Orthostatic hypotension

Definition

Orthostatic hypotension is an abnormal decrease in blood pressure when a person stands up. This may lead to fainting.

Description

When a person stands upright, a certain amount of blood normally pools in the veins of the ankles and legs. This pooling means that there is slightly less blood for the heart to pump and causes a drop in blood pressure. Usually, the body responds to this drop so quickly, a person is unaware of the change. The brain tells the blood vessels to constrict so they have less capacity to carry blood, and at the same time tells the heart to beat faster and harder. These responses last for a very brief time. If the body's response to a change in vertical position is slow or absent, the result is orthostatic hypotension. It is not a true disease, but the inability to regulate blood pressure quickly.

— Dorothy Elinor Stonely

Definition

Orthostatic hypotension refers to a reduction of blood pressure (systolic blood pressure that occurs when the heart contracts) of at lest 20 mmHg or a diastolic pressure (pressure when the heart muscle relaxes) of at least 10 mmHg within three minutes of standing.

Description

Orthostatic hypotension is a decrease of blood pressure when standing, due to changes in the blood pressure regulation systems within the body. Normally in a healthy human there is an orthostatic pooling of venous blood in the abdomen and legs when shifting positions from the supine (lying on the back) to an erect position (standing up). This redistribution of blood flow is the result of normal physiological compensatory mechanisms built into body systems to prevent any adverse outcome (decrease in blood pressure, or hypotension) during positional change. Compensatory mechanisms include sympathetic nervous system activation and parasympathetic inhibition and increased heart rate and vascular resistance. Compensation responses restore cardiac output to vital organs and return blood pressure to normal. Orthostatic hypotension can occur if normal physiological mechanisms become faulty, such as inadequate cardiovascular compensation when shifting positions (i.e. change from supine to erect position), or due to excessive reduction in blood volume. Elderly persons seemed predisposed to orthostatic hypotension because of age-related changes; possible cardiovascular disease and the medications commonly taken by the elderly all predispose autonomic nervous system (ANS) functions. Additionally, hypertension present in 30% of persons over 75 years of age also predisposes a person to orthostatic hypotension, since hypertension reduces baroreflex sensitivity. Hypertension and the normal aging process (which typically causes blood vessel stiffness) decrease the sensitivity of specialized structures called baroreceptors, which function to maintain blood pressure, but initiating compensatory mechanisms such as increasing heart rate and vascular resistance. Persons affected with symptomatic orthostatic hypotension have symptoms when tilting head upward or when moving toward an erect position. Symptom severity varies among affected persons, but can include blurred vision, light-headedness, weakness, vertigo, tremulousness and cognitive impairment. Symptoms can be relieved within one minute of lying down. Some persons have orthostatic hypertension without symptoms.

Demographics

The demographics of orthostatic hypotension are different due to variables that include the subject's position change, the specific population, and when measurements are taken. It is estimated that elderly in community living environments have prevalence rates of approximately 20% among individuals over 65 years of age and 30% in persons over 75 years of age. In frail elderly persons, the prevalence of orthostatic hypotension can be more than 50%. The disorder seems more prevalent among the elderly (especially if systolic blood pressure rises) with chronic diseases (i.e. hypertension and/or diabetes).

Causes and symptoms

Orthostatic hypotension can be caused by several different disorders that affect the entire body (systemic disorders), the central nervous system (CNS, consisting of the brain and spinal cord), and the autonomic nervous system (peripheral autonomic neuropathy) or as a result of taking certain medications that are commonly prescribed by clinicians. Systemic causes can include dehydration, prolonged immobility or an endocrine disorder called adrenal insufficiency. Diseases of the CNS that can cause orthostatic hypotension include MSA (multiple systems atrophy), Parkinson's disease, multiple strokes, brain stem lesions, myelopathy.

Medications that can cause orthostatic hypotension include Tricyclic antidepressants, antipsychotics, monoamine oxidase inhibitors, antihypertensives, diuretics, vasodilators, Levodopa, beta-blockers (heart medications), and blood pressure medications that inhibit a chemical called angiotensin (angiotensin-converting-enzyme inhibitors). Disorders that cause peripheral autonomic neuropathy include diabetes mellitus, amyloidosis, tabes dorsalis (late manifestations of syphilis infection), alcoholism, nutritional deficiency, pure autonomic failure or paraneoplastic syndromes.

