Orthostatic hypotension

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Sogand Goudarzi, MD [2]

Synonyms and keywords: Postural hypotension; orthostatic intolerance; head rush; dizzy spell

Overview

Orthostatic hypotension is a physical finding demarcated by the American Academy of Neurology and the American Autonomic Society as a reduction in systolic blood pressure of 20 mm Hg or a drop of 10 mm Hg in diastolic blood pressure within three minutes of standing compared with blood pressure from the sitting or supine position. Orthostatic hypotension is frequently found in frail patients and those who are older.2 It is noticed in up to 20 percent of patients older than 65 years .

Classification

Initial orthostatic hypotension (iOH)

It is most common in healthy adolescents and is demarcated as a brief BP decrease of >40 mmHg systolic or >20 mmHg diastolic with symptomatic cerebral hypoperfusion within five to fifteen seconds after standing, typically resolves by twenty seconds.

Neurogenic orthostatic hypotension (nOH)

In Neurogenic orthostatic hypotension, the sympathetic noradrenergic nerves continually fail to facilitate the reflexive cardiovascular responses essential to sustain blood pressure in response to orthostatic stress. It is described as a constant BP decrease of >20 mmHg systolic or >10 mmHg diastolic, without or with symptoms, within three minutes of head-up tilt or standing.

Delayed orthostatic hypotension (dOH)

Delayed orthostatic hypotension (dOH) is demarcated as a fall in blood pressure that accomplishes neurogenic orthostatic hypotension criteria but ensues after three minutes.

Neurally mediated syncope (vOH)

It is also recognized as vasodepressor or vasovagal syncope, It involves a paroxysmal extraction of sympathetic vasopressor tone, frequently during prolonged standing, in patients with an effective autonomic nervous system.

Cardiovascular orthostatic hypotension (cOH)

Cardiovascular orthostatic hypotension occurs from intravascular hypovolemia or reduced cardiac output along with compensatory tachycardia.

Orthostatic pseudohypotension (pOH)

It is stated as apparent orthostatic hypotension when baseline supine blood pressure is raised, which may be due to a short time at rest to create a valid baseline, related recumbent hypertension, or fluctuation of baseline blood pressure with labile hypertension.

Pathophysiology

• In standing position, 300 to 800 mL of blood pools in the lower extremities. Preservation of blood pressure while changing the position requires many organs like cardiac,neurologic, vascular, muscular, and neurohumoral to respond rapidly.9 If any of these responses are irregular, organ perfusion and blood pressure can be reduced. Therefore, symptoms of central nervous system hypoperfusion may arise, including nausea, weakness, dizziness, headache, lightheadedness, fatigue, blurred vision, palpitations, tremulousness, vertigo, and impaired cognition.
• The autonomic nervous system plays a significant role in sustaining blood pressure when a person changes position. The sympathetic nervous system regulates the tone in the heart, arteries, and veins.
• Baroreceptors located mainly in the aorta and carotid arteries are very sensitive to fluctuations in blood pressure. As soon as the baroreceptors sense the minor decrease in blood pressure, a synchronized increase in sympathetic stimulation occurs. Arteries contract to increase blood pressure and peripheral resistance, and subsequently increases heart rate and contractility.
• All of these responses are designed to sustain perfusion and blood pressure. Additional physiologic mechanisms can also be involved including the renin-angiotensin-aldosterone system, low-pressure receptors in the heart and lungs, the systemic release of norepinephrine, and vasopressin.
• Over-all, all parts of the nervous systems and cardiovascular must work together. If there is insufficient intravascular volume, a decrease of venous return, impairment of the autonomic nervous system, or the heart's incapability to pump with the higher power, orthostatic hypotension may result.

Causes

Common Causes

Common causes of orthostatic hypotension may include:

• Medical conditions:
  • Pregnancy
  • Heart problems: Bradycardia, heart valve problems, heart attack and heart failure.
  • Dehydration: Fever, vomiting, severe diarrhea, overuse of diuretics and strenuous exercise can lead to dehydration.
  • Endocrine problems
  • Blood loss
  • Septicemia
  • Aanaphylaxis: reaction include foods, certain medications, insect venoms and latex.
  • Anemia: Lack of nutrients (vitamins B-12, folate)
• Medication:
  • Apomorphine hydrochloride
  • Bromocriptine
  • Cidofovir
  • Entacapone
  • Ethacrynic Acid
  • Fluphenazine
  • Hydrochlorothiazide
  • Iloperidone
  • Loxapine
  • Niacin
  • Pergolide
  • Perphenazine
  • Rasagiline
  • Risperidone
  • Ritonavir
  • Rotigotine
  • Thioridazine hydrochloride
  • Thiothixene,
  • Tiagabine
  • Vincristine sulfate liposome
  • Diuretics especially furosemide, Lisinopril and Hydrochlorothiazide
  • Beta Blockers,
  • Calcium channel blockers
  • ACE Inhibitors
  • Prazosin
  • Tamsulosin
  • Nitrates
  • Anti-psychotics Clozapine, zotepine, Olanzapine,
  • Neuroleptics
  • Sedative hypnotics
  • Anti-depressants,duloxetine,tricyclics
  • MAOIs
  • Pramipexole
  • Ropinirole.

