Orthostatic hypotension
Encyclopedia
Orthostatic hypotension, also known as postural hypotension, orthostasis, and colloquially as head rush or dizzy spell, is a form of hypotension
in which a person's blood pressure
suddenly falls when the person stands up or stretches. The decrease is typically greater than 20/10 mm Hg, and may be most pronounced after resting. The incidence increases with age.
, euphoria or dysphoria, bodily dissociation, distortions in hearing, lightheadedness, nausea, 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
(a specific type of fainting). 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.
and subsequent lowering of arterial pressure. For example, changing from a lying position to standing, loses about 700 ml
of blood from the thorax. It can also be noted that there is a decreased systolic blood pressure and a decreased diastolic blood pressure. 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. (Often this mechanism is exaggerated and that is why diastolic blood pressure is a bit higher when a person is standing up, compared to a person in horizontal position.) 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.
Heat exhaustion can also be a cause of postural hypotension.
(a decreased amount of blood
in the body), resulting from bleeding, the excessive use of diuretic
s, vasodilators, or other types of drugs, dehydration
, or prolonged bed rest
. It also occurs in people with anemia
.
, 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.
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, 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.
(THC) can on occasion produce marked orthostatic hypotension. 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.
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. There is increasing evidence from a number of studies at Liverpool John Moores University that orthostatic tolerance is worse in the morning even when the effects of prior rest and sleep are controlled
. A sudden, significant fall in blood pressure (>20 mmHg) between 2 and 5 minutes after standing from the supine position indicates orthostatic hypotension. 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.
(Florinef) and erythropoietin
to aid in fluid retention, and vasoconstrictors like midodrine
. Pyridostigmine bromide (Mestinon) is also now used to treat the condition.
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
in which a person's blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
suddenly falls when the person stands up or stretches. The decrease is typically greater than 20/10 mm Hg, and may be most pronounced after resting. The incidence increases with age.
Signs and symptoms
Symptoms, which generally occur after sudden standing or stretching (after standing), include dizzinessDizziness
Dizziness refers to an impairment in spatial perception and stability. The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness....
, euphoria or dysphoria, bodily dissociation, distortions in hearing, lightheadedness, nausea, headache
Headache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...
, blurred or dimmed vision
Tunnel vision
Tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision.- Medical / biological causes :Tunnel vision can be caused by:...
(possibly to the point of momentary blindness
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
), generalized (or extremity) numbness/tingling
Tingling
Tingling or Tili was a tribe union west of China before 300 BC. After c.300BC they were called tieloe or kauko. The avars was the tieloe tribe union most west members....
and fainting, coat hanger pain (pain centered in the neck and shoulders), and in rare, extreme cases, vasovagal syncope
Vasovagal syncope
A vasovagal episode or vasovagal response or vasovagal attack is a malaise mediated by the vagus nerve. When it leads to syncope or "fainting", it is called a vasovagal syncope, which is the most common type of fainting.There are a number of different syncope syndromes which all fall under the...
(a specific type of fainting). They are consequences of insufficient blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
and cerebral perfusion
Perfusion
In physiology, perfusion is the process of nutritive delivery of arterial blood to a capillary bed in the biological tissue. The word is derived from the French verb "perfuser" meaning to "pour over or through."...
(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 outputCardiac output
Cardiac output is the volume of blood being pumped by the heart, in particular by a left or right ventricle in the time interval of one minute. CO may be measured in many ways, for example dm3/min...
and subsequent lowering of arterial pressure. For example, changing from a lying position to standing, loses about 700 ml
Litre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
of blood from the thorax. It can also be noted that there is a decreased systolic blood pressure and a decreased diastolic blood pressure. 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
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
(baroreceptor reflex), pressing the blood up into the body again. (Often this mechanism is exaggerated and that is why diastolic blood pressure is a bit higher when a person is standing up, compared to a person in horizontal position.) 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.
Heat exhaustion can also be a cause of postural hypotension.
