Orthostatic Hypotension

[Ann Iacobucci]

<div>Orthostatic hypotension is defined as a decrease in systolic blood pressure of 20 mm Hg or a decrease in diastolic blood pressure of 10 mm Hg within three minutes of standing when compared with blood pressure from the sitting or supine position. It results from an inadequate physiologic response to postural changes in blood pressure. Orthostatic hypotension may be acute or chronic, as well as symptomatic or asymptomatic. Common symptoms include dizziness, lightheadedness, blurred vision, weakness, fatigue, nausea, palpitations, and headache. Less common symptoms include syncope, dyspnea, chest pain, and neck and shoulder pain. Causes include dehydration or blood loss; disorders of the neurologic, cardiovascular, or endocrine systems; and several classes of medications. Evaluation of suspected orthostatic hypotension begins by identifying reversible causes and underlying associated medical conditions. Head-up tilt-table testing can aid in confirming a diagnosis of suspected orthostatic hypotension when standard orthostatic vital signs are nondiagnostic; it also can aid in assessing treatment response in patients with an autonomic disorder. Goals of treatment involve improving hypotension without excessive supine hypertension, relieving orthostatic symptoms, and improving standing time. Treatment includes correcting reversible causes and discontinuing responsible medications, when possible. Nonpharmacologic treatment should be offered to all patients. For patients who do not respond adequately to nonpharmacologic treatment, fludrocortisone, midodrine, and pyridostigmine are pharmacologic therapies proven to be beneficial.</div><div></div><div></div><div></div><div></div><div></div><div>orthostatic hypotension</div><div></div><div>Download: https://t.co/eHi00r01q3 </div><div></div><div></div><div>Orthostatic hypotension is defined as a decrease in systolic blood pressure of 20 mm Hg or a decrease in diastolic blood pressure of 10 mm Hg within three minutes of standing compared with blood pressure from the sitting or supine position. Alternatively, the diagnosis can be made by head-up tilt-table testing at an angle of at least 60 degrees.1 Orthostatic hypotension is often found in older patients and in those who are frail.2 It is present in up to 20 percent of patients older than 65 years.3 In one study, the prevalence of orthostatic hypotension was 18 percent in patients older than 65 years, but only 2 percent of these patients were symptomatic.3</div><div></div><div></div><div>In the absence of volume depletion, younger patients with orthostatic hypotension usually have chronic autonomic failure. A related problem, postprandial hypotension, is common in older patients and those with autonomic dysfunction. In postprandial hypotension, there is a decrease in systolic blood pressure of at least 20 mm Hg within 75 minutes of a meal.4</div><div></div><div></div><div>These compensatory mechanisms result in a decrease in systolic blood pressure (5 to 10 mm Hg), an increase in diastolic blood pressure (5 to 10 mm Hg), and an increase in pulse rate (10 to 25 beats per minute). However, orthostatic hypotension may result if there is inadequate intravascular volume, autonomic nervous system dysfunction, decreased venous return, or inability to increase cardiac output in response to postural changes.5 Decreased cerebral perfusion produces the neurologic symptoms of orthostatic hypotension.5</div><div></div><div></div><div>Key physical examination findings in the evaluation of suspected orthostatic hypotension are listed in Table 3.11,12 A detailed assessment of the motor nervous system should be performed to evaluate for signs of Parkinson disease, as well as cerebellar ataxia.7 Blood pressure and pulse rate should be measured in the supine position and repeated after the patient has been standing for three minutes. As many as two-thirds of patients with orthostatic hypotension may go undetected if blood pressure is not measured while supine.13 However, a retrospective review of 730 patients found that orthostatic vital signs had poor test characteristics (positive predictive value = 61.7 percent; negative predictive value = 50.2 percent) when compared with tilt-table testing for the diagnosis of orthostatic hypotension.14 Head-up tilt-table testing should be ordered if there is a high index of suspicion for orthostatic hypotension despite normal orthostatic vital signs, and it may be considered in patients who are unable to stand for orthostatic vital sign measurements.6,14</div><div></div><div></div><div>A description of head-up tilt-table testing and its indications are outlined in Table 4,6,9 and Figure 1 shows a patient undergoing the testing. The procedure is generally considered safe, but serious adverse events such as syncope and arrhythmias have been reported. All staff involved in performing tilt-table testing should be trained in advanced cardiac life support, and resuscitation equipment should be readily available.6 Four common abnormal patterns can be seen in response to tilt-table testing (Table 5).15 The test may be useful in distinguishing orthostatic hypotension from other disorders that can present with symptoms of orthostasis, such as neurocardiogenic syncope.7 Sensitivity of tilt-table testing for diagnosing neurocardiogenic syncope is as high as 65 percent, and specificity is as high as 100 percent.15</div><div></div><div></div><div></div><div></div><div></div><div></div><div>Certain patients may