Click Here to Download this Blog Post –  Orthostatic Hypotension: Part 4 Of 6

Dr. Nicholas L. DePace, M.D., F.A.C.C.

This is Part 4 of a 6 Part Series about Orthostatic-Hypotension

The first thing when a person presents with orthostatic hypotension is to determine if there is a volume depletion issue or if there is truly an autonomic (baroreflex) failure.  Neurogenic autonomic hypotension, which means not related to dehydration, volume depletion, or a drug effect, can be classified into disorders with either a primary or secondary cause of autonomic failure.  It is estimated that up to 40% of people have no definite cause of orthostatic hypotension, and therefore, it is idiopathic.  About a quarter can have underlying neurodegenerative disorders, a third autonomic failure to diabetic neuropathy or paraneoplastic syndromes (cancer-related neuropathies).  The use of antidepressant drugs is often the cause of orthostatic hypotension if really sought for.

Secondary causes of autonomic dysfunction include peripheral neuropathies that affect the peripheral small fibers, which include the autonomic nerves.  The most common is diabetes mellitus.  However, usually, before this occurs in diabetes, one will have sensory abnormalities of the hands and feet, such as numbness and tingling, and then autonomic neuropathy will follow with drops in blood pressure.  Amyloidosis is not an uncommon cause of a peripheral neuropathy that can leave a person with orthostatic hypotension.  We will do an amyloid workup on patients who present with orthostatic hypotension and also a diabetic workup, including a hemoglobin A1c.  The amyloid workup may include genetic testing and blood and urine workup, especially to look for special types of proteins and immunoglobulins.

Click Here to Download this Blog Post –  Orthostatic Hypotension: Part 3 Of 6

Dr. Nicholas L. DePace, M.D., F.A.C.C.

This is Part 3 of a 6 Part Series about Orthostatic-Hypotension

If an increase in heart rate disproportionately occurs in a patient who has orthostatic hypotension, one has to suspect dehydration as the cause.  There are formulas to compute what is a normal response and not a normal response to heart rate when the blood pressure falls below 20 mmHg.  Usually, with a fall in blood pressure and thoracic volume, a reflex compensatory mechanism occurs in the central and peripheral nervous systems, which increases sympathetic and reduces parasympathetic outflow, and this is the baroreflex.  The increase in outflow raises peripheral and vascular resistance, decreases venous return in cardiac output, and will attempt to limit the fall in blood pressure.  Usually, when one assumes the upright position, 500 to 1000 cc of blood goes to the lower extremities and to the GI (splanchnic circulation).  The normal response when one assumes an upright position is no change or a small fall in systolic blood pressure, an increase in diastolic blood pressure, and an increase in pulse rate at 10 to 25 beats per minute.

However, patients who have orthostatic hypotension will have some of these compensatory mechanisms fall, and the blood pressure will drop.

The reason orthostatic hypotension is more common in older patients is due to the fact that they have impaired baroreceptor sensitivity.  Antihypertensive medicines may be related to orthostatic hypotension in older patients.  These include vasodilators such as nitrates, which also can reduce preload, and calcium channel blockers, more commonly called the so-called “hydro” calcium blockers, such as amlodipine and nifedipine.  Antidepressant drugs, such as tricyclics, especially in high doses, may also contribute to orthostatic hypotension as do antipsychotic agents and opiates.  Alcohol is a vasodilating agent and can exacerbate orthostatic hypotension based on many mechanisms, including over-diuresis, vasodilatation, and dehydration effects.

Click Here to Download this Blog Post –  Orthostatic Hypotension: Part 2 Of 6

Dr. Nicholas L. DePace, M.D., F.A.C.C.

This is Part 2 of a 6 Part Series about Orthostatic-Hypotension

Orthostatic hypotension could be due to impaired autonomic reflexes or intravascular volume depletion (dehydration). Symptoms commonly include dizziness, muscle aches, lightheadedness, fainting, and discomfort in the neck and shoulders, a so-called coat hanger syndrome. Even anginal chest pain can occur with orthostatic hypertension. Other symptoms commonly seen are blurred vision, generalized weakness, cognitive impairment, nausea, palpitations, tremulousness, headaches, and, as mentioned, presyncope and syncope. These symptoms can be incapacitating in patients who have more advanced forms of orthostatic hypotension and can impair them from even walking 10 or 20 feet before they have to sit down or lean against an object. Even more troublesome is that many people who have orthostatic drops have symptoms of autonomic dysfunction in other organs, such as the stomach (gastroparesis), the colon (constipation), the bladder (bladder dysfunction), and in the sweat glands (anhidrosis or the inability to sweat). Some people sweat in patchy distributions and not throughout their whole body and loose body water sweating in certain parts of the body. More worrisome is when orthostatic hypotension is accompanied by movement disorders that can affect balance and gait.

Patients also with postural orthostatic tachycardia may have similar symptoms as described above, as those with postural orthostatic hypotension. In these patients, the blood pressure does not drop, and they usually do not have fainting episodes. Rather, they have racing heart rates, often above 120 and 130 beats per minute. Usually, they are a younger subset of patients, whereas patients over the age of 50 usually will manifest orthostatic hypotension with blood pressure drops. Patients with postural orthostatic tachycardia syndrome, or POTS as it is commonly called, are normally seen in patients in their teens, 20s, and 30s but not commonly after the age of 40

Click Here to Download this Blog Post –  Orthostatic Hypotension: Part 1 Of 6

Dr. Nicholas L. DePace, M.D., F.A.C.C.

This is Part 1 of a 6 Part Series about Orthostatic-Hypotension

Orthostatic hypotension is defined as a decrease in systolic blood pressure greater than or equal to 20 mmHg or diastolic blood pressure greater than or equal to 10 mmHg within three minutes of one assuming the upright position.  Most of the time by two minutes, one could get a reliable estimate if orthostatic hypotension is present.  If someone has significant supine high blood pressure or hypotension, that is when they are lying down their blood pressure is greater than 160 systolic, we often require a systolic blood pressure drop of 30 mmHg or greater.   There are occasional rare cases where we see delayed orthostatic hypotension when the blood pressure will drop after three minutes, and this may actually represent a mild form of an abnormality of the sympathetic nervous system.  The sympathetic nervous system is like the accelerator of a car, and the parasympathetic nervous system is like the brakes of a car.  This is an analogy that we often use.   An accelerated sympathetic nervous system will raise heart rate and blood pressure

When syncope, or fainting, occurs, studies have shown that orthostatic hypotension may be responsible for about ten percent of the time for this.  In one European study, up to a quarter of syncope-associated complaints were associated with orthostatic hypotension in the emergency room.  Orthostatic hypotension, or more specifically neurogenic orthostatic hypotension, as it is often referred to, usually occurs in about one-fifth of patients over the age of 65 years of age and increases with age.  Many hospitalized patients, if they are tested, will show this, even if they are not symptomatic.  In addition, if one shows evidence of orthostatic hypotension, it is a strong predictor of future cardiovascular events and is in itself an adverse marker portending a worse prognosis in patients who have it.  Patients who have severe drops in orthostatic hypotension are even more jeopardized to have future cardiovascular events and, of course, falls as time goes on.  It is a serious disorder that needs to be recognized and treated aggressively.