Dizziness





Definition

As a disorder, dizziness is classified into three categories: vertigo, syncope, and nonsyncope nonvertigo. Each category has its own set of symptoms, all related to the sense of balance. In general, syncope is defined by a brief loss of consciousness (fainting) or by dimmed vision and feeling uncoordinated, confused, and lightheaded. Many people experience a sensation like syncope when they stand up too fast. Vertigo is the feeling that either the individual or the surroundings are spinning. This sensation is like being on a spinning amusement park ride. Individuals with nonsyncope nonvertigo dizziness feel as though they cannot keep their balance. This feeling may become worse with movement.

Description

The brain coordinates information from the eyes, the inner ear, and the body's senses to maintain balance. If any of these information sources is disrupted, the brain may not be able to compensate. For example, people sometimes experience motion sickness because the information from their body tells the brain that they are sitting still, but information from the eyes indicates that they are moving. The messages do not correspond and dizziness results.

Vision and the body's senses are the most important systems for maintaining balance, but problems in the inner ear are the most frequent cause of dizziness. The inner ear, also called the vestibular system, contains fluid that helps fine tune the information the brain receives from the eyes and the body. When fluid volume or pressure in one inner ear changes, information about balance is altered. The discrepancy gives conflicting messages to the brain about balance and induces dizziness.

Certain medical conditions can cause dizziness because they affect the systems that maintain balance. For example, the inner ear is very sensitive to changes in blood flow. Because medical conditions such as high blood pressure or low blood sugar can affect blood flow, these conditions are frequently accompanied by dizziness. Circulation disorders are the most common causes of dizziness. Other causes are head injury , ear infection, allergies , and nervous system disorders.

Dizziness often disappears without treatment or with treatment of the underlying problem, but it can be long term or chronic.

Demographics

According to the National Institutes of Health, 42 percent of Americans seek medical help for dizziness at some point in their lives. The costs may exceed a billion dollars and account for 5 million doctor visits annually. Episodes of dizziness increase with age, and are common among the elderly.

Causes and symptoms

Careful attention to symptoms can help determine the underlying cause of the dizziness. Underlying problems may be benign and easily treated, or they may be dangerous and in need of intensive therapy. Not all cases of dizziness can be linked to a specific cause. More than one type of dizziness can be experienced at the same time, and symptoms may be mixed. Episodes of dizziness may last for a few seconds or for days. The length of an episode is related to the underlying cause.

The symptoms of syncope include dimmed vision, loss of coordination, confusion, lightheadedness, and sweating. These symptoms can lead to a brief loss of consciousness or fainting. They are related to a reduced flow of blood to the brain; they often occur when a person is standing up and can be relieved by sitting or lying down. Vertigo is characterized by a sensation of spinning or turning, accompanied by nausea , vomiting , ringing in the ears, headache , or fatigue. An individual may have trouble walking, remaining coordinated, or keeping balance. Nonsyncope nonvertigo dizziness is characterized by a feeling of being off balance that becomes worse if the individual tries moving or performing detail-intense tasks.

A person may experience dizziness for many reasons. Syncope is associated with low blood pressure, heart problems, and disorders in the autonomic nervous system, the system of involuntary functions such as breathing. Syncope may also arise from emotional distress, pain , and other reactions to outside stressors. Nonsyncope nonvertigo dizziness may be caused by rapid breathing, low blood sugar, or migraine headache, or by more serious medical conditions.

Vertigo is often associated with inner ear problems called vestibular disorders. A particularly intense vestibular disorder, Meniere's disease, interferes with the volume of fluid in the inner ear. This disease, which affects approximately one in every 1,000 people, causes intermittent vertigo over the course of weeks, months, or years. Meniere's disease is often accompanied by ringing or buzzing in the ear, hearing loss, and a feeling that the ear is blocked. Damage to the nerve that leads from the ear to the brain can also cause vertigo. Such damage can result from head injury or a tumor. An acoustic neuroma, for example, is a benign tumor that wraps around the nerve. Vertigo can also be caused by disorders of the central nervous system and the circulatory system, such as hardening of the arteries (arteriosclerosis), stroke , or multiple sclerosis.

Some medications cause changes in blood pressure or blood flow. These medications can cause dizziness in some people. Prescription medications carry warnings of such side effects, but common drugs, such as caffeine or nicotine, can also cause dizziness. Certain antibiotics can damage the inner ear and cause hearing loss and dizziness.

