Dizziness

 

Dizziness is a symptom, not a disease. It may be defined as a subjective sensation of unsteadiness or imbalance, a disorientation in relation to one’s surroundings. Dizziness can be caused by many different diseases and varies from a mild unsteadiness to a severe whirling sensation known as vertigo. Dizziness may or may not be accompanied by a hearing impairment.

MAINTAINING YOUR BALANCE
The human balance system is made up of four parts. The brain acts as a central computer receiving information in the form of nerve impulses (messages) from its three input terminals: the eyes, the inner ear, and the muscles and joints of the body, and the soles of the feet. There is a constant stream of impulses arriving at the brain from these input terminals. All three systems work independently and yet work together to keep the body in balance.

The eyes receive visual clues from light receptors that give the brain information as to the position of the body relative to its surroundings. The receptors in the muscles and joints are called proprioceptors. The most important ones are in the head and neck (head position relative to the rest of the body) and the ankles, joints, and soles of the feet (body sway relative to the ground).

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 fourth, making the surroundings appear to spin. It is this eye movement (called nystagmus) that creates a sensation of things spinning.

Remember to think of the brain a s a computer with three input terminals feeding it constant up-to-date information from the eyes, inner ear and muscles, joints and soles of the feet (somatosensory system). The brain itself is divided into seven different parts. The most primitive area is known as the brainstem, and it is here that processing of the input from the three sensory terminals occurs. The brainstem is affected by two other parts of the brain, the cerebral cortex and the cerebellum.

The cerebral cortex is where past information and memories are stored. The cerebellum, on the other hand, provides automatic (involuntary) information from activities which have been repeated often.

The brainstem receives all these nerve impulses: sensory from the eyes, inner ear, muscles, joints and the soles of the feet; regulatory from the cerebellum; and voluntary from the cerebral cortex. The information is then processed and fed back to the muscles of the body to help maintain a sense of balance.

Because the cortex, cerebellum and brainstem can eventually become used to (ignore) abnormal or unequal impulses from the inner ear, exercise may be helpful. Exercise often helps the brain to habituate (to get used to) the dizziness problem so that it does not respond in an abnormal way, and does not result in the individual feeling dizzy. An example of habituation is seen with the ice skaters who twirl around, stop suddenly, and do not apparently have any balance disturbance.

TYPES OF DIZZINESSS
Sensations of unsteadiness, imbalance or disorientation in relationship to one’s surroundings may result from disturbances in the ear, the neck, the muscles and joints, the eyes, the nervous system connections of these structures or a combination of these.

Ear Dizziness
Ear dizziness results from disturbances in the circulation of fluid pressure in the inner ear chambers or from direct pressure on the balance nerve which transmits impulses from the inner ear to the brain.

The inner ear mechanism approximates 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 brainstem 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 to the nerve may result in similar symptoms.

Dizziness may also be produced by over stimulation of the inner ear fluids. This can happen when the patient spins very fast and then stops suddenly.

Central Dizziness
Central dizziness is an unsteadiness brought about by failure of the brainstem to coordinate or interpret correctly the nerve impulses which it receives. An example of this is the “swimming feeling” or unsteadiness that may accompany congestion or a circulation problem in the brainstem. This circulatory inefficiency, producing unsteadiness, with or without hearing impairment, may be due to age, metabolic or allergic dysfunction, a mild stroke, tumors or injury.

This same type of problem can be due to autonomic dysfunction (disturbances of the “automatic” nervous system), panic attacks, stress, tension or depression. A feeling of pressure or fullness in the head and ears is common under these circumstances.

Neck Dizziness
Neck dizziness (cervical vertigo) results from abnormal or uncoordinated nerve impulses being sent to the brain from the neck muscles.

The neck muscles are constantly sending nerve impulses to the brainstem to help maintain equilibrium. Spasm (tenseness) of the muscles may result in an abnormal nerve discharge, leading to unsteadiness or dizziness. This spasm may result from injury, from arthritis of the spine, or from pressure on nerves in the neck.

Muscle-Joint Dizziness
Muscle-joint dizziness is relatively uncommon. Any disturbance of sensation arising from the muscles and joints in the limbs such as occurs in the muscular dystrophies and other abnormalities produce this type of unsteadiness. Such an example is the unsteadiness experienced when one tries to walk on a leg that has “gone to sleep.”