The most common symptoms of orthostatic hypotension include weakness, lightheadedness, cognitive impairment, blurred vision, vertigo and tremulousness. Other symptoms that have been reported include headache, paracervical pain, lower back pain, syncope, palpitations, angina pectoris, unsteadiness, falling, and calf claudication.

Diagnosis

It is important that the clinician take numerous blood pressure measurements on different occasions, since blood pressure can vary (i.e. postural hypotension, another disorder causing hypotension, is often worse in the morning when rising from bed). A detailed history and physical examination is important. The clinician should focus medical evaluation on autonomic symptoms and diseases. There are bedside tests that can determine autonomic (baroreceptor) response (i.e. Valsalva maneuver). Measurements of a chemical in blood called norepinephrine while lying down and for five to 10 minutes after standing, can produce some useful information concerning deficits in autonomic nervous system functioning. Additionally, levels of another chemical in blood (called vasopressin) during upright tilting, can help to distinguish if the cause is due to ANS failure or from as a result of MSA. Pure ANS failure is characterized by increased vasopressin levels, whereas patients with MSA have no appreciable increase of vasopressin levels during head tilting.

Treatment team

Primary care practitioner (internist); or in complicated cases (severe orthostatic hypotension) a neurologist is consulted.

Treatment

Nonsymptomatic orthostatic hypotension is a threat for falls or syncope and could be treated by preventive measures that include avoiding warm environments and increasing one's blood pressure by squatting, stooping forward, or crossing one's leg. Additionally, persons affected with the nonsymptomatic variation should increase salt intake, sleep in the head-up position, wear waist-high compression stockings and withdraw from drugs that are known to cause orthostatic hypotension as a side effect. Treatment for symptomatic orthostatic hypotension is important since it is a manifestation of a new illness or as a result of medications. Intervention can initially be nonpharmacologic (preventive measures and adjustments) or pharmacologic therapy. Nonpharmacologic intervention includes a review of medications, since elderly patients may be taking either OTC or prescribed drugs that can induce orthostatic hypotension. Persons affected should rise slowly to the erect position after a long period of sitting or lying down. They should avoid excess heat environments (i.e. in shower or central heating systems), coughing, straining or heavy lifting since these events can precipitate episodes of orthostatic hypotension. There are certain measures that can redirect blood to increase blood pressure and reduce symptoms associated with orthostatic hypotension. These measures include squatting, sitting down, crossing legs, and stooping forward.

Pharmacological Treatment

One of the most commonly prescribed medications for treating orthostatic hypotension is fludrocortisone acetate. This chemical is a synthetic mineralocorticoid which expands circulatory volume. This drug can cause a decrease of an important body element called potassium (hypokalemia, a decrease in potassium in plasma) which is important for normal heart contraction. Elderly persons should be monitored for blood levels of potassium and cardiac status. A drug called midodrine is useful for cases of orthostatic hypotension caused by peripheral autonomic dysfunction, usually in conjunction with fludrocortisone. However, midodrine is not recommended in persons with coronary or peripheral arterial disease. Other medications that may be helpful include clonidine or antihypertension medications. In severe cases of ANS deficits, a combination of medications may be indicated to provide brief periods of upright posture.

Recovery and rehabilitation

The recovery is variable and is also dependent on the cause. Recovery varies according to specific health status of affected person, age complications, and comorbidities (other existing disorders).

Clinical trials

Government-sponsored research includes studies concerning treatment of orthostatic hypotension. Details can be obtained from the website:

Prognosis

Careful evaluation and management is important for outcome. Identifying the source is an important first step. Preventive measures and posture modification techniques and avoidance of triggers can result in significant reduction of falls, fractures, functional decline, and syncope.

Special concerns

Special attention should be given to medications that are prescribed, which may cause orthostatic hypotension as a side effect.

Resources

BOOKS

Goetz, Christopher G., et al, eds. Textbook of Clinical Neurology, 1st ed. Philadelphia: W.B. Saunders Company, 1999.

Marx, John A., et al eds. Rosen's Emergency Medicine: Concepts and Clinical Practice, 5th ed. St. Louis: Mosby, Inc., 2002.

Noble, John., et al eds. Textbook of Primary Care Medicine, 3rd ed. St. Louis: Mosby, Inc., 2001.

