A Discussion of Dizziness
Dizziness is a symptom, not a disease. It may be defined as a sensation of unsteadiness, imbalance, or disorientation in relation to an individual’s surroundings. The symptom of dizziness may vary widely from person to person and be caused by many different diseases. Dizziness may or may not be accompanied by a hearing impairment.
Movement of fluid in the balance chambers (vestibule and three semicircular canals) also stimulates nerve endings, resulting in electrical impulses to the brain, where they are interpreted as motion.
MAINTENANCE OF BALANCE
The inner ear balance mechanism has two main parts: the three semicircular canals and the vestibule. Together they are called the vestibular labyrinth and are filled with fluid. When the head moves, fluid within the labyrinth moves and stimulates nerve endings that send impulses along the balance nerve to the brain. Those impulses are sent to the brain in equal amounts from both the right and left inner ear. Nerve impulses may be started by the semicircular canals when turning suddenly, or the impulses may come from the vestibule, which responds to changes of position, such as lying down, turning over or getting out of bed.
When one inner ear is not functioning correctly the brain receives nerve impulses that are no longer equal, causing it to perceive this information as distorted or off balance. The brain sends messages to the eyes, causing them to move back and forth, making the surroundings appear to spin. It is this eye movement (called nystagmus) that creates a sensation of things spinning.
TYPES OF DIZZINESS
Ear dizziness, one of the most common types of dizziness, results from disturbances in the blood circulation or fluid pressure in the inner ear chambers, from direct pressure on the balance nerve, or physiologic changes involving the balance nerve. Inflammation or infection of the inner ear or balance nerve is also a major cause of ear dizziness.
The inner ear mechanism is about the size of a pea, and is extremely sensitive. There are two inner ear chambers: One for hearing (cochlea), and one for balance (vestibule and semicircular canals). These chambers contain a fluid which bathes the delicate nerve endings. These nerve endings are stimulated when there is movement of the fluid. Nerve impulses are then transmitted to the brain by the hearing and balance nerves. The nerves pass through a small bony canal (internal auditory canal), accompanied by the facial nerve.
Any disturbance in pressure, consistency or circulation of the inner ear fluids may result in acute, chronic, or recurrent dizziness, with or without hearing loss and head noise. Likewise, any disturbance in the blood circulation to this area or infection of the region may result in similar symptoms. Dizziness may also be produced by over stimulation of the inner ear fluids, such as one encounters when he spins very fast and then stops suddenly.
This nystagmus is common during severe dizziness.
Persons subject to dizziness should exercise caution when swimming. Buoyancy of the water results in an essentially weightless condition, and visual orientation is greatly impaired if one’s head is under water. As a result, orientation depends almost entirely on the inner ear balance canals. An attack of dizziness at this time could be very dangerous. Similarly, individuals who have lost both inner ear balance canals should avoid underwater swimming.
EAR DIZZINESS: SYMPTOMS
Ear dizziness may appear as a whirling or spinning sensation (vertigo), unsteadiness, or giddiness and lightheadedness. It may be constant, but is more often intermittent, and is frequently aggravated by head motion or sudden positional changes, nausea and vomiting may occur, but one does not lose consciousness as a result of inner ear dizziness.
DIAGNOSING THE CAUSE OF DIZZINESS
Dizziness may be caused by any disturbance in the inner ear, the balance nerve or its central connections. This can be due to a disturbance in circulation, fluid pressure or metabolism, infections, neuritis, drugs, injury, or growths.
An extensive evaluation is required to determine the cause of dizziness. The tests necessary are determined at the time of examination and may include detailed hearing and balance tests, x-rays, and blood tests. A general physical examination and neurological tests may be advised.
As one gets older, blood vessel walls tend to thicken due to an aging process known as arteriosclerosis. This thickening results in partial occlusion, with a gradual decrease of blood flow to the inner ear structures. The balance mechanism usually adjusts to this, but at times persistent unsteadiness develops. This may be aggravated by sudden position changes such as that encountered when one gets up quickly or turns suddenly.