Visual Dizziness
Eye muscle imbalance or errors of refraction may produce unsteadiness. An example of this is the unsteadiness which may result when one attempts to walk while wearing glasses belonging to another individual.

Another example of visual dizziness is that occasionally produced if one is seated in a car, looking out the side window at passing objects. The eyes respond by sending a rapid series of impulses to the brain indicating that the body is rotating. On the other hand, the ears and muscle-joint systems send impulses to the brain indicating that the body is not rotating only moving forward. The brainstem, receiving these confused impulses (from the eyes indicating rotation, from the ears and muscle-joint systems indicating forward motion), sends out equally confused orders to the various muscles and glands that may result in sweating, nausea and vomiting. In this situation when one sits in the front seat looking forward, the eyes, ears and muscle-joint systems work more in uniform and one is less likely to develop car sickness.

A visual disturbance may be caused by dizziness from other sources. Intermittent inability to focus the eyes, difficulty reading or intermittent blurring of vision, although at times the result of anxiety or tension, may result from small reflex movements of the eye called nystagmus. This nystagmus is common during severe dizziness.

WARNING: Persons subject to dizziness should exercise caution when swimming. Buoyancy of the water results in essentially a 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.

SYMPTOMS OF EAR DIZZINESS
Any disturbance affecting the function of the inner ear or its central connections may result in dizziness, hearing loss or tinnitus (head noise). These symptoms may occur singly or in combination, depending upon which functions of the inner ear are disturbed.

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 position change. 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 at times 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, blood tests and metabolic and allergic evaluations. A general physical examination and neurological tests may be advised. The object of this evaluation is to be certain that there is no serious or life-threatening disease, and to pinpoint the exact site of the problem. This lays the groundwork for the effective medical or surgical treatment.

Changes in Circulation
Any interference with the circulation to the delicate inner ear structures or their central connections may result in dizziness, at times with hearing loss and tinnitus. These circulatory changes may be the result of blood vessel spasm, partial or total occlusion or rupture with hemorrhage.

Spasm
Inner ear dizziness due to blood vessel spasm is usually sudden in onset and intermittent in character. Predisposing causes include nervous fatigue and emotional stress. Certain drugs such as caffeine (coffee) and nicotine (cigarettes) tend to produce blood vessel spasm or constriction and should be avoided.

Occlusion
As one gets older the 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 change such as encountered when one gets up quickly or turns suddenly.

Complete occlusion of an inner ear blood vessel (thrombosis) results in acute dizziness often associated with nausea and vomiting. Symptoms may persist for several days, followed by gradual decrease of dizziness over a period of weeks or months, as the opposite unaffected ear takes over the function of the involved ear.

Hemorrhage
Occasionally one of the small blood vessels in the balance mechanism ruptures. This may occur spontaneously, for no apparent reason, or it may be the result of high blood pressure or head injury. Symptoms are the same as those of occlusion.

Treatment
Treatment of dizziness due to changes in circulation consists of anti-dizziness medication, medications to stimulate the circulation (vasodilators) and, at times, mild sedation. One 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.

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 on motion or change of head position. Commonly it is noticed when lying down or arising, or when turning over in bed. This type of dizziness is rarely progressive, usually responds to treatment, but may recur.

Epley Maneuver/Canalith Repositioning
This procedure is used to improve the balance of patients who suffer from positional dizziness and/or vertigo. The procedure uses a series of positions to reduce the dizziness. In most cases, more than one treatment is necessary. It is advisable to bring a driver, as you may feel some imbalance after the procedure. Time: 1 visit takes 45 minutes to 1 hour. Follow-up visits are 30 minutes to 1 hour.

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
Postural or positional vertigo 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 are often helpful.

Ear Infection
Symptoms
Imbalance due to ear infection is usually insidious and mild in onset. Such imbalance may occur with or without hearing impairment. As the infection gets closer to the vital balance mechanism in the inner ear, the dizziness becomes more constant and severe in nature, often associated with nausea and vomiting.

