Postural Hypotension Flashcards
What is important to know about Postural hypotension?
It is a CF, not a condition
What is the definition of Postural hypotension? (2 things)
One of these when standing up:
1. Fall in Systolic BP of 20+
1. Fall in Diastolic BP of 10+
What are the RF for Post Hypotension? (4 things)
- Age
- Autonomic neuropathy
- Anti-HTN meds
- Over diuresis (too much peeing)
What are the pathophysiological steps of Post hypotension? (4 steps)
- Person stands up
- Blood pools in lower extremities of body bc of gravity
- Venous return compromised –> reduces CO –> reduces arterial pressure
- Hypoperfusion of upper body
Why do healthy people not get Post hypotension when they stand up?
Baroreceptor reflex triggered
What is the Baroreceptor reflex mediated by?
Autonomic NS
What are the different Baroreceptors and what nerves are they innervated by? (2 things)
- Carotid sinus baroreceptor: CN 9
- Aortic arch baroreceptor: CN 10
How do Baroreceptors stop you from having Post Hypotension? (5 things)
- BP falls
- Baroreceptors detect blood vessels are less distended
- SNS activated + PNS inhibited
- Vasoconstriction + Increased HR
- BP elevated
What are the different titles of causes of Post Hypotension? (3 things)
- Hypovolaemia
- Meds
- Disease
What are the Hypovolaemia causes of Post Hypotension? (6 things)
- Dehydration (D+V / fever / heat stroke)
- Blood loss
- Excessive diuretic use
- Vasodilators
- Prolonged bed rest
- Anaemia
What are the Meds causes of Post Hypotension? (4 things)
- Beta blockers
- Sildenafil (aka Viagra)
- Tricyclic antidepressants
- Monoamine Oxidase Inhibitors
How do Beta blockers cause Post Hypotension? (3 things)
Block B-adrenergic receptors in body –> this prevents 3 things:
1. HR from increasing
1. Heart from contracting strongly
1. Vasodilation
How does Sildenafil cause Post Hypotension?
Dilates blood vessels
What are the Diseases that cause of Post Hypotension? (8 things)
- Addisons
- Atherosclerosis
- Autonomic neuropathy
- DM
- Phaeochromocytoma
- Parkinsons
- CVS
- Hypopituitarism (low ACTH)
How does DM cause Post Hypotension? (3 things)
- Peripheral neuropathy
- Affects Autonomic NS
- Interferes w Baroreceptor Reflex