Athletes' dizziness has many causes, mostly benign

NEW YORK (Reuters Health) - Dizziness is a common complaint of athletes, and while diagnosing the roots of the problem may take a little digging, the cause is usually benign, according to a new report.

Many athletes and non-athletes alike at some point have the vague symptom of "feeling dizzy." However, diagnosing the cause can be somewhat trickier in athletic people, according to Dr. Chris A. Klenck of the Indiana University Center for Sports Medicine, the author of the report.

This is because an athlete's normal physiology -- marked by a slow resting heart rate or low blood pressure, for example -- may mimic certain causes of dizziness. Writing in the journal Current Sports Medicine Reports, Klenck details the steps to diagnosing and treating dizziness in athletes.

The first step, he says, is to define "dizziness." Athletes most commonly suffer from one of two forms of dizziness: vertigo and presyncope. Vertigo, which accounts for about half of all cases of dizziness, causes a spinning sensation, while presyncope causes lightheadedness and the sensation that you might faint.

A third, less common form of dizziness is disequilibrium, an off-balance sensation that comes from the trunk and limbs, but not the head. Finally, there is "nonspecific dizziness," which includes vague symptoms that don't fit neatly into the other three categories, according to Klenck.

Once the type of dizziness is defined, he writes, patients should have their medical history carefully evaluated and undergo a physical exam. Diagnostic tests may also be needed.

With vertigo, Klenck explains, the cause is usually related to the vestibular system, structures in the inner ear that help maintain orientation and balance. In many of these cases, the problem arises when normal calcium carbonate crystals in the inner ear break loose and stimulate balance-related sensors. Special head-movement exercises are the typical treatment.

Other common vertigo causes include infections or inflammation in the inner ear, which can be treated with head exercises and medication. Less common but far more serious causes of vertigo include migraine, multiple sclerosis, stroke and tumors.

Presyncope also frequently has a benign cause, according to Klenck, but serious underlying conditions, such as heart disease, should be ruled out.

Perhaps the most common non-cardiac cause, he writes, is vasovagal syncope, which involves inappropriate activity in the vagus nerves; in these cases, a stimulus -- such as standing up quickly or standing for long periods -- causes a drop in heart rate and blood pressure that leads to lightheadedness and sometimes fainting.

Besides a medical history and physical exam, people with vertigo may need an electrocardiogram and possibly other tests to look for cardiac causes. Additional tests for non-cardiac causes include the "head-up tilt," or HUT, test, which uses a special table to tilt patients upright at various angles while their heart and blood pressure are monitored.

In contrast to vertigo and presyncope, disequilibrium is uncommon among athletes, according to Klenck. Potential causes of this condition include Parkinson's disease and nerve damage in the limbs; people with this form of dizziness need a neurological evaluation.

For its part, nonspecific dizziness often has psychiatric roots, such as major depression and panic disorder, which means mental health screening may be necessary for some people, according to Klenck.

For some athletes, he notes, hyperventilation may cause nonspecific dizziness; if that's suspected, a doctor can have the patient hyperventilate to see if that produces a dizzy spell.

SOURCE: Current Sports Medicine Reports, February 2007.