PERIODICALS

Mukai, Seiji, and Lewis A. Lipsitz. "Orthostatic Hypotension." Clinics in Geriatric Medicine 18:2: (May 2002).

Viramo, Petteri. "Orthostatic Hypotension and Cognotive Decline in Older People." Journal of the American Geriatrics Society 47:5 (May 1999).

The Consensus Committee of the American Autonomic Society and the American Academy of Neurology. "Consensus statement on the definition of orthostatic hypotension, pure autonomic failure, and multiple system atrophy." Neurology 46:5 (May 1996).

WEBSITES

The Family Practice Notebook.com. Orthostatic Hypotension.http://www.fpnotebook.com.

ORGANIZATIONS

American Academy of Neurology. 1080 Montreal Avenue, Saint Paul, MN 55116. 800-879-1960; Fax: (651) 695-2791. http://www.aan.com.

Laith Farid Gulli, MD

Alfredo Mori, MBBS

Plummeting blood pressure that occurs when standing; dizziness and fainting may result.

A fall in blood pressure that occurs on standing up after lying down.

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

Orthostatic hypotension (also known as postural hypotension,^[1], orthostasis, and, colloquially, as head rush or a dizzy spell and to some people "the elevator effect") 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,^[2] and may be most pronounced after resting.

The incidence increases with age.^[3]

Contents 1 Symptoms 2 Diagnosis 3 Causes 3.1 Hypovolemia 3.2 Diseases 3.3 Medication 3.4 Harnesses 3.5 Other risk factors 4 Treatment and management 4.1 Medical management 4.2 Lifestyle advice 5 Prognosis 6 See also 7 References 8 External links

Symptoms

Symptoms, which generally occur after sudden standing or stretching (after standing), include dizziness, euphoria, bodily dissociation, distortions in hearing, lightheadedness, headache, blurred or 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.

Diagnosis

A simple test for OH measures the person's blood pressure while seated or reclining at rest, and again upon 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.

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 ml of blood from the thorax. It can also be noted that there is a decreased systolic (contracting) blood pressure and a decreased diastolic (resting) blood pressure.^[4] 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.^[5]

Hypovolemia

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

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 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.^[6]

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]} 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 and the saccule, affect brain blood flow; thus inner ear problems, which increase with old age, may be involved in orthostatic hypotension.^[7]

Medication

Orthostatic hypotension can be a side effect of certain anti-depressants, such as tricyclics^[8] or MAOIs.^[9]. ^[10] Orthostatic hypotension can also be a side effect of alpha₁ adrenergic blocking agents. Alpha₁ blockers inhibit vasoconstriction normally initiated by the baroreceptor reflex upon postural change and the subsequent drop in pressure.^[11]

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 cannibis or opioids may cause a head rush. 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 several lifestyle issues, which however are most often specific to 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.^[12] Selective serotonin reuptake inhibitors (SSRI's) and Serotonin-norepinephrine reuptake inhibitors (SNRI's) are helpful in many patients.^{[citation needed]} Sometimes stimulant drugs such as Adderall or Ritalin can be of assistance. Benzodiazepines are commonly prescribed as well.

Lifestyle advice

This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (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 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 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 (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

1. ^ Orthostatic hypotension at Dorland's Medical Dictionary
2. ^ Medow MS, Stewart JM, Sanyal S, Mumtaz A, Sica D, Frishman WH (2008). "Pathophysiology, diagnosis, and treatment of orthostatic hypotension and vasovagal syncope". Cardiol Rev 16 (1): 4–20. doi:10.1097/CRD.0b013e31815c8032. PMID 18091397. http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?an=00045415-200801000-00002. 
3. ^ Shibao C, Grijalva CG, Raj SR, Biaggioni I, Griffin MR (2007). "Orthostatic hypotension-related hospitalizations in the United States". Am. J. Med. 120 (11): 975–80. doi:10.1016/j.amjmed.2007.05.009. PMID 17976425. http://linkinghub.elsevier.com/retrieve/pii/S0002-9343(07)00655-9. 
4. ^ [1]
5. ^ Lee C, Porter KM (Apr 2007). "Suspension trauma". Emerg Med J. 24 (4): 237–8. doi:10.1136/emj.2007.046391. PMID 17384373. 
6. ^ "Dopamine Beta-Hydroxylase Deficiency". GeneReviews — NCBI Bookshelf. http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=dbh#dbh. 
7. ^ "Minute organs in the ear can alter brain blood flow". BBC News. http://news.bbc.co.uk/2/hi/health/8268336.stm. Retrieved 2009-12-27. 
8. ^ 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. 
9. ^ 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. 
10. ^ Jones RT. (2002). "Cardiovascular system effects of marijuana.". J Clin Pharmacol 42 (11 Suppl): 58S–63S. PMID 12412837. 
11. ^ Orthostatic Hypotension at Merck Manual of Diagnosis and Therapy Home Edition
12. ^ Singer W, Opfer-Gehrking TL, McPhee BR, Hilz MJ, Bharucha AE, Low PA. (2003). "Acetylcholinesterase inhibition: a novel approach in the treatment of neurogenic orthostatic hypotension.". J Neurol Nosurg Psychiatry 74 (9): 1294–8. doi:10.1136/jnnp.74.9.1294. PMID 12933939. .

