Sudden deafness – Early Treatment

In our last article, I wrote about sudden hearing loss, its causes and why it happens. This catastrophic condition is regarded as one of the few ear emergencies where early treatment within the first two weeks has been shown to significantly improve the outcome and potential recovery of the hearing loss.

Often the cause of the hearing loss is not obvious. The hearing suddenly drops and may be associated with a ringing noise in the ear and /or disequilibrium. This depends on whether the effect is limited to the hearing organ only or also affect our balance organ function too as they share the same inner ear fluids. The screening battery tests may not show any obvious diagnosis but treatment for this condition should not be delayed. The current medical thinking is that there is an insult to the inner ear which could be a blocked micro-vessel that starves the cochlear of its blood supply and oxygen or perhaps it is an inflammation of the cochlea by possibly a virus. In either cases, the ear often looks normal and imaging is usually unremarkable. The dilemma that physicians face is do we wait for the condition to declare itself to get the right diagnosis, or do we act with a “shotgun” treatment of different drugs to prevent further ear damage and set the course for early recovery? The answer is we should act “blindly”. We have to remember that we are unable to cut out the inner ear for test sampling as doing so is a major operation and the operation would certainly kill the ear and its hearing.

What constitutes this shotgun rescue treatment? It is thought that perhaps a virus might be the cause so a week’s course of high dose antiviral medication is given. Inflammation from a viral attack, diabetes mellitus event or deoxygenation of the nerves, is treated with a two week course of high dose steroids which is frontloaded at a high dose, slowly tailoring downwards over two weeks to maintain a treatment effect without causing a sudden steroid withdrawal that could affect the body. This steroid treatment has been studied extensively and research has shown that if it is given timely with in two-week golden window from the first reported ate of the sudden hearting loss symptoms, it is statistically beneficial in improving partially or totally the loss hearing. It is this research that effects sudden hearing loss as an emergency, to be recognized early and confirmed so that treatment can be provided. Such a large dose of oral steroids can cause complications. One of them is stomach ulcers so this course is accompanied with a two-week course of proton pump inhibitors that reduces gastric acid production.

Some patients are unable to take such high dose steroids e.g. diabetics, patients with viral hepatitis or known gastric ulcer disease. With these patients, research has shown that liquid steroids can be injected into the middle ear cavity every 2-3 days for 2 weeks to permit the steroid drug to diffuse directly into the inner ear where there is “supposed” to be inflammation and failing nerve function.  This prevents the steroid drug to be in the blood system where it can exert its side effects on the rest of the body organs even though its target is only the ear. Attractive as this may sound, it is more invasive and less economical for the patient, as every two days, the eardrum needs to be pierce by a needle to deliver the drugs on site. The decision is a risk-benefit exercise to be discussed with the patient.

Another reason maybe that the blood vessels are blocked and insufficient blood and oxygen are getting to the delicate hearing cells. Vasodilators are prescribed to dilate the small blood vessels to the brain thereby improving brain blood flow. With any nerve insult, it takes time and ingredients for a nerve to recover so high-dose Vitamin B Complex, the building blocks of nerve function, is also prescribed.

Any improvement in the ear’s hearing would usually be known within the first 6 weeks. Thereafter recovery rates diminish. An MRI scan is naturally important diagnostically to exclude a brain/ nerfve tumour. If seen, treatment may include simply observing with annual MRI scanning (as acoustic neuroma can grow so slowly that no treatment may ever be required), or radiotherapy or neurosurgery to remove a tumor. Again the choice of treatment is an exercise of risk versus benefit for such major operations. If diabetes mellitus is diagnosed, then anti-diabetic medication would be required.

