View source for Orthostatic hypotension

{{Infobox Disease |
  Name           = Orthostatic hypotension |
  Image          = |
  Caption        = |
  DiseasesDB     = 10470 |
  ICD10          = {{ICD10|I|95|1|i|95}} |
  ICD9           = {{ICD9|458.0}} |
  ICDO           = |
  OMIM           = |
  MedlinePlus    = |
  eMedicineSubj  = ped |
  eMedicineTopic = 2860 |
  MeshID         = D007024 |
}}

'''Orthostatic hypotension''', also known as '''postural hypotension''',<ref>{{DorlandsDict|nine/100012758|Orthostatic hypotension}}</ref>, orthostasis, and colloquially as '''head rush''' or a '''dizzy spell''', is a form of [[hypotension]] in which a person's [[blood pressure]] suddenly falls when the person stands up. The decrease is typically greater than 20/10 [[mm Hg]],<ref name="pmid18091397">{{cite journal |author=Medow MS, Stewart JM, Sanyal S, Mumtaz A, Sica D, Frishman WH |title=Pathophysiology, diagnosis, and treatment of orthostatic hypotension and vasovagal syncope |journal=[[Cardiol Rev]] |volume=16 |issue=1 |pages=4–20 |year=2008 |pmid=18091397 |doi=10.1097/CRD.0b013e31815c8032 |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?an=00045415-200801000-00002}}</ref> and may be most pronounced after resting. The incidence increases with age.<ref name="pmid17976425">{{cite journal |author=Shibao C, Grijalva CG, Raj SR, Biaggioni I, Griffin MR |title=Orthostatic hypotension-related hospitalizations in the United States |journal=[[Am. J. Med.]] |volume=120 |issue=11 |pages=975–80 |year=2007 |pmid=17976425 |doi=10.1016/j.amjmed.2007.05.009 |url=http://linkinghub.elsevier.com/retrieve/pii/S0002-9343(07)00655-9}}</ref>

==Signs and symptoms==
Symptoms, which generally occur after sudden standing or stretching (after standing), include [[dizziness]], euphoria, bodily dissociation, distortions in hearing,  lightheadedness, nausea, [[headache]], blurred or [[tunnel vision|dimmed vision]] (possibly to the point of momentary [[blindness]]), generalized (or extremity) [[numbness]]/[[tingling]] and [[fainting]], coat hanger pain (pain centered in the neck and shoulders), and in rare, extreme cases, [[vasovagal syncope]]. 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.

==Causes==
Orthostatic hypotension is primarily caused 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, if a person changes from a lying position to standing, he or she will lose about 700 [[litre|ml]] of blood from the [[thorax]]. It can also be noted that there is a decreased [[systolic blood pressure|systolic (contracting) blood pressure]] and a decreased [[diastolic blood pressure|diastolic (resting) blood pressure]].<ref>[http://emedicine.medscape.com/article/1154266-overview]</ref> 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.  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.<ref>{{cite journal |author=Lee C, Porter KM |title=Suspension trauma |journal=Emerg Med J. |volume=24 |issue=4 |pages=237–8 |year=2007 |month=Apr |pmid=17384373 |doi=10.1136/emj.2007.046391 |url= |pmc=2658225}}</ref>

===Hypovolemia===
Orthostatic hypotension may be caused by [[hypovolemia]] (a decreased amount of [[blood]] in the body), resulting from bleeding, the excessive use of [[diuretic]]s, [[vasodilator]]s, or other types of drugs, [[dehydration]], or prolonged [[bed rest]]. It also occurs in people with [[anemia]].

===Diseases===
The disorder may be associated with [[Addison's disease]], [[atherosclerosis]] (build-up of fatty deposits in the arteries), [[diabetes]], [[pheochromocytoma]], and certain [[neurology|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 (medicine)|syncope]] unless the patient has developed true [[autonomic nervous system|autonomic]] failure or has an unrelated cardiac problem.

