What is Dizziness & Vertigo?
The term dizziness can mean different things to different people. In most cases it encompasses a feeling of unsteadiness, light-headedness, faintness, a whoozy feeling, giddiness or simply imbalance. There are many different possible causes of dizziness, many of which are not related to the balance organ in the inner ear. For example, patients with cardiovascular disease, anaemia, diabetes or thyroid disturbances are more likely to suffer with a non-specific lightheaded feeling or dizziness.
One specific type of dizziness is called ‘vertigo’, which describes the sensation of spinning or rotation either of oneself or the environment around oneself. Vertigo is almost always caused by an inner ear disorder or in some cases a disorder of the connections from the inner ear to the central processing areas for balance in the brain, situated in the cerebellum and brainstem. Contrary to popular misconception, vertigo is not a condition itself or a diagnosis. It is a very specific feeling of rotation or spinning which may have, as its cause, one of a number of possible diagnoses.
How is normal balance controlled?
The ability to remain upright and well balanced depends on the proper working of three main systems in the body:
- Visual system (eyes)
- Inner ear balance organ (inner ears or vestibular system)
- Information from sensors in the skin and joints
All three systems send information to the brain about the position of the body in space. Generally people can keep their balance if two of the three systems are working correctly, although in these situations it will not take much for the individual to become unsteady with the slightest of provocation, such as a dark room, wobbly cobblestoned surface on which you are walking, or even excess alcohol! However if only one system is working, it is almost impossible to remain well balanced. This explains why most people tend to become more unsteady as they get older, because all of the above systems gradually deteriorate with time. Arthritis may occur in the lower limb joints, neck stiffness increases and vision becomes worse.
What role does the ear play in balance?
The balance organ of the inner ear or vestibular labyrinth is made up of three semicircular canals and a central vestibule, which contain fluid and which are orientated at roughly right angles to each other. This means that they are able to sense rotational movement and acceleration and deceleration in any direction. Each inner ear collects similar information about the movement of the head and direction but as a mirror image to each other. This increases the accuracy of information reaching the brain and therefore rapidity of response.
What are the causes of vertigo?
There are many different factors that can affect the inner ear and thereby give rise to vertigo. One simple yet effective way of categorising these different causes of vertigo is in terms of the duration of the dizziness episode.
1. Very short-lived episodes of vertigo lasting seconds to minutes
Benign paroxysmal positional vertigo (BPPV) is probably the most common example of vertigo lasting seconds to minutes, provoked by head movements in a specific direction. It is associated with a very sudden onset of dizziness, which settles rapidly after a few seconds or at most one or two minutes. It typically occurs in bed at night when the individual turns over in bed. Its cause is thought to be due to small calcified fragments of the inner ear breaking free, which float around the inner ear fluid thereby causing increased nerve stimuli to the brain. The attacks usually disappear with time. Treatment ranges from medicines (but these are not always effective) to the Epley manoeuvre.
2. Medium length episodes of dizziness lasting several hours
Menière’s disease is a condition of the inner ear which results in episodes of severe vertigo that can last up to several hours at a time. They are usually associated with an increase in tinnitus and hearing loss in the affected ear, as well as nausea and vomiting on occasions. The hearing and tinnitus usually recover once the vertigo has settled, but the hearing may gradually deteriorate with time. It is thought to be due to an increase in the pressure or fluid within the inner ear known as endolymphatic hydrops. Treatment of Menière’s disease can involve medications and, on occasions, surgery if the medicines prove ineffective. An advance in the treatment of Menière’s disease has come in the form of intratympanic injections of either gentamicin or steroids, medications which are administered directly into the middle ear.
3. Longer episodes of dizziness lasting at least 24 hours to days
If an episode of vertigo lasts for more than 24 hours, the likelihood is that there has been an infection of the inner ear, called labyrinthitis, or inflammation of the nerve of balance, called vestibular neuronitis. Both conditions can cause severe rotatory dizziness and imbalance for days and weeks, followed by a gradual improvement in balance over the next few weeks. The initial severe episode is often associated with nausea and vomiting and the severity of the attack usually renders the patient bed-bound. Initial treatment involves strong vestibular sedatives such as Stemetil, which are quite effective in the early phase. Treatment should however be stopped soon after the acute attack of vertigo begins to subside in order to allow the brain to compensate and recover from the dizziness by itself.
Are any tests required if I suffer with dizziness or vertigo?
The vast majority of causes of vertigo can be diagnosed by an ENT surgeon following a detailed history and examination of the patient. Most patients with vertigo will recover without any long-term adverse effects within a few weeks of its onset. Specialist investigations are therefore not routinely required although they may be of use in selected cases, perhaps in situations where the diagnosis may not be clear. Tests that may be requested include blood tests, an audiological or hearing assessment, tests of balance and radiological investigations such as an MRI or CT scan.
What treatment options are there for patients with dizziness or vertigo?
First and foremost, the treatment of vertigo is symptomatic and supportive, in other words treatment is given to control the symptoms without initially considering the precise cause of the vertigo.
Exercises may be recommended which are specifically designed to accelerate the brain’s natural compensatory response following an inner ear problem. Examples of this type of rehabilitation include the Cawthorne Cooksey exercises.
Drugs such as Stemetil are powerful suppressants of the inner ear. They act by reducing the over activity of the balance organ in the inner ear, thereby effectively controlling the dizziness and vertigo. However, if used for prolonged periods, they delay the body’s natural recovery and readjustment after the vertigo.
Surgery is rarely required in patients with dizziness or vertigo. There are one or two notable exceptions to this, such as in patients with Menière’s disease or a sudden sensorineural hearing loss associated with vertigo, who may benefit from injection of a medicine such as gentamicin or a steroid directly into the middle ear (intratympanic injection). This operation is extremely safe and usually effective, and is gradually taking over other, more invasive and riskier procedures which used to be undertaken.