Differentiating Xyz from Other Diseases

Intravascular volume depletion: Blood loss

• Dehydration
• Pregnancy/postpartum
• Shock

Cardiovascular:

• Anemia
• Cardiac arrhythmia
• Congestive heart failure
• Myocardial infarction
• Myocarditis
• Pericarditis
• Valvular heart disease
• Venous insufficiency
• Postprandial hypotension

Neurologic Causes:

• Amyloidosis (hereditary and primary)
• Diabetic autonomic neuropathy
• Lewy body dementia
• Multisystem atrophy(Shy-Drager syndrome)
• Parkinson disease
• Pure autonomic failure

Drugs:

• Alcohol
• Antiadrenergic
• Antianginals
• Antiarrhythmics
• Anticholinergics
• Antidepressants
• Antihypertensives
• Antiparkinsonian agents
• Diuretics
• Narcotics
• Neuroleptics
• Sedatives

Endocrine Causes:

• Adrenal insufficiency
• Diabetes insipidus
• Hyperglycemia, acute
• Hypoaldosteronism
• Hypokalemia
• Hypothyroidism
• Pheochromocytoma

Miscellaneous:

• AIDS
• Anxiety or panic disorder
• Eating disorders
• Prolonged bed rest

Epidemiology and Demographics

Incidence

• The approximation of Orthostatic hypotension‐associated hospitalization is 36 per 100,000 adults, and the rate can be as high as 233 per 100,000 patients >75 years of age.

Prevalence

• The overall prevalence of Orthostatic hypotension depends on age as it increases with age in the general population.
• The prevalence ranges from 5% in patients <50 years of age to 30% in those >70 years of age.
• It is ~20% in > 65-year-old patients.

Age

• Orthostatic Hypotension is commonly seen in individuals older than 50 years of age.

Gender

• Orthostatic hypotension affects men and women equally.

Risk Factors

Common risk factors in the development of orthostatic hypotension include:

• Age (>65)
• Medications (alpha blockers)
• Disease: Parkinson's disease, diabetes
• Postpartum period
• Prolong bedrest.

Screening

• Orthostatic hypotension, screening consists of blood pressure measurements in supine (or sitting) and standing position during clinical consultations.

Natural History, Complications, and Prognosis

Natural History

• The symptoms of orthostatic hypotension mainly develop in the elderly, and start with generalized symptoms of dizziness, lightheadedness, or syncope and less frequently with headache, leg buckling, or chest pain.

Complications

Common complications of orthostatic hypotension include:

• Moderate low blood pressure:
  • Dizziness
  • Weakness
  • Fainting (increase risk of injury by falling down)
    
• Severely low blood pressure:
  • Heart damage (Heart failur)
  • Brian damage (Stroke)

Prognosis

• Depending on the underlying condition of orthostatic hypotension at the time of diagnosis, the prognosis may vary.

Diagnostic study of choice

• Orthostatic vitals are the best diagnostic tests that are simple and easy to perform in a clinical setting.

History and Symptoms

• Symptoms are predominant when standing, less often when sitting, and they subside when lying down.
• Symptoms of orthostatic hypotension may include the following:

• Generalized weakness
• Lightheadedness
• Dizziness
• headache
• Blurred or dimmed vision (possibly to the point of momentary blindness)
• Fatigue
• Cognitive slowing
• Leg buckling
• Neck pain
• Localized headache (in the suboccipital, posterior cervical, and shoulder region)

Physical Examination

The physical exam must include orthostatic vital signs

Diagnosis

Laboratory Findings

There are no diagnostic laboratory findings associated with orthostatic hypotension. While the definitive diagnosis of orthostatic hypotension is made clinically, other tests contribute to understanding the risks of disease and may provide clues to the selection of treatment options. These tests include those that access the underlying cause that may be altered in patients suffering from orthostatic hypotension. Addressing these conditions may improve the quality of life of a patient.

• CBC
• Basic metabolic panel
• Serum electrolytes
• Blood Glucose
• Creatinine
• TSH

Electrocardiogram

An ECG may be helpful in the diagnosis of orthostatic hypotension. Findings on an ECG suggestive of orthostatic hypotension include:

• [Longer PR]
• [Longer QT intervals]
• [Larger Systolic blood pressure reduction]

X-ray

• There are no x-ray findings associated with orthostatic hypotension.

Echocardiography and Ultrasound

• Echocardiography can be helpful in severe cases.

CT scan

CT scan may be helpful in the diagnosis of orthostatic hypotension. Findings on CT scan diagnostic of orthostatic hypotension include the presence of a cerebral tumor or communicating hydrocephalus.

MRI

• Brain MRI may be helpful in the diagnosis of neurogenic orthostatic hypotension.

Other Imaging Findings

• There are PET or MIBG imaging findings that are optional.