Treatment
Control of ear infection is imperative in this type of dizziness in order to prevent spread of the infection directly into the balance center of the inner ear. Should this develop, serious complications, including total loss of hearing in the involve ear, may result. If the infection cannot be eliminated by medical treatment, surgery is indicated to remove the infection.

Neuritis
Neuritis, due to a virus, may affect the balance nerve or balance centers of the brainstem. When this occurs the balance function is impaired resulting in a severe, at times prolonged, episode of dizziness followed by some unsteadiness on motion for weeks or months. Fortunately this balance disturbance subsides in time and usually does not recur.

Metabolic Disturbances and Allergies
Metabolic disturbances and allergies can produce dizziness, with or without associated hearing loss, by interfering with the function of the inner ear or its central connections. Occasionally hearing loss may occur without the presence of dizziness.
The common metabolic disturbances result from decreased thyroid function, abnormal sugar tolerance and inhalant or food allergies.
Thyroid dysfunction is diagnosed by blood tests. Treatment consists of thyroid hormone. Abnormal sugar tolerance is diagnosed by blood sugar studies (glucose tolerance test). Treatment consists of diet control, with or without drug therapy.
Allergies may be diagnosed by blood tests and skin tests with inhalants and foods. Treatment consists of elimination of the offending agents when possible. If avoidance of these agents is not possible, then extracts of the different substances may be administered by injection to stimulate an immunity.

Injury
Injury to the head occasionally results in dizziness due to damage to the inner ear and its blood vessels. The unsteadiness is at times prolonged, and may or may not be associated with hearing loss and head noises.

Treatment consists of vasodilators, sedatives and anti-dizzy medication. The symptoms usually disappear but occasionally surgery (vestibular nerve section) may be necessary.

Perilymphatic Fistula
Dizziness, with or without hearing impairment, may result from a perilymphatic fistula, a leak of inner ear fluid into the middle ear through one of the two inner ear windows. The fistula may appear spontaneously or may follow a head injury, a sudden change in atmospheric pressure (barotrauma) or ear surgery.

A perilymphatic fistula may close spontaneously. If symptoms persist, exploratory surgery may be advised to repair the fistula with ear tissue. This usually eliminates the dizziness but often does not help the hearing. At times the hearing is worse following fistula repair.

Autoimmune Inner Ear Disease
Disease of the immune system may cause sensorineural (nerve) hearing impairment or dizziness or both.
The diagnosis is based on the symptoms and the results of blood tests. Treatment with Cortisone, and at times anti-immune drugs, usually prevents further hearing loss and relieves dizziness. Frequently the hearing is improved. Long-term therapy is often necessary.

Acoustic Tumors (Acoustic Neuroma)
A non-cancerous tumor occasionally develops on the balance nerve deep in the ear bone. When this occurs, unsteadiness, hearing loss and head noise may develop.

Extensive hearing tests, balance tests and x-rays are necessary to diagnose such tumors.
If the diagnosis of a tumor is established, surgical removal is imperative. Continued growth of the tumor would lead to complications by producing pressure on vital adjacent nerves and the brainstem.
An operation has been developed which allows the removal of these tumors at an early stage. Best results can be obtained if the tumor is diagnosed early and removed while the only symptoms are hearing loss, dizziness and tinnitus.

Dandy’s Syndrome
A total loss of inner ear balance function in both ears is rare. It results in a condition called Dandy’s syndrome. This may result from infections, injuries or tumor removal.

There may be serious dizziness at the time the individual first loses the balance mechanism. Other portions of the balance mechanism (eyes, muscles and joints) help the individual to compensate for the loss of inner ear function. Most do quite well except in the dark or when swimming. Many notice oscillopsia, a tendency for objects to appear to move up and down when observed while in motion.

There is no treatment for Dandy’s syndrome. Most patients compensate well and lead normal lives. One should avoid movement in total darkness and avoid underwater swimming.

Vascular Compression Syndrome
The vestibular (balance) nerve is located in a very complex part of the skull called the posterior fossa. A number of blood vessels are in close proximity to the nerve. If a blood vessel happens to compress or pulsate against the vestibular nerve, dizziness may result.

The diagnosis of this syndrome is difficult. A careful history and the results of specialized auditory and balance test provide the physician with the suspicion of a vascular compression syndrome. The treatment is microvascular vestibular nerve decompression.

