| 词条 | Orthostatic hypotension |
| 释义 |
| name = Orthostatic hypotension | synonyms = Orthostasis, postural, positional hypotension | image = | caption = | field = Cardiology | pronounce = {{IPAc-en|ˌ|ɔr|θ|ə|ˈ|s|t|æ|t|ɪ|k|ˌ|h|aɪ|p|ə|ˈ|t|ɛ|n|ʃ|ə|n}} | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }} Orthostatic hypotension, also known as postural hypotension,[1] occurs when a person's blood pressure falls when suddenly standing up from a lying or sitting position.[2] 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. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain an adequate blood pressure when changing position to standing. As a result, blood pools in the blood vessels of the legs for a longer period and less is returned to the heart, thereby leading to a reduced cardiac output. Mild orthostatic hypotension is common and can occur briefly in anyone, although it is prevalent in particular among the elderly and those with known low blood pressure. Severe drops in blood pressure can lead to fainting, with a possibility of injury. There are numerous possible causes for orthostatic hypotension, such as certain medications (e.g. alpha blockers), autonomic neuropathy, decreased blood volume, and age-related blood vessel stiffness. Apart from addressing the underlying cause, orthostatic hypotension may be treated with a recommendation to increase salt and water intake (to increase the blood volume), wearing compression stockings, and sometimes medication (fludrocortisone, midodrine or others). Signs and symptomsOrthostatic hypotension is characterized by symptoms that occur after standing (from lying or sitting), particularly when this is done rapidly. Many report lightheadedness (a feeling that one might be about to faint), sometimes severe. Generalized weakness or tiredness may also occur. Some also report difficulty concentrating, blurred vision, tremulousness, vertigo, anxiety, palpitations (awareness of the heartbeat), feeling sweaty or clammy, and sometimes nausea. A person may look pale.[3] Associated diseasesThe disorder may be associated with Addison's disease, atherosclerosis (build-up of fatty deposits in the arteries), diabetes, pheochromocytoma, porphyria,[4] and certain neurological disorders, including multiple system atrophy and other forms of dysautonomia. It is also associated with Ehlers–Danlos syndrome and anorexia nervosa. 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.{{citation needed|date=October 2016}} 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.[5] 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.{{citation needed|date=October 2016}} CausesSome causes of orthostatic hypotension include: low blood volume (e.g. caused by dehydration, bleeding, or the use of diuretics), drugs that causes vasodilation, other types of drugs, discontinuation of vasoconstrictors, prolonged bed rest (immobility), significant recent weight loss, anemia,[6] or recent bariatric surgery.[7] MedicationOrthostatic hypotension can be a side-effect of certain antidepressants, such as tricyclics[8] or monoamine oxidase inhibitors (MAOIs).[9] Marijuana and tetrahydrocannabinol can on occasion produce marked orthostatic hypotension.[10] Alcohol can potentiate orthostatic hypotension to the point of syncope.[11] 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.[12] Other factorsPatients 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 | date=April 2015}} MechanismOrthostatic hypotension happens when gravity causes blood to pool 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.[13] The overall effect is an insufficient blood perfusion in the upper part of the body.{{citation needed|date=March 2017}} Normally, a series of cardiac, vascular, neurologic, muscular, and neurohumoral responses occur quickly so the blood pressure does not fall very much. One response is 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 the horizontal position.) Therefore, some factor that inhibits one of these responses and causes a greater than normal fall in blood pressure is required. Such factors include low blood volume, diseases, and medications.