Hypovolemia
Orthostatic hypotension may be caused by hypovolemiaHypovolemia
In physiology and medicine, hypovolemia is a state of decreased blood volume; more specifically, decrease in volume of blood plasma...
(a decreased amount of blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
in the body), resulting from bleeding, the excessive use of diuretic
Diuretic
A diuretic provides a means of forced diuresis which elevates the rate of urination. There are several categories of diuretics. All diuretics increase the excretion of water from bodies, although each class does so in a distinct way.- Medical uses :...
s, vasodilators, or other types of drugs, dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
, or prolonged bed rest
Bed rest
Bed rest is a medical treatment involving a period of consistent recumbence in bed. It is used as a treatment for an illness or medical condition, especially when prescribed or chosen rather than resulting from severe prostration or imminent death...
. It also occurs in people with anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
.
Diseases
The disorder may be associated with Addison's diseaseAddison's disease
Addison’s disease is a rare, chronic endocrine disorder in which the adrenal glands do not produce sufficient steroid hormones...
, atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
(build-up of fatty deposits in the arteries), diabetes, pheochromocytoma
Pheochromocytoma
A pheochromocytoma or phaeochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands , or extra-adrenal chromaffin tissue that failed to involute after birth and secretes excessive amounts of catecholamines, usually noradrenaline , and adrenaline to a lesser extent...
, and certain neurological
Neurology
Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...
disorders including multiple system atrophy
Multiple system atrophy
Multiple system atrophy is a degenerative neurological disorder. MSA is associated with the degeneration of nerve cells in specific areas of the brain. This cell degeneration causes problems with movement, balance and other autonomic functions of the body such as bladder control or blood pressure...
and other forms of dysautonomia
Dysautonomia
Dysautonomia is a broad term that describes any disease or malfunction of the autonomic nervous system. This includes postural orthostatic tachycardia syndrome , inappropriate sinus tachycardia , vasovagal syncope, mitral valve prolapse dysautonomia, pure autonomic failure, neurocardiogenic...
. It is also associated with Ehlers-Danlos Syndrome
Ehlers-Danlos syndrome
Ehlers–Danlos syndrome is a group of inherited connective tissue disorders, caused by a defect in the synthesis of collagen . The collagen in connective tissue helps tissues to resist deformation...
. It is also present in many patients with Parkinson's Disease
Parkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
resulting from sympathetic denervation of the heart or as a side effect of dopaminomimetic therapy. This rarely leads to syncope
Syncope (medicine)
Syncope , the medical term for fainting, is precisely defined as a transient loss of consciousness and postural tone characterized by rapid onset, short duration, and spontaneous recovery due to global cerebral hypoperfusion that most often results from hypotension.Many forms of syncope are...
unless the patient has developed true autonomic
Autonomic nervous system
The autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...
failure or has an unrelated cardiac problem.
Another disease is called dopamine beta hydroxylase deficiency
Dopamine beta hydroxylase deficiency
Dopamine beta hydroxylase deficiency is a condition involving inadequate Dopamine beta hydroxylase.-Symptoms:A deficiency of norepinephrine and epinephrine that causes orthostatic hypotension, nasal stuffiness, and droopy eyelids among other symptoms. Some people refer to this as norepinephrine...
, 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.
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, which results from cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
leakage. It affects women more than men and peaks at ages between 40 to 50.
A study by a Harvard Medical School
Harvard Medical School
Harvard Medical School is the graduate medical school of Harvard University. It is located in the Longwood Medical Area of the Mission Hill neighborhood of Boston, Massachusetts....
team found that two sacs in the inner ear
Inner ear
The inner ear is the innermost part of the vertebrate ear. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:...
, the utricle and the saccule
Saccule
The saccule is a bed of sensory cells situated in the inner ear. The saccule translates head movements into neural impulses which the brain can interpret. The saccule is sensitive to linear translations of the head, specifically movements up and down...