Meniere’s Disease
Meniere’s disease is a common cause of repeated attacks of dizziness. It is due to increased pressure of the inner ear fluids.

Fluids in the inner ear chambers are constantly being produced and absorbed by the circulatory system. Any disturbance in this delicate relationship results in over-production or under-absorption of the fluids. This leads to increased fluid pressure (hydrops) that in turn produces dizziness which may or may not be associated with fluctuating hearing loss and tinnitus. Fortunately this usually affects only one ear.

A thorough evaluation is necessary in most cases of Meniere’s disease to determine the cause of the increased fluid pressure. Circulatory, metabolic, toxic, allergic or emotional factors may play a part in any case.

Symptoms
Meniere’s disease is characterized by attacks of dizziness that vary in duration from a few minutes to several hours. Hearing loss and head noise usually accompany the attacks. The attacks of dizziness may occur suddenly and without warning. Violent spinning, whirling and falling, associated with nausea and vomiting, are common symptoms. A sensation of pressure and fullness in the ear is usually present.

Attacks of dizziness may recur at irregular intervals. The individual may be free of symptoms for years at a time. If the attacks do recur, they are usually less severe and of shorter duration than in the initial attack. In between attacks the individual tends to remain free of symptoms.

Occasionally hearing impairment, head noise and ear pressure occur without dizziness. This type of Meniere’s disease is called cochlear hydrops. Similarly, episodic dizziness and ear pressure may occur without hearing loss and tinnitus; this is called vestibular hydrops. Treatment of both of these is the same as for Meniere’s disease.

Treatment
Treatment of Meniere’s disease may be medical or surgical. It is aimed at improving the inner ear circulation and controlling the fluid pressure changes of the inner ear chambers. At times it is necessary to cut the balance nerve or remove the inner ear structures.

Medical treatment of Meniere’s disease varies with the individual patient according to suspected cause and magnitude and frequency of symptoms. It is effective in decreasing the frequency and severity of attacks in 80% of patients. Treatment may consist of medication to stimulate the inner ear circulation, decrease the inner ear fluid pressure or prevent inner ear allergic reactions.

Various vasodilating drugs are used to stimulate the inner ear circulation and are prescribed together with 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 streptomycin 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.

DIZZINESS: SURGICAL TREATMENT
Surgery is indicated when medical treatment fails to relieve the acute attacks of dizziness. The type of operation selected depends upon the degree of hearing impairment in the affected ear since every effort is made to preserve this hearing. In some cases the hearing may be improved following surgery and in others it may become worse; usually it remains the same. Head noise may or may not be relieved and in some cases may even become more marked.

Surgery is successful in relieving acute attacks of dizziness in the majority of patients. In the event that a conservative operative procedure does not relieve the attacks of dizziness, a second operation may be necessary.

Endolymphatic Shunt
This operation alters the function of the endolymphatic sac such that its abnormally low resorption of inner ear fluids and/or secretion of molecules disrupting normal fluid balance is positively changed. It is usually performed under general anesthesia as an outpatient.

An incision is made behind the ear. A mastoid operation is performed and a tube is inserted into the endolymphatic sac of the inner ear to control the abnormal fluid pressure.

A shunt operation usually is advised when hearing is relatively good in the involved ear. Further permanent loss of hearing occurs in 5% of patients. Total loss of hearing in the operated ear occurs in 1%.

Cochleosacculotomy
This operation is performed through the ear canal under local anesthesia and usually requires one or two days hospitalization. A shunt is created by direct puncture of the membrane of the inner ear chambers.

Cochleosacculotomy usually is advised only when the hearing is greatly diminished. Further hearing impairment following surgery is common, as ins a temporary increase in dizziness.

Transcanal (Oval Window) Labyrinthectomy
This procedure is performed through the ear canal under local or general anesthesia and requires one to three days of hospitalization. Fluid is removed from the inner ear chambers together with the secreting membranes.

Oval window labyrinthectomy usually is advised only when the hearing is poor; it results in total loss of hearing in the operated ear and a temporary increase in dizziness.