Diet may cause dizziness. The role of diet may be direct, as through alcohol intake. It may be also be indirect, as through arteriosclerosis caused by a high-fat diet. Some people experience a slight dip in blood sugar and mild dizziness if they miss a meal, but this condition is rarely dangerous unless the person is diabetic. Food sensitivities or allergies can also be a cause of dizziness. Chronic conditions, such as heart disease, and serious acute problems, such as seizures and strokes, can cause dizziness. However, such conditions usually exhibit other characteristic symptoms.

When to call the doctor

A doctor should be called whenever a person experiences dizziness or other unusual state of mental confusion that does not spontaneously resolve within a few minutes.

Diagnosis

During the initial medical examination, an individual with dizziness should provide a detailed description of the type of dizziness experienced, when it occurs, and how often each episode lasts. A diary of symptoms may help track this information. The person should report any symptoms that accompany the dizziness, such as a ringing in the ear or nausea, any recent injury or infection, and any medication taken.

Blood pressure, pulse, respiration, and body temperature are checked, and the ear, nose, and throat are scrutinized. The sense of balance is assessed by moving the individual's head to various positions or by tilt-table testing. (In tilt-table testing, the person lies on a table that can be shifted into different positions and reports any dizziness that occurs.)

Further tests may be indicated by the initial examination. Hearing tests help assess ear damage. X rays , computed tomography scan (CT scan), and magnetic resonance imaging (MRI) can pinpoint evidence of nerve damage, tumor, or other structural problems. If a vestibular disorder is suspected, a technique called electronystagmography (ENG) may be used. ENG measures the electrical impulses generated by eye movements. Blood tests can determine diabetes, high cholesterol , and other diseases. In some cases, a heart evaluation may be useful. Despite thorough testing, however, an underlying cause cannot always be determined.

Treatment

Treatment is determined by the underlying cause. If an individual has a cold or influenza , a few days of bed rest is usually adequate to resolve dizziness. Other causes of dizziness, such as mild vestibular system damage, may resolve without medical treatment.

If dizziness continues, drug therapy may prove helpful. Because circulatory problems often cause dizziness, medication may be prescribed to control blood pressure or to treat arteriosclerosis. Sedatives may be useful to relieve the tension that can trigger or aggravate dizziness. Low blood sugar associated with diabetes sometimes causes dizziness and is treated by controlling blood sugar levels. An individual may be asked to avoid caffeine, nicotine, alcohol, and those substances that cause allergic reactions. A low-salt diet may also help some people.

When other measures have failed, surgery may be suggested to relieve pressure on the inner ear. If the dizziness is not treatable by drugs, surgery, or other means, physical therapy may be used and the person may be taught coping mechanisms for the problem.

Because dizziness may arise from serious conditions, it is advisable to seek medical treatment. Alternative treatments can often be used alongside conventional medicine without conflict. Relaxation techniques, such as yoga and massage therapy , that focus on relieving tension are popularly recommended methods for reducing stress. Aroma therapists recommend a warm bath scented with essential oils of lavender, geranium, and sandalwood.

Homeopathic therapies can work very effectively for dizziness and are especially applicable when no organic cause can be identified. An osteopath or chiropractor may suggest adjustments of the head, jaw, neck, and lower back to relieve pressure on the inner ear. Acupuncturists also offer some treatment options for acute and chronic cases of dizziness. Nutritionists may be able to offer advice and guidance in choosing dietary supplements, identifying foods to avoid and balancing nutritional needs.

Prognosis

Outcome depends on the cause of dizziness. Controlling or curing the underlying factors usually relieves dizziness. In some cases, dizziness disappears without treatment. In a few cases, dizziness can become a permanent disabling condition and a person's options are limited.

Prevention

Most people learn through experience that certain activities make them dizzy and they learn to avoid them. For example, if reading in a car produces motion sickness, an individual leaves reading materials for after arrival. Changes to the diet can also cut down on episodes of dizziness in susceptible people. Relaxation techniques can help ward off tension and anxiety that can cause dizziness.

These techniques can help minimize or even prevent dizziness for people with chronic diseases. For example, persons with Meniere's disease may avoid episodes of vertigo by omitting salt, alcohol, and caffeine from their diets. Reducing blood cholesterol can help diminish arteriosclerosis and indirectly treat dizziness.

