Everything about Orthostatic Hypotension totally explained
Orthostatic hypotension (also known as
postural hypotension, and, colloquially, as
head rush or a
dizzy spell) is a form of
hypotension in which there's a sudden (less than 3 minutes) fall in
blood pressure, typically greater than 20/10
mm Hg, that occurs when a person assumes a
standing position, usually after a prolonged period of rest.
The incidence increases with age.
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. They are consequences of insufficient
blood pressure and
cerebral perfusion (blood supply).
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'll lose about 700
ml of blood from the
thorax. It can also be noted that although there's a decreased
systolic (contracting) blood pressure, there's 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 doesn't 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.
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
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.
Medication
Orthostatic hypotension can be a side effect of certain
anti-depressants, such as
tricyclics or
MAOIs. It is also a side effect of the short-term use of
marijuana. Orthostatic hypotension can also be a side effect of alpha
1 adrenergic blocking agents. Alpha
1 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 nervosa and bulimia nervosa often suffer from orthostatic hypotension and 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.
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.
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.
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.
Lifestyle advice
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 don't 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.
Prognosis
The prognosis for individuals with orthostatic hypotension depends on the underlying cause of the condition.
Further Information
Get more info on 'Orthostatic Hypotension'.
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