関: orthostatic dysregulation

WordNet

impatience with annoyances; "his intolerance of interruptions"
unwillingness to recognize and respect differences in opinions or beliefs
pertaining to an upright standing posture; "orthostatic hypotension"

PrepTutorEJDIC

〈U〉(宗教・意見・習慣の相違について)偏狭で認めないこと / 〈U〉(寒暑・痛みなどに)耐えられないこと;〈C〉過敏症

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/09/21 12:18:47」(JST)

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Orthostatic intolerance (OI) is the development of symptoms when standing upright which are relieved when sitting back down again.^[1] There are many types of orthostatic intolerance. OI can be a subcategory of dysautonomia, a disorder of the autonomic nervous system^[2] occurring when an individual stands up.^[3]

It affects more women than men (female-to-male ratio is at least 4:1), usually under the age of 35.^[4] Up to 97% of those who have chronic fatigue syndrome (CFIDS) have been said been shown in studies to have some form of OI. ^[5]

Orthostatic intolerance occurs in humans because standing upright is a fundamental stressor and requires rapid and effective circulatory and neurologic compensations to maintain blood pressure, cerebral blood flow, and consciousness. When a human stands, approximately 750 mL of thoracic blood is abruptly translocated downward. People who suffer from OI lack the basic mechanisms to compensate for this deficit.^[1] Changes in heart rate, blood pressure, and cerebral blood flow that produce OI may be caused by abnormalities in the interactions between blood volume control, the cardiovascular system, the nervous system and circulation control systems.^[6]

Triggers[edit source | edit]

Symptoms of OI are triggered by the following:

An upright posture for long periods of time (e.g. standing in line, standing in a shower, or even sitting at a desk).
A warm environment (such as in hot summer weather, a hot crowded room, a hot shower or bath, after exercise).
Emotionally stressful events (seeing blood or gory scenes, being scared or anxious).
Astronauts returning from space not yet re-adapted to gravity.^[7]
Extended bedrest^[7]
Inadequate fluid and salt intake.^[8]

Symptoms[edit source | edit]

Orthostatic intolerance is divided, roughly based on patient history, in two variants: acute and chronic.

Acute OI[edit source | edit]

Patients who suffer from acute OI usually manifest the disorder by a temporary loss of consciousness and posture, with rapid recovery (simple faints, or syncope), as well as remaining conscious during their loss of posture. This is different than a syncope caused by cardiac problems because there are known triggers for the fainting spell (standing, heat, emotion) and identifiable prodromal symptoms (nausea, blurred vision, headache). As Dr. Julian M. Stewart, an expert in OI from New York Medical College states, "Many syncopal patients have no intercurrent illness; between faints, they are well."^[1]

Symptoms:^[6]

Lightheadedness
Headache
Fatigue
Altered vision (blurred vision, "white outs," black outs)
Weakness
Hyperpnea or sensation of difficulty breathing or swallowing (see also hyperventilation syndrome)
Tremulousness
Sweating
Anxiety
Heart palpitations, as the heart races to compensate for the falling blood pressure
Exercise intolerance

A classic manifestation of acute OI is a soldier who faints after standing rigidly at attention for an extended period of time.

Chronic OI[edit source | edit]

Patients with chronic orthostatic intolerance have symptoms on most or all days. Their symptoms may include most of the symptoms of acute OI, plus:

Sensitivity to heat
Nausea
Neurocognitive deficits, such as attention problems
Sleep problems
Pallor
Other vasomotor symptoms.^[1]

Diagnosis[edit source | edit]

OI is "notoriously difficult to diagnose."^[9] As a result, many patients have gone undiagnosed or misdiagnosed and either untreated or treated for other disorders. Current tests for OI (Tilt table test, autonomic assessment, and vascular integrity) can also specify and simplify treatment.^[6] (See Dr. Julian Stewart's article, "Orthostatic Intolerance: An Overview" for a more detailed description of OI tests.)

Management and prognosis[edit source | edit]

Most patients experience an improvement of their symptoms, but for some, OI can be gravely disabling and can be progressive in nature, particularly if it is caused by an underlying condition which is deteriorating. The ways in which symptoms present themselves vary greatly from patient to patient; as a result, individualized treatment plans are necessary.^[10]

OI is treated both pharmacologically and non-pharmacologically. Treatment does not cure OI; rather, it controls symptoms.

Physicians who specialize in treating OI agree that the single most important treatment is drinking more than two liters (eight cups) of fluids each day. A steady, large supply of water or other fluids reduces most, and for some patients all, of the major symptoms of this condition. Typically, patients fare best when they drink a glass of water no less frequently than every two hours during the day, instead of drinking a large quantity of water at a single point in the day.^[8]

For most severe cases and some milder cases, a combination of medications are used. Individual responses to different medications vary widely, and a drug which dramatically improves one patient's symptoms may make another patient's symptoms much worse. Medications focus on three main issues:^[8]

Medications that increase blood volume:

Fludrocortisone (Florinef)
Erythropoietin
Hormonal contraception

Medications that inhibit acetylcholinesterase:

Pyridostigmine

Medications that improve vasoconstriction:

Stimulants: (e.g., Ritalin or Dexedrine)
Midodrine (Proamatine)
Ephedrine and pseudoephedrine (Sudafed)
Theophylline (low-dose)
Selective serotonin reuptake inhibitors (Prozac, Zoloft, and Paxil)

