Vertigo and balance disorders – a brief overview
The term vertigo indicates a rotating or a spinning sensation. On a broader perspective it also includes the sensation of imbalance or instability. The symptoms of vertigo and imbalance are referred to in medical parlance as ‘Balance disorders’ and signifies a disorder in the balance system (also termed as the vestibular system). The maintenance of the body’s balance is a very complex mechanism and involves many different organs of the body, the most important of which are the brain, the ears, the eyes, the spinal cord, the nerves and the muscles of the limbs and trunk as well as the small muscles of the eyes. A defect in any one of them can completely jeopardize the balance system and cause vertigo/ imbalance. Over and above these, other systemic (i.e. general) causes like anemia, diabetes, thyroid disorders, heart diseases etc can cause balance disorders by inducing functional changes in the brain, eyes, ears, nerves etc. Psychological disorders / psychiatric diseases can also be the cause of balance disorders.
Balance disorders are pretty common and according to available international statistics about 5% of all patients seeking medical advice from the family physician and about 10% of all patients visiting neurologists and ENT doctors present with vertigo / imbalance.
The maintenance of the body's balance is primarily a function of the brain. The brain collects information about the position of the body (irrespective of whether it is stationary or, it is moving), from different sensors located in different parts of the body. The sensors are the (1) the two eyes, (2) two specialized balance organs called vestibular labyrinths, which are situated deep inside the ears, and (3) some special sensors called proprioceptors which are located in the soles of the feet, in the buttocks, in the back and in the neck. Information from the sensors are conveyed to the brain and from this information , the brain learns about the stability of the ground on which the person is standing, sitting or lying down and also about the stability of the surroundings. Once the brain has learnt about the stability of the ground and the surroundings, that is after it has accessed how much the condition of the ground and the surroundings is conducive to the subject's stability, and found out how much the person is liable to be instable or to fall and if so in which direction, it spontaneously and instantaneously generates a corrective action which is a very precise and accurate contraction and of certain selected muscles of the body and the eyes so as to restore stability and prevent any imbalance or vertigo. For example, if the person is tending to fall towards the left side, then the brain as soon as it recognizes this tendency of falling towards the left immediately brings about a contraction of the muscles of the right side of the body so that the fall towards the left side is prevented. This entire process occurs reflexly, that is it is automatic and the person does not have to make any conscious effort to do so. This is a unique system and the above description though a bit complicated is over-simplification of a very complex mechanism. Even a very minor defect in the any of the organs concerned with the maintenance of balance can completely jeopardize the balance system and result in vertigo or imbalance.
Since the mechanism of maintenance of balance is so very complex, the correct diagnosis and management of balance disorders is equally complicated and nowadays there is a specific medical discipline called neurotology that deals specifically with balance disorders. Doctors specializing in the diagnosis and management of balance disorders are called neurotologists. Many hospitals now have separate neurotology departments, where patients suffering from balance disorders and /or hearing disorders only are catered to.
Balance disorders can occur from are huge range of medical disorders some of which may be very trivial and some of which may be very sinister life-threatening conditions. Vertigo or imbalance is not a disease in itself. Like fever or pain, vertigo is just a symptom of some disease that may be due to a very simple self-limiting condition like vestibular neuritis, which is a viral inflammation of the nerve of balancing or it may be the only manifestation of a very serious disease like a tumor in the brain. So, the symptom of vertigo should never be taken lightly and should be thoroughly investigated to determine the cause and then treated scientifically. ‘Vertigo’ can never be a diagnosis; it is merely a symptom and a manifestation of some disease, which must be identified by the treating physician. Just like we denounce and abhor the indiscriminate use of antipyretics and pain killers and our objective is always to identify and correct the causative factor instead of symptomatic relief only, similarly, the indiscriminate and long-continued use of anti-vertigo drugs is best avoided as it camouflages the actual underlying disease and gives the patient and the doctor a false sense of complacency. Not only that it allows the causative disorder to grow unabated and what is still worse is that it jeopardizes the body’s stability..
