Timothy C. Hain,
MD. Please read our disclaimer. Return to Index. Content last updated: 12/2002
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Orthostasis means upright posture, and hypotension means low blood pressure. Thus,
orthostatic hypotension consists of symptoms of dizziness, faintness or lightheadedness
which appear only on standing, and which are caused by low blood pressure. Only rarely is
spinning vertigo caused by orthostasis.
Symptoms that often accompany orthostatic hypotension include chest pain, trouble
holding the urine, impotence, and dry skin from loss of sweating.
What Causes Orthostatic Hypotension ?
Blood pressure is maintained by a combination of several things. The heart is the
central pump, and a weak or irregular heart can cause orthostasis. Conditions such
as arrhythmia, heart failure, deconditioning, and pregnancy are examples where the heart
may not be up to the task of providing an adequate blood pressure.
The heart pumps blood, and if there is too little blood volume (anemia, dehydration,
dialysis), the pressure drops. The blood vessels in the body also can squeeze
(constrict) to raise blood pressure, and if this action is paralyzed, blood
pressure may fall. Numerous medications affect blood vessels including most
of the medications used for blood pressure, and many of the medications used
in psychiatry and for anginal heart pain. Heat, such as a hot shower or from
a fever can also dilate blood vessels and cause orthostasis. The nervous system
senses and responds to regulate blood pressure. If something is wrong in this
control system, blood pressure may fluctuate.
Blood pressure is usually lowered (in persons with orthostasis) by upright
posture, food, infection, hyperventilation, hot weather, and lifting of heavy
objects. General anesthesia may be unusually dangerous due to blood pressure
fluctuations (Bevan et al, 1979).
Vestibular disorders may interact with blood pressure and heart rate control.
The vestibular system is one source of information about uprightness (the
otoliths), there are some effects of vestibular stimulation on the heart
(Radtke, 1992), and there are some patients who have a combination of autonomic
and vestibular symptoms.
Neurological disorders can also be caused by orthostasis. This usually takes
the form of a TIA precipitated by a blood
pressure drop (Brozman et al, 2002).
Diagnosis of Orthostatic Hypotension
Syndromes with orthostatic dizziness or lightheadedness, not associated with
low blood pressure include:
- Positional orthostatic tachycardia (POT) syndrome. Here, the pulse races
- Low CSF pressure syndrome
- Primary orthostatic tremor
- Positional vertigo (i.e. BPPV)
Syndromes with orthostatic hypotension that may be diagnosed include:
- Cardiogenic (heart related) orthostatic hypotension. In this instance the
heart doesn't respond to demands for greater pumping and blood pressure drops.
- Low blood volume (e.g. anemia, dehydration, dialysis)
- Medication related (usually too high doses of blood pressure medications
or medications for depression)
- Neurogenic orthostatic hypotension
- Sensory neuropathies (diabetes, alcohol, syphilis, Holmes-Adie syndrome,
Carotid sinus obliteration by endarterectomy, Riley-Day syndrome)
- Central types:
- MSA - multiple system
atrophy or Shy-Drager, Parkinsons
- Medullary strokes or injuries (rare)
- Wernickes (rare)
- Output types:
- Peripheral neuropathy, especially diabetes and amyloidosis
- Spinal cord lesions
- PAF - pure autonomic failure or idiopathic orthostatic hypotension
- Parkinson's disease (sympathetic denervation)
- Dopamine beta-hydroxylase deficiency (hereditary, very rare)
- Unknown type
- Orthostatic intolerance in chronic fatigue syndrome (this mainly seems
to be a syndrome of adolescents)
The diagnosis of orthostatis is made by finding that the systolic/diastolic
blood pressure drops at least 25/10 mm mercury on going from lying to standing.
The pulse should be checked also. The lack of a pulse response increase when
the blood pressure drops implies a neurological cause. An excessive pulse response
is termed "POTS" or positional orthostatic tachycardia syndrome. Once
an orthostatic syndrome is determined, additional tests are used to determine
why the blood pressure isn't properly regulated.
TESTS for orthostatic hyptension
|CBC (blood count)
||Check for anemia
|EKG, other heart tests
||Check for weakness or irregularity of the heart
|CT or MRI scan of head
||Exclude nervous system disorders such as multiple system atrophy
||Localize lesion in nervous system
|Plasma norepinephrine (supine and standing)
||Low levels indicate post-ganglionic level lesion(vasoconstrictors
like midodrine will not work in this case)
|Glucose tolerance test
|RPR or FTA
|Serum Creatinine and BUN
||If amyloid is suspected
Not every test is needed in every situation. More tests may be recommended
based on the results of the previous tests. Tilt table tests are not needed
in orthostatic hypotension, but may be indicated in persons with fainting (syncope).
A 57 year old man presented complaining of lightheadness on standing and a
pressure sensation in the back of his neck (on standing). Other medical problems
included a low thyroid. Blood pressure was 90/65 standing vs 130/80 supine (on
medication). This documents a significant orthostatic hypotension. A sweat test
showed about 50% anhidrosis. Norepinephrine level was about 30 units lower supine
than upright. He was diagnosed as having neurogenic orthostatic hypotension.
Present treatment includes Proamatine (mitodrine) 10 mg TID, salt supplements,
Note that neither drug nor non-drug treatment can do as good a job as a well
working body. All of the strategies outlined in the next section are intended to alleviate
symptoms, but they are unlikely to cure orthostatic hypotension.
Non-Drug Treatment for Orthostatic Hypotension
Generally it is best to start with non-pharmacological treatment,
and proceed to drug treatment only when this fails.
- Use an automatic blood pressure cuff (about $30 at Walgreens or Radio Shack).