{{citation needed|date=October 2016}} DiagnosisOrthostatic hypotension can be confirmed by measuring a person's blood pressure after lying flat for 5 minutes, then 1 minute after standing, and 3 minutes after standing.[14] 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.[15] DefinitionOrthostatic hypotension (or postural hypotension) is a drop in blood pressure upon standing. One definition (AAFP) calls for a systolic blood pressure decrease of at least 20 mm Hg or a diastolic blood pressure decrease of at least 10 mm Hg within three minutes of standing.[16] It is not a disease, but a physical finding. It may or may not be associated with symptoms (or disease), but a common first symptom is lightheadedness upon standing, possibly followed by more severe symptoms: narrowing or loss of vision, dizziness, weakness, and even syncope (fainting). SubcategoriesOrthostatic hypotension can be subcategorized into three groups: initial, 'classic', and delayed.[17][18][19] Initial orthostatic hypotension is frequently characterized by a systolic blood pressure decrease of ≥40 mmHg and/or diastolic blood pressure decrease of ≥20 mmHg within 15 seconds of standing.[17] Blood pressure then spontaneously and rapidly returns to normal, so the period of hypotension and symptoms is short (<30 s).[17] Only continuous beat-to-beat BP measurement during an active standing-up maneuver can document this condition.[17] 'Classic' orthostatic hypotension is frequently characterized by a systolic blood pressure decrease of ≥20 mmHg and/or diastolic blood pressure decrease of ≥10 mmHg between 30 seconds and 3 min of standing.[18] Delayed orthostatic hypotension is frequently characterized a sustained systolic blood pressure decrease of ≥20 mm Hg or a sustained diastolic blood pressure decrease ≥10 mm Hg beyond 3 minutes of standing or upright tilt table testing.[19] ManagementLifestyle changesApart from treating underlying reversible causes (e.g., stopping or reducing certain medications), there are a number of measures that can improve the symptoms of orthostatic hypotension and prevent episodes of syncope. Even small increases in the blood pressure may be sufficient to maintain blood flow to the brain on standing.[18] In people who do not have a diagnosis of high blood pressure, drinking 2–3 liters of fluid a day and taking 10 grams of salt can improve symptoms, by maximizing the amount of fluid in the bloodstream.[18] Another strategy is keeping the head of the bed slightly elevated. This reduces the return of fluid from the limbs to the kidneys at night, thereby reducing nighttime urine production and maintaining fluid in the circulation.[18] Various measures can be used to improve the return of blood to the heart: the wearing of compression stockings and exercises ("physical counterpressure manoeuvres" or PCMs) that can be undertaken just before standing up (e.g., leg crossing and squatting).[18] MedicationsThe medication midodrine can benefit people with orthostatic hypotension,[18][20] The main side-effect is piloerection ("goose bumps").[20] Fludrocortisone is also used, although based on more limited evidence.[18] A number of other measures have slight evidence to support their use indomethacin, fluoxetine, dopamine antagonists, metoclopramide, domperidone, monoamine oxidase inhibitors with tyramine (can produce severe hypertension), oxilofrine, potassium chloride, and yohimbine.[21] PrognosisOrthostatic hypotension may cause accidental falls.[22] It is also linked to an increased risk of cardiovascular disease, heart failure, and stroke.[23] There is also observational data suggesting that orthostatic hypotension in middle age increases the risk of eventual dementia and reduced cognitive function.[24] See also