The diagnosis of vertigo is a time consuming affair as the treating doctor is expected to take a very detailed history which is the mainstay in the diagnosis of vertigo, carry out certain clinical tests and if required perform certain specialized investigations called vestibular function tests. Only then can one make a proper diagnosis and treat the cause of the vertigo. The specialized investigations that are required in a patient of vertigo are Electronystagmography (ENG) or Videonystagmography (VNG), Video Head Impulse Test (VHIT), Vestibular Evoked Myogenic Potentials (VEMP) tests, Subjective Visual Vertical (SVV) test, Dynamic Visual Acuity (DVA) test, Craniocorpography (CCG), posturography and some audiological tests like Pure tone audiometry, Electrocochleography (ECochG) and BERA. Over and above this, some other tests like blood tests, imaging studies like CT scan and / or MRI of the brain, cervical spine and the spinal cord, color Doppler studies of the blood vessels of the neck, some functional imaging studies like SPECT etc. are sometimes required. However, the role of the costly imaging studies like CT scans and MRIs is very limited and it is the functional studies like VNG, CCG, VHIT, ocular and cervical VEMP posturography and sometimes audiometry that are primarily helpful and much more informative in the diagnosis of balance disorders. Most neurotological clinics are equipped with these facilities and without these basic facilities it is impossible to diagnose and treat a patient suffering from vertigo / imbalance. Though some private and even Govt hospitals put up a signboard of ‘VERTIGO CLINIC’ to lure naïve patients or even use it as a status symbol very few if any of them actually have the infrastructure to evaluate and manage patients suffering from balance disorders. A vertigo clinic needs dedicated and trained manpower with a lot of time and very special sophisticated diagnostic equipment.
The management of vertigo is now done by an integrated therapy, which is a 4 pronged therapeutic protocol and consists of:-
1) Treatment of the etiological factor after a definite cause has identified through detailed history-taking, clinical neurotological tests and the relevant neurotological investigations. There are specific medications for each of the specific neurotological diseases like Meniere’s disease, vestibular neuritis, benign positional vertigo, migraine related vertigo, vertebrobasilar insufficiency, vestibular seizures, multiple sclerosis etc.etc. There are numerous diseases that can present with vertigo and there is no blanket therapy i.e. there is no medicine that can treat all the causes. Each of the causative diseases has a very specific medication for it. The treating physician has to identify the precise cause of the vertigo and only then treat the disease. Just camouflaging the symptom of vertigo by empirically prescribing antivertigo drugs like cinnarizine/ betahistine/ meclizine/ dimenhydrinate/prochlorperazine for prolonged periods is unethical, unscientific and illogical. Not only is that it detrimental to the patient’s balance system. This needs to be stressed over and over again as there is perverted over-prescribing of anti-vertigo drugs.
2) Provide symptomatic relief from the vertigo with anti-vertigo drugs. This however has its limitations as discussed below and is to be done cautiously.
3) Physical exercises for vestibular re-education or re-calibration of the vestibular system through some specific exercises.
4) Psychological counseling and psychotherapy as and when required especially in cases of chronic / persistent vertigo where the persistence of the vertigo / imbalance and the failure of diagnosis / treatment has led to psychological disorders like helplessness, depression, anxiety and frustration. Vertigo and psychological disorders often perpetuate one another and the treatment is incomplete if the frustration / anxiety / depression is not attended to by the clinician.