not present with classic historical features of orthostatic hypotension. In older patients, a report of dizziness upon standing may not correlate with the finding of orthostatic hypotension. A prospective study of older women found that use of anxiolytics or sleeping aids once weekly and cigarette smoking were more closely associated with postural dizziness without orthostatic hypotension than with a finding of orthostatic hypotension on tilt-table testing.16 In patients with Parkinson disease, classic symptoms of orthostatic hypotension are not reliably present in those who have autonomic dysfunction.17,18 A study of 50 patients with Parkinson disease found that only one-half of the patients who developed orthostatic hypotension during tilt-table testing were symptomatic.17 The study also found that patients with Parkinson disease who undergo tilt-table testing may need to be tested for longer than the recommended three minutes because only nine of 20 patients who developed orthostatic hypotension did so within three minutes. Extending the test to 11 minutes resulted in 15 of 20 patients being diagnosed, whereas 29 minutes was necessary to detect orthostatic hypotension in all patients.17</div><div></div><div></div><div>In acute care settings (Figure 2), syncope may be the initial presentation of orthostatic hypotension. A prospective study of 611 patients presenting to an emergency department following a syncopal episode found that 24 percent had orthostatic hypotension.19 Patients with syncope should be admitted if they have known cardiovascular disease, associated chest pain, an abnormal electrocardiogram, suspected pulmonary embolism, or new cardiovascular or neurologic findings on examination.20</div><div></div><div></div><div>Acute orthostatic hypotension generally resolves with treatment of the underlying cause. In patients with chronic orthostatic hypotension, pharmacologic and nonpharmacologic treatments may be beneficial. All patients with chronic orthostatic hypotension should be educated about their diagnosis and goals of treatment, which include improving orthostatic blood pressure without excessive supine hypertension, improving standing time, and relieving orthostatic symptoms.21</div><div></div><div></div><div>Nonpharmacologic treatment should be offered to all patients initially. If potentially contributing medications cannot be discontinued, then patients should be instructed to take them at bedtime when possible, particularly antihypertensives.7 Patients should avoid large carbohydrate-rich meals (to prevent postprandial hypotension), limit alcohol intake, and ensure adequate hydration.6,22 Patients should be encouraged to keep a symptom diary and avoid identified precipitating factors. Older patients should consume a minimum of 1.25 to 2.50 L of fluid per day to balance expected 24-hour urine losses. Water boluses (one 480-mL glass of tap water in one study and two 250-mL glasses of water in rapid succession in another study) have been shown to increase standing systolic blood pressure by more than 20 mm Hg for approximately two hours.22</div><div></div><div></div><div>Lower-extremity and abdominal binders may be beneficial. A randomized, single-blind controlled study using tilt-table testing demonstrated effective management of orthostatic hypotension by application of lower-limb compression bandages.23</div><div></div><div></div><div>An exercise program focused on improving conditioning and teaching physical maneuvers to avoid orthostatic hypotension has proven to be beneficial.24 Patients should actively stand with legs crossed, with or without leaning forward. Squatting has been used to alleviate symptomatic orthostatic hypotension.24 Other maneuvers include isometric exercises involving the arms, legs, and abdominal muscles during positional changes or prolonged standing.10 Toe raises, thigh contractions, and bending over at the waist are recommended.21</div><div></div><div></div><div>Fludrocortisone. Fludrocortisone, which is a synthetic mineralocorticoid, is considered first-line therapy for the treatment of orthostatic hypotension. Dosing should be titrated within the therapeutic range until symptoms are relieved, or until the patient develops peripheral edema or has a weight gain of 4 to 8 lb (1.8 to 3.6 kg).9,24 Adverse effects include headache, supine hypertension, and congestive heart failure. Hypokalemia, which is dose-dependent and can appear within one to two weeks of treatment, may occur.9,24 In one study, hypokalemia developed in 24 percent of participants taking fludrocortisone, with a mean onset of eight months.25</div><div></div><div></div><div>Midodrine. Midodrine, a peripheral selective alpha-1-adrenergic agonist, significantly increases standing systolic blood pressure and improves symptoms in patients with neurogenic orthostatic hypotension.26 Patients should not take the last dose after 6:00 p.m. to avoid supine hypertension. Adverse effects include piloerection, pruritus, and paresthesia. Its use is contra-indicated in patients with coronary heart disease, urinary retention, thyrotoxicosis, or acute renal failure. The U.S. Food and Drug Administration has issued a recommendation to withdraw midodrine from the market because of a lack of post-approval effectiveness data.27 Continued approval of the drug is currently under review. Its use generally should be restricted to subspecialists. It is believed to have a synergistic effect when combined with fludrocortisone.</div><div></div><div> 8d45195817</div>