Timothy C. Hain, MD. Page last modified: January 2, 2016
See also related pages on: Syncope, POTs
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. Fainting (syncope) is covered in another page. Excessive pulse responses to being upright (POTs) without blood pressure changes are also covered on another page.
According to Wu et al (2008), symptoms of dizziness provoked by standing ranges from 4.4% (young) to 5.8% (>=70). Thus orthostatic dizziness is common and much more frequent than dizziness due to inner ear disturbances.
Blood pressure is maintained by a combination of several things. The heart is the central pump, and a weak or irregular heart can cause orthostatic hypotension. 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 transient ischemic attack (TIA) precipitated by a blood pressure drop (Brozman et al, 2002).
Syndromes with orthostatic dizziness or lightheadedness, not associated with low blood pressure include:
Syndromes with orthostatic hypotension that may be diagnosed include:
The diagnosis of orthostasis is made by finding that the systolic/diastolic blood pressure drops at least 25/10 mm mercury on going from lying to standing. After measuring the supine blood pressure, it is recommended that one should have the subject stand for 2 minutes (if tolerated) before measuring the upright blood pressure (Tarazi and Fouad, 1983).
|Tilt table used at Chicago Dizziness and Hearing|
An alternative and more quantitative method of determining if there is orthostatic hypotension is the tilt table test. This procedure uses equipment to record blood pressure and pulse after a 70 degree tilt using a motorized table.
Roughly as many indiivduals with orthostatic hypotension have a milder form, called delayed orthostatic hypotension (DOH ?>. Subjects who are stood for longer periods of time than 2 minutes may exhibit progressive decline in blood pressure (Gibbons and Freeman, 2006; 2015). Delayed orthostatic hypotension (DOH) is defined as a greater than 20 mm Hg fall after 3 minutes or more of tilt-table or active standing. This seems to take a rather long time -- many (39%) subjects were positive only after 10 minutes of standing or tilt. A tilt (or stand) of 20 minutes was recommended by these authors for diagnosis. In a follow-up study, 54% of patients with DOH preogressed to orthostatic hypotension, and 31% developed a degenerative neurological disease. The 10-year mortality was 29%, compared to 9% of controls.While the tilt table test would seem to be an ideal method of diagnosing delayed orthostatic hypotension, because insurance companies generally only "cover" testing of persons who have passed out (syncope), this milder form of orthostatic hypotension can easily be missed.
The pulse (heart rate) should be checked also.
The lack of a pulse response increase to a drop in blood pressure implies either a lack of sensors to detect blood pressure, an inability to develop an appropriate CNS command, or a drug in ones system (such as a beta-blocker) that prevents the pulse from rising.
An excessive rise pulse to upright is termed "POTS" or positional orthostatic tachycardia syndrome. POTS can be associated with considerable disability (Benrud-Larson et al, 2002). Note that pulse can increase due to anxiety and deconditioning as well as autonomic disorders and considerable caution must be used in making this diagnosis.
Once an orthostatic syndrome is determined, additional tests are used to determine why the blood pressure isn't properly regulated.
|CBC (blood count)||Check for anemia -- especially important in persons who are bleeding.|
|EKG, other heart tests||Check for weakness or irregularity of the heart|
|CT or MRI scan of head||Exclude other nervous system disorders such as multiple system atrophy (MSA)|
|Autonomic testing (a battery of tests often including tests of blood pressure control and sweating). Tilt table testing, Valsalva testing, and QSART are often included.||Localize lesion in nervous system|
|Cortisol, 6-8 AM||Levels less than 3 indicate adrenal insufficiency. Levels greater than 18 are normal. Levels in the middle can be sorted out with a dynamic cortisol test (e.g. ACTH stimulation or related test)|
Plasma norepinephrine (NE) (supine and standing)
Low levels indicate post-ganglionic level lesion (vasoconstrictors like midodrine will not work in this case). Patients with orthostatic hypotension associated with Parkinsonism have low plasma levels of NE while supine, and thus should not respond to Midodrine. Patients with MSA have normal levels. See Goldstein (2003). Patients with dopamine beta-hydroxylase deficiency have very high dopamine levels. POTS patients often have high levels of upright norepinephrine (> 600 pg/ml) (Raj, 2006). This should be done after 15 minutes of standing.
|Glucose tolerance test, or glycosylated Hgb.||Diabetes|
|RPR or FTA||Syphilis|
|Serum creatinine and BUN||Kidney failure when high|
|Gastric and small bowel motility studies||Detect diabetic gastroparesis and related conditions.|
|Posturography||Should be normal|
|Rectal biopsy||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, as the problem has already been identified, but may be indicated in persons with fainting (syncope) or simply an undiagnosed orthostatic syndrome.
Persons with orthostatic intolerance are reported to have more MRI abnormalities called periventricular white matter lesions (Kruit et al, 2013). The reason for this is unknown. We have never noticed this association ourselves in our 18,000+ patients seen over the years with dizziness.
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 (midodrine.) 10 mg TID, salt supplements, and erythropoetin.