One would think that diagnosing a condition and providing a “shotgun” or highly specific targeted treatment for a known diagnosis will solve and rescue the hearing. In this regard, you would be wrong! In spite of the best efforts and timely care, some patients will continue to have hearing loss on one side. For these patients, the treatment is symptomatic. That is to say that if they are socially and professionally bothered by their one sided hearing loss, normal hearing aids or a surgically implanted hearing system for single sided deafness may help. If the ear generates a disturbing ringing ie tinnitus, medical treatment with tinnitus retraining therapy (TRT) may help.

So losing one’s hearing suddenly should be taken seriously. Early medical attention to confirm single sided sudden deafness and the provision of early treatment within two weeks of the episode, may just arrest and improve the deafness.

The Chinese version of this article was published in Hong Kong Economic Journal on 18 Jul 2016 and 1 Aug 2016

Sudden deafness – The how and why

Have you ever been unfortunate to suddenly lose your hearing, or know of someone who had? This is a disaster if it should happen. Thankfully the likelihood is very uncommon and estimated to happen to 12 out of every 100, 000 persons each year. Nonetheless this condition has a name - it is commonly called sudden sensorineural hearing loss and is regarded as one of the few medical emergencies of the ear.

Why does it happen? There are many reasons why we might suddenly lose our sensorineural hearing. The easiest way to understand this is to consider what could damage our hearing pathway from our inner ear to our auditory nerve (nerve of hearing) and to our auditory cortex, the part of the brain that interprets sound. Sufferers often claim they wake up with reduced or no hearing, or pressure in the ear with a ringing noise, with the hearing gradually getting worse without recovery. This sudden loss of hearing may or may not be accompanied by a sense of unbalance, dizziness, nausea and vomiting. Sometimes there is ear pain with a painful rash around the affected ear.

It should be said that some obvious causes do not come under this medical label of sudden hearing loss even though hearing loss may be a result. This includes history of trauma to the head which can cause concussion and/or bleeds in the brain as well as shock and fracture damage to the cochlea. Surgery to the ear and/or brain for other conditions, may also cause hearing loss. This causes are obvious and treated accordingly.

So what are the possible causes that are not so obvious? At the cochlear and auditory nerve level, viruses have been often cited as a cause especially the Herpes family of viruses. A herpes zoster infection, which is the same as secondary chicken pox viral infection or shingles, can cause an inner hearing loss with a painful shingles rash on the ear and face. Bacterial infection e.g. syphilis, of the cochlear is very rare and patients are usually very sick. Diabetes mellitus has also been said to be a cause. This condition is known to cause small vessel disease, blocking the vessels that feed the cochlea, and hence it dies. Similarly, autoimmune conditions in general are thought to also cause vessel blockage and nerve tissue inflammation, which can damage the cochlea and the auditory nerve. As there are many types of autoimmune diseases, identifying the hearing loss as due to that possibility usually starts the diagnostic process for that autoimmune condition.

Tumors are sometimes the cause of the sudden hearing loss. This is often what the patient fears the most, yet it is even less likely to occur and much easier to diagnose with highly sensitive magnetic resonance imaging of the brain today. The commonest tumor grows from the nerve lining of the auditory nerve. These tumors are called acoustic neuromas and occur in 2-3 out of every 100,000 Hong Kong persons each year. They are almost always benign and grow very slowly. However, as the auditory nerve passes through a narrow bony canal to get to the brain, it can get compressed even with a small growth, starving and paralyzing the auditory nerve and causing hearing loss.

When a patient seeks a medical consultation for sudden hearing loss, it is important to diagnose the reason and to offer the correct treatment. A hearing test is mandatory after a complete ear examination and can confirm or refute cochlear hearing loss. If it is confirmed that a sudden hearing loss event has occurred, then the diagnosis should be established if possible. A battery of tests to view the blood profile, kidney function, inflammatory blood markers, thyroid function, the fasting glucose and cholesterol profile as well as a magnetic resonance imaging of the brain and auditory nerve, are usually performed to seek the cause. Unfortunately, or fortunately, the cause is not usually found with this test battery screen. The true-positive hit rate of this test battery for a diagnosis is about 0.1% i.e. 1 out of every 1000 patients screened. Hence most of the time, the diagnosis is idiopathic sudden sensorineural hearing loss, which is to say we have search for all possible diagnoses but cannot establish one as yet. Nonetheless the test battery is important as it screens for treatable conditions. Understandably the sufferer may not be satisfied that a cause cannot be clearly established. However, in the absence of a clear diagnosis, hearing rescue treatment can still and is given, and this will be discussed later.

