Orthostatic Hypotension
Orthostatic Hypotension: Excerpt from Field Guide to Bedside Diagnosis
Differential Overview
Dysautonomia
❑ Diabetes
❑ Drugs
❑ Pernicious anemia
❑ Amyloidosis
❑ Guillain-Barré syndrome
❑ Wernicke syndrome
Other
❑ Dehydration
❑ Prolonged standing
❑ Hemorrhage
❑ Thermodilation
❑ Vasovagal response
❑ Pregnancy
❑ Addison disease
Diagnostic Approach
Dysautonomia is characterized by orthostatic hypotension (postural lightheadedness, fainting, dim vision, weakness, unsteady gait), urinary dysfunction (frequency, urgency, stress incontinence), sexual dysfunction (impotence, retrograde ejaculation), bowel dysfunction (nocturnal diarrhea, incontinence), and/or decreased sweating. It is most easily recognized by the presence of orthostatic hypotension without reflex tachycardia. Within 2 to 5 minutes of quiet standing there will be a 20 mm Hg drop in systolic pressue, a 10 mm Hg drop in diastolic pressure, or symptoms of cerebral hypoperfusion.
With gastrointestinal hemorrhage, an orthostatic blood pressure change of 10 mm Hg suggests a loss of at least 20% of intravascular volume.
Clinical Findings
Diabetes Early in the course of diabetic autonomic neuropathy, orthostatic hypotension with a preserved cardioaccelerator mechanism develops, along with gastroparesis with early satiety and vomiting, nocturnal diarrhea, and retrograde ejaculation. A common finding is a bilateral symmetric neuropathy with decreased vibration sensation and absent ankle jerks.
Drugs Dysautonomia can be caused by methyldopa, barbiturates, clonidine, isoniazid, L-dopa, MAO inhibitors, phenothiazines, tricyclics, prazocin, quinidine, procainamide, reserpine, and vincristine. Volume depletion may occur with diuretics, alcohol, and vasodilators (calcium channel blockers and nitrates).
Pernicious anemia Lower limb paresthesias and distal areflexia are early findings, followed by pallor with anemia; either of these may contribute to orthostasis.
Amyloidosis It often presents as a sensory neuropathy with autonomic dysfunction, occurring in the setting of a chronic inflammatory disease (cancer or infection). Associated findings include edema caused by congestive heart failure or nephrotic syndrome, an enlarged tongue, and waxy purpuric periorbital plaques.
Guillain-Barré syndrome The onset is subacute but rapid. Classically, the patient reports tingling in the hands and feet, an ascending motor weakness manifesting as a gait disorder, a mild distal sensory loss, and areflexia. Bilateral facial weakness, if present, is an important clue.
Wernicke syndrome Autonomic dysfunction is a late finding in a patient with abducens gaze palsy, ataxia, and confusion.
Dehydration Mucous membranes are dry, there is decreased skin turgor (tenting), and eyes appear sunken. A precipitating cause such as diarrhea or vomiting is usually evident.
Prolonged standing Orthostatic fainting occurs with prolonged motionless standing, especially in combination with cutaneous vasodilation produced by a hot day.
Hemorrhage The source is usually acute gastrointestinal blood loss or trauma, but significant volume loss may occur with retroperitoneal hemorrhage (renal trauma, hemorrhagic pancreatitis, or aortic rupture), in which localization is more obscure.
Thermodilation The skin will be flushed and perspiring.
Vasovagal response It occurs most often in the setting of psychological stress. The patient appears pale and diaphoretic, and has a slow pulse. Orthostatic changes will disappear when symptomatic recovery occurs.
Pregnancy Impaired venous return causes blood pooling and an orthostatic drop in blood pressure.
Addison disease The patient will complain of asthenia and vague abdominal pains. Hyperpigmentation, especially in the palmar creases and mucous membranes, is a critical clue.
Book Source Details
- Book Title: Field Guide to Bedside Diagnosis
- Author(s): David S. Smith
- Year of Publication: 2007
- Copyright Details: Field Guide to Bedside Diagnosis, Copyright © 2007 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Field Guide to Bedside Diagnosis
Authors: David S. Smith
Publisher: Lippincott Williams & Wilkins
Copyright: 2007
ISBN: 0-78178-165-5
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Hypotension, orthostatic (Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series)
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