Pathophysiology BMS 243 Hypotension Dr Aya M Serry

Pathophysiology BMS 243 Hypotension Dr. Aya M. Serry 2016

CONTENTS… • DEFINITION • RISK FACTORS • SIGNS AND SYMPTOMS • TYPES AND PATHOPHYSIOLOGY • TREATMENT

Definition of hypotension • Hypotension is abnormally low blood pressure. • Blood pressure is the force of blood pushing against the walls of the arteries when the heart pumps out blood. • Normal blood pressure in adults is lower than 120/80 mm. Hg. • Hypotension is blood pressure that's lower than 90/60 mm. Hg.

Risk Factors 1. Older adults are more likely to have orthostatic and postprandial hypotension. Children and young adults are more likely to have neurally mediated hypotension. 2. People who take certain medicines such as diuretics or other high blood pressure medicines are at increased risk for hypotension.

Risk Factors 4. Central nervous system disorders (such as Parkinson's disease) and some heart conditions. 5. Pregnancy, hypotension during pregnancy is normal and usually goes away after birth.

Signs And Symptoms 1. Dizziness or light-headedness 2. Blurred vision 3. Confusion 4. Weakness 5. Fatigue (feeling tired) 6. Nausea (feeling sick to your stomach)

Severe Hypotension Linked to Shock • In SHOCK , not enough blood and oxygen flow to the body's major organs, including the brain due to major blood loss or heart failure. • The early signs and symptoms of reduced blood flow to the brain include light-headedness, sleepiness, and confusion. • If the shock continues, the person will lose consciousness. • Shock often is fatal if not treated right away.

Severe Hypotension Linked to Shock • The skin becomes cold and sweaty. • It often looks blue or pale, If pressed, the color returns to normal more slowly than usual. • A bluish network of lines appears under the skin. • The pulse becomes weak and rapid. • The person begins to breathe very quickly.

Types of hypotension Orthostatic (postural) Acute (sudden) Chronic Postprandial

1 -Orthostatic (postural) hypotension • It is defined as a drop in BP within 3 minutes of standing. • Normal pooling of the blood in the lower limbs is not corrected for by the cardiovascular system on moving to a vertical position. • This is usually due either to a defective autonomic reflex arc, or hypovolaemia that can be the result of blood or fluid loss, diuretic or vasodilator therapy. • Can also be associated with prolonged bed rest and drugs that affect reflex control of BP, including antidepressants.

MANAGEMENT OF POSTURAL HYPOTENSION • A morning dose of caffeine as coffee or tablet form can be effective. • If symptoms still persist consider midodrine: This is a peripherally acting alpha-1 -adrenoceptor agonist. It increases BP via vasoconstriction.

2. Acute hypotension • In the acute form it can be a serious clinical feature that may cause renal, cerebral and myocardial hypoxic damage. It is often associated with the different forms of shock including: 1. 2. 3. 4. Septic - Gram-negative septicaemia. Following myocardial infarction MI. Hypovolaemia - blood loss (haemorrhage), plasma loss (burns), dehydration (diarrhoea and/or vomiting). Anaphylactic shock.

Acute hypotension management 1. Check airways. 2. Give O 2 by mask. 3. Place patient head down. 4. Administer IV fluids (0. 9% saline). 5. Treat underlying cause (diarrhea and vomiting ).

3. Chronic hypotension • Primary acquired disease of the adrenals gland (Addison's disease). • Systolic BP is rarely >110 mm. Hg. • Aderenal gland can not secret Adrenaline and nor adrenaline. • No sympathetic activation of the CVS.

4. Postprandial hypotension • It mainly occurs in the elderly and those with autonomic neuropathy. • Cause is unclear but is associated with high carbohydrate meals. • Defined as fall in BP (20 mm. Hg within 2 hours of a meal but usually occurs much sooner). Symptoms : 1. Dizziness 2. Feeling faint

Management of Postprandial hypotension 1. Patients need to take smaller, more frequent meals containing fewer sugars and starches. 2. Lying down after meals needs to be balanced with risk of reflux.

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