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Dementia with Lewy Body and Parkinson's Disease PatientsPatient, Family, and Clinician Working Together for Better Outcomes$
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J. Eric Ahlskog

Print publication date: 2013

Print ISBN-13: 9780199977567

Published to Oxford Scholarship Online: November 2020

DOI: 10.1093/oso/9780199977567.001.0001

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PRINTED FROM OXFORD SCHOLARSHIP ONLINE (oxford.universitypressscholarship.com). (c) Copyright Oxford University Press, 2021. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 24 October 2021

Blood Pressure and Orthostatic Hypotension: Faints, Near-Faints, and Lightheadedness

Blood Pressure and Orthostatic Hypotension: Faints, Near-Faints, and Lightheadedness

Chapter:
(p.141) 13 Blood Pressure and Orthostatic Hypotension: Faints, Near-Faints, and Lightheadedness
Source:
Dementia with Lewy Body and Parkinson's Disease Patients
Author(s):

J. Eric Ahlskog

Publisher:
Oxford University Press
DOI:10.1093/oso/9780199977567.003.0022

Case example: Mrs. H. feels lightheaded intermittently during the day. This happens exclusively when she is up and about. Sometimes she notes graying of vision with these episodes. The feeling is not spinning (i.e., not vertigo). She has fainted twice when standing in line at the grocery store. If she sits, she feels much better. It is worse in the morning but may recur any time of the day. She feels fine while lying in bed at night. Older adults often worry about high blood pressure (BP), yet the opposite problem, low BP, is common among those with DLB or PDD. This is because the Lewy neurodegenerative process impairs the autonomic nervous system. The specific condition that may afflict those with DLB or PDD is orthostatic hypotension. The term orthostatic implies the upright position (i.e., standing); hypotension translates into low BP. Thus, the low BP occurring in these Lewy disorders develops in the upright position; conversely, it is normal or even high when lying down. When standing or walking, the BP may drop so low that fainting occurs. Among people with orthostatic hypotension, the BP is normal when sitting, although in severe cases, even the sitting BP is low. Whereas most people with DLB or PDD do not experience symptoms of orthostatic hypotension, it is sufficiently frequent to deserve attention. It often goes undiagnosed, even when fainting occurs. Unrecognized orthostatic hypotension may limit activities and impair the person’s quality of life. The first half of this chapter provides further background, with focus on BP measurement and recognition of orthostatic hypotension. The last half addresses treatment. The normal autonomic nervous system senses the position of our body with respect to the pull of gravity. It is able to reflexively counter gravity’s downward pull on the blood volume when standing (gravity tends to draw blood toward our feet when standing). An important mechanism for countering gravity’s pull is the constriction of blood vessel diameter in the lower half of the body. These vessels reflexively constrict during standing, in effect forcing blood up to the brain. The autonomic nervous system mediates these and other reflexive changes to stabilize BP.

Keywords:   abdominal binder, atenolol (Tenormin), beta-blockers, calcium-channel blockers, chlorthalidone, essential tremor, faintness, in orthostatic hypotension, felodipine (Plendil), hydrochlorothiazide (HCTZ), propranolol (Inderal), spironolactone (Aldactone), tricyclic antidepressants, water pills (diuretics)

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