Persistent Tinnitus: Causes and Solutions for Better Sleep - Otolaryngology

Dr. Ye Dawei reply Otolaryngology

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Dear Sir/Madam,
Please visit the outpatient clinic for examination.

Inner Ear Tinnitus
As the name suggests, inner ear tinnitus is caused by lesions in the inner ear.
The most well-known conditions associated with this are Meniere's disease and the increasingly common sudden sensorineural hearing loss.
I have previously discussed this in the article "A Talk 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 may diagnose it as such.
In reality, 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 in a neurotology clinic, the physician's competence in managing dizziness may be called into question.
Simply put, if a patient presents with dizziness, tinnitus, and hearing loss, the physician will consider this disease.
The renowned Japanese physician, Ichiro Chikuwaki, even described it as a "7-point disease" due to the following characteristics:
1) Severe Dizziness: The sensation is akin to the world spinning, often lasting several hours, with the first episode being the most intense.
2) Spontaneous Dizziness: Occurs without any apparent trigger and can strike suddenly.
3) Recurrent Dizziness: Patients with Meniere's disease often experience repeated episodes rather than just a single occurrence.
4) Reversible Dizziness: There are periods of complete normalcy between episodes; dizziness does not persist for days.
5) Dizziness Accompanied by Cochlear Symptoms: Hearing often fluctuates in Meniere's patients, with severe tinnitus during acute episodes, and sometimes they perceive sounds at different frequencies.
6) Hearing Loss Typically Affects Low Frequencies.
7) "Recruitment Phenomenon": Patients often complain of discomfort in noisy environments, such as markets or train stations.
To date, no laboratory test 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 sensation of ear fullness, and hearing loss.
These episodes do not occur daily and last longer than the brief episodes seen in benign paroxysmal positional vertigo (BPPV) or the prolonged episodes of vestibular neuritis.
Most patients experience dizziness for about 3 to 4 hours before gradually improving, only to have another episode weeks later.
Many elderly patients report having recurrent dizziness since their youth, eventually leading to progressive hearing loss 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 neurotropic agents, vasodilators, and mild sedatives.
If episodes occur monthly, treatment should last at least four months; if they occur bi-monthly, treatment should last at least five months, which is the interval between episodes plus an additional three months.
If medical treatment is ineffective or the patient cannot tolerate long-term medication, endolymphatic sac decompression surgery may be considered.
2.
Sudden Sensorineural Hearing Loss
"Sudden" indicates that patients can clearly identify a specific day or even moment when they suddenly lose hearing or experience severe tinnitus.
This is an ENT emergency, and patients are generally advised to seek immediate hospitalization.
Some patients may also experience dizziness and vomiting, necessitating a differential diagnosis with Meniere's disease.
Typically, it presents with dizziness only once, lasting a day or several days, but does not recur, although hearing loss and tinnitus persist.
In contrast, Meniere's disease involves recurrent dizziness, but hearing often recovers more quickly after episodes.
A small number of acoustic neuroma cases may also present with sudden sensorineural hearing loss, requiring a CT scan for differential diagnosis.
The causes are widely accepted to include inner ear circulatory disturbances, viral infections, and autoimmune diseases.
Treatment has shifted from a "shotgun" approach to targeting the specific underlying cause for each case:
1) Inner Ear Circulatory Disturbance: This occurs due to obstruction or spasm of the blood vessels supplying the inner ear, leading to hypoxia and hearing impairment.
It is more common in patients with systemic vascular diseases such as diabetes, hypertension, or hyperlipidemia.
Treatment focuses on plasma expanders (e.g., Dextran), which is a glucose polymer that reduces blood viscosity and prevents thrombosis.
2) Viral Infection: Various viruses can infect the inner ear, such as the rubella virus and cytomegalovirus, which can cause congenital hearing loss; mumps virus, measles virus, varicella-zoster virus, and the currently circulating influenza virus can cause acquired hearing loss.
Treatment involves administering corticosteroids, starting with 60 mg daily for six days, then tapering over a total of two weeks.
3) Autoimmune Diseases: Patients often have systemic autoimmune diseases such as lupus or rheumatoid arthritis, and bilateral hearing loss is common.
Diagnosis involves history, physical examination, and electronystagmography (ENG) to differentiate between central and peripheral causes.
Patients are typically advised to be hospitalized for at least a week; if hearing does not improve, they may be discharged, but if there is improvement, they may stay for another week.
During hospitalization, daily hearing tests and eye movement changes are recorded, and follow-up occurs every two weeks after discharge for three months.
Noise-Induced Tinnitus
Generally, noise-induced tinnitus can be divided into chronic noise exposure and acute trauma-induced tinnitus.
The former results from long-term exposure to noisy environments, while the latter can occur from events such as explosions, gunfire, or loud concerts.
1.
Chronic Noise-Induced Hearing Loss
Modern industrial society has brought prosperity but also created a noisy environment.
Many occupational settings can lead to this type of injury, such as railroads, factories, airports, auto repair shops, DJs, arcade workers, and stockbrokers.
Noise levels below 80 decibels are less likely to cause hearing damage, but exposure to noise levels above 100 decibels for over 8 hours can lead to temporary threshold shifts.
