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"Head rush" redirects here. For the television science series, see Head Rush (TV series).
Orthostatic hypotension
Classification and external resources
ICD-10 I95.1
ICD-9 458.0
DiseasesDB 10470
eMedicine ped/2860
MeSH D007024

Orthostatic hypotension (/ˌɔrθəˈstætɪkˌhpəˈtɛnʃən/), also known as postural hypotension,[1] orthostasis, and colloquially as head rush or dizzy spell, is a form of low blood pressure in which a person's blood pressure falls when suddenly standing up or stretching. In medical terms, it is defined as a fall in systolic blood pressure of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg when a person assumes a standing position.

The symptom is caused by blood pooling in the lower extremities upon a change in body position. It is quite common and can occur briefly in anyone, although it is prevalent in particular among the elderly, and those with low blood pressure.

Signs and symptoms[edit]

When orthostatic hypotension is present, the following symptoms can occur after sudden standing or stretching (after sitting):

They are consequences of insufficient blood pressure and cerebral perfusion (blood supply). Occasionally, there may be a feeling of warmth in the head and shoulders for a few seconds after the dizziness subsides. The drop in blood pressure may cause a vasovagal episode to occur.

Causes[edit]

Orthostatic hypotension is caused primarily by gravity-induced blood-pooling in the lower extremities, which in turn compromises venous return, resulting in decreased cardiac output and subsequent lowering of arterial pressure. For example, changing from a lying position to standing loses about 700 ml of blood from the thorax, with a decrease in systolic and diastolic blood pressures.[2] The overall effect is an insufficient blood perfusion in the upper part of the body.

Still, the blood pressure does not normally fall very much, because it immediately triggers a vasoconstriction (baroreceptor reflex), pressing the blood up into the body again. (Often, this mechanism is exaggerated and is why diastolic blood pressure is a bit higher when a person is standing up, compared to a person in horizontal position.) Therefore, a secondary factor that causes a greater than normal fall in blood pressure is often required. Such factors include low blood volume, diseases, and medications.

Hypovolemia[edit]

Orthostatic hypotension may be caused by low blood volume, resulting from bleeding, the excessive use of diuretics, vasodilators, or other types of drugs, dehydration, or prolonged bed rest. It also occurs in people with anemia.

Diseases[edit]

The disorder may be associated with Addison's disease, atherosclerosis (build-up of fatty deposits in the arteries), diabetes, pheochromocytoma, and certain neurological disorders, including multiple system atrophy and other forms of dysautonomia. It is also associated with Ehlers-Danlos syndrome. It is also present in many patients with Parkinson's disease resulting from sympathetic denervation of the heart or as a side-effect of dopaminomimetic therapy. This rarely leads to fainting unless the person has developed true autonomic failure or has an unrelated heart problem.

Another disease, dopamine beta hydroxylase deficiency, also thought to be underdiagnosed, causes loss of sympathetic noradrenergic function and is characterized by a low or extremely low levels of norepinephrine, but an excess of dopamine.[3]

Quadriplegics and paraplegics also might experience these symptoms due to multiple systems' inability to maintain a normal blood pressure and blood flow to the upper part of the body.

A study by a Harvard Medical School team found the two sacs in the inner ear, the utricle and the saccule, affect brain blood flow; thus, inner ear problems, which increase with old age, may be involved in orthostatic hypotension.[4]

Medication[edit]

Orthostatic hypotension can be a side-effect of certain antidepressants, such as tricyclics[5] or monoamine oxidase inhibitors (MAOIs).[6] Marijuana and tetrahydrocannabinol can on occasion produce marked orthostatic hypotension.[7] Orthostatic hypotension can also be a side effect of Alpha-1 blockers (alpha1 adrenergic blocking agents). Alpha1 blockers inhibit vasoconstriction normally initiated by the baroreceptor reflex upon postural change and the subsequent drop in pressure.[8]

B12 deficiency[edit]

Orthostatic hypotension sometimes is a reversible neurological complication of vitamin B12 deficiency.[9]

Harnesses[edit]

The use of a safety harness does not contribute to orthostatic hypotension in the event of a fall. This notion is a hypothetical risk which has all but been eliminated due to modern design and safety regulations.[10] If worn properly, a safety harness may safely rescue its user from a fall without any further complications so long as the individual does not remain suspended for prolonged periods of time.[10]

Other factors[edit]

Patients prone to orthostatic hypotension are the elderly, post partum mothers, and those having been on bedrest. People suffering from anorexia nervosa and bulimia nervosa often suffer from orthostatic hypotension as a common side-effect. Consuming alcohol may also lead to orthostatic hypotension due to its dehydrating effects.[citation needed]

Diagnosis[edit]

There is a simple test for OH that measures the person's blood pressure after lying flat for 5 minutes, then 1 minute after standing, and 3 minutes after standing.[11] Orthostatic hypotension is defined as a fall in systolic blood pressure of at least 20 mmHg and/or in the diastolic blood pressure of at least 10 mmHg between the supine reading and the upright reading. In addition, the heart rate should also be measured for both positions. A significant increase in heart rate from supine to standing may indicate a compensatory effort by the heart to maintain cardiac output or Postural Orthostatic Tachycardia Syndrome (POTS). A tilt table test may also be performed.

Management[edit]

The evidence to support treatment is poor. A number of measures have slight evidence to support their use including compression bandages, midodrine, indomethacin, oxilofrine, potassium chloride, and yohimbine.[12] Midodrine can reduce dizzy spells and faints by about a third, although the quality of the evidence underlying this finding is limited.[13] The main side-effect is piloerection ("goose bumps").[13]

Prognosis[edit]

Orthostatic hypotension may cause accidental falls.[14]

See also[edit]

References[edit]

  1. ^ "Orthostatic hypotension" at Dorland's Medical Dictionary
  2. ^ http://emedicine.medscape.com/article/1154266-overview
  3. ^ "Dopamine Beta-Hydroxylase Deficiency". GeneReviews — NCBI Bookshelf. 
  4. ^ "Minute organs in the ear can alter brain blood flow". BBC News. 2009-12-27. Retrieved 2009-12-27. 
  5. ^ Jiang W, Davidson JR. (2005). "Antidepressant therapy in patients with ischemic heart disease". Am Heart J 150 (5): 871–81. doi:10.1016/j.ahj.2005.01.041. PMID 16290952. 
  6. ^ Delini-Stula A, Baier D, Kohnen R, Laux G, Philipp M, Scholz HJ. (1999). "Undesirable blood pressure changes under naturalistic treatment with moclobemide, a reversible MAO-A inhibitor—results of the drug utilization observation studies". Pharmacopsychiatry 32 (2): 61–7. doi:10.1055/s-2007-979193. PMID 10333164. 
  7. ^ Jones RT. (2002). "Cardiovascular system effects of marijuana". J Clin Pharmacol 42 (11 Suppl): 58S–63S. doi:10.1002/j.1552-4604.2002.tb06004.x. PMID 12412837. 
  8. ^ Orthostatic Hypotension at Merck Manual of Diagnosis and Therapy Home Edition
  9. ^ Beitzkea, Markus; Peter Pfistera; Jürgen Fortinb; Falko Skrabal (2002-04-18). "Autonomic dysfunction and hemodynamics in vitamin B12 deficiency". Autonomic Neuroscience 97 (1): 45–54. doi:10.1016/S1566-0702(01)00393-9. PMID 12036186. 
  10. ^ a b Lee C, Porter KM (Apr 2007). "Suspension trauma". Emerg Med J. 24 (4): 237–8. doi:10.1136/emj.2007.046391. PMC 2658225. PMID 17384373. 
  11. ^ "STEADI - Measuring Orthostatic Blood Pressure" (PDF). Centers for Disease Control and Prevention. Retrieved 20 December 2014. 
  12. ^ Logan, IC; Witham, MD (September 2012). "Efficacy of treatments for orthostatic hypotension: a systematic review.". Age and ageing 41 (5): 587–94. doi:10.1093/ageing/afs061. PMID 22591985. 
  13. ^ a b Izcovich, A.; Gonzalez Malla, C.; Manzotti, M.; Catalano, H. N.; Guyatt, G. (22 August 2014). "Midodrine for orthostatic hypotension and recurrent reflex syncope: A systematic review". Neurology 83 (13): 1170–1177. doi:10.1212/WNL.0000000000000815. PMID 25150287. 
  14. ^ Romero-Ortuno R, Cogan L, Foran T, Kenny RA, Fan CW (2011). "Continuous noninvasive orthostatic blood pressure measurements and their relationship with orthostatic intolerance, falls, and frailty in older people". J Am Geriatr Soc 59 (4): 655–65. doi:10.1111/j.1532-5415.2011.03352.x. PMID 21438868. 

External links[edit]


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Orthostatic_hypotension — Please support Wikipedia.
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681 news items

Pharmacy Times

Pharmacy Times
Wed, 13 May 2015 11:21:46 -0700

By definition, orthostatic hypotension (OH) is a persistent decrease in systolic blood pressure of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg within 3 minutes of standing.1 Although there are several common causes of OH, it may ...
 
Nature.com
Wed, 27 May 2015 23:22:30 -0700

No atypical features such as prominent oculomotor palsy, cerebellar signs, vocal cord paresis, severe orthostatic hypotension, pyramidal signs, amyotrophy or limb apraxia. The Unified Parkinson's Disease Scale, Hoehn and Yahr (H&Y) staging, activities ...
 
Abante Online
Fri, 15 May 2015 09:07:30 -0700

Orthostatic hypotension can occur for a variety of reasons, including dehydration, prolonged bed rest, pregnancy, diabetes, heart problems, burns, excessive heat, large varicose veins and certain neurological disorders,” ayon sa mga doktor ng Mayo ...
 
GlobeNewswire (press release)
Thu, 21 May 2015 02:56:15 -0700

Our key areas of focus are alcohol dependence, Alzheimer's disease, bipolar disorder, depression/anxiety, epilepsy, Huntington's disease, Parkinson's disease, schizophrenia and symptomatic neurogenic orthostatic hypotension (NOH). An estimated 700 ...

The Pharmaceutical Journal

The Pharmaceutical Journal
Wed, 20 May 2015 02:07:58 -0700

It is contraindicated in patients taking monoamine oxidase inhibitors, and close monitoring is required in patients with depression, cerebral or coronary vascular insufficiency, Raynaud's phenomenon, orthostatic hypotension or thromboangiitis obliterans.

Everyday Health (blog)

Everyday Health (blog)
Fri, 08 May 2015 11:33:45 -0700

People with pre-existing heart disease, kidney disease, orthostatic hypotension (low blood pressure), or a prior history of passing out should avoid these types of fluid losses until they have met with their physician. When you lose that much sweat ...
 
Forimmediaterelease.net (press release)
Tue, 26 May 2015 00:30:00 -0700

With enhanced antagonistic activity at a1 receptor sites and low activity on histamine H1 receptors, Fanapt has been associated with an issue of orthostatic hypotension (due to a1 blockade) rather than weight gain and sedation like other agents within ...
 
PR Newswire (press release)
Mon, 11 May 2015 14:49:47 -0700

Clinical monitoring of weight is recommended. Orthostatic Hypotension and Syncope: INVEGA SUSTENNA® may induce orthostatic hypotension in some patients due to its alpha-blocking activity. INVEGA SUSTENNA® should be used with caution in patients ...
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