michigan hypertension core curriculum - State of Michigan

Physical Exam: BP sitting 120/74 mmHg and standing 100/60 mmHg. Pulse: 68 and regular (pulse
rate does not change with standing) HEENT: Arteriovenous nicking but no other fundoscopic changes;
Heart: RRR, normal S1 and S2; Lungs: grossly clear. Extremities: no edema.
What are the risk factor(s) in this patient for orthostatic hypotension? What is the most likely
cause of his orthostatic hypotension?
Impression: This is a 68-year old male with multiple risk factor(s) for orthostatic hypotension – Age,
diabetes, diuretics and taking both a diuretic and an alpha antagonist for control of BP. Orthostatic
hypotension is defined as a drop in systolic blood pressure of > 20 mmHg which can be associated with
symptoms. Nevertheless, practitioners should pay attention to orthostatic declines in BP that are even
less in magnitude than a 20 mm Hg decline. His doxazosin was recently increased with a subsequent
development of his symptoms for orthostatic hypotension. However, the lack of rise in his pulse on
standing as his BP falls is consistent with autonomic neuropathy, a likely consequence of his diabetes.
Plan: He should also be evaluated carefully for over-diuresis. And, even if over-diuresis is not
detected, an empiric reduction in the diuretic dose is a meritorious consideration. Another
consideration would be to switch him from chlorthalidone to HCTZ without a change in the daily dose;
this would also effectively reduce his diuretic dose. It is likely that several factors have conspired to
contribute to his orthostatic hypotension. Without question his dose of doxazosin should be reduced.
If all of these changes do not eliminate his orthostatic BP decline, you must use his standing – not
seated – BP as the guide to your therapeutic intensity.
References:
1. Brater DC. Diuretic therapy. N Engl J Med. Aug 6 1998;339(6):387-395.
2. Weiner ID, Wingo CS. Hypokalemia--consequences, causes, and correction. J Am Soc Nephrol.
Jul 1997;8(7):1179-1188.
3. Wong NL, Sutton RA, Mavichak V, Quamme GA, Dirks JH. Enhanced distal absorption of
potassium by magnesium-deficient rats. Clin Sci (Lond). Nov 1985;69(5):625-630.
NKFM & MDCH 275