Section 6. Brain, Spinal Cord, and Nerve Disorders

Chapter 80. Dizziness and Vertigo

Topics: Introduction | Vertigo | Motion Sickness | Benign Paroxysmal Positional Vertigo

Vertigo

Vertigo is a false sensation that one's self or the surroundings are moving or spinning, usually accompanied by nausea and loss of balance.

Vertigo, a type of dizziness, resembles the feeling produced by the childhood game of spinning round and round, then suddenly stopping and watching the surroundings spin around. Most cases of dizziness are not vertigo.

Causes

Vertigo can be caused by disorders affecting the inner ear (including the semicircular canals), which enables the body to sense position and maintain balance. Vertigo may also be caused by disorders affecting the acoustic nerve (cranial nerve VIII), which connects the inner ear to the brain, or disorders affecting the connections in the brain stem and the cerebellum, which also help control balance.

Most commonly, vertigo results from motion sickness. Motion sickness may develop in people whose inner ear is sensitive to particular motions, such as swaying or sudden stopping and starting.

Another common cause of vertigo is the formation of sludge in the semicircular canals of the inner ear. The resulting disorder, called benign paroxysmal positional vertigo, is especially common among older people. It occurs when the head is moved in certain ways.

Meniere's disease, another disorder of the inner ear, produces attacks of vertigo. The cause of Meniere's disease is thought to involve swelling in the inner ear. Meniere's disease may result from a viral infection, an injury, or an allergy, but the cause is often unknown.

Other disorders that cause vertigo by affecting the inner ear or its nerve connections include bacterial or viral infections (such as viral labyrinthitis, herpes zoster, and mastoiditis), Paget's disease, tumors (such as an auditory nerve tumor), inflammation of nerves, or use of drugs that damage the inner ear (such as aminoglycoside antibiotics, aspirin, the chemotherapy drug cisplatin, and certain diuretics, including furosemide).

A transient ischemic attack commonly causes vertigo when the blood supply through arteries to the brain stem, cerebellum, and back of the brain is reduced. This disorder is called vertebrobasilar insufficiency. The arteries affected include the vertebral arteries and basilar artery, which is formed when the two vertebral arteries join together in the back of the head. Less common disorders that cause vertigo by affecting the brain stem or cerebellum include multiple sclerosis, skull fractures, seizures, infections, and tumors growing in or near the base of the brain.

Occasionally, vertigo is caused by disorders that suddenly increase pressure within the skull, putting pressure on the brain. These disorders include benign intracranial hypertension, brain tumors, and bleeding (hemorrhage) within the skull.

Vertigo may be caused by damage to nerves in the neck. If these nerves are damaged, the brain has difficulty monitoring the relative position of the neck and trunk. This type of vertigo is called cervical vertigo. Whiplash injuries, blunt injuries to the top of the head, or severe arthritis in the neck (cervical spondylosis) may cause cervical vertigo.

Vertigo may be caused by drugs, including the sedative phenobarbital, the anticonvulsant phenytoin, and the antipsychotic chlorpromazine. Excessive use of alcohol can also cause temporary vertigo.

Symptoms

Vertigo is characterized by an unusual and uncomfortable sense of spinning: the person, the surroundings, or both seem to spin around. The resulting loss of balance makes walking and driving difficult. Nystagmus (the rapid movement of the eyes in one direction followed by a slower drift back to the original position) occurs repeatedly during an episode of vertigo. Nausea, sometimes with vomiting, often accompanies vertigo.

Vertigo may last for only a few moments or may continue for hours or even days. People who have vertigo sometimes feel better when lying down or sitting still; however, vertigo may continue even when they are not moving at all.

People with Meniere's disease may have sudden, episodic attacks of vertigo, with noise in the ears (tinnitus), progressive deafness, and a sense of fullness in the affected ear. Often, severe nausea and vomiting accompany the vertigo. Episodes usually last from several minutes to several hours.

In people with a viral infection of the inner ear (viral labyrinthitis), vertigo usually begins suddenly and worsens over several hours. Nausea may be intense. People with this disorder may sit very still, because moving the head or eyes may trigger vomiting. Labyrinthitis begins to subside over a period of days, but it may last weeks or even months.