Some cases of dizziness cannot be prevented. Acoustic neuromas, for example, were not as of 2004 predictable or preventable. When the underlying cause of dizziness cannot be discovered, it may be difficult to recommend preventive measures. Alternative approaches designed to rebalance the body's energy flow, such as acupuncture and constitutional homeopathy, may be helpful in cases where the cause of dizziness cannot be pinpointed.

Nutritional concerns

Persons who experience dizziness should limit alcohol intake and avoid diets that are high in fat. Persons with diabetes should eat their meals on a regular schedule. People for whom some foods cause allergic reactions or sensitivities or dizziness, should avoid consuming the offending substances.

Parental concerns

Parents should be alert for complaints from their children of dizziness or other states of mental confusion that do not spontaneously resolve within a minute or so.

KEY TERMS

Acoustic neuroma —A benign tumor that grows on the nerve leading from the inner ear to the brain. As the tumor grows, it exerts pressure on the inner ear and causes severe vertigo.

Arteriosclerosis —A chronic condition characterized by thickening, loss of leasticity, and hardening of the arteries and the build-up of plaque on the arterial walls. Arteriosclerosis can slow or impair blood circulation. It includes atherosclerosis, but the two terms are often used synonymously.

Autonomic nervous system —The part of the nervous system that controls so-called involuntary functions, such as heart rate, salivary gland secretion, respiratory function, and pupil dilation.

Computed tomography (CT) —An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body's internal structures; also called computed axial tomography.

Electronystagmography —A method for measuring the electricity generated by eye movements. Electrodes are placed on the skin around the eye and the individual is subjected to a variety of stimuli so that the quality of eye movements can be assessed.

Magnetic resonance imaging (MRI) —An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct detailed images of internal body structures and organs, including the brain.

Vestibular system —The brain and parts of the inner ear that work together to detect movement and position.

Resources

BOOKS

Benditt, David G. Evaluation and Treatment of Syncope: A Handbook for Clinical Practice. Malden, MA: Blackwell, 2003.

Daroff, Robert B., and Mark D. Carlson. "Faintness, Syncope, Dizziness, and Vertigo." In Harrison's Principles of Internal Medicine , 15th ed. Edited by Eugene Braunwald et al., New York: McGraw-Hill, 2001, pp. 111–8.

Grubb, Blair P., and Mary C. McMann. Fainting Phenomenon: Understanding Why People Faint and What Can Be Done about It. Malden, MA: Futura Publishing, 2001.

The Official Patient's Sourcebook on Syncope: A Revised and Updated Directory for the Internet Age. San Diego, CA: ICON Health Publications, 2003.

Simon, Roger P. "Syncope." In Cecil Textbook of Medicine , 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 2268–71.

PERIODICALS

Chamelian, L., and A. Feinstein. "Outcome after mild to moderate traumatic brain injury: The role of dizziness." Archives of Physical Medicine and Rehabilitation 85, no. 10 (2004): 1662–6.

Heid, L., et al. "Vertigo, dizziness, and tinnitus after otobasal fractures." International Tinnitus Journal 10, no. 1 (2004): 94–100.

ORGANIZATIONS

American Academy of Neurology. 1080 Montreal Avenue, St. Paul, MN 55116. Web site: http://www.aan.com/.

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007–1098. Web site: http://www.aap.org.

American Council for Headache Education. 19 Mantua Rd., Mt. Royal, NJ 08061. Web site: http://www.achenet.org.

WEB SITES

"Dizziness." Mayo Clinic , August 6, 2004. Available online at http://www.mayoclinic.com/invoke.cfm?id=DS00435 (accessed January 5, 2005).

"Dizziness and Motion Sickness." American Academy of Otolaryngology/Head and Neck Surgery. Available online at http://www.entnet.org/healthinfo/balance/dizziness.cfm (accessed January 5, 2005).

"Dizziness and Vertigo." MedlinePlus. Available online at http://www.nlm.nih.gov/medlineplus/dizzinessandvertigo.html (accessed January 5, 2005).

"Dizziness and Vertigo." National Multiple Sclerosis Society , March 2003. Available online at http://www.nationalmssociety.org/Sourcebook-Dizziness.asp (accessed January 5, 2005).

L. Fleming Fallon, Jr., MD, DrPH



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