Behavioral changes that patients with OI can make are:

avoiding triggers such as prolonged sitting, quiet standing, warm environments, or vasodilating medications
using postural maneuvers and pressure garments
treating co-existing medical conditions
increasing salt and fluid intake
physical therapy and exercise^[8]

Famous patients[edit source | edit]

A notable sufferer of orthostatic intolerance is Greg Page, from The Wiggles. It is due to this illness that Greg chose to leave the group in 2006.^[9]^[11] He went on to create his own fund for OI, to help fund research into this little known disorder. ^[12] Greg recovered sufficiently to announce his return to The Wiggles in 2012. ^[13]

References[edit source | edit]

^ ^a ^b ^c ^d Julian M. Stewart. "Orthostatic Intolerance: An overview". WebMD. Retrieved 2007-08-20.
^ "What is dysautonomia?". National Dysautonomia Research Foundation (NDRF). Retrieved 2007-08-20.
^ Definition at Dorland's Illustrated Medical Dictionary Retrieved through web archive on 2008-10-09.
^ "Vanderbilt autonomic dysfunction center". Vanderbilt Medical Center. Retrieved 2007-08-20.
^ http://www.cfids.org/about-cfids/orthostatic-intolerance.asp
^ ^a ^b ^c Julian M. Stewart. "Orthostatic Intolerance". New York Medical College. Retrieved 2007-08-20.
^ ^a ^b Joyner MJ, Masuki S (December 2008). "POTS versus deconditioning: the same or different?". Clin. Auton. Res. 18 (6): 300–7. doi:10.1007/s10286-008-0487-7. PMID 18704621.
^ ^a ^b ^c ^d Peter C. Rowe. "General information brochure on Orthostatic Intolerance and its treatment". The Pediatric Network. Archived from the original on 2007-07-28. Retrieved 2007-08-21.
^ ^a ^b "Greg Page leaves the Wiggles". The Wiggles Home Page. Retrieved 2007-08-21.
^ "National Dysautonomia Research Foundation". National Dysautonomia Research Foundation (NDRF). Retrieved 2007-08-21.
^ Maddox, Greg. "Life without a skivvie". The Sydney Morning Herald Online. Retrieved 2008-11-29.
^ http://www.bakeridi.edu.au/support/greg_page_fund/
^ "Original Yellow Wiggle Greg Page gets his skivvy back". The Daily Telegraph. 2012-01-18.

UpToDate Contents

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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. 体位性頻脈症候群 postural tachycardia syndrome
3. 起立性低血圧および食後低血圧の治療 treatment of orthostatic and postprandial hypotension
4. 小児や青年の失神の原因 causes of syncope in children and adolescents
5. 糖尿病性自律神経障害 diabetic autonomic neuropathy

English Journal

Increasing orthostatic stress impairs neurocognitive functioning in chronic fatigue syndrome with postural tachycardia syndrome.

Ocon AJ, Messer ZR, Medow MS, Stewart JM.SourceDepartment of Physiology, New York Medical College, Valhalla, NY, USA. anthony_ocon@nymc.edu
Clinical science (London, England : 1979).Clin Sci (Lond).2012 Mar 1;122(5):227-38.
CFS (chronic fatigue syndrome) is commonly co-morbid with POTS (postural tachycardia syndrome). Individuals with CFS/POTS experience unrelenting fatigue, tachycardia during orthostatic stress and ill-defined neurocognitive impairment, often described as 'mental fog'. We hypothesized that orthostatic
PMID 21919887

Neurohumoral and haemodynamic profile in postural tachycardia and chronic fatigue syndromes.

Okamoto LE, Raj SR, Peltier A, Gamboa A, Shibao C, Diedrich A, Black BK, Robertson D, Biaggioni I.SourceVanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN, U.S.A.
Clinical science (London, England : 1979).Clin Sci (Lond).2012 Feb;122(4):183-92. doi: 10.1042/CS20110200.
Several studies recognized an overlap between CFS (chronic fatigue syndrome) and POTS (postural tachycardia syndrome). We compared the autonomic and neurohormonal phenotype of POTS patients with CFS (CFS-POTS) to those without CFS (non-CFS-POTS), to determine whether CFS-POTS represents a unique cli
PMID 21906029

Japanese Journal

宇宙環境が循環調節に及ぼす影響とその要因解明へのアプローチ : 衛生学における実験的研究の観点から

青木健,小川洋二郎,岩崎賢一,向井千秋
日本衞生學雜誌 66(3), 568-572, 2011-05-15
… Many physiological changes associated with spaceflight, including decreases in orthostatic tolerance, exercise capacity, and blood volume have been reported. … Orthostatic intolerance is a problem affecting many astronauts immediately postspaceflight. … In particular, the relationship between orthostatic intolerance and cerebral autoregulation has been the focus of study in our research group. …
NAID 10029364318

起立性調節障害は起立時の下大静脈径の変化から2タイプに分類される

藤井由里,ISHIZAKI Yuko,KINO Minoru,TANIUCHI Shoichiro,KOBAYASHI Yohnosuke,KANEKO Kazunari
Pediatrics international : official journal of the Japan Pediatric Society 53(2), 162-167, 2011-04-01
NAID 10029557575