External links

• Bradley JG, Davis KA (Dec 2003). "Orthostatic hypotension". Am Fam Physician. 68 (12): 2393–8. PMID 14705758. http://www.aafp.org/afp/20031215/2393.html. 
• 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

v • d • e Autonomic diseases, Dysautonomia, autonomic- neuropathy (G90, 337) HSAN I · II · III/Familial dysautonomia · IV/Congenital insensitivity to pain with anhidrosis · V Orthostatic intolerance Postural orthostatic tachycardia syndrome · Orthostatic hypotension Other Horner's syndrome · Multiple system atrophy · Pure autonomic failure · Autonomic dysreflexia peripheral nervous system navs: anat/histo/physio/dev, noncongen PNS somatic/autonomic/congen/neoplasia, symptoms+signs/eponymous, proc

v • d • e Cardiovascular disease: vascular disease · Circulatory system pathology (I70-I99, 440-456) Arteries, arterioles and capillaries Inflammation Arteritis (Aortitis) · Buerger's disease Arterial occlusive disease/ peripheral vascular disease Arteriosclerosis Atherosclerosis (Foam cell, Fatty streak, Atheroma, Intermittent claudication) · Monckeberg's arteriosclerosis · Arteriolosclerosis (Hyaline, Hyperplastic, oxycholesterol, cholesterol, LDL, trans fat) Stenosis Renal artery stenosis · Carotid artery stenosis Other Fibromuscular dysplasia · Degos disease · Aortoiliac occlusive disease · Raynaud's phenomenon/Raynaud's disease · Erythromelalgia Aneurysm/dissection/ pseudoaneurysm torso: Aortic aneurysm (Thoracic aortic aneurysm, Abdominal aortic aneurysm) · Aortic dissection · Coronary artery aneurysm head/neck: Cerebral aneurysm · Intracranial berry aneurysm · Carotid artery dissection · Vertebral artery dissection · Familial aortic dissection Vascular malformation Arteriovenous fistula · Telangiectasia (Hereditary hemorrhagic telangiectasia) Vascular nevus Spider angioma · Halo nevus · Cherry hemangioma Veins Inflammation Phlebitis Venous thrombosis/ Thrombophlebitis primarily lower limb (Deep vein thrombosis) abdomen (May-Thurner syndrome, Portal vein thrombosis, Budd-Chiari syndrome, Renal vein thrombosis) upper limb/torso (Paget-Schroetter disease, Mondor's disease) head (Cerebral venous sinus thrombosis) Post-thrombotic syndrome Varicose veins Varicocele · Gastric varices · Portacaval anastomosis (Hemorrhoid, Esophageal varices, Caput medusae) Other Superior vena cava syndrome · Inferior vena cava syndrome · Venous ulcer · Chronic venous insufficiency · Chronic cerebrospinal venous insufficiency Arteries or veins Vasculitis · Thrombosis · Embolism (Pulmonary embolism, Cholesterol embolism, Paradoxical embolism) · Angiopathy (Macroangiopathy, Microangiopathy) Blood pressure Hypertension Hypertensive heart disease · Hypertensive nephropathy · Essential hypertension  · Secondary hypertension (Renovascular hypertension) · Pulmonary hypertension · Malignant hypertension · Benign hypertension · Systolic hypertension · White coat hypertension Hypotension Orthostatic hypotension vascular navs: anat/physio/dev, noncongen/systemic vasculitis/congen/neoplasia, symptoms+signs/eponymous, proc

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