Another disease is called [[dopamine beta hydroxylase deficiency]], that is thought to be underdiagnosed also, that causes loss of sympathetic noradrenergic function and is characterized by a low or extremely low levels of norepinephrine but an excess of dopamine.<ref>{{cite web |url=http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=dbh#dbh |title=Dopamine Beta-Hydroxylase Deficiency |work=GeneReviews — NCBI Bookshelf  |accessdate=}}</ref>

It is a symptom that quadriplegics and paraplegics might experience 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 that is suspected to be closely related to orthostatic hypotension is [[spontaneous intracranial hypotension]],{{Citation needed|date=July 2008}} which results from [[cerebrospinal fluid]] leakage. It affects women more than men and peaks at ages between 40 to 50.

A study by a [[Harvard Medical School]] team found that two sacs in the [[inner ear]], the [[utricle (ear)|utricle]] and the [[saccule]], affect brain blood flow; thus inner ear problems, which increase with old age, may be involved in orthostatic hypotension.<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/health/8268336.stm|title=Minute organs in the ear can alter brain blood flow|work=[[BBC News]]|accessdate=2009-12-27 | date=2009-12-27}}</ref>

===Medication===
Orthostatic hypotension can be a side effect of certain [[anti-depressants]], such as [[tricyclics]]<ref name="Jiang-2005">{{cite journal | author=Jiang W, Davidson JR. | title=Antidepressant therapy in patients with ischemic heart disease. | journal=Am Heart J | year=2005 | volume=150 | issue=5 | pages=871–81 | pmid=16290952 | doi=10.1016/j.ahj.2005.01.041}}</ref> or [[MAOIs]].<ref name="Delini-Stula-1999">{{cite journal | author=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 | year=1999 | volume=32 | issue=2 | pages=61–7 | pmid=10333164 | doi=10.1055/s-2007-979193}}</ref>.<ref name="Jones-2002">{{cite journal | author=Jones RT. | title=Cardiovascular system effects of marijuana. | journal=J Clin Pharmacol | year=2002 | volume=42 | issue=11 Suppl | pages=58S–63S | pmid=12412837}}</ref> Orthostatic hypotension can also be a side effect of alpha<sub>1</sub> adrenergic blocking agents.  Alpha<sub>1</sub> blockers inhibit vasoconstriction normally initiated by the [[baroreceptor reflex]] upon postural change and the subsequent drop in pressure.<ref>{{MerckHome|03|023|c||Orthostatic Hypotension}}</ref>

===Harnesses===
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 risk factors===
Patients who are prone to orthostatic hypotension are the elderly, [[postpartum]] mothers, those who have been on bedrest and teenagers because of their large amounts of growth in a short period of time. People suffering from [[anorexia nervosa]] and [[bulimia nervosa]] often suffer from orthostatic hypotension and it is a common side effect of these mental illnesses. Certain recreational drugs such as cannabis or opioids may cause a head rush.
Consuming alcohol may also lead to orthostatic hypotension due to its dehydrating effects on the body.

==Diagnosis==
A simple test for OH measures the person's blood pressure while seated or reclining at rest, and again upon [[standing (position)|standing up]].  A sudden, significant fall in blood pressure upon standing indicates orthostatic hypotension.  Blood pressure may drop immediately upon standing, or any time during the first couple of minutes after standing.  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==
There are medications to treat hypotension. In addition there are several lifestyle issues, which however are most often specific to a certain cause of orthostatic hypotension.

