ORTHOSTATIC HYPOTENSION, also known as POSTURAL HYPOTENSION, occurs when a person's blood pressure falls when suddenly standing up from a lying or sitting position. It is defined as a fall in systolic blood pressure of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg when a person assumes a standing position. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain an adequate blood pressure when changing position to standing. As a result, blood pools in the blood vessels of the legs for a longer period and less is returned to the heart, thereby leading to a reduced cardiac output . Mild orthostatic hypotension is common and can occur briefly in anyone, although it is prevalent in particular among the elderly and those with known low blood pressure. Severe drops in blood pressure can lead to fainting , with a possibility of injury.
There are numerous possible causes for orthostatic hypotension, such as certain medications (e.g. alpha blockers ), autonomic neuropathy , decreased blood volume , and age-related blood vessel stiffness.
Apart from addressing the underlying cause, orthostatic hypotension may be treated with a recommendation to increase salt and water intake (to increase the blood volume), wearing compression stockings , and sometimes medication (fludrocortisone , midodrine or others).
* 1 Signs and symptoms
* 2 Causes
* 2.1 Hypovolemia * 2.2 Diseases * 2.3 Medication * 2.4 Other factors
* 3 Diagnosis
* 4 Management
* 4.1 Non-pharmacological management * 4.2 Pharmacological management
* 5 Prognosis * 6 See also * 7 References * 8 External links
SIGNS AND SYMPTOMS
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 is why diastolic blood pressure is a bit higher when a person is standing up, compared to a person in the horizontal position.) Therefore, a secondary factor that causes a greater than normal fall in blood pressure is often required. Such factors include low blood volume, diseases, and medications.
The disorder may be associated with Addison\'s disease , atherosclerosis (build-up of fatty deposits in the arteries), diabetes , pheochromocytoma , porphyria , and certain neurological disorders, including multiple system atrophy and other forms of dysautonomia . It is also associated with Ehlers–Danlos syndrome and anorexia nervosa . 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 fainting unless the person has developed true autonomic failure or has an unrelated heart problem.
Another disease, dopamine beta hydroxylase deficiency , also thought to be underdiagnosed, causes loss of sympathetic noradrenergic function and is characterized by a low or extremely low levels of norepinephrine, but an excess of dopamine.
Quadriplegics and paraplegics also might experience these symptoms due to multiple systems' inability to maintain a normal blood pressure and blood flow to the upper part of the body.
Patients prone to orthostatic hypotension are the elderly, post partum mothers, and those having been on bedrest. People suffering from anorexia nervosa and bulimia nervosa often suffer from orthostatic hypotension as a common side-effect. Consuming alcohol may also lead to orthostatic hypotension due to its dehydrating effects.
Apart from treating underlying reversible causes (e.g., stopping or reducing certain medications), there are a number of measures that can improve the symptoms of orthostatic hypotension and prevent episodes of syncope. Even small increases in the blood pressure may be sufficient to maintain blood flow to the brain on standing.
In people who do not have a diagnosis of high blood pressure, drinking 2–3 liters of fluid a day and taking 10 grams of salt can improve symptoms, by maximizing the amount of fluid in the bloodstream. Another strategy is keeping the head of the bed slightly elevated. This reduces the return of fluid from the limbs to the kidneys at night, thereby reducing nighttime urine production and maintaining fluid in the circulation. Various measures can be used to improve the return of blood to the heart: the wearing of compression stockings and exercises ("physical counterpressure manoeuvres" or PCMs) that can be undertaken just before standing up (e.g., leg crossing and squatting).
The medication midodrine can benefit people with orthostatic
hypotension, The main side-effect is piloerection ("goose bumps").
A number of other measures have slight evidence to support their use indomethacin , fluoxetine , dopamine antagonists , metoclopramide , domperidone , monoamine oxidase inhibitors with tyramine (can produce severe hypertension ), oxilofrine , potassium chloride , and yohimbine .
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* ^ Idiopathic Orthostatic
Hypotension and other Autonomic Failure
Syndromes at eMedicine
* ^ "What Causes Hypotension? - NHLBI, NIH". www.nhlbi.nih.gov.
Retrieved 27 March 2017.
* ^ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1704473/
* ^ "Dopamine Beta-Hydroxylase Deficiency". GeneReviews — NCBI
* ^ Jiang W, Davidson JR (2005). "Antidepressant therapy in
patients with ischemic heart disease". Am Heart J. 150 (5): 871–81.
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(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):
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* ^ Jones RT. (2002). "Cardiovascular system effects of marijuana".
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* ^ Orthostatic
Hypotension at Merck Manual of Diagnosis and
Therapy Home Edition
* ^ "STEADI - Measuring Orthostatic Blood Pressure" (PDF). Centers
for Disease Control and Prevention. Retrieved 20 December 2014.
* ^ A B C D E F Moya, A.; Sutton, R.; Ammirati, F.; et al. (27
August 2009). "Guidelines for the diagnosis and management of syncope
(version 2009): The Task Force for the Diagnosis and Management of
Syncope of the European Society of