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An episode of dizziness is one of the things most likely to drive you to the doctor --- and for good reason. The sense that you're literally losing your footing can be terrifying.
As medical director of the vestibular diagnostic laboratory at Harvard-affiliated Massachusetts Eye and Ear Infirmary, Dr. Richard Lewis sees a lot of dizzy people. He says that when people say they feel dizzy, it could mean that they have vertigo (an illusion of motion, usually spinning). But it could also mean they have a balance problem or a feeling of faintness that's usually due to low blood pressure.
While each of those problems has a different origin and a different treatment, generally they're not serious or life-threatening.
WHAT IS VERTIGO?
Vertigo originates in your inner ear or, less commonly, in the brain. The balance (or vestibular) part of the inner ear is responsible for orienting you in space. When your inner ear and other senses send mixed signals to your brain, everything around you seems to be in motion or spinning.
Nausea often accompanies vertigo. The condition becomes more common with age, affecting almost 10 percent of people over 65, women more commonly than men.
Vertigo can be caused by almost anything that interferes with the normal function of the inner ear, from age-related changes to infections and tumors. The most common types of vertigo--and their causes--are listed below:
1. Benign paroxysmal positional vertigo (BPPV)
The name says it all: "benign" because it isn't serious or progressive; "paroxysmal" because it comes on suddenly and is gone just as fast; and "positional," because it's caused by a change in the position of your head. BPPV results when tiny calcium carbonate crystals detach from the gelatinous material in one part of the inner ear and settle into a semicircular canal, triggering a false message to the brain about the direction in which the head is moving and the speed of its motion.
Dizziness is a result of the brain's attempt to resolve the conflicting messages from the ear and the other senses. The signal from the ear lasts only a few seconds, so the vertigo episode is brief.
"BPPV is easy to diagnose because almost nothing mimics it," Dr. Lewis says. Doctors familiar with the condition can trigger it by having you lie down and turn your head in a certain way. As the crystals settle, your eyes involuntarily oscillate, a phenomenon known as nystagmus that allows the doctor to make an immediate diagnosis.
BPPV is treated with a simple procedure. Although the Epley maneuver usually resolves the problem immediately, there is a 50 percent chance that it will recur within the year. You can have a physical therapist execute the maneuver, or learn it yourself. But if you don't learn the right way to do it, you could create further problems by sending the crystals into a different semicircular canal.
2. Vestibular migraine (migraine-associated vertigo)
Migraine may be the second most common cause of vertigo, especially in women, Dr. Lewis says, primarily because women are more likely than men to develop migraine. About 40 percent of migraine patients have vertigo before, during, or after a headache, or even unrelated to a headache. Vestibular migraine episodes are likely to be more severe, longer lasting, and more frequent than those of BPPV.
There isn't much evidence from clinical trials to indicate what approaches to preventing and treating vestibular migraines are most effective. If you have migraine, you've probably been advised to keep a "migraine diary" tracking your activities and the foods and beverages you consume, as well as the occurrence of your headaches.
It's a good idea to add vertigo episodes to your diary to determine whether particular foods or activities trigger those episodes. For now, it looks like avoiding the common migraine triggers may help to prevent episodes of migraine-associated vertigo, as well as the headaches themselves. Regular exercise and adequate sleep are also advised.
The drug treatments used to prevent and treat migraine--beta blockers such as atenolol (Tenormin), calcium-channel blockers such as amlodipine (Norvasc), tricyclic antidepressants such as amitriptyline (Elavil), and antiseizure drugs such as gabapentin (Neurontin) and topiramate (Topamax)--often reduce symptoms in patients with migraine-associated vertigo. And there is some evidence that treatment with zolmitriptan (Zomig) can abort episodes of ventricular migraine, and dimenhydrinate (Dramamine) can alleviate symptoms.
While you're sitting on an examining table, a therapist will turn your head to the position that triggers vertigo (1). Keeping your head in that position, you'll be lowered until your shoulders touch the table (2). Your head will be rotated to the other side (3) and you'll turn your body in that direction (4). Each position moves the loose crystals through the ear canal, repositioning them to relieve symptoms. When you sit up (5), your symptoms should be gone.
3. Meniere's disease
Episodes of Meniere's disease don't come out of the blue like those of BPPV. Instead, they may begin with a fullness or ringing in the ear and a heightened sensitivity to sound, then progress to an episode of vertigo and hearing loss, accompanied by a sense of pressure in the ear and eventually nausea, diarrhea and trembling. If you've had an episode of Meniere's disease, you probably emerged exhausted and had to sleep for hours afterward.
Meniere's disease is chronic and incurable, largely because its cause still hasn't been identified. Doctors do know it's related to excess fluid in the inner ear, but no one has discovered why this occurs.
Treatment is designed to reduce the volume of fluid in the ear and begins with a diet based on limiting salt intake to 1,500 milligrams per day and eliminating caffeine and alcohol altogether. It may also include a diuretic--often a hydrochlorothiazide/triamterene combination (Dyazide)--to reduce fluid levels and a medication to reduce anxiety, which may trigger attacks.
When conservative treatments aren't effective, a corticosteroid like dexamethasone can provide substantial relief. After the eardrum is numbed with a topical anesthetic, the drug is injected through the eardrum into the inner ear using a thin needle. The procedure is performed in the doctor's office or clinic and takes 10-15 minutes. If steroid injections aren't effective, the antibiotic gentamicin may be injected in a similar brief procedure.
However, gentamicin is considered a treatment of last resort because it works by destroying hair cells, and can therefore affect hearing. In this case, the trade-off for an 80 percent chance of reducing episodes of vertigo can be a risk of permanent hearing loss.
4. Vestibular neuritis
The most frightening type of vertigo results from vestibular neuritis--an inflammation of the nerves in the inner ear. It causes immobilizing vertigo and nausea, which can occur so suddenly that many people go directly to the emergency room.
"It's common for people to assume they're having a stroke," Dr. Lewis says.
Most instances of vestibular neuritis are thought to be due to a reactivation of a latent herpes virus (similar to the viruses responsible for cold sores, chickenpox and genital warts). Once a herpes virus infection has run its course, the virus doesn't leave the body, but becomes dormant in the nerve cells.
Steroid treatment soon after symptoms begin may provide some relief. Vestibular neuritis usually clears up within two months, but people who have had an episode may be left with balance problems or with a hearing loss requiring further treatment.
DIZZINESS WITHOUT THE SPIN
Vertigo isn't the only way to experience dizziness. You can also feel lightheaded and uneasy on your feet without the sense of spinning. In such cases, your dizziness may be caused by one of the following:
a) Balance problems. A host of conditions that affect your bones, nerves, and muscles, including spinal stenosis, spinal curvature, and multiple sclerosis, can throw you off balance. Nerve damage from spinal stenosis or diabetes can make it difficult to feel the ground under your feet.
b) Low blood pressure. In older people, blood pressure may fall precipitously when they stand up. This usually happens because blood in the legs and feet isn't pumped to the brain quickly enough.
c) Medications. Dizziness is a side effect of many common drugs, including blood pressure medications, antidepressants, anti-anxiety drugs and sleeping pills.
d) Dehydration. Diarrhea, respiratory infections and other illnesses can leave you dehydrated, which may also lower your blood pressure excessively.