Treatment of dizziness due to changes in circulation consists of anti-dizziness medications to suppress the symptoms. They also stimulate the circulation and enhance the effectiveness of the brain centers in controlling the symptoms. An individual with this type of dizziness should avoid drugs that constrict the blood vessels, such as caffeine (coffee) and nicotine (tobacco). Emotional stress, anxiety and excessive fatigue should be avoided as much as possible. Often, increased exercise will aid in the suppression of dizziness in many patients by stimulating the remaining function to be more effective.
BENIGN POSITIONAL VERTIGO
Postural or Positional Dizziness
Postural or positional dizziness is a common form of balance disturbance due to circulatory changes or to loose calcium deposits in the inner ear. It is characterized by sudden, brief episodes of imbalance when moving or changing head position. Commonly it is noticed when lying down or arising or when turning over in bed. This type of dizziness is rarely progressive and usually responds to treatment, but it may recur. Treatment usually consists of exercises designed to provoke the dizziness until it fatigues. This type of exercise may be recommended by your physician to cause the positional dizziness to run its course more quickly. Occasionally, postural dizziness may be permanent and surgery may be required.
IMBALANCE RELATED TO AGING
Some individuals develop imbalance as a result of the aging process. In many cases this is due to circulatory changes in the very small blood vessels supplying the inner ear and balance nerve mechanism. Fortunately, these disturbances, although they may persist, rarely become worse.
Postural or positional vertigo (see above) is the most common balance disturbance of aging. This may develop in younger individuals as a result of head injuries or circulatory disturbances. Dizziness on change of head position is a distressing symptom, which is often helped by vestibular exercises.
Temporary unsteadiness upon arising from bed in the morning is not uncommon in older individuals. At times this feeling of imbalance may persist for an hour or two. Arising from bed slowly usually minimizes the disturbance. Unsteadiness when walking, particularly on stepping up or down, or walking on uneven surfaces, develops in some individuals as they progress in age. Using a cane and learning to use the eyes to help the balance is often helpful.
Rarely, allergies may cause dizziness and/or vertigo. Allergies are usually diagnosed by obtaining a careful history and occasionally performing a series of skin tests with inhalants and food, and/or blood tests. Treatment usually consists of elimination of the offending agents when possible, or, if this is not possible, by allergy shots to stimulate immunity.
Injury to the head occasionally results in dizziness of long-standing origin. If the trauma is severe, it is usually due to the combined damage to the inner ear, balance nerve, and central nervous system. Lesser injury may damage any one, or a combination of these components. The unsteadiness is at times prolonged, and may or may not be associated with hearing loss and head noise as well as other symptoms.
Labyrinthine dysfunction describes one of the non-specific conditions where the inner ear is not functioning properly. Although the cause is often unknown, viral illnesses, medication, and trauma are known at times to cause this condition. In order to reach this diagnosis definitively, hearing and balance testing must be done.
Symptoms may be highly variable. They can range from occasional unsteadiness to episodic vertigo or constant unsteadiness. Hearing loss is occasionally present.
Initially, treatment is medical and a wide variety of medications may be used. Occasionally, vertigo exercises are helpful. When vertigo cannot be controlled with medication or exercises, surgery is sometimes indicated.
Endolymphatic hydrops is a term which describes increased fluid pressure in the inner ear. In this respect it is similar but not related to glaucoma of the eye fluids. A special clinical form of endolymphatic hydrops is called Meniere’s disease, described elsewhere in this book. All patients with Meniere’s disease have endolymphatic hydrops, but not all patients with hydrops have Meniere’s disease.
There may be many causes of endolymphatic hydrops. It occurs widely in people of European descent and rarely in oriental or black people. It may be caused or aggravated by excessive salt intake or certain medications. The symptoms are highly variable. The patient may have one symptom or a combination. Often there is a combination of hearing changes, disequilibrium, motion intolerance, or short dizzy episodes. There may be tinnitus and/or a pressure feeling in the head or ears. The patient does not have the well defined attacks of Meniere’s disease (fluctuating hearing loss, tinnitus and episodes of spinning lasting minutes to hours). Often the division between the two diagnoses may be blurred and difficult to separate, even for the patient. Endolymphatic hydrops may progress to Meniere’s disease in some patients.