The final take home message for readers is that sudden hearing loss is regarded as a medical emergency as the available evidence–based medicine research shows that early treatment within two weeks of the hearing loss event has the best chance of recovery. So here, early medical attention is the rule. If in doubt, do not be. Seek medical advice early.

The Chinese version of this article was published in Hong Kong Economic Journal on 20 Jun 2016 and 4 Jul 2016

Voice loss Part 2 – Treatment options

In the first part of this article, we understand how our voice is produced, and in simple terms, how we lose our voice. Losing our voice is a problem for anyone as we are always communicating our wishes, dreams, love and needs to others.

So what can we do if we lose our voice? Firstly, we should not panic as common things happen commonly, and the commonest cause by far, is an acute viral laryngitis. The swelling from acute laryngitis is usually maximal at three days, after which the swelling subsides gradually, and the voice gradually returns to normal. During the inflamed phase, sufferers are best advised not to use their voice, as continuing voice use could damage and permanently scar the vocal cord lining. This scarring could result in a permanent hoarse voice by impairing the movement of the mucosal lining over the vocal ligaments.

Losing one’s voice is not unusual at all and most voices recover very quickly. If our voice doesn’t return to normal and you remain hoarse beyond three weeks, medical attention to make a diagnosis and to prevent long term irreversible damage would be recommended. Your ENT Surgeon can easily inspect your voice box by performing a flexible endoscopic examination of the larynx. So what conditions can cause chronic loss of voice that can be seen by endoscopy?

A growth on one or both vocal cords can prevent optimal closure of the cords. Excess air then leaks through the gap and voice production is impaired in terms of quality as well as intensity of the voice. Commonly the early formation of vocal cord nodules is the cause. Two non-cancerous thickening of the vocal cords on exactly opposite vocal cord surfaces prevent the cords from coming together well. With the leak, the voice is lost, and we try even harder to produce a voice by speaking louder. This means that the nodules can get bigger, and the hoarseness continues. Treatment here is primarily by speech therapy to re-educate the user how to use their voice better like a singer. If the nodules are too large and /or speech therapy has not worked, then phonosurgery to trim away the nodules may be necessary. If a growth is seen only on one vocal cord, then early surgery may be necessary to exclude cancer. Here the lesion is examined close up, excised and sent for testing. If it is cancerous, then follow up treatment protocols will be advised. However if the lesion looks like a cyst or a polyp under close up endoscopic examination during surgery, the lesion is removed with gentle and careful preservation of the vocal cord lining. This is called phonosurgery and requires great skill. The removal of the lesion is both diagnostic (as we sent the lesion for testing to know what it is) as well as also therapeutic (as the hoarse voice is treated as well)

A total loss of one’s voice is a catastrophe. This is unusual but it happens when one of the two vocal cords is paralysed. They are unable to meet in the midline, the gap is left wide open and therefore no turbulence or voice can be made. The cause here is damage to the nerve that moves the vocal cord. This nerve travels from our brain, down our neck pass our thyroid gland and even as far down as our lung, before turning around to innervate our voice box, one on each side. Cancer in the neck, lung cancer, strokes, penetrating trauma and surgery to the neck and thyroid are the usual causes that damage this nerve. If this is the case and recovery is not forthcoming, the voice can be improved by surgical treatment that pushes the affected cord to the center to a “closed” position. By re-siting the affected vocal cord to the midline “closed” position, surgeons allow the voice to be reproduced again when the normally functioning opposite vocal cord moves and easily close the gap. Rushing air from the lung re-vibrates the cords once again, turbulence of the air is produced and a voice is regenerated again. This particular treatment is important for these paralyzed vocal cords sufferers, as aside from a more normal voice, upper body strength is improved with an improved cough to maintain a clean and sputum free lung.

