orthostatic hypotension

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Dr AMIT KUMAR MALLIK DEPT. OF PHYSICAL MEDICINE AND REHABILITATION RIMS,IMPHAL ORTHOSTATIC HYPOTENSION

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Page 1: Orthostatic Hypotension

Dr AMIT KUMAR MALLIK

DEPT. OF PHYSICAL MEDICINE AND REHABILITATION

RIMS,IMPHAL

ORTHOSTATIC HYPOTENSION

Page 2: Orthostatic Hypotension

Definition

BLOOD PRESSURE

The pressure exerted by flowing column of blood on arterial wall.

Normal BP- Systolic 100-140 mm Hg

Diastolic 60-90 mm Hg

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Orthostatic hypotension

• Decrease in systolic BP≥20 mm Hg or decrease in diastolic BP≥10 mm Hg within 3 minutes of standing when compared with BP from sitting or supine position

or

• Similar drop in BP within 3 minutes in a head up position on tilt table test at angle ≥60°

Page 4: Orthostatic Hypotension

Normal mechanism of BP regulation

There are two basic mechanisms for regulating blood pressure:

(1) short-term mechanisms

(2) long-term mechanisms

Blood Pressure = cardiac output x peripheral resistance

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Location of Baroreceptor and Chemoreceptor

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Control of Blood pressure

I. Nervous system

II. Chemoreceptor

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I. Nervous System

• Control BP by changing blood distribution in the body and by changing blood vessel diameter.

• Sympathetic & Parasympathetic activity

• The vasomotor center – medulla

It sends efferent motor fibers that innervate smooth muscle of blood vessels

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Regulation of Rising Blood Pressure

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Baroreceptors

• The best known of nervous mechanisms for arterial pressure control(baroreceptor reflex)

• Baroreceptor are stretch receptors found in the carotid sinus ,aortic sinus

• Respond more to a rapidly changing pressure than stationary

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Baroreceptors

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Effect of Baroreceptors

EFFECT

VASODILATATION OF THE VEINS AND ARTERIOLES

DECREASED HEART RATE AND STRENGTH OF HEART

CONTRACTION

Therefore, excitation of baroreceptors by high pressure in the arteries reflexly causes arterial pressure to decrease (as decrease in PR and CO)

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Increased Parasympathetic Activity

• Reduction of heart rate

• Lower cardiac output

• Lower blood pressure

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Regulation of Falling Blood PressureBaroreceptors inhibited

Decreased impulses to the brain

Decreased parasympathetic activity, increased sympathetic activity

Effects

Heartincreased heart rate and

increased contractility

Vesselsincreased vasoconstriction

Adrenal glandrelease of epinephrine and

norepinephrine which enhance heart rate

Contractility and vasoconstriction

Increased blood pressure

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Page 15: Orthostatic Hypotension

II. Chemoreceptor

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Chemoreceptor

• Chemosensitive cells that respond to changes in pCO2 and pO2 and pH levels (Hydrogen ion).

pCO2 pO2 and pH

Stimulation of vasomotor center

CO HR vasoconstriction

BP (speeding return of blood to the heart and lungs)

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Chemoreceptor

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• Any interruption in the body's natural process of counteracting low blood pressure

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Causes of Postural HypotensionNeurogenic causes

Primary causes-

Autonomic failure due to idiopathic central and peripheral neurodegenerative diseases—the “synucleinopathies”

• Parkinson’s disease

• Lewy body dementia

• Pure autonomic failure

• Multiple system atrophy (Shy-Drager syndrome)

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Secondary causes1.Spinal cord injury

2.Secondary autonomic failure • Diabetes

• Hereditary amyloidosis (familial amyloid polyneuropathy)

• Primary amyloidosis (AL amyloidosis; immunoglobulin light chain associated)

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• Idiopathic immune-mediated autonomic neuropathy

• Autoimmune autonomic ganglionopathy

• HIV neuropathy

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Non-neurogenic Causes of Orthostatic Hypotension

• Age related

Cardiac pump failure

• Myocardial infarction

• Myocarditis

• Constrictive pericarditis

• Aortic stenosis

• Tachy-arrhythmias

• Brady-arrhythmias

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Reduced intravascular volume

• Dehydration

• Diarrhea, emesis

• Hemorrhage

• Burns

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Metabolic

• Adrenocortical insufficiency

• Hypo-aldosteronism

• Pheo-chromocytoma

• Severe potassium depletion

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Venous pooling• Postprandial dilation of splanchnic vessel beds

• Vigorous exercise with dilation of skeletal vessel beds

• Heat: hot environment, hot showers and baths, fever

• Prolonged recumbency or standing

Page 26: Orthostatic Hypotension

Medications

• Antihypertensives

• Diuretics

• Vasodilators: nitrates, hydralazine

• Alpha- and beta-blocking agents

• CNS sedatives: barbiturates,opiates

• Tricyclic antidepressants

• Phenothiazines

Page 27: Orthostatic Hypotension

Symptoms

Characteristic symptoms are

• Light-headedness

• Dizziness

• Presyncope (near-faintness)

However, symptoms may be absent or nonspecific like

• Generalized weakness

• Fatigue

• Cognitive slowing

• Headache.

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• Visual blurring

• Neck pain—typically in

-suboccipital

-posterior cervical

-shoulder region

( “coat-

hanger headache”)

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• Patients may report orthostatic dyspnea

• Symptoms may be exacerbated by exertion, prolonged standing, increased ambient temperature, or meals

• Syncope is usually preceded by warning symptoms, but may occur suddenly, suggesting the possibility of a seizure or cardiac cause

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Percentage wise symptoms

• Lightheadedness (dizziness) 88%• Weakness or tiredness 72%• Cognitive difficulty (thinking/concentrating) 47%• Blurred vision 47%• Tremulousness 38%• Vertigo 37%• Pallor 31%• Anxiety 29%• Palpitations 26%• Clammy feeling 19%• Nausea 18%

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Diagnosis

• By taking BP in supine and standing

• By comparing both BP

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Management

Non pharmacological

• Patient education: mechanisms and stressors of OH

• Compression garments

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• The head of the bed of a patient with orthostatic hypotension should be elevated by 10 to 20 degrees or 4 inches (10 cm)

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• Move legs while standing

• Get up slowly

• Avoid bending at waist

• FES

• Exercise-Calf muscle exercise, when getting out of bed, sit on edge of bed for a minute before standing

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• High-salt diet (1g/d) QID

• High-fluid intake (2 l/d)

• Learn physical counter-maneuvers

• Correct anemia

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Medicines(pharmacological)

• Fludrocortisone

• L-dopa-to treat hypotension a/w Parkinson ds.

• Midodrine or Ephedrine

• Erythropoitin

• Pyridostigmine

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Page 38: Orthostatic Hypotension

Thank You