Orthostatic hypotension may be cause of frequent light-headedness

DEAR MAYO CLINIC: What’s the difference between feeling dizzy every now and then and orthostatic hypotension? How is it diagnosed, and can it be treated?

ANSWER: Most people remember an occasion when they felt dizzy or light-headed after standing up too quickly. This happens because the pull of gravity causes your blood pressure to drop after you stand. For most people, this occasional phenomenon lasts only a few seconds and usually isn’t a serious problem.

On the other hand, if you frequently feel light-headed, experience dimming of your vision, ringing in your ears, weakness of your legs, or pain of the neck and shoulders when standing up, and your symptoms go away once you sit down, you may have orthostatic hypotension. This means that your blood pressure remains much lower than normal as long as you continue standing.

Orthostatic hypotension can limit activities that involve standing. Feeling unsteady when you stand can increase your risk of falling and fracturing a bone, which can be life-changing. Simple steps can help improve symptoms.

Normally, when you stand, gravity causes blood to be pulled into your legs and your blood pressure to drop slightly. Your body makes up for the increased blood pooling in your legs by constricting your blood vessels and increasing your heart rate. This reflexive response is carried out by your autonomic nervous system.

With aging, the autonomic nervous system may lose some of its ability to regulate blood flow in response to the pull of gravity. Occasionally certain diseases — such as Parkinson’s disease — can disrupt the chemical balance and structure of autonomic nerve cells, resulting in orthostatic hypotension. Orthostatic hypotension also can be a side effect of medications, such as those used to treat high blood pressure, an enlarged prostate or depression.

A sudden drop in blood pressure can mean there is less blood available to reach your brain. Symptoms of decreased blood flow to the brain may range from light-headedness, dizziness and fatigue to confusion, vision changes or fainting on standing. Less commonly, you might have nausea, trouble breathing, headache, or neck or chest pain when standing.

Some people get light-headed or dizzy every time they stand, while others do only when their bodies are stressed, such as from dehydration, heat or after illness. Others have hypotension after a large meal. Not everyone with low blood pressure has symptoms.

Your doctor may be able to make a diagnosis by monitoring your blood pressure while you transition from sitting to standing. A fall of more than 20 to 30 millimeters of mercury in your systolic blood pressure or 10 millimeters of mercury diastolic blood pressure, or both within three minutes of standing is considered orthostatic hypotension. Another way to diagnose orthostatic hypotension is by a tilt table test or an autonomic reflex screen.

Your health care provider may request blood and urine tests to rule out underlying problems, such as anemia or dehydration. He or she also may recommend monitoring your blood pressure over a 24-hour period or specific tests to check your autonomic function.

The next goal is finding ways to improve your symptoms. First steps may include — with your health care provider’s advice — drinking more fluids, adding salt to your diet or adjusting medications. Waist-high compression stockings or an abdominal binder can help prevent symptoms by keeping blood from pooling in your abdomen and legs. You can learn to anticipate when you are likely to have symptoms and take measures to help keep your blood pressure steady. In general, always try to move from lying to sitting to standing in gradual stages. Start walking only after you feel steady.

Finally, orthostatic hypotension can occur as a medication side effect. When medicine that might cause hypotension can’t be stopped, other strategies or medications are available that can help address the symptoms of orthostatic hypotension. (adapted from Mayo Clinic Health Letter) — Sarah Berini, M.D., Neurology, Mayo Clinic, Rochester, Minn.