Remember, our voice is important and most loss of voice conditions are mild, short-lasting with full recovery. A persistent hoarse voice should not be regarded as normal as diagnosis is easily made with endoscopy in a clinic setting. Timely treatment ensures a good quality strong voice either by medication, speech therapy, surgery or all a combination of treatment to suit the problem.

The Chinese version of this article was published in Hong Kong Economic Journal on 22 Feb 2016 and 7 Mar 2016

Voice loss Part 1 – How our voice is produce and lost

Humans are social beings. We communicate with others using our voice as well as body language. So it naturally becomes a problem when we lose our voice.

We make our voice in our larynx. Here sit two ligaments called vocal cords, that are joined together in the front and sit apart at the back, like an open “V”. The vocal cords are covered with a soft mucosa lining, and lie horizontally immediately above our windpipe, acting as two guards protecting our airway.

So how do these two vocal cords make a voice? We need two things to occur for sound to be made. First the two vocal cords are brought together by a muscle, and at the same time, air from our lung is expelled through these closed cords. The air passing through our cords cause the mucosa covering to vibrate, and hence a sound (voice) is made. The pitch of this sound, our voice, is changed by other muscles tightening or relaxing the tension of the vocal ligaments. When the vocal ligaments are tightened, the voice becomes higher pitched, like when we strum a tightly stretched guitar string to create a higher note. For a lower tone sound, the tension is reduced, and a lower, more bass voice is produced. The voice of children, adult males and adult females also vary due to the size of the vocal cords and the “laryngeal” box that it sits in. A shorter vocal cord in a smaller box as in children produce a shriller, high tone voice whilst at the other extreme, a longer vocal cord in a bigger box of an adult male produces a deeper voice. Here the analogy is that of a child ukulele as compared to an adult double bass. The female adult voice is somewhere in between. So that is how the voice is made. Speech and language which strings sounds together to form words is different. Speech that form words of what we want to say, in the form of phonetics as well as the tone in tonal languages like Putonghua and Cantonese, comes from movements of our tongue above our voice box.

So how do we lose our voice? The commonest cause is an acute inflammation of our larynx (acute laryngitis) e.g. when we catch the flu. The lining of the vocal cords become swollen, inflamed and stiff and the inflammation causes pain when we try to speak. As air passes through the cords, the vibration is impaired. Making a sound is difficult as well as painful, and the voice changes to a very hoarse rasp or total loss altogether.

Another way that voice production can be impaired is if there is a growth on a vocal cord that prevents both the vocal cords from coming together perfectly. Conditions that could do this are e.g. cancer of the vocal cords commonly seen in smokers. These growths tents open the gap between the cords, and allows air to leak through the gap, making voice production inefficient at best, and sometimes impossible at worst.

The ultimate voice loss occurs when the vocal cords cannot come together. This is definitely an uncommon condition. We need both vocal cords to vibrate to make a sound. When one of the vocal cords cannot be drawn close, the gap between the vocal cord is too wide for turbulence of the air, and therefore sound, to made by the passing air. It is the same as when we try to whistle. We can only make a whistle with “closed” lips and not an “open” mouth. Here the reasons why a cord cannot “close” is usually due to damage to the nerve that supplies the “closing” muscle of that vocal cord.

To lose one’s voice is not unusual at all and most voices recover very quickly. However, a persistent hoarse voice or loss of voice for more than three weeks is not normal. If this continues, further medical attention for a diagnosis would normally be advised.

  

The Chinese version of this article was published in Hong Kong Economic Journal on 1 Feb 2016