Military Officer - July 2007 - (Page 44)

askthedoctor Hypotension High blood pressure is a serious health problem — but low blood pressure, or hypotension, also can be dangerous. Rear Adm. Joyce Johnson, D.O., reviews its causes and risks. B Hypotension Is Normal for Some ■ Some people always have an unusually low blood pressure. As long as it does not present any symptoms, this hypotension is considered normal and requires no intervention. lood pressure is a measure of how forcefully your heart pumps blood through your body. Most people are aware that high blood pressure (hypertension) can cause health problems, but you might not know that blood pressure also can be too low. This is called hypotension, and it can prevent the brain from getting enough oxygen-laden blood, which can cause dizziness and possibly fainting. Serious falls can be a life-threatening consequence of hypotension. Possible causes of hypotension include: ■ hypovolemia (reduced blood volume). Causes include dehydration due to inadequate ﬂuid intake, excessive perspiration due to exercise or heat, vomiting and diarrhea, and sudden blood loss. ■ cardiac problems. These include severe congestive heart failure, in which the heart muscle loses strength and isn’t able to constrict and adequately pump to circulate the blood. A myocardial infarction (heart attack) can have a similar effect. ■ vasodilation (dilation of the blood vessels). Just as widening a pipe will lower the pressure of the water ﬂowing through it, dilating blood vessels can lower blood pressure. A physician treating a patient with heart disease might prescribe medication (nitroglycerine is one example) that dilates the blood vessels to reduce stress on the patient’s heart. However, sometimes these medications can dilate the vessels too much, causing hypotension. Management of cardiac disease requires a very delicate balance of many factors. ■ problems in the autonomic nervous sys- tem. The autonomic nervous system regulates blood vessel dilation and constriction; when this goes awry, it can cause a speciﬁc type of hypotension called neurocardiogenic syncope. The most common experience of low blood pressure is probably orthostatic, or postural, hypotension, which occurs when a person stands up from a sitting or reclining position and blood pressure doesn’t increase quickly enough to keep the brain supplied with blood. Postural hypotension can result from hypovolemia or from some medications that treat hypertension. Long periods of bed rest can contribute to postural hypotension. Postprandial hypotension can occur about an hour after eating, if the body is unable to accommodate the ﬂow of blood from other parts of the body to the gastroinstestinal tract that is a normal part of the digestive process. Hypotension that causes dizziness or fainting must be treated to prevent serious falls. Replacing ﬂuids helps. Vasoconstrictors (medications that constrict the blood vessels) might be prescribed. Acute hypotension due to serious blood loss, a heart attack, or other problem requires immediate treatment of the medical emergency. MO — Rear Adm. Joyce Johnson, USPHS-Ret., D.O., M.A., is vice president, Health Sciences, Battelle Memorial Institute, Arlington, Va. Find more health and wellness resources at www .moaa.org/wellness. For submission information, see page 20. PHOTO: STEVE BARRETT 44 MILITARY OFFICER J U LY 2 0 0 7 http://www.moaa.org/wellness http://www.moaa.org/wellness

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Military Officer - July 2007 Contents From the Editor From the President Your Views MOAA Directory Rapid Fire Washington Scene Financial Forum Ask the Doctor Chapter Activities Cover Story: In Focus After the Kim Dynasty Animal House Paying Tribute MOAA Member Services Pages of History Faces of MOAA Information Exchange Advertising Index MOAA Scholarship Donors MOAA Calendar Sounding Taps Encore

Military Officer - July 2007

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