Orthostatic hypotension
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{{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>{{Dorlands|h_23|12440366}}</ref>, and, colloquially, as '''head rush''' or a '''dizzy spell''') is a form of [[hypotension]] in which there is a sudden (less than 3 minutes) fall in [[blood pressure]], 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> that occurs when a person assumes a [[standing (position)|standing position]], usually after a prolonged period of rest.
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>
==Symptoms==
Symptoms, which generally occur after sudden standing, include [[dizziness]], lightheadedness, [[headache]], blurred or [[tunnel vision|dimmed vision]] (possibly to the point of momentary [[blindness]]), generalized (or extremity) [[numbness]]/[[tingling]] and [[fainting]], and in rare, extreme cases, [[vasovagal syncope]]. They are consequences of insufficient [[blood pressure]] and [[cerebral]] [[perfusion]] (blood supply).
==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 subsequently 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 although there is a decreased [[systolic blood pressure|systolic (contracting) blood pressure]], there is actually an increased [[diastolic blood pressure|diastolic (resting) blood pressure]]. However, 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>[http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=search&term=harnesses%20hypotension Suspension trauma. Lee C, Porter KM.]</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 [[Shy-Drager syndrome]] 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.
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]],{{Fact|date=July 2008}} which results from [[cerebrospinal fluid]] leakage. It affects women more than men and peaks at ages between 40 to 50.
===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}}</ref> It is also a side effect of the short-term use of [[cannabis (drug)|marijuana]].<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>[http://www.merck.com/mmhe/sec03/ch023/ch023c.html Orthostatic Hypotension: Low Blood Pressure: Merck Manual Home Edition<!-- Bot generated title -->]</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.
Consuming alcohol may also lead to orthostatic hypotension due to its dehydrating effects on the body.
==Treatment and management==
There are medications to treat hypotension. In addition, there are many lifestyle advices. Many of them, however, are specific for a certain cause of orthostatic hypotension.
===Medical management===
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}}.</ref> Beta blockers such as [[Metoprolol]] succinate (Toprol-XL) may also be used.
[[Selective serotonin reuptake inhibitors|Selective Serotonin reuptake inhibitors]] (SSRI's) and [[Serotonin-norepinephrine reuptake inhibitor]]s (SNRI's) are helpful in many patients. Sometimes stimulant drugs such as Adderall or Ritalin can be of assistance. [[Benzodiazepenes]] are commonly prescribed as well.
===Lifestyle advice===
{{Unreferencedsection|date=October 2007}}
Some suggestions for minimizing the effects include:
* Standing 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, eat multiple smaller meals rather than fewer larger 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.
==Prognosis==
The prognosis for individuals with orthostatic hypotension depends on the underlying cause of the condition.
==See also==
* [[Orthostatic intolerance]]
==References==
{{reflist|2}}
==External links==
* John G. Bradley, M.D., and Kathy A. Davis, R.N. ''Orthostatic Hypotension'' [http://www.aafp.org/afp/20031215/2393.html American Family Physician]
* 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]
* {{MerckManual|16|200|a}}
{{Vascular diseases}}
[[Category:Cardiology]]
[[de:Orthostatische Hypotonie]]
[[es:Hipotensión ortostática]]
[[fr:Hypotension orthostatique]]
[[nl:Orthostatische hypotensie]]
[[ja:起立性低血圧]]
[[ru:Ортостатический коллапс]]