Check blood pressure daily, preferably standing and lying flat, and record
it. Also check blood pressure when you have symptoms.
- If possible, eliminate medications that lower blood pressure (usually blood-pressure
or heart medications). Check with your doctor first, however, to be sure that
this is safe.
- Take in extra amounts of salt - about 10 gm/day total. If you start to have
trouble breathing or get excessive swelling at the ankles, you may have to
use less than 10 gm.
- Wear Jobst stockings (tight custom made
leotard like garment -- worn by both men and women).
- Sleep with head of bed elevated about 15-20 degrees (4-6 inches). This maneuver
increases blood volume and, after a few days, is helpful. It is also
helpful in that it may reduce supine hypertension( sometimes blood pressure
is too high lying flat, and too low standing up). Try to be up during the
day, not lying in bed. Reconditioning may be helpful for persons who have
been on bed rest for long periods of time.
- Eat frequent small meals (because eating lowers blood pressure). Avoid sudden
standing after eating.
- Avoid straining at stool (because this may lower the blood pressure)
- Avoid hot showers or excessive heat. Use air conditioners.
- Get up gradually in the morning. Take 5 minutes to get up and use support.
Perform isometric exercises before moving about.
DRUG TREATMENT for Orthostatic Hypotension
Certain medications may be helpful, usually as a combination. Most useful drugs
are Florinef (fludrocortisone), erythropoetin and Midodrine.
- Two strong cups of coffee in the morning
- Fludrocortisone (Florinef) forces more salt into the bloodstream,
0.1 mg daily starting dose. Blood pressure raises gradually over several days
with maximum effect at 1-2 weeks. Alter doses at weekly or biweekly intervals.
Hypokalemia (low potassium) occurs in 50%, and hypomagnesemia in 5%. These
may need to be corrected with supplements. Florinef should not be used in
persons with CHF (congestive heart failure). Florinef does not work in the
orthostatic intolerance syndrome of chronic fatigue syndrome (Rowe et al,
2001). Headache is a common side effect.
- Effexor (an antidepressant which raises blood pressure as a side effect).
- Inderal and other beta-blockers (small doses are used for positional-orthostatic-tachycardia
syndrome (POTS), start inderal at 10 mg/d, increase to 30-60 mg/d over 2-3
weeks. Other useful agents are Nadolol (10 mg qd), Pindolol (2.5-5 mg 2-3
times/day) and atenolol (25).
- Motrin or Indocin (blocks blood-pressure lowering effects of prostaglandins).
- Midodrine. An alpha-1 agonist. Causes increased blood pressure, vasoconstriction,
pupil dilation, and "hair standing on end". Other common side effects
are paresthesia of the scalp or itching. Usual doses are 2.5 mg at breakfast
and lunch or three times daily. Doses are increased quickly until a response
occurs or a dose of 30 mg/day is attained (Wright et al, 1998). Midodrine
does not cross the blood-brain barrier and it is thus not associated with
CNS effects. Most patients on Midodrine also take Florinef (see above).
- Erythropoietin. This agent is used if there is also anemia and other measures
have failed. Doses of 25 to 75 U/kg TIW are used, by injection.
- Methylphenidate 5-10 mg orally 3 times/day given with meals. An amphetamine
-- side effects may include agitation, tremor, insomnia, supine hypertension.
- Ephedrine 12.5-25 mg orally three times/day. Side effects may include tachycardia,
tremor and supine hypertension.
- Fluoxetine 10-20 mg daily. Side effects may include nausea and anorexia.
- Phenobarbital may improve POTS.
- Desmopressin. This analog of vasopressin is used as a nasal spray. Low blood
sodium is a possible side effect.
Atrial pacing can be considered when the heart rate is very low
3,4 Dl-threo-dihydroxyphenylserine (DOPS), an artificial amino-acid, may be helpful in
certain situations (Freeman, 1996) including dopamine beta-hydroxylase deficiency and
post-prandial hypotension from various etiologies.
- Benarroch EE, Schmeichel AM, Parisi JE. Involvement of the ventrolateral
medulla in parkinsonism with autonomic failure. Neurology 2000:54:963-968
- Bevan, D. R. (1979). "Shy-Drager syndrome. A review and a description of
the anaesthetic management." Anaesthesia 34(9): 866-73.
- Brozman B and others (2002). Postural vertigo and impaired vasoreflexes
caused by a posterior inferior cerebellar artery infarct. Neurology, 59, 9,
- Freeman R, Young J, Landsberg L, Lipsitz L. The treatment of postprandial
hypotension in autonomic failure with 3,4-Dl-threo-dihydroxyphenylserine.
- Goldstein DS et al. Orthostatic hypotension from sympathetic denervation
in Parkinson's disease. Neurology 2002:58:1247-55
- Radke A, et. al. Evidence for a vestibulo-cardiac reflex in man. The Lancet
- Wright RA and others. A double-blind, dose-response study of midodrine in
neurogenic orthostatic hypotension. Neurology 1998, 51:120-124
- Stewart JM and others. Orthostatic intolerance in adolescent chronic fatigue
syndrome. Pediatrics 1999:103:116-121
- LaMaca et al. Cardiovascular response during head-up tilt in chronic fatigue
syndrome. Clin Physiol 1999:19:111-120
- Poole J and others. Results of isoproterenol tilt table testing in monozygotic
twins discordant for chronic fatigue syndrome. Arch Intern Med 2000:160:3461-3468
- Rowe and others. Fludrocortisone acetate to treate neurally mediated hypotension
in chronic fatigue syndrome. A randomized controlled trial. JAMA 2001, 285:52-59
- Yarrow and others. Force platform recordings in the diagnosis of primary
orthostatic tremor. Gait and Posture 2001:13, 27-34
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