===Medical===
Some drugs that are used in the treatment of orthostatic hypotension include [[fludrocortisone]] (Florinef) and [[erythropoietin]] to aid in fluid retention, and vasoconstrictors like [[midodrine]]. [[Pyridostigmine bromide]] (Mestinon) is also now used to treat the condition.<ref name="Singer-2003">{{cite journal | author=Singer W, Opfer-Gehrking TL, McPhee BR, Hilz MJ, Bharucha AE, Low PA. | title=Acetylcholinesterase inhibition: a novel approach in the treatment of neurogenic orthostatic hypotension. | journal=J Neurol Nosurg Psychiatry | year=2003 | volume=74 | issue=9 | pages=1294–8 | pmid=12933939 | doi=10.1136/jnnp.74.9.1294 | pmc=1738643}}.</ref> 
[[Selective serotonin reuptake inhibitors]] (SSRI's) and [[serotonin-norepinephrine reuptake inhibitor]]s (SNRI's) are helpful in many patients.{{Citation needed|date=April 2009}} Sometimes stimulant drugs such as Adderall or Ritalin can be of assistance. [[benzodiazepines]] are commonly prescribed as well.

===Lifestyle advice===
Some suggestions for minimizing the effects include:

* Standing up slowly rather than quickly, as the delay can give the blood vessels more time to constrict properly. This can help avoid incidents of [[fainting|syncope]] (fainting).
* Take a deep breath and flex your abdominal muscles while rising to maintain blood and oxygen in the brain. This, however, may be contraindicated in individuals with [[hypertension|Stage 2 hypertension]]. Usually medical personnel have their patients "dangle" before rising from bed to decrease the likelihood of dizziness/falling due to orthostatic hypotension. The dangling is done by having the patient sit on the side of their bed for about a minute so they do not have the sudden dizziness. 
* Maintaining an elevated salt intake, through sodium supplements or electrolyte-enriched drinks. A suggested value is 10 g per day; overuse can lead to hypertension and should be avoided.
* Maintaining a proper fluid intake to prevent the effects of dehydration.
* As eating lowers blood pressure, take your food in a larger number of smaller meals. Take extra care when standing after eating.
* When orthostatic hypotension is caused by hypovolemia due to medications, the disorder may be reversed by adjusting the dosage or by discontinuing the medication. 
* When the condition is caused by prolonged bed rest, improvement may occur by sitting up with increasing frequency each day. In some cases, physical counterpressure such as elastic [[Hose (clothing)|hose]] ([[stockings]]) or whole-body inflatable suits may be required.
* Many people who experience orthostatic hypotension are able to recognise the symptoms and quickly adopt a "squat position" to avoid falling during an episode. This is because they are usually unable to co-ordinate a return to sitting in a chair, once the episode has commenced.
* Avoiding bodily positions that impede blood flow, such as sitting with knees up to chest or crossing legs.

==Prognosis==
The prognosis for individuals with orthostatic hypotension depends on the underlying cause of the condition.

==See also==
* [[Orthostatic intolerance]]

==References==
;Notes
{{reflist|2}}

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{{refimprove|date=October 2007}}

==External links==
* {{cite journal |author=Bradley JG, Davis KA |title=Orthostatic hypotension |journal=Am Fam Physician. |volume=68 |issue=12 |pages=2393–8 |year=2003 |month=Dec |pmid=14705758 |doi= |url=http://www.aafp.org/afp/20031215/2393.html}}
* DYNA [http://www.dynakids.org Dysautonomia Youth Network of America, Inc.]
* [http://www.dinet.org Dysautonomia Information Network]
* [http://www.supportdysautonomia.org Dysautonomia Support Network]
* [http://www.wrongdiagnosis.com/o/orthostatic_hypotension/causes.htm Drugs that cause Orthostatic hypotension] - wrongdiagnosis.com
* Timothy C. Hain, MD. [http://www.dizziness-and-balance.com/disorders/medical/orthostatic.html  Orthostatic hypotension]

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{{Autonomic diseases}}
{{Vascular diseases}}

[[Category:Cardiology]]
[[Category:Hypotension]]

[[de:Orthostatische Hypotonie]]
[[et:Ortostaatiline hüpotensioon]]
[[es:Hipotensión ortostática]]
[[fr:Hypotension orthostatique]]
[[nl:Orthostatische hypotensie]]
[[ja:起立性低血圧]]
[[pl:Hipotonia ortostatyczna]]
[[ru:Ортостатический коллапс]]
[[zh:姿位性低血壓/temp]]
[[Category:2Fix]]