Orthostatic Hypotension – Diagnosis, Symptoms, and Treatment

What is Orthostatic Hypotension?

Orthostatic hypotension is a medical condition characterized by a significant drop in blood pressure upon standing.  This often leads to symptoms of dizziness and faintness and may occasionally result in loss of consciousness.  Rarely, orthostatic hypotension can lead to angina (chest pain) or even stroke.  The most common causes of orthostatic hypotension include intravascular volume depletion (dehydration) or autonomic reflex impairment.

Volume depletion frequently occurs in the setting of antihypertensive use, particularly with diuretics.  This is especially common in the elderly population.  Autonomic dysreflexia may occur in individuals with central or peripheral nervous system disorders such as Parkinson's disease.

What Causes Orthostatic Hypotension?

The most common causes of orthostatic hypotension include intravascular volume depletion (dehydration) or autonomic reflex impairment.  Volume depletion frequently occurs in the setting of diuretic use, especially in the elderly population.  It may also affect athletes who drink inadequate amounts of fluids with extreme physical activity.  Individuals at higher altitudes who do not keep up with insensible water loss are also at increased risk.  Patients with coexisting illnesses resulting in fever, nausea, vomiting, diarrhea, or inadequate oral intake can also become significantly dehydrated and develop orthostatic hypotension.

Autonomic dysreflexia may occur in individuals with central or peripheral nervous system disorders.  This may include individuals with Parkinson's disease, multiple system atrophy, diabetic autonomic neuropathy, paraneoplastic autonomic failure, or stroke.  Patients with the spinal disease also often develop autonomic dysfunction.  When an autonomic function is impaired, blood pressure decreases upon standing because sympathetic vasoconstriction cannot compensate appropriately – this results in decreased blood perfusion to the brain, leading to dizziness and potentially loss of consciousness.

Substances that increase the risk of orthostatic hypotension include:

•         Alcohol
•         Opiates (e.g., oxycodone)
•         Beta-blockers (e.g., metoprolol)
•         Nitrates (e.g., isosorbide mononitrate)
•         Calcium channel blockers (e.g., amlodipine)
•         Tricyclic antidepressants (e.g., amitriptyline)

Complications include:

•         Increased risk for cardiovascular disease, including stroke
•         Increased risk for falls, particularly in the elderly population
•         Anxiety and depression due to disability

How Common is Orthostatic Hypotension?

Orthostatic hypotension is exceedingly common in the United States and responsible for many primary care and emergency department visits.  The condition may require referral to a cardiologist if first-line diagnostic workup and treatment are unsuccessful.

The prevalence is approximately 5%-20%.  Up to 40% of patients have no identified cause of orthostatic hypotension despite undergoing a comprehensive medical evaluation.  One study showed that about 27% of patients with orthostatic hypotension had a primary autonomic failure, approximately 35% had a secondary autonomic failure (e.g., diabetic, paraneoplastic), and 38% had no autonomic dysfunction.  An estimated 20% of individuals age >65 have orthostatic hypotension.

Signs and Symptoms

The most common symptom and signs of orthostatic hypotension include:

•         Dizziness
•         Faintness
•         Loss of consciousness
•         Features of angina or stroke (rare)

Symptoms typically occur when going from a sitting or laying down position to standing.

Diagnosis

The diagnosis is suggested based on symptoms but typically confirmed with orthostatic vital sign testing.  Within 2-5 minutes of standing, one or two of the following must be present:

•         20 mmHg drop in systolic blood pressure
•         10 mmHg drop in diastolic pressure

Laboratory tests are often obtained in patients to identify treatable conditions that may be causing orthostatic hypotension.  Commonly ordered blood tests include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), and thyroid function (TSH, free T4).  They will also usually check your cholesterol levels and screen for diabetes.  If a heart disease is suspected, your doctor will usually obtain an EKG (electrocardiogram) and ultrasound of the heart (echocardiogram).  If you have symptoms or signs suggestive of neuropathy, your doctor may order electromyography and nerve conduction studies to identify the underlying cause.

Orthostatic Hypotension Treatment

Orthostatic hypotension is initially managed by discontinuing medications that may be contributing to the condition (e.g., diuretics or beta-blockers).  Other conservative measures include increased sodium and fluid intake, leg stockings, and physical maneuvers' performance before symptom onset.  Physical techniques that may be beneficial include isometric handgrip.  Crossing the legs while actively standing on them may also help.  Daily caffeine in the mornings is also helpful in many individuals.

Individuals that remain symptomatic despite conservative measures are often started on a mineralocorticoid called Florinef (fludrocortisone).  Sympathomimetic medications such as ProAmatine (midodrine) are occasionally added in patients with refractory symptoms.  ProAmatine (midodrine) can also be substituted for Florinef (fludrocortisone).  Patients taking these medications are monitored closely with serial blood pressure readings over several days.  Measurements are often recorded multiple times throughout the day, taken lying down, sitting, and standing up.

Some experts suggest nonsteroidal anti-inflammatory drugs (e.g., Naproxyn – naproxen) as a last resort option in individuals refractory to the treatments above.  Recombinant erythropoietin may be considered in patients with coexisting anemia.

References:

1.     Miller ER 3rd, Appel LJ. High prevalence but uncertain clinical significance of orthostatic hypotension without symptoms. Circulation 2014; 130:1772.
2.     Mills PB, Fung CK, Travlos A, Krassioukov A. Nonpharmacologic management of orthostatic hypotension: a systematic review. Arch Phys Med Rehabil 2015; 96:366.
3.     Raj SR, Coffin ST. Medical therapy and physical maneuvers in the treatment of the vasovagal syncope and orthostatic hypotension. Prog Cardiovasc Dis 2013; 55:425.