References1. ^{{DorlandsDict|nine/100012758|Orthostatic hypotension}} 2. ^{{Cite web|url=https://www.ninds.nih.gov/disorders/all-disorders/orthostatic-hypotension-information-page|title=Orthostatic Hypotension Information Page {{!}} National Institute of Neurological Disorders and Stroke|website=www.ninds.nih.gov|access-date=2017-03-26}} 3. ^{{cite book |vauthors=Kasper DL, Fauci AS, Hauser SL, Longo DL, James JL, Loscalzo J |title=Harrison's principles of internal medicine |publisher=McGraw-Hill Medical Publishing Division |location=New York |year=2015 |edition=19th |isbn=978-0-07-180215-4 | volume=2 | page=2639}} 4. ^{{cite journal | vauthors = Sim M, Hudon R | title = Acute intermittent porphyria associated with postural hypotension | journal = Canadian Medical Association Journal | volume = 121 | issue = 7 | pages = 845–6 | date = October 1979 | pmid = 497968 | pmc = 1704473 }} 5. ^{{cite book | vauthors = Robertson D, Garland EM | chapter = Dopamine Beta-Hydroxylase Deficiency | date = September 2003 | pmid = 20301647 | url = https://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=dbh#dbh | publisher = University of Washington, Seattle | veditors = Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJ, Stephens K, Amemiya A | title = GeneReviews | via = NCBI Bookshelf }} 6. ^{{cite web|title=What Causes Hypotension? - |url=https://www.nhlbi.nih.gov/health/health-topics/topics/hyp/causes|work = National Heart, Lung, and Blood Institute (NHLBI) | publisher = U.S. National Institutes of Health |access-date=27 March 2017 }} 7. ^{{cite journal | vauthors = Christou GA, Kiortsis DN | title = The effects of body weight status on orthostatic intolerance and predisposition to noncardiac syncope | journal = Obesity Reviews | volume = 18 | issue = 3 | pages = 370–379 | date = March 2017 | pmid = 28112481 | doi = 10.1111/obr.12501 }} 8. ^{{cite journal | vauthors = Jiang W, Davidson JR | title = Antidepressant therapy in patients with ischemic heart disease | journal = American Heart Journal | volume = 150 | issue = 5 | pages = 871–81 | date = November 2005 | pmid = 16290952 | doi = 10.1016/j.ahj.2005.01.041 }} 9. ^{{cite journal | vauthors = Delini-Stula A, Baier D, Kohnen R, Laux G, Philipp M, Scholz HJ | title = Undesirable blood pressure changes under naturalistic treatment with moclobemide, a reversible MAO-A inhibitor--results of the drug utilization observation studies | journal = Pharmacopsychiatry | volume = 32 | issue = 2 | pages = 61–7 | date = March 1999 | pmid = 10333164 | doi = 10.1055/s-2007-979193 }} 10. ^{{cite journal | vauthors = Jones RT | title = Cardiovascular system effects of marijuana | journal = Journal of Clinical Pharmacology | volume = 42 | issue = S1 | pages = 58S–63S | date = November 2002 | pmid = 12412837 | doi = 10.1002/j.1552-4604.2002.tb06004.x }} 11. ^{{cite journal | vauthors = Narkiewicz K, Cooley RL, Somers VK | title = Alcohol potentiates orthostatic hypotension : implications for alcohol-related syncope | journal = Circulation | volume = 101 | issue = 4 | pages = 398–402 | date = February 2000 | pmid = 10653831 | url = http://circ.ahajournals.org/cgi/pmidlookup?view=long&pmid=10653831 | doi = 10.1161/01.CIR.101.4.398 }} 12. ^{{cite web | vauthors = Shea MJ, Thompson AD | title = Orthostatic Hypotension | url = https://www.msdmanuals.com/professional/cardiovascular-disorders/symptoms-of-cardiovascular-disorders/orthostatic-hypotension | work = Merck Manual }} 13. ^{{EMedicine|article|1154266|Idiopathic Orthostatic Hypotension and other Autonomic Failure Syndromes}} 14. ^{{cite web | url=https://www.cdc.gov/steadi/pdf/measuring_orthostatic_blood_pressure-a.pdf | archive-url = https://web.archive.org/web/20170222020824/https://www.cdc.gov/steadi/pdf/measuring_orthostatic_blood_pressure-a.pdf | archive-date = 22 February 2017 | dead-url = yes | title = Measuring Orthostatic Blood Pressure | work = Stopping Elderly Accidents, Deaths, and Injuries (STEADI) | publisher = Centers for Disease Control and Prevention | access-date=20 December 2014}} 15. ^Natale, A., Akhtar, M., Jazayeri, M., Dhala, A., Blanck, Z., Deshpande, S., et al. (1995). Provocation of Hypotension During Head-Up Tilt Testing in Subjects With No History of Syncope or Presyncop. American Heart Association, (92), 