The treatment of endolymphatic hydrops is similar to that for Meniere’s disease. Medications are first used. Diuretics (water pills) are almost always used. Their purpose is to decrease the fluid pressure in the inner ear. In addition to diuretics, other medications may be indicated, depending on the cause of symptoms in each patient’s case. If these fail, surgery is sometimes indicated. (See Surgery for vertigo elsewhere in this document).
Meniere’s disease is a common cause of repeated attacks of dizziness, and is thought to be due (in most cases) to increased pressure of the inner ear fluids due to impaired metabolism of the inner ear. Fluids in the inner ear chamber are constantly being produced and absorbed by the circulatory system. Any disturbance of this delicate relationship results in overproduction or under absorption of the fluid. This leads to an increase in the fluid pressure (hydrops) that may, in turn, produce dizziness which may or may not be associated with fluctuating hearing loss and tinnitus.
A thorough evaluation is necessary to determine the cause of Meniere’s disease, if possible. Circulatory, metabolic, toxic and allergic factors may play a part in any individual. Emotional stress, while making the disease worse, does not cause it.
Meniere’s disease is usually characterized by attacks consisting of vertigo (spinning) that varies in duration from a few minutes to several hours. Hearing loss and head noise, usually accompanying the attacks, may occur suddenly. Violent spinning, whirling, and falling associated with nausea and vomiting are common symptoms. Sensations of pressure and fullness in the ear or head are usually present during the attacks. The individual may be very tired for several hours after the overt spinning stops.
Treatment of Meniere’s Disease
Treatment of cochlear and vestibular hydrops is the same as for classic Meniere’s disease. The treatment of Meniere’s disease may be medical or surgical, depending upon the patient’s stage of the disease, life circumstances, and the condition of the ears. The purpose of the treatment is to prevent the hearing loss, and stop the vertigo (spinning).
It is aimed at improving the inner ear circulation and controlling the fluid pressure changes of the inner ear chambers. Treatment may consist of medication to decrease the inner ear fluid pressure or prevent inner ear allergic reactions. Various drugs are used as anti-dizziness medication. Vasoconstricting substances have an opposite effect and, therefore, should be avoided. Such substances are caffeine (coffee) and nicotine (cigarettes).
Diuretics (“water pills”) may be prescribed to decrease the inner ear fluid pressure.
Meniere’s disease may be caused or aggravated by metabolic or allergic disorders. Special diets or drug therapy are indicated at times to control these problems.
On rare occasions we may use gentamycin injections which selectively destroy balance function. This treatment is reserved for patients with Meniere’s disease in their only hearing ear or with Meniere’s disease in both ears.
Surgery is most successful in relieving acute attacks of dizziness in the majority of patients. Some unsteadiness may persist over a period of several months until the opposite ear and the central nervous system are able to compensate and stabilize the balance system.
DIZZINESS: NONSURGICAL TREATMENT
Current retrospective studies indicate that 85% of patients with chronic vestibular dysfunction gain at least partial relief of their symptoms after undergoing vestibular rehabilitation. One of the most difficult things for patients with vestibular disorders to do is walk and move the head. Different combinations of head and neck movements are performed during gait to provoke symptoms.
Following the evaluation, a treatment plan is developed. The treatment consists of habitual exercises, balance retraining exercises, and usually a general conditioning program. Balance retraining exercises are also given when appropriate and consist of activities directed towards improving the patient’s balance. Exercises are chosen according to the problem areas discovered in the evaluation and often involve interaction among the three sensory inputs involved in balance: vision, somatosensory cues and vestibular inputs.
There are many causes of dizziness. This dizziness may or may not be associated with hearing loss. In most instances the distressing symptoms of dizziness can be greatly benefited or eliminated by medical, surgical, or rehabilitative treatments.