If individuals can avoid loud noise quickly, their hearing may recover.
However, if permanent threshold shifts occur, hearing loss may be irreversible due to pathological changes in the inner ear, such as degeneration of outer hair cells and fusion or loss of stereocilia.
Labor safety regulations have established permissible noise exposure limits to protect workers' hearing, with a maximum industrial noise level of 90 decibels for no more than 8 hours daily.
2.
Acute Trauma-Induced Hearing Loss
Acute trauma-induced hearing loss refers to inner ear damage caused by sudden exposure to loud sounds.
Young people often frequent rock concerts, karaoke bars, and pubs, experiencing tinnitus, hearing loss, and a sensation of ear fullness the next day, termed "disco hearing loss," "karaoke hearing loss," or "iPod hearing loss." Following the presidential election, several patients presented with symptoms of ear fullness, ear pain, and tinnitus after exposure to loudspeakers at campaign headquarters, referred to as "election hearing loss." Additionally, the high-pressure shock waves from events like the Wall Street explosion last longer than 1.5 milliseconds, while gunfire shock waves last less than 1.5 milliseconds.
Unlike irreversible hearing loss from chronic noise exposure, these acute cases respond well to medical treatment, and prompt intervention is strongly recommended to restore hearing.
However, exposure to noise levels exceeding 130 decibels for extended periods can lead to fatigue and decreased adaptability to noise, resulting in irreversible damage similar to chronic noise-induced hearing loss.
Metabolic Tinnitus
The most common cause of metabolic tinnitus among the population is hyperlipidemia.
Due to economic prosperity, there is a widespread phenomenon of nutritional excess, leading to 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." The mechanisms causing tinnitus include:
1.
The inner ear's blood vessels 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.
Patients with hyperlipidemia often present with other conditions such as hypertension, diabetes, atherosclerosis, or heart disease, requiring several months of medication to see results.
However, in neurotology patients, tinnitus and dizziness are often the initial symptoms, and they typically feel significantly better after just one week of medication.
The most effective treatment is for dizziness, followed by tinnitus, with no effect on hearing loss.
If patients normalize their lipid levels and stop medication without dietary control, recurrence is likely, but medication can quickly alleviate symptoms.
Blood tests may show normalized lipid levels, supporting this hypothesis.
Vascular Tinnitus
The vertebral arteries supply blood to the brain and inner ear.
If the arteries supplying the inner ear become obstructed or spasmodic, it can lead to ischemia, resulting in abnormal discharges from the auditory nerve, clinically presenting as tinnitus.
These patients often experience dizziness, nausea, vomiting, and hearing loss, along with systemic symptoms such as occipital headaches, neck and shoulder pain, and numbness in the limbs.
Most patients are elderly and frequently have comorbidities such as hypertension, diabetes, heart disease, or hyperlipidemia.
For vascular tinnitus, treatment typically involves vasodilators to improve blood flow.
However, for vascular narrowing due to atherosclerosis, systemic vasodilators do not selectively target the inner ear.
It is now believed that improving hemodynamics, increasing the deformability of red blood cells, and reducing blood viscosity are essential for ensuring the inner ear receives adequate oxygen and nutrients.
"Vasoactive agents" are designed with this concept in mind, derived from natural ginkgo biloba or synthesized.
Red blood cells are approximately 7 micrometers in diameter, while the true diameter of capillaries is only 3 to 4 micrometers.
These medications can enhance the deformability of red blood cells, allowing them to pass through narrowed vessels more easily, reduce spasms, and prevent platelet aggregation, thus promoting better blood flow.
Tumor-Related Tinnitus
In otolaryngology, unilateral tinnitus raises suspicion for two types of tumors: nasopharyngeal carcinoma and acoustic neuroma.
This was also mentioned in "A Talk on Dizziness," and I will post it again.
Acoustic Neuroma
The acoustic nerve runs from the inner ear to the brainstem, with tumors most commonly occurring at the cerebellopontine angle (CPA).
Initially, patients may experience gradual unilateral hearing loss or tinnitus.
This tumor grows very slowly, so even if it compresses the vestibular nerve, central compensation may prevent 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 may be 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 to see if air fails to fill the internal auditory canal, known as "air CT." However, this method can cause headaches for about a week due to the air in the cranial cavity.
With the advent of 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 and no dizziness, but absent auditory brainstem responses must be considered for this condition.
Prevention is Better than Cure
After categorizing the causes of tinnitus, we find that many are preventable.
Patients with Meniere's disease should pay attention to their diet and avoid excessive salt intake.
The increase in cases of sudden sensorineural hearing loss may be related to modern civilization and stress.
Occupational noise exposure often leads to irreversible damage, so controlling noise levels in the workplace is crucial.
Early treatment of acute trauma-induced hearing loss is highly effective, and it is essential to avoid potentially harmful environments.
For metabolic tinnitus, controlling underlying medical conditions, engaging in appropriate exercise, and avoiding fatty foods can help maintain normal cholesterol levels.
Sincerely,
Dr.
Da-Wei Yeh, Director of the ENT Department, Hsinchu Hospital

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Reply Date: 2009/02/23