistent "dizziness, brain fog, and tinnitus," experiencing an indescribable discomfort.
The mechanisms causing tinnitus include:
1.
The blood vessels in the inner ear are very delicate and lack collateral circulation, making it easy for lipids to deposit in the cochlea.

2.
Increased blood viscosity can lead to poor circulation and embolism in the inner ear blood vessels.
Patients with hyperlipidemia seen in internal medicine clinics often have other comorbidities such as hypertension, diabetes, atherosclerosis, or heart disease, requiring several months of medication before seeing results.
In contrast, patients with hyperlipidemia seen in neurotology clinics often present with tinnitus and dizziness as their initial symptoms, without accompanying internal diseases, and usually feel significantly better after just a week of medication.
Among all symptoms, dizziness responds best to treatment, followed by tinnitus, while hearing loss shows no improvement.
If patients stop medication after normalizing their lipid levels but do not pay attention to their diet, recurrence is likely.
However, once they resume medication, they immediately feel relief.
Subsequent blood tests may show normalized lipid levels, supporting our hypothesis.
○ Vascular Tinnitus The vertebral arteries supply blood to the brainstem, cerebellum, and inner ear.
If the arteries supplying the inner ear become obstructed or spasmodic, it can easily lead to ischemia in the inner ear, resulting in abnormal discharges from the auditory nerve, clinically presenting as tinnitus.
These patients often experience dizziness, nausea, vomiting, and hearing loss, and may also have systemic symptoms such as occipital headaches, neck and shoulder pain, and numbness in the limbs due to insufficient blood supply to the posterior cranial fossa.
Most patients are elderly and often have comorbidities such as hypertension, diabetes, heart disease, and hyperlipidemia.
For vascular tinnitus caused by poor blood circulation, traditional treatment often involves vasodilators to expand blood vessels for therapeutic effect.
However, in cases of vascular narrowing due to atherosclerosis, vasodilators cause systemic vasodilation and do not selectively target the inner ear blood vessels.
It is now widely accepted that treatment should focus on improving hemodynamics, increasing the deformability of red blood cells, and reducing blood viscosity to ensure the inner ear receives adequate oxygen and nutrients.
○ Tumor-Related Tinnitus In otolaryngology, unilateral tinnitus should raise suspicion for two types of tumors: nasopharyngeal carcinoma and acoustic neuroma.
This disease has also been mentioned in "A Discussion on Dizziness," and I will post it again.

◎ Acoustic Neuroma The auditory nerve runs from the inner ear to the brainstem, with tumors most commonly occurring at the opening of the internal auditory canal, specifically at the cerebellopontine angle (CPA).
Initially, patients may only experience gradual unilateral hearing loss or tinnitus.
This tumor grows very slowly, so although it compresses the vestibular nerve, central compensation prevents dizziness.
As the tumor enlarges and compresses blood vessels, it can lead to sudden hearing loss or dizziness, and symptoms can become quite varied as the disease progresses.
If an acoustic neuroma is confined to the internal auditory canal and is less than 1 cm, it is difficult to detect on a CT scan.
Some have attempted lumbar puncture to introduce air into the ventricles, allowing the patient to lie on their side so that air enters the internal auditory canal; if an acoustic neuroma is present, the air will not fill the internal auditory canal, known as "air CT." Its drawback is that patients may experience continuous headaches for about a week due to the air in the cranial cavity.
With the advent of magnetic resonance imaging (MRI), tumors smaller than 1 cm can now be easily diagnosed.
If the tumor grows larger and extends toward the cerebellum or brainstem, it may pose a life-threatening risk.
Clinically, patients may present with normal hearing but no response in auditory brainstem responses, necessitating consideration of this condition.
● Prevention is Better than Cure After classifying the various causes of tinnitus, we learn that many of them can be prevented in advance.
Patients with Meniere's disease should pay attention to their diet and avoid excessive salt intake; the increase in sudden sensorineural hearing loss cases may be related to the development of civilization and life stress.
Occupational noise-induced damage is often untreatable, so it is crucial to monitor noise levels in the work environment.
Acute trauma-induced hearing loss responds well to early treatment, and it is even more important to avoid potentially harmful environments.
For metabolic tinnitus, in addition to managing underlying medical conditions, appropriate exercise and avoiding fatty foods can help maintain normal cholesterol levels.
● Self-Assessment for Tinnitus Through some carefully designed questions, we can often determine the possible causes of a patient's tinnitus.
Here are some simple questions:
1.
Is the tinnitus accompanied by dizziness? Does it become louder during dizziness? Tinnitus associated with dizziness raises the possibility of "cochlear tinnitus." Meniere's disease, sudden sensorineural hearing loss, and anterior inferior cerebellar artery disorders are often unilateral; vertebrobasilar insufficiency tends to be bilateral.
Additionally, tinnitus in Meniere's disease may become louder during dizziness.

2.
Is the work environment noisy? Have you worked in a high-noise environment for an extended period? Have you been exposed to gunfire? Have you experienced injury from fireworks? As mentioned earlier, the human ear can tolerate noise levels up to 90 decibels, and exposure should not exceed 8 hours per day.
When tinnitus occurs, it is essential to leave the noisy environment to prevent irreversible damage to the cochlear hair cells.
Standard ear protection only attenuates noise by 30 to 40 decibels and is ineffective against high-decibel noise from sources like airplane engines, trains, or lathes.

3.
Have you had blood tests to check cholesterol levels? Do you have anemia, hypertension, thyroid disease, diabetes, or atherosclerosis? Tinnitus caused by systemic vascular diseases is often bilateral, so it is essential to rule out these internal medical conditions in tinnitus patients.

4.
Are you taking any long-term medications? Have you received antibiotic injections? Some medications, such as aspirin, quinine, contraceptives, antihypertensives, and antipsychotics, can sometimes cause bilateral tinnitus, which resolves upon discontinuation.
Previously, older physicians sometimes administered streptomycin, kanamycin, or gentamicin, which could also lead to tinnitus over time.
Therefore, if tinnitus occurs after an injection, it is advisable to stop the injection to prevent irreversible damage.

5.
Is the tinnitus high-pitched or low-pitched? Is it unilateral or bilateral? Auditory nerve lesions often present with high-pitched tinnitus, while Meniere's disease or middle ear disorders typically present with low-pitched tinnitus.
Cochlear tinnitus is often unilateral, while central vascular tinnitus is usually bilateral.

6.
Is the tinnitus synchronized with your heartbeat? If the tinnitus is synchronized with the heartbeat or pulse, it may indicate a vascular malformation or venous anomaly.
If turning the neck toward the affected side reduces or eliminates the tinnitus, it may be due to excessive pulsation of the neck vessels.

7.
Is the tinnitus related to breathing? General respiratory infections or Eustachian tube obstruction from flying can cause tinnitus, while excessive Eustachian tube opening can also lead to tinnitus, often accompanied by a sensation of ear vibration during breathing.
If the body bends down to tie shoelaces, the symptoms may immediately improve due to increased blood flow to the brain.

8.
Please visit the ENT department for a hearing test.
Dr.
Yeh Da-Wei, Director of the ENT Department, Hsinchu Hospital.

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Reply Date: 2008/02/14