For the proper management of vestibular disorders, a good doctor-patient relationship, explanation of the disease to the patient, justification for the therapeutic schedule prescribed by the doctor, information on the prognosis, psychological help, reduction of stress and the strict adherence to the treatment protocol by the patient is necessary. The treatment of balance disorders does not mean simply using some anti-vertigo drugs. Most of these drugs can at best provide some degree of temporary symptomatic relief only and that too not in all cases. It is the clinician’s duty to identify the underlying cause of the vertigo/ imbalance and then treat the cause of the vertigo rather than trying to camouflage the symptom of vertigo by empirically prescribing anti-vertigo drugs. The underlying cause of the vertigo CAN be identified in nearly all if not in all cases of vertigo and not being able to identify the cause is a failure of medical management. Very sophisticated tests to evaluate the structure and function of the balance system are now available and this if combined with a thorough history and clinical examination should lead to a proper diagnosis and there is no reason why the cause of the vertigo cannot be accurately diagnosed. Symptomatic relief is definitely necessary in many cases not only to ameliorate the patient’s physical distress but also to relieve the patient from the severe mental distress and the anxiety that accompanies the attack of vertigo. The flip-side of it is that trying to provide symptomatic relief not only camouflages the underlying disease as already discussed, but what is still worse is that it may (and does) jeopardize the natural vestibular compensatory mechanism which is nature’s way of restoring stability after there has been a permanent damage to the balance organ. These anti-vertigo drugs are for symptomatic relief ONLY and are hence best used if at all for very short spells only. Whenever there is a damage to the balance system especially the balance organs (vestibular labyrinths) in the ears, the damage is very often permanent and the damaged vestibular labyrinths cannot be regenerated by any medical or surgical means. It is the vestibular compensatory mechanism which is nature’s unique system that comes to our help and not only ameliorates the patient’s vertigo but also restores stability in spite of there being a damaged balance system. The objective of treatment should always be to enhance and expedite the vestibular compensatory mechanism and to refrain from anything that will jeopardize this natural mechanism. All anti-vertigo (also called vestibular sedatives) and all sleeping pills destroy this natural mechanism to restore balance. Balance dysfunction cannot be corrected or the balance function improved just by taking anti-vertigo drugs for an indefinite period of time. The current consensus is to restrict the use of vestibular sedatives to just 3-5 days only and definitely not beyond that; in fact most authorities recommend not to use anti vertigo medicines for more than a day. A holistic approach to management of the patient’s balance disorder that comprises of correcting the underlying medical disorder that is causing the vertigo rather than suppressing the symptom of vertigo by anti-vertigo drugs and managing any concomitant psychological or systemic disorder that is present along with the vertigo is the current mode of management.
Certain specified physical exercises have been found to play a very big role in curing a patient of vertigo and imbalance. Internationally, physical therapy i.e. some specific exercises called vestibular rehabilitation exercises (Cawthrone Cooksey exercises) is now medically recognized to play not only a major part, but probably the most effective part in the long term management of balance disorders. It is all the more effective especially in cases where the balance disorder is due to damage in one of the vestibular labyrinths (that is the organ of balance in the ear). The exercises help to enhance and expedite the vestibular compensatory mechanism. In addition to the Vestibular Rehabilitation Exercises, some specific yogic asanas and some Taichi exercises have also been found to be very helpful in enhancing the vestibular compensation and in restoring stability. Poor compensation occurs if the patient has a neurological disorder that is some disorder in the brain, is under sedative medication that is the patient is taking medicines (e.g. sleeping pills) that sedate him, is taking anti-vertigo drugs for a prolonged period (i.e., more than 5days), is non-ambulatory, is kept in a dark environment or has a poor motivation for recovery. Patients suffering from balance disorders need to be taught these Vestibular Rehabilitation exercises and if possible also the asanas and the taichi exercises. Physical therapy to enhance and expedite the vestibular compensatory mechanism is the mainstay of treatment in the management of vertigo. Over and above this, proper counseling to motivate the patient for recovery and some medicines for treatment of the causative disease (i.e. etiological factor) and some neurotropic agents and antioxidants to prevent further degeneration of the balance system is necessary for the management. Surgery has a very limited role in the management of vertigo / imbalance except in rare cases where the vertigo is being caused by a tumour in the brain / spinal cord. In very rare cases of Meniere’s disease and in some other intractable cases of Vertigo, ablative surgery is attempted but the results are often not very gratifying. Moreover there is a small but definite chance of a permanent hearing loss being induced by surgery and hence except in very rare and very judiciously selected cases, surgery is best avoided in vertigo.
Dr Anirban Biswas
VERTIGO and DEAFNESS CLINIC
BJ252 Salt Lake Kolkata -91
Belle Vue Clinic, Kolkata-17