Treatment

Medical Therapy

Pharmacological: Some drugs that are used in the treatment of orthostatic hypotension include fludrocortisone (Florinef), erythropoietin, midodrine and Pyridostigmine bromide (Mestinon)

Non-phamacological: Avoid triggers: large meals, hot bath, prolong standing

Steps to approach a patient
When we should suspect orthostatic hypotension?:
Unexplained fall/syncope
Typical symptoms (dizziness, lightheadedness, confusion, fatigue, gait disorder, neck pain, and vision disturbance)
Patient history (age, neurodegenerative disorder disease, renal failure, amyloidosis, autoimmune disease, heart disease, hypertension, autoimmune disease)
Current pharmacological treatment (vasodilator, alpha-and beta-blockers, diuretics, tricyclic-antidepressants
Initial assessment (outpatient clinic. ED and hospital):
Physical examination
Laboratory assessment (Hb, electrolytes, glucose, TSH, creatinine)
Bedside BP supine/standing test (after 1-3.5 min)
Cardiac assessment (ECG, telemetry or Holter-ECG, echocardiography, exercise-ECG, angiography if indicated i.e., history or signs of cardiac disease)
Neurological assessment (neurological status, and brain imaging if indicated, i.e., history of trauma and neurological symptoms)
Orthostatic Hypotension confirmed:
Nonpharmacological methods+ drug modification (mild-moderate cases)
Pharmacological/compression therapy (severe cases)
Advanced cardiac and autonomic assessment (investigation unit led by an expert):
Head-up tilt test with continuous BP monitoring plus active standings, carotid sinus massage, and Valsalva test (if positive, indicates neurogenic orthostatic hypotension); neuroendocrine assessment (supine and standing epinephrine/norepinephrine; other biomarkers such as vasopressin, renin, endothelin-1, the natriuretic peptide can be considered)
24 -h-ambulatory BP monitoring (BP variability pattern? Non-dipping? Reversed dipping? Diurnal hypotension period? Overtreatment? White Coat Syndrome?)
Long-term ECG monitoring if indicated (Cardiac arrhythmia? Chronotropic insufficiency?)
Cardiac sympathetic neuroimaging (PET or MIBG, optional if available)
Specialist consultation/referrals (if indicated):
Cardiologist (OH with concurrent cardiac arrhythmia, structural heart disease, and/or severe hypertension)
Neurologist (neurogenic OH and/or concurrent neurodegenerative diseases such as pure autonomic failure, Parkinson's disease, or multiple system atrophy)
Endocrinologists (patient with suspected or confirmed endocrine disorder such as hypothyroidism, electrolyte abnormalities, or adrenal diseases)
Geriatrician (older patient with special needs and comorbidities, dementia, cognitive impairment, fall tendency)
Otolaryngologist ("dizziness" with preserved hemodynamic parameters or typical vertigo)

Intervention

The mainstay of treatment for Orthostatic hypotension is medical therapy and lifestyle changes.

Lifestyle Advice

Some suggestions for minimizing the effects include:

• Checking blood pressure regularly with a home monitoring kit. Check when lying flat and when standing as well as when symptoms occur.
• Standing slowly rather than quickly, as the delay can give the blood vessels more time to constrict properly. This can help avoid incidents of syncope (fainting).
• Take a deep breath and flex your abdominal muscles while rising to maintain blood and oxygen in the brain. This, however, may be contraindicated in individuals with Stage 3 hypertension.
• Usually, medical personnel has their patients "dangle" before rising from bed to decrease dizziness/falling due to orthostatic hypotension. The dangling is done by having the patient sit on the side of their bed for about a minute so they do not have the sudden dizziness.
• Maintaining an elevated salt intake, through sodium supplements or electrolyte-enriched drinks. A suggested value is 10 g per day; overuse can lead to hypertension and should be avoided.
• Maintaining a proper fluid intake to prevent the effects of dehydration.
• As eating lowers blood pressure, eat multiple smaller meals rather than fewer more substantial meals. Take extra care when standing after eating.
• When orthostatic hypotension is caused by hypovolemia due to medications, the disorder may be reversed by adjusting the dosage or by discontinuing the medication.
• When the condition is caused by prolonged bed rest, improvement may occur by sitting up with increasing frequency each day. In some cases, physical counterpressure, such as an elastic hose or whole-body inflatable suits, may be required.

Primary Prevention

Effective measures for the primary prevention of orthostatic hypotension include:

ABCDEF method .

• A Abdominal compression: Wear an abdominal binder when out of bed
• B. A bolus of water/elevate Bed: On bad days, drink two 8-ounce glasses of cold water prior to prolonged standing and sleep with the head of the bed raised about 4 inches
• C. Counter-maneuvers: While standing, contract the lower abdominal muscles for about 30 seconds
• D. Drugs: Midodrine, Pyridostigmine, or Fludrocortisone can be used to elevate blood pressure (acknowledge any medications currently taken that can lower blood pressure)
• E. Education & Exercise: Note any symptoms that indicate a fall in blood pressure while standing, recognize conditions that lower blood pressure (i.e. heavy metals, temperature changes, exercise, change in position)
• F. Fluids: Stay hydrated

External Links

• John G. Bradley, M.D., and Kathy A. Davis, R.N. Orthostatic Hypotension American Family Physician
• DYNA Dysautonomia Youth Network of America, Inc.

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