Orthostatic Hypotension

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Contents 1 More Specific Terms 2 Introduction 3 Etiology 4 Epidemiology 5 Pathology 6 Genetics 7 Clinical-manifestations 8 Laboratory 9 Complications 10 Management 11 More General Terms 12 Additional Terms 13 Internet Database 14 References

More Specific Terms

• orthostatic hypotension in Parkinson's disease

Introduction

• Low blood pressure with dizziness, fainting, & blurred vision upon standing or when standing motionless in a fixed position. Sometimes defined as a drop in systolic blood pressure of 20 mm of Hg with a change in position from supine to standing with a concomittant increase in heart rate of > 10/min.

• More formal criteria from ref 2:

• a postural decrease of blood pressure, either:

• 20 mmHg in systolic, or
• 10 mmHg in diastolic

• sustained for at least 3 minutes* in standing position
• distinguished from sluggish baroreflex (see pathology)

• * hypotension may be delayed > 10 minutes [9]

Etiology

• inadequate vasoconstrictor mechanisms

• precipitating factor: standing up
• predisposing factors:

• peripheral neuropathy affecting autonomic nervous system**
• pharmacologic agents

• antihypertensive agents

• alpha-blockers
• diuretics

• vasodilators (includes PDE-5 inhibitors < Viagra>) [7]
• opiates [4]
• bromocryptine [4]
• tricyclic antidepressants [7]
• antipsychotic agents [7]
• anticholinergic agents [7]
• anti-Parkinson agents [7] -> L-dopa ( Sinemet), benztropine ( Cogentin), deprenyl
• > 4 medications

• prolonged bedrest

• hypovolemia

• precipitating factor: standing up
• predisposing factors

• bleeding from GI tract or from trauma
• diarrhea
• vomiting
• diuretics
• polyuria
  ** Orthostatic hypotension is the most disabling feature of autonomic system dysfunction. Pure autonomic system failure & multiple system atrophy, i.e. Shy-Drager syndrome, is relatively uncommon. Autonomic dysfunction more commonly occurs in association with Parkinson's disease, Huntington's disease, progressive supranuclear palsy, adrenomedullary insufficiency & diabetes mellitus [7].

Epidemiology

• 50% of nursing home patients
• < 20% of healthy community-dwelling elderly [12]
• more common in patients with hypertension
• associated with falls in patient with history of fall within the past 6 months

Pathology

• inadequate vasoconstrictor mechanisms in both arterioles & veins resulting in venous pooling, or
• hypovolemia - diminished blood volume
• failure of compensatory tachycardia
• decreased cardiac output
• fall in blood pressure

• most pronounced when standing
• both initial & delayed
• a drop in systolic blood pressure of ~35 mm Hg within 30 seconds with return to near-baseline within 2 minutes is the most common pattern [12]

• syncope results when cerebral perfusion is impaired

Genetics

• associated with defects in SLC6A2

Clinical-manifestations

• headache
• neck/ shoulder pain
• dimming or loss of vision
• weakness
• prompt return to normal when supine

Laboratory

• plasma norepinephrine may be abnormally high

Complications

• increased risk of falls [12]

Management

• no treatment unless symptomatic
• general measures:

• arise slowly [4]
• adequate hydration [6]
• compression stockings if lower extremity edema [11]

• supine hypertension a consideration & limiting factor
• maximize salt intake
• drug therapy

• fludrocortisone, KCl supplementation
• prostaglandin inhibitors
• beta-blockers ( diastolic dysfunction)

• propranolol
• pindolol

• calcium channel blocker [5]
• sympathomimetics

• ephedrine
• midodrine ( ProAmatine) {expensive}

• dopamine antagonists ( metoclopramide)
• venoconstrictors ( dihydroergotamine)
• desmopressin (minimizes fluid loss)
• octreotide (inhibits release of gastrointestinal peptides, some of which have hypotensive properties
• caffeine is worth a try [10]

More General Terms

• hypotension

Additional Terms

• beta adrenergic receptor antagonist (beta-blocker)
• dihydroergotamine (DHE 45, Migranal)
• ephedrine
• fludrocortisone (Florinef)
• metoclopramide (Reglan, Metozolv ODT)
• midodrine (ProAmatine, Gutron)
• neuropathic tachycardia syndrome
• octreotide (Sandostatin)

Internet Database

OMIM: 604715

References

1. nlmpubs.nlm.nih.gov/hstat/ahcpr/
2. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 2344-45, 2346-47
3. Guide to Physical Examination & History Taking, 6th edition, Bates B, JB Lippincott, Philadelphia, 1995, pg 90-91
4. Geriatrics Review Syllabus, American Geriatrics Society, 5th edition, 2002-2004
5. Castle, S. Veterans Administration (personal communication)
6. Journal Watch 24(2):15, 2004 Lu C-C et al,Ciculation 108:2660, 2003 PMID: [1]
7. Prescriber's Letter 11(7):38 2004 Detail-Document#: [2] (subscription needed) [3]
8. Neurology. 1996 May;46(5):1470. Consensus statement on the definition of orthostatic hypotension, pure autonomic failure, and multiple system atrophy. The Consensus Committee of the American Autonomic Society and the American Academy of Neurology. PMID: [4]
9. Gibbons CH and Freeman R, Delayed orthostatic hypotension: A frequent cause of orthostatic intolerance. Neurology 2006, 67:28 PMID: [5]
10. Prescriber's Letter 16(7): 2009 Detail-Document#: [6] (subscription needed) [7]
    - Prescriber's Letter 16(9): 2009 Orthostatic Hypotension Detail-Document#: [8] (subscription needed) [9]
11. Medical Knowledge Self Assessment Program (MKSAP) 14, American College of Physicians, Philadelphia 2006
12. Romero-Ortuno R et al. Continuous noninvasive orthostatic blood pressure measurements and their relationship with orthostatic intolerance, falls, and frailty in older people. J Am Geriatr Soc 2011 Apr; 59:655 PMID: [10]
13. NINDS Postural Tachycardia Syndrome Information Page [11]
    - NINDS Orthostatic Hypotension Information Page [12]
14. National Guideline Clearinghouse Orthostatic hypotension. European Federation of Neurological Societies ngc-guideline: [13]

orthostatic hypotension (postural tachycardia syndrome, POTS, Bradbury-Eggleston Syndrome)