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 standing up or stretching.
In medical terms, 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. The symptom is caused by blood pooling in
the lower extremities upon a change in body position. It is quite common and can occur
briefly in anyone, although it is prevalent in particular among the elderly, and those
with low blood pressure. Signs and symptoms
When orthostatic hypotension is present, the following symptoms can occur after sudden
standing or stretching: Dizziness
Euphoria or dysphoria Bodily dissociation
Distortions in hearing Lightheadedness
Temporary decrease in hearing Blurred or dimmed vision
Seizures Generalized numbness/tingling and fainting
Coat hanger pain And in rare, extreme cases, vasovagal syncope.
They are consequences of insufficient blood pressure and cerebral perfusion. Occasionally,
there may be a feeling of warmth in the head and shoulders for a few seconds after the
dizziness subsides. The drop in blood pressure may cause a vasovagal episode to occur.
Causes Orthostatic hypotension is caused primarily
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, changing from a lying position to standing loses about 700 ml of blood from
the thorax, with a decrease in systolic and diastolic blood pressures. 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, 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, and medications.
Hypovolemia Orthostatic hypotension may be caused by hypovolemia,
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, 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, 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. Recently, a common but underdiagnosed condition
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 and 50. A study by a Harvard Medical School team found
the 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.
Medication Orthostatic hypotension can be a side-effect
of certain antidepressants, such as tricyclics or monoamine oxidase inhibitors. Marijuana
and tetrahydrocannabinol can on occasion produce marked orthostatic hypotension. Orthostatic
hypotension can also be a side effect of Alpha-1 blockers. Alpha1 blockers inhibit vasoconstriction
normally initiated by the baroreceptor reflex upon postural change and the subsequent drop
in pressure. B12 Deficiency
Orthostatic hypotension sometimes is a reversible neurological complication of vitamin B12 deficiency.
Harnesses The use of a safety harness does not contribute
to orthostatic hypotension in the event of a fall. This notion is a hypothetical risk
which has all but been eliminated due to modern design and safety regulations. If worn properly,
a safety harness may safely rescue its user from a fall without any further complications
so long as the individual does not remain suspended for prolonged periods of time.
Other factors 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. Orthostatic hypotension is also associated
with Naturopathic treatment and the practice of yoga, when the pressure gradient varies
during these practices. Diagnosis
There is a simple test for OH that measures the person’s blood pressure while seated or
reclining at rest, and again upon standing up. Orthostatic hypotension is defined as
a fall in systolic blood pressure of at least 20 mmHg and/or in the diastolic blood pressure
of at least 10 mmHg between the supine reading and the upright reading. 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. Management
The evidence to support treatment is poor. A number of measures with slight evidence
to support their use include: compression bandages, midodrine, indomethacin, oxilofrine,
potassium chloride, and yohimbine. Prognosis
Orthostatic hypotension may cause accidental falls.
See also Orthostatic intolerance
References Notes External links
Bradley JG, Davis KA. “Orthostatic hypotension”. Am Fam Physician. 68: 2393–8. PMID 14705758.
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