Orthostatic hypotension
From Wikipedia, the free encyclopedia
| Orthostatic hypotension Classification and external resources |
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| ICD-10 | I95.1 |
|---|---|
| ICD-9 | 458.0 |
| DiseasesDB | 10470 |
| eMedicine | ped/2860 |
| MeSH | D007024 |
Orthostatic hypotension (also known as postural hypotension[1], 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,[2] that occurs when a person assumes a standing position, usually after a prolonged period of rest.
The incidence increases with age.[3]
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[edit] Symptoms
Symptoms, which generally occur after sudden standing, include dizziness, lightheadedness, headache, blurred or dimmed vision (possibly to the point of momentary blindness), generalized (or extremity) numbness/tingling and fainting, and in rare, extreme cases, syncope. They are consequences of insufficient blood pressure and cerebral perfusion (blood supply).
[edit] 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 ml of blood from the thorax. It can also be noted that although there is a decreased systolic (contracting) blood pressure, there is actually an increased 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.[4]
[edit] 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.
[edit] 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 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.
[edit] Medication
Orthostatic hypotension can be a side effect of certain anti-depressants, such as tricyclics[5] or MAOIs.[6] It is also a side effect of the short-term use of marijuana.[7] 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.[8]
[edit] 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.
[edit] 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.
[edit] 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.
[edit] 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 now also used to treat orthostatic hypotension.[9]
Beta blockers such as Metoprolol succinate (Toprol-XL) are also used in treating orthostatic hypotension.
SSRI's and 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.
[edit] Lifestyle advice
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This section does not cite any references or sources. (October 2007) Please help improve this section by adding citations to reliable sources. Unverifiable material may be challenged and removed. |
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, 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 (stockings) or whole-body inflatable suits may be required.
[edit] Prognosis
The prognosis for individuals with orthostatic hypotension depends on the underlying cause of the condition.
[edit] See also
[edit] References
- ^ h_23/12440366 at Dorland's Medical Dictionary
- ^ 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:. PMID 18091397.
- ^ 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:. PMID 17976425.
- ^ Suspension trauma. Lee C, Porter KM.
- ^ Jiang W, Davidson JR. (2005). "Antidepressant therapy in patients with ischemic heart disease.". Am Heart J 150 (5): 871-81. doi:. PMID 16290952.
- ^ 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. PMID 10333164.
- ^ Jones RT. (2002). "Cardiovascular system effects of marijuana.". J Clin Pharmacol 42 (11 Suppl): 58S-63S. PMID 12412837.
- ^ Orthostatic Hypotension: Low Blood Pressure: Merck Manual Home Edition
- ^ 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:. PMID 12933939.
[edit] External links
- John G. Bradley, M.D., and Kathy A. Davis, R.N. Orthostatic Hypotension American Family Physician
- 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
- 16-200a. at Merck Manual of Diagnosis and Therapy Professional Edition