54-58. doi: 10.1161/01.CIR.92.1.54; url: http://circ.ahajournals.org/content/92/1/54.full 16. ^{{cite journal | vauthors = Bradley JG, Davis KA | title = Orthostatic hypotension | journal = American Family Physician | volume = 68 | issue = 12 | pages = 2393–8 | date = December 2003 | pmid = 14705758 | doi = | url = https://www.aafp.org/afp/2003/1215/p2393.html }} 17. ^1 2 3 {{cite journal | vauthors = Wieling W, Krediet CT, van Dijk N, Linzer M, Tschakovsky ME | title = Initial orthostatic hypotension: review of a forgotten condition | journal = Clinical Science | volume = 112 | issue = 3 | pages = 157–65 | date = February 2007 | pmid = 17199559 | doi = 10.1042/CS20060091 }} 18. ^1 2 3 4 5 6 7 {{cite journal | vauthors = Moya A, Sutton R, Ammirati F, Blanc JJ, Brignole M, Dahm JB, Deharo JC, Gajek J, Gjesdal K, Krahn A, Massin M, Pepi M, Pezawas T, Ruiz Granell R, Sarasin F, Ungar A, van Dijk JG, Walma EP, Wieling W | title = Guidelines for the diagnosis and management of syncope (version 2009) | journal = European Heart Journal | volume = 30 | issue = 21 | pages = 2631–71 | date = November 2009 | pmid = 19713422 | pmc = 3295536 | doi = 10.1093/eurheartj/ehp298 }} 19. ^1 {{cite journal | vauthors = Gibbons CH, Freeman R | title = Delayed orthostatic hypotension: a frequent cause of orthostatic intolerance | journal = Neurology | volume = 67 | issue = 1 | pages = 28–32 | date = July 2006 | pmid = 16832073 | doi = 10.1212/01.wnl.0000223828.28215.0b }} 20. ^1 {{cite journal | vauthors = Izcovich A, González Malla C, Manzotti M, Catalano HN, Guyatt G | title = Midodrine for orthostatic hypotension and recurrent reflex syncope: A systematic review | journal = Neurology | volume = 83 | issue = 13 | pages = 1170–7 | date = September 2014 | pmid = 25150287 | doi = 10.1212/WNL.0000000000000815 }} 21. ^{{cite journal | vauthors = Logan IC, Witham MD | title = Efficacy of treatments for orthostatic hypotension: a systematic review | journal = Age and Ageing | volume = 41 | issue = 5 | pages = 587–94 | date = September 2012 | pmid = 22591985 | doi = 10.1093/ageing/afs061 }} 22. ^{{cite journal | vauthors = Romero-Ortuno R, Cogan L, Foran T, Kenny RA, Fan CW | title = Continuous noninvasive orthostatic blood pressure measurements and their relationship with orthostatic intolerance, falls, and frailty in older people | journal = Journal of the American Geriatrics Society | volume = 59 | issue = 4 | pages = 655–65 | date = April 2011 | pmid = 21438868 | doi = 10.1111/j.1532-5415.2011.03352.x | url = http://www.tara.tcd.ie/bitstream/2262/57382/1/Continuous%20noninvasive%20orthostatic%20blood%20pressure%20measurements%20and%20their%20relationship%20with%20orthostatic%20intolerance%2c%20falls%2c%20and%20frailty%20in%20older%20people.pdf }} 23. ^{{cite journal | vauthors = Ricci F, Fedorowski A, Radico F, Romanello M, Tatasciore A, Di Nicola M, Zimarino M, De Caterina R | title = Cardiovascular morbidity and mortality related to orthostatic hypotension: a meta-analysis of prospective observational studies | journal = European Heart Journal | volume = 36 | issue = 25 | pages = 1609–17 | date = July 2015 | pmid = 25852216 | doi = 10.1093/eurheartj/ehv093 }} 24. ^{{cite conference | vauthors = Rawlings A, Juraschek S, Heiss G, Hughes T, Meyer M, Selvin E, Sharrett AR, Windham BG, Gottesman R |title=Orthostatic Hypotension is Associated With 20-year Cognitive Decline and Incident Dementia: the Atherosclerosis Risk in Communities (ARIC) Study |conference=Epidemiology and Prevention / Lifestyle and Cardiometabolic Health 2017 Scientific Sessions |location=Portland, Oregon |date= March 2017 |url=http://professional.heart.org/idc/groups/ahamah-public/@wcm/@sop/@scon/documents/downloadable/ucm_492225.pdf }} External links{{Medical resources| DiseasesDB = 10470 | ICD10 = {{ICD10|I|95|1|i|95}} | ICD9 = {{ICD9|458.0}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = 2860 | MeshID = D007024 }}
3 : Vascular diseases|Hypotension|Peripheral nervous system disorders |
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