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.
Generally it is best to start with non-pharmacological treatment, and proceed to drug treatment only when this fails. Note that measures such as volume expansion with increased salt and fluid, moderate exercise and tilt training are relatively safe but their effectiveness has not been demonstrated by controlled trials (Kapoor, 2003). Nevertheless, we think it is reasonable to give these things a try.
Use an automatic blood pressure cuff (about $30 at Walgreens or Radio Shack). Check blood pressure and pulse 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. Sometimes it is helpful to take the blood pressure medications in the evening, as well as to use longer acting ones rather than ones that act quickly.
Take in extra amounts of salt - about 10 gm/day total. Another way to get extra salt is to use salt containing beverages (e.g. "gatorade"). If you start to have trouble breathing or get excessive swelling at the ankles, you may have to use less than 10 gm. Similarly, be careful not to overdo it and end up with hypertension.
Two strong cups of coffee in the morning may be helpful.
Wear Jobst stockings (tight custom made leotard like garment -- worn by both men and women). These are often not well tolerated, especially in the summer. There are also similar compression garments for sports use that cover more territory.
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.
Water ingestion - -drinking 16 oz of water over 5 minutes can prevent a fainting spell (Lu et al, 2003).. This should not be done very often as it could lead to water intoxication.
Orthostatic training. Under the supervision of a physical therapist, gradually increased upright stance. Also use physical countermeasures (see page on tilt training). The literature suggests that this is very effective. Tilt training also includes some effective physical countermeasures such as leg-crossing with lower body tensing, squatting, and arm-tensing (Benditt and Nguyen, 2009)
Physical conditioning may also be useful for patients with orthostatic intolerance as deconditioning is present in almost all patients (Parsaik et al, 2014).
Certain medications may be helpful, usually as a combination. Most useful drugs are Florinef (fludrocortisone) and Midodrine. As a general comment, these drugs can be dangerous. Be sure that you monitor your blood pressure every day if you are taking the more powerful agents (e.g. Florinef, Midodrine, Droxidopa).
Taking blood pressure medications in the evening rather than in the morning may be helpful as blood pressure often goes down while upright (during the day), and gets too high while in bed.
Fludrocortisone (Florinef) forces more salt into the bloodstream, 0.1 mg is the 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.
Motrin or Indocin (blocks blood-pressure lowering effects of prostaglandins). The good effect was supported in a systematic review (Logan and Witham, 2012) .
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). Several controlled trials did not show these agents to be effective in preventing syncope (Kapoor, 2003)
Midodrine. An alpha-1 adrenergic agonist. Causes increased blood pressure, vasoconstriction, pupil dilation, and "hair standing on end". Other common side effects are parenthesis of the scalp or itching. Very recent studies suggest that it doesn't work (e.g. Parsaik et al, 2013), but our patients say otherwise. 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 levels peak at about 1-2 hours after administration, and have a half-life of about 3-4 hours. Midodrine does not cross the blood-brain barrier and it is thus not associated with CNS effects. In theory, Midodrine might work for the orthostatic hypotension of MSA (or Shy-Drager), but not that of Parkinsonism. Most patients on Midodrine also take Florinef (see above). Midodrine has been shown to be helpful in controlled trials (Kapoor, 2003), but as of 2012, meta-analyses of multiple trials have suggested that it is not especially useful. (Logan and Witham, 2012; Parasaik et al, 2013) .
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. Paroxetine (Paxil) has also been shown to reduce syncope at 2 years.
Phenobarbital may improve POTS.
Desmopressin. This analog of vasopressin is used as a nasal spray. Low blood sodium is a possible side effect.
Pyridostigmine (mestinon), is a medication for another neurological disorder (Myasthenia gravis), that has been suggested as useful for orthostatic hypotension. Logan and Witham (2012) suggested that it overall worsened the postural drop in blood pressure.
Yohimbine is an alpha-2 blocker, used mainly for treatment of erectile dysfunction, but it also can be useful to elevate blood pressure (Logan and Witham, 2012).
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. L-DOPS is a precursor of norepinephrine and epinephrine. L-DOPs has also been used on an investigational basis (Gibbons et al) in persons refractory to other drugs. It is sold under the brand name of Droxidopa. L-DOPS can be combined with a peripheral dopamine decarboxylase inhibitor such as carbidopa (Lodosyn) to increase levels of the drug within the CNS. Very little is known about drug interactions, but it would seem to us that they would be very likely. It is difficult for us to see how this medication differs substantially from other adrenergic agonists such as Midodrine or ephedrine. Supine hypertension is a significant risk.
Atrial pacing can be considered when the heart rate is very low. Pacing has been reported not helpful in treatment of recurrent vasovagal syncope by Connolly (2003) but is reported helpful by others (Wohrle and Kochs, 2003). We think it is best to be conservative and skeptical in situations where implantable devices are studied due to the impossibility of obtaining placebo controls. Pacemakers may be effective in carotid sinus syndrome (a cause of syncope, not orthostatic hypotension).