Translabyrinthine Labyrinthectomy and Section of the Vestibular (Balance) Nerve
The operation is performed under general anesthesia and requires hospitalization for approximately five to seven days. Through an incision behind the ear a mastoidectomy is performed, the inner ear balance chambers are removed and the balance nerve is cut.

In cases selected for labyrinthectomy and section of the vestibular nerve, hearing is severely impaired. The operation results in total loss of hearing in the operated ear and frequently a temporary increase in dizziness. Fortunately, the attacks of dizziness are eliminated in nearly every instance. Persistent unsteadiness, however, may continue for a period of weeks or months until the opposite ear stabilizes the balance system.

When necessary, this operation can be performed if other surgery is not successful.

Retrolabyrinthine Section of the Vestibular (Balance) Nerve
This procedure is performed under general anesthesia and usually requires five to seven days of hospitalization. Through an incision behind the ear a mastoidectomy is performed and the balance nerve is cut before it enters the inner ear. Retrolabyrinthine section of the vestibular nerve may be advised when hearing is good in the involved ear. Up to 2% of patients may develop a severe hearing impairment in the operated ear following surgery. Fortunately the attacks of dizziness are eliminated in nearly every instance. Persistent unsteadiness, however, may continue for weeks or months until the opposite ear stabilizes the balance system.

Middle Fossa Section of the Vestibular (Balance) Nerve
This procedure is performed under general anesthesia and usually requires four to seven days of hospitalization. Through an incision above the ear, the balance nerve is cut before it enters the inner chamber.

Middle fossa section of the vestibular nerve may be advised when hearing is good in the involved ear. Up to 5% of patients may develop a severe hearing impairment in the operated ear. Fortunately, the attacks of dizziness are eliminated in nearly every instance. Persistent unsteadiness, however, may continue for a period of weeks or months until the opposite ear stabilizes the balance system. Temporary paralysis of half the body has occurred following a middle fossa nerve section, due to brain swelling. This complication is, however, extremely rare.

Retrosigmoid Microvascular Vestibular Nerve Decompression
This operation is performed under general anesthesia and requires four to seven days of hospitalization. Through an incision behind the ear, the balance nerve is identified along with the offending vascular loop. The blood vessel is dissected free from the nerve and material is interposed between the blood vessel and the nerve to act as a cushion.

In cases where a definitive blood vessel is identified, the results of this procedure are quite satisfying. In cases where no offending blood vessel is seen, the dizziness may persist. Some patients may experience unsteadiness which may require several weeks or months to stabilize.

RISKS AND COMPLICATIONS OF SURGERY FOR DIZZINESS
Hearing Loss
Further hearing impairment in the operated ear may occur following any of the procedures and is the expected result following some. This has been commented upon for each procedure.

Tinnitus
Tinnitus (head noise) usually remains the same as before surgery. If the hearing is worse following surgery, tinnitus may likewise be more noticeable.

Taste Disturbance and Mouth Dryness
Taste disturbance and mouth dryness are not uncommon for a few weeks following surgery. In some patients this disturbance is prolonged.

Weakness of the Face
The facial nerve travels through the ear bone in close association with the hearing and balance nerves, the inner ear and mastoid. Temporary weakness of one side of the face is an uncommon postoperative complication of ear surgery. It may occur as the result of an abnormality or a swelling of the nerve.

Permanent paralysis of the face is extremely rare. Should it occur, however, eye complications could develop, requiring treatment by an eye specialist.

Spinal Fluid Leak
All of the operations described above result in a temporary leak of cerebral spinal fluid (fluid surrounding the brain). This leak is always closed prior to the completion of surgery. On occasion, however, the leak reopens and further surgery may be necessary to stop it.

Infection
Infection is a rare occurrence following dizziness surgery. Should it develop, however, it could lead to meningitis, an infection in the fluid surrounding the brain and might require prolonged hospital treatment. Fortunately, this complication is very rare.

Hematoma
A hematoma (collection of blood under the skin incision) develops in a small percentage of cases, prolonging hospitalization and healing. Re-operation to remove the clot may be necessary if this complication occurs.

SUMMARY
There are many causes of dizziness. This dizziness may or may not be associated with a hearing loss. In most instances the distressing symptoms of dizziness can be greatly benefited or eliminated by medical or surgical management.