Vertigo due to a brain disorder, including vertebrobasilar insufficiency, may be accompanied by headaches, slurred speech, double vision, weakness of an arm or a leg, uncoordinated movements, and loss of consciousness.

Vertigo due to a disorder that suddenly increases pressure within the skull may be accompanied by temporary blurring of vision and unsteadiness when walking.

Cervical vertigo occurs when the head is turned, especially if the chin is brought down to a shoulder. The neck's range of motion may be limited.

Diagnosis

Doctors ask the person to describe the nature and circumstances of the sensations felt. Balance and hearing are tested.

The eyes are checked for abnormal movements, such as nystagmus. Abnormal eye movements suggest a disorder affecting the inner ear or nerve connections in the brain stem. Doctors may deliberately induce nystagmus, because the direction in which the eyes move helps doctors make the diagnosis. Before nystagmus is induced, the person may be given thick magnifying glasses called Frenzel glasses to wear. Doctors can easily see the person's magnified eyes through the lenses, but the person sees a blur and cannot fix the eyes on an object. Fixing the eyes on an unmoving object can prevent nystagmus from occurring. During the maneuver, eye movements may be recorded using electrodes (small round sensors that stick to the skin) placed around each eye. This procedure is called electronystagmography.

Maneuvers to induce nystagmus include putting ice-cold water into the ear canal (caloric testing), rapidly shaking the person's head from side to side for 20 seconds, or rapidly changing the position of the person's head using the Dix-Hallpike maneuver. The Dix-Hallpike maneuver, which is used in diagnosis, resembles the Epley maneuver, which is used to treat benign paroxysmal positional vertigo (see Section 6, Chapter 80). In the Dix-Hallpike maneuver, the head is not turned as far.

If cervical vertigo is suspected, the person wears Frenzel glasses and is seated in a swivel chair. The doctor holds the person's head still while the person swivels from right to left. If nystagmus and vertigo occur, cervical vertigo is diagnosed.

Computed tomography (CT) or magnetic resonance imaging (MRI) of the head can detect some of the disorders that can cause vertigo. CT can show abnormalities in bone, such as an infection of the bone behind the ear (mastoiditis), fractures at the base of the skull, erosion of bone by tumors, and abnormal bone formation as occurs in Paget's disease. MRI produces better images of the brain stem and cranial nerves than CT. If an ear infection is suspected, doctors may take a sample of pus or fluid from the ear with a needle or swab. If multiple sclerosis or a brain infection is suspected, a spinal tap (lumbar puncture) may be performed to obtain a sample of cerebrospinal fluid from the spine. If doctors suspect that the blood supply to the brain is inadequate, angiography, magnetic resonance angiography (MRA), or Doppler ultrasonography of the head may be performed.

Prevention and Treatment

Vertigo due to certain disorders can be prevented. For example, if vertigo is due to motion sickness, situations that cause it (such as a rocking boat) can be avoided, and fixing the eyes on an unmoving object can help avert an attack. Taking the drug scopolamine can help prevent as well as treat vertigo.

Drugs that relieve vertigo and the accompanying nausea include cyclizine, dimenhydrinate, diphenhydramine, hydroxyzine, meclizine, and promethazine. These drugs are taken by mouth. Scopolamine, taken through a skin patch worn behind the ear, may also be used. It is effective for several days and may be preferred if nausea is present. All of these drugs are antihistamines (see Section 2, Chapter 18) and may cause drowsiness, dry mouth, and other side effects, especially in older people. Scopolamine given through a patch tends to produce the fewest side effects. These drugs may cause agitation in infants and very young children and should not be given to them except under a doctor's supervision.

See the figure A Cure for Vertigo?

If the vertigo is severe and causes anxiety, sedatives may be needed. Most often, benzodiazepines, such as diazepam, are used. For older people, the benzodiazepines alprazolam and lorazepam are preferred, because they are shorter-acting.

If the cause is cervical vertigo, muscle relaxants such as cyclobenzaprine, given by mouth, may be used. Wearing a soft support (cervical) collar for several hours a day can help, and physical therapy may improve the range of motion in the neck. If the cause is viral labyrinthitis, sedatives (such as benzodiazepines) and drugs that relieve vertigo, nausea, and vomiting (such as meclizine, prochlorperazine, and promethazine) are used. Occasionally, when vertigo is disabling--as it sometimes is in Meniere's disease--surgery is recommended.