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Flashcards in Syncope Deck (27)
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1

General definition of syncope

transient loss of consciousness and postural tone

2

General underlying cause of all syncope

global cerebral hypofusion

3

Time course of syncope

Onset is rapid, duration brief, and recovery spontaneous and complete

4

Epidemiology of syncope

Lifetime incidence 35%
F > M
More after 70 yo

5

Pathophysiology of syncope

Decrease venous return -> diminished CO and BP -> baroreceptors in carotid sinus and AA provoke reflex -> increased sympathetic and decreased vagal -> peripheral vasoconstriction to promote venous return and CO -> failure results in hypoperfusion, occurs at 50mmHg -> cessation of blood flow for 6-8 sec results LOC

6

Categories of syncope

1) Neurally mediated - reflex, transient change in hemostatic reflexes

2) Neurogenic orthostatic hypotension - autonomic, chronically impaired homeostatic reflexes

3) Cardiogenic - cardiac conditions cause a decrease in CO

7

Initial eval of all syncope patients

History: Witnesses, precipitating events, associated sx, and medical Hx

PE: cardio/neurologic exam, vital signs (orthostatic)

ECG if any cardiac suspicion

identifies cause in 50%
helps risk stratify the remainder

8

Usual labs to dx syncope

CBC, BMP, UA

9

RF for adverse outcomes of syncope

- Abnormal ECG
- H/O heart disease
- Systolic <30
- Older age
- FHX sudden cardiac death

10

How to treat syncope patients with high-risk criteria

admit for eval and cardiac monitoring

11

Cause of neurally mediated syncope

transient change in autonomic efferent activity
- increased parasympathetic excitation = bradycardia
- increased sympathetic inhibition = vasodilation

MUST HAVE INTACT AUNTONOMIC NS

12

Which syncope is benign, usually associated with known trigger

neurally mediated

13

Subtypes of NMS

1) vasovagal syncope (common faint)

2) situational reflex syncope (triggers include fear, intense emotion, unpleasant sight/odor)

14

Tx for NMS

Reassurance, avoid provocative stimuli, IV fluids prn

15

Prodromal sx of syncope

Caused by autonomic activation -> diaphoresis, pallor, palpitations, nausea, hyperventilation

16

orthostatic hypotension

reduction of at least 20 systolic or 10 diastolic within 3 min of standing

17

2 classifications of orthostatic hypotension

Volume depletion
Neurogenic (Autonomic)

18

Volume depletion orthