WordNet

the falling to earth of any form of water (rain or snow or hail or sleet or mist) (同)downfall
the process of forming a chemical precipitate
the quantity of water falling to earth at a specific place within a specified period of time; "the storm brought several inches of precipitation"
an unexpected acceleration or hastening; "he is responsible for the precipitation of his own demise"
the act of casting down or falling headlong from a height
pertaining to an upright standing posture; "orthostatic hypotension"
abnormally low blood pressure

PrepTutorEJDIC

〈U〉突然の大あわて / 〈C〉〈U〉(化学で)沈殿物;〈U〉沈殿 / 〈U〉降雨,降雪;降雨量,降雪量
低血圧[症]

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/11/15 19:45:57」(JST)

wiki en

"Head rush" redirects here. For the television science series, see Head Rush (TV series).

Orthostatic hypotension, also known as postural hypotension,^[1] orthostasis, and colloquially as head rush or dizzy spell, is a form of hypotension in which a person's blood pressure suddenly falls when 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 standing):

Dizziness
Euphoria or dysphoria
Bodily dissociation
Distortions in hearing
Lightheadedness
Nausea
Headache
Temporary decrease in hearing
Blurred or dimmed vision (possibly to the point of momentary blindness)
Seizures
Generalized (or extremity) numbness/tingling and fainting
Coat hanger pain (pain centered in the neck and shoulders)
And in rare, extreme cases, vasovagal syncope (a specific type of fainting).

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 hypovolemia, diseases, medications, or, very rarely, safety harnesses.^[3]

Hypovolemia[edit]

Orthostatic hypotension may be caused by hypovolemia (a decreased amount of blood in the body), 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 syncope unless the patient has developed true autonomic failure or has an unrelated cardiac 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.^[4]

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.

Recently, a common but underdiagnosed condition suspected to be closely related to orthostatic hypotension is spontaneous intracranial hypotension,^{[citation needed]} which results from cerebrospinal fluid leakage. It affects women more than men and peaks at ages between 40 and 50.

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.^[5]

Medication[edit]

Orthostatic hypotension can be a side-effect of certain antidepressants, such as tricyclics^[6] or monoamine oxidase inhibitors (MAOIs).^[7] Marijuana and tetrahydrocannabinol can on occasion produce marked orthostatic hypotension.^[8] 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.^[9]

Harnesses[edit]

The use of a safety harness can also contribute to orthostatic hypotension in the event of a fall. While a harness may safely rescue its user from a fall, the leg loops of a standard safety or climbing harness further restrict return blood flow from the legs to the heart, contributing to the decrease in blood pressure.

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.

The Orthostatic hypotension is also associated with Naturopathy treatment and during practice of yoga, wherein the pressure gradient varies during these practices.

Diagnosis[edit]

There is a simple test for OH that measures the person's blood pressure while seated or reclining at rest, and again upon standing up. 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 from supine to standing may indicate a compensatory effort by the heart to maintain cardiac output.

A tilt table test may also be performed.

Management[edit]

The evidence to support treatment is poor. A number of measures with slight evidence to support their use include: compression bandages, indomethacin, oxilofrine, potassium chloride, and yohimbine.^[10]

Prognosis[edit]

Orthostatic hypotension may cause accidental falls.^[11]

References[edit]

^ "Orthostatic hypotension" at Dorland's Medical Dictionary
^ http://emedicine.medscape.com/article/1154266-overview
^ 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.
^ "Dopamine Beta-Hydroxylase Deficiency". GeneReviews — NCBI Bookshelf.
^ "Minute organs in the ear can alter brain blood flow". BBC News. 2009-12-27. Retrieved 2009-12-27.
^ 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.
^ 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.
^ Jones RT. (2002). "Cardiovascular system effects of marijuana". J Clin Pharmacol 42 (11 Suppl): 58S–63S. PMID 12412837.
^ Orthostatic Hypotension at Merck Manual of Diagnosis and Therapy Home Edition
^ Logan, IC; Witham, MD (2012 Sep). "Efficacy of treatments for orthostatic hypotension: a systematic review.". Age and ageing 41 (5): 587–94. doi:10.1093/ageing/afs061. PMID 22591985. Check date values in: |date= (help)
^ 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]

Bradley JG, Davis KA (Dec 2003). "Orthostatic hypotension". Am Fam Physician. 68 (12): 2393–8. PMID 14705758.
DYNA Dysautonomia Youth Network of America, Inc.
Dysautonomia Information Network
Dysautonomia Support Network
Drugs that cause Orthostatic hypotension – wrongdiagnosis.com
Timothy C. Hain, MD. Orthostatic hypotension

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 起立性低血圧のメカニズム、原因、および評価 mechanisms causes and evaluation of orthostatic hypotension
2. 起立性低血圧および食後低血圧の治療 treatment of orthostatic and postprandial hypotension
3. 糖尿病症例解説20：長期に渡る2型糖尿病、起立性低血圧および再発性失神を有する
76歳男性 interactive diabetes case 20 a 76 year old man with long standing type 2 diabetes orthostatic hypotension and recurrent syncope
4. 進行性核上性麻痺（PSP） progressive supranuclear palsy psp
5. 高齢者の病院でのマネージメント hospital management of older adults

English Journal

Impaired cerebral haemodynamic function associated with chronic traumatic brain injury in professional boxers.

Bailey DM, Jones DW, Sinnott A, Brugniaux JV, New KJ, Hodson D, Marley CJ, Smirl JD, Ogoh S, Ainslie PN.Source*Neurovascular Research Laboratory, Faculty of Health, Science and Sport, University of Glamorgan, Pontypridd, Wales, U.K.
Clinical science (London, England : 1979).Clin Sci (Lond).2013 Feb 1;124(3):177-89. doi: 10.1042/CS20120259.
The present study examined to what extent professional boxing compromises cerebral haemodynamic function and its association with CTBI (chronic traumatic brain injury). A total of 12 male professional boxers were compared with 12 age-, gender- and physical fitness-matched non-boxing controls. We ass
PMID 22913765

Pacing System Malfunction is a Rare Cause of Hospital Admission for Syncope in Patients with a Permanent Pacemaker.

Ofman P, Rahilly-Tierney C, Djousse L, Peralta A, Hoffmeister P, Gaziano JM, Weiss A, Lotan C, Rosenheck S.SourceDepartment of Cardiology, Hadassah-Hebrew University Medical Center, Ein Karem Campus, Jerusalem, Israel; Massachusetts Veterans Epidemiology and Research Information Center (MAVERIC), Boston Veterans Affairs Healthcare System, Boston, Massachusetts; Division of Cardiology, Department of Medicine, VA Boston Healthcare System and Harvard Medical School, Boston, Massachusetts; Division of Aging, Department of Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, Massachusetts; Division of Preventive Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, Massachusetts.
Pacing and clinical electrophysiology : PACE.Pacing Clin Electrophysiol.2012 Nov 4. doi: 10.1111/pace.12041. [Epub ahead of print]
BACKGROUND: Few studies have examined the prevalence of permanent pacemaker (PPM) malfunction among patients with a previously implanted pacemaker admitted to the hospital with syncope.OBJECTIVE: This study sought to examine causes of syncope in patients with a previously implanted pacemaker admitte
PMID 23121111

Japanese Journal

症例報告起立試験で典型的なT？波の減高を認めた起立性調節障害の1例

佐藤工,三浦文武,三上珠希 [他]
弘前病院紀要 5(2), 13-16, 2012
NAID 40019412947

頭部外傷に伴う低髄液圧症候群の考え方(<特集>頭部外傷update)

佐藤慎哉,嘉山孝正
脳神経外科ジャーナル 20(12), 887-895, 2011-12-20
低髄液圧症候群は,脳脊髄液の漏出による起立時の牽引性頭痛を主症状とする症候群である.この疾患概念は70年以上も前からあり,また,1988年の国際頭痛分類(初版)にも記載されるなど,単に古いだけでなく,広く知られている病態である.しかし,近年,本症候群と外傷性頚部症候群との関係が取りざたされ,その診断・治療が社会問題化している.現在,低髄液圧症候群(脳脊髄液減少症)に関して,厚生労働科学研究費補助金 …
NAID 110008799373

Related Pictures

Neurogenic orthostatic hypotension and supine hypertension in Parkinson's disease and Mayo Clinic Q and A: Treating orthostatic hypotension – Mayo Clinic News Network hypotension - DriverLayer Search Engine Orthostatic Hypotension (Postural Hypotension) - SCIRE Community Orthostatic Hypotension | JACC: Journal of the American College of Cardiology Prevention and Treatment of Orthostatic Hypotension in the Orthopedic Patient Population

★リンクテーブル★

リンク元	「失神」「起立性低血圧」「precipitation」「incapacitating」「postural hypotension」
拡張検索	「idiopathic orthostatic hypotension」
関連記事	「orthostatic」

「失神」

Orthostatic hypotension
	Classification and external resources
ICD-10	I95.1
ICD-9	458.0
DiseasesDB	10470
eMedicine	ped/2860
MeSH	D007024

　　[★]

英: syncope, faint
関: 一過性意識障害

定義

1. 発作的に起こる脳の血流低下による一過性の意識消失
2.

一過性の意識消失の結果、姿勢が保持できなくなり、かつ自然に、また完全に意識の回復が見られること(失神の診断・治療ガイドライン)
発症は比較的速やかであり、意識は多くの場合速やかに回復する。「意識障害」のうちで、特異な臨床像を持った1 つの症候である。(失神の診断・治療ガイドライン)

3. 元来、一過性の全脳虚血による一時的な意識消失で、かつ数秒から数分で意識を回復する物を指していたが、現在ではあいまい、より広義となっている。例えば、てんかん発作、低血糖、過換気、一過性脳虚血発作を含んでいる。(IMD.241)　←　ホント？誰かが誤用しつづけているだけなんちゃうか？

症状

眼前暗黒感、めまい感、悪心などの前駆症状に引き続き、顔面が蒼白となり、ついに意識が消失

意識消失までの時間経過と症状

脳への血流停止が5-10秒程度で失神、10秒前後で筋弛緩・尿失禁、15秒以上で痙攣を生じる、らしい(参考2)　　←　根拠となる文献を調査中

原因

救急での覚え方

SYNCOPE

situational
vasovagal
neurogenic
cardiac
orthostatic hypotension
psychiatric
everything else

QB.C345

心臓：不整脈(→Adams-Stokes症候群)、大動脈弁狭窄症、閉塞性肥大型心筋症、心筋梗塞、心臓腫瘍、原発性肺高血圧症
心外：

起立性低血圧
局所的脳血流低下：subclavian steal症候群
血管迷走神経反射
循環血液量の一過性の低下：胸腔内圧の上昇(排尿、咳嗽)
過換気症候群：過換気による動脈血炭酸ガス分圧の低下　→　脳血管収縮　→　脳血流が減少

研修医当直御法度症例帳 p.36

		(%)
1	血管迷走神経性失神	39.5
2	体位性低血圧による失神	7.6
3	心血管性失神	4.1
4	目撃者なしの痙攣	8.8
5	低血糖	1.8
6	ヒステリー	0.6
7	原因不明	37.6

参考

1. 失神の診断・治療ガイドライン(2007)

http://www.j-circ.or.jp/guideline/pdf/JCS2007_inoue_h.pdf

2. 失神　国立療養所西札幌病院循環器科別役徹生

http://www.aurora-net.or.jp/life/heart/saizensen/86/index.html

「起立性低血圧」

　　[★]

英: orthostatic hypotension
同: 体位性低血圧 postural hypotension、起立性調節障害 orthostatische dysregulation OD
関: 低血圧、失神

定義

起立により静脈還流が減少し、心拍出量が減少するために血圧が低下する状態

起立して3分以内に収縮期血圧20mmHg以上、拡張期血圧10mmHg以上低下を来す場合 (BAT.916)

分類

本態性起立性低血圧症
二次性起立性低血圧

シャイ・ドレーガー症候群(Shy-Drager syndrome)、糖尿病性自律神経障害、褐色細胞腫、老人性起立性低血圧

病因

起立により静脈系が弛緩することにより低血圧になりやすく、頭部への血液供給のためには血圧を上昇させる必要がある。
種々の原因により、血圧が維持できない時に起立性低血圧を呈する。

自律神経疾患
薬物

antihypertensives, diuretics, vasodilators(nitrates, hydralazine), alpha-blocking agents, beta-blocking agents, CNS sedatives(barbiturates, opiates), tricyclic antidepressants, phonothiazines

症状

参考2

脳の低灌流状態、全身脱力、眩暈・ふらつき感、visual blurringや眼前暗黒感、(重症)失神。まれに狭心痛や梗塞もある。

参考

1. 起立性調節障害 - Mymed

http://www.mymed.jp/di/c8i.html

2. Mechanisms, causes, and evaluation of orthostatic and postprandial hypotension - uptodate [1]

診察

10分間臥位で安静にしてもらい、血圧を測定。その後、起立してもらい、3分以内に血圧を測定する。
立位３分以内に収縮期血圧が20mmHg以上、または拡張期血圧が10mmHg以上低下する場合

「precipitation」

　　[★]

n.

投下、落下。(気)降水/降水量、降雨量。沈積。(理・化)沈殿。(理・化)析出。(生)沈降。
急激、邁進。大騒ぎ、あわてて。軽挙。促進。

the main classes of drugs that may cause orthostatic hypotension are diuretics. however, the precipitation of orthostatic hypotension by medications may also be the first sign of an underlying autonomic disorder.

「incapacitating」

　　[★]

adj.

不自由な、無力な、または無能な

Symptoms of orthostatic hypotension vary in severity from mild to incapacitating.(uptodate)

「postural hypotension」

　　[★] 起立性低血圧 orthostatic hypotension、体位性低血圧

「idiopathic orthostatic hypotension」

　　[★] 特発性起立性低血圧

「orthostatic」

　　[★]

ortho+static

adj.

起立性の

ex.

orthostatic hypotension 起立性低血圧

[1] "Orthostatic hypotension" at Dorland's Medical Dictionary

[2] ttp://emedicine.medscape.com/article/1154266-overview

[3] 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.

[4] "Dopamine Beta-Hydroxylase Deficiency". GeneReviews — NCBI Bookshelf.

[5] "Minute organs in the ear can alter brain blood flow". BBC News. 2009-12-27. Retrieved 2009-12-27.

[Jiang-2005-6] 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.

[Delini-Stula-1999-7] 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.

[Jones-2002-8] Jones RT. (2002). "Cardiovascular system effects of marijuana". J Clin Pharmacol 42 (11 Suppl): 58S–63S. PMID 12412837.

[9] Orthostatic Hypotension at Merck Manual of Diagnosis and Therapy Home Edition

[10] Logan, IC; Witham, MD (2012 Sep). "Efficacy of treatments for orthostatic hypotension: a systematic review.". Age and ageing 41 (5): 587–94. doi:10.1093/ageing/afs061. PMID 22591985. Check date values in: |date= (help)

[pmid21438868-11] 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.

Orthostatic hypotension
Classification and external resources
ICD-10	I95.1
ICD-9	458.0
DiseasesDB	10470
eMedicine	ped/2860
MeSH	D007024

匿名

検索

案内

orthostatic hypotension