, affect brain blood flow; thus inner ear problems, which increase with old age, may be involved in orthostatic hypotension.
Medication
Orthostatic hypotension can be a side effect of certain anti-depressants, such as tricyclics or MAOIs. Marijuana and delta9-tetrahydrocannabinolTetrahydrocannabinol
Tetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...
(THC) can on occasion produce marked orthostatic hypotension. 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.
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 nervosaAnorexia nervosa
Anorexia nervosa is an eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight. Although commonly called "anorexia", that term on its own denotes any symptomatic loss of appetite and is not strictly accurate...
and bulimia nervosa
Bulimia nervosa
Bulimia nervosa is an eating disorder characterized by binge eating and purging or consuming a large amount of food in a short amount of time, followed by an attempt to rid oneself of the food consumed, usually by purging and/or by laxative, diuretics or excessive exercise. Bulimia nervosa is...
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. There is increasing evidence from a number of studies at Liverpool John Moores University that orthostatic tolerance is worse in the morning even when the effects of prior rest and sleep are controlled
Diagnosis
There is a simple test for OH measures the person's blood pressure while seated or reclining at rest, and again upon standing upStanding (position)
Standing is a human position in which the body is held upright and supported only by the feet, referred to as an orthostatic state.Although quiet standing appears to be static, modern instrumentation shows it to be a process of rocking from the ankle in the sagittal plane...
. A sudden, significant fall in blood pressure (>20 mmHg) between 2 and 5 minutes after standing from the supine position indicates orthostatic hypotension. 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
Tilt table test
A tilt table test, occasionally called upright tilt testing, is a medical procedure often used to diagnose dysautonomia or syncope. Patients with symptoms of dizziness or lightheadedness, with or without a loss of consciousness , suspected to be associated with a drop in blood pressure or...
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 fludrocortisoneFludrocortisone
Fludrocortisone is a synthetic corticosteroid with moderate glucocorticoid potency and much greater mineralocorticoid potency. The brand name in the U.S. and Canada is Florinef.-Uses:...
(Florinef) and erythropoietin
Erythropoietin
Erythropoietin, or its alternatives erythropoetin or erthropoyetin or EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production...
to aid in fluid retention, and vasoconstrictors like midodrine
Midodrine
Midodrine is a vasopressor/antihypotensive agent. Midodrine was approved in the United States by the Food and Drug Administration in 1996 for the treatment of orthostatic hypotension...
. Pyridostigmine bromide (Mestinon) is also now used to treat the condition.
Lifestyle factors
- Standing up more slowly can give the blood vessels more time to constrict properly. This can help avoid incidents of syncope (fainting).
- Breathing deeply and flexing the abdominal muscles while rising helps maintain blood and oxygen flow to the brain. This may be contraindicated in individuals with Stage 2 hypertensionHypertensionHypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
. 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, can reduce incidence of orthostatic hypotension. A suggested value is 10g per day; overuse can lead to hypertension and should be avoided.
- Maintaining proper fluid intake helps prevent the effects of dehydration, a potential causative factor.
- Eating more, smaller meals can help, as digestion lowers blood pressure more when eating larger meals.
- Taking 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 counter-pressure such as elastic hoseHose (clothing)Hose are any of various styles of men's clothing for the legs and lower body, worn from the Middle Ages through the 17th century, when the term fell out of use in favor of breeches and stockings. The old plural form of "hose" was hosen...
(stockings) or whole-body inflatable suits may be required. - Many people who experience orthostatic hypotension are able to recognize 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.
- Many also find it helpful to slightly clench muscles in the upper body (abdominals and diaphragm) in order to slow the flow of blood out of upper extremities. (A procedure similar to this is the Anti-G-Maneuver (AGM), used by some personnel in racing or performance aviation to avoid unconsciousness as blood leaves the head, due to similar forces of gravity)
- Avoiding bodily positions that impede blood flow, such as sitting with knees up to chest or crossing legs, can help prevent incidents.
External links
- 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