Dizziness is not a disease. It is a symptom. Most often it is mild and temporary and a cause cannot be found. Sometimes it is a signal of some other problem. Feelings of dizziness or vertigo may be caused by an infection or disease in the inner ear. For example, one possible cause is inflammation of the inner ear called labyrinthitis.Other inner ear problems that can trigger dizziness are Meniere's disease and benign positional vertigo. Dizziness can be caused by tiredness, stress, fever, dehydration, low blood sugar, anemia, head injury, heart or circulation problems, or stroke. It can also be caused by some medicines.

Older people who have either atherosclerosis (hardening of the arteries) or osteoarthritis of the joints in the neck (which may cause pressure on nerves and blood vessels) may experience vertigo when they suddenly move their heads or look up. Dizziness occurs more often in older adults than in other age groups but it is not necessarily caused by disease. Some psychological problems can cause dizziness. For example, anxiety might cause hyperventilation (rapid, shallow breathing), which may then cause you to feel dizzy. Less common causes of dizziness include tumors or infections in the brain, or multiple sclerosis.

We've all had that dizzy feeling once in a while. Maybe you felt it when you suddenly stood up after sitting down for a long time. Or when you were looking up to search for something on a top shelf.Now, imagine what it would be like to feel that dizzy and off-balance for minutes, hours, days — or even years. As a child, spinning until you were dizzy was great fun. But otherwise, finding the room spinning when you get out of bed isn't pleasant at all.

The word "dizzy" is used to describe everything from feeling faint or lightheaded to feeling weak or unsteady. This kind of serious dizziness, called vertigo, makes life miserable for millions of people each year, and keeps some from driving or working. It starts without warning for no apparent reason, and comes and goes.

Good balance depends on at least two of these three sensory systems working well. For instance, closing your eyes while washing your hair in the shower doesn't mean you'll lose your balance. Signals from your inner ear and sensory nerves help keep you upright.However, if your central nervous system can't process signals from all of these locations, if the messages are contradictory, or if the sensory systems aren't functioning properly, you may experience loss of balance.

If you tend to get lightheaded when you stand up, avoid sudden changes in posture.If you are thirsty or lightheaded, drink fluids. If you are unable to keep fluids down from nausea or vomiting, you may need intravenous fluids. These are delivered to you at the hospital.In many patients, lightheadedness is a symptom of orthostatic hypotension. Orthostatic hypotension occurs when the blood pressure drops significantly when the patient stands from a supine or seated position. If loss of consciousness occurs in this situation, it is termed syncope. Syncope is brief -- on the order of seconds -- and is not a seizure. It results from transient alterations in cerebral perfusion.

Chronic dizziness that is not due to vertigo, a problem that has puzzled doctors for years, may have a variety of causes including anxiety disorders and brain injury, according to a study .

Vertigo, a feeling of turning or whirling usually involving inner ear problems, is well recognized, according to the report from the University of Pennsylvania Health System in Philadelphia.

But so-called "chronic nonspecific dizziness" in which victims also suffer imbalance and are super-sensitive to some motions such as walking in a busy store or driving in the rain, is more complex, it added.

The study, published in the Archives of Otolaryngology-Head & Neck Surgery, tracked 345 men and women ages 15 to 89 who had dizziness for three months or longer due to unknown causes.

"All but six patients were diagnosed as having psychiatric or neurologic conditions, including primary or secondary anxiety disorders, migraine, traumatic brain injury" and abnormalities in the body system which controls involuntary actions, the study said.

"The results of this investigation provide some insight into ... mechanisms that may precipitate and perpetuate chronic dizziness," the study added."Two-thirds of patients had medical conditions associated with the onset of dizziness, whereas one third had anxiety disorders as the initial cause," it said.

Some people only experience vertigo when they move their heads into certain positions, and in many cases doctors believe this may be related to the movement of these tiny crystals. This form of vertigo is called benign positional vertigo, or BPV.Vertigo is also one of the main symptoms of Meniere's disease, an inner-ear disorder that affects an estimated 2.6 million people in the United States and Europe.

People with Meniere's disease also experience hearing loss, a feeling of pressure in their ears, and ringing in their ears. Their vertigo attacks come on without warning and last between 20 minutes and a full day, causing nausea and vomiting and debilitating patients for days at a time. A low-salt diet, medications, surgery and special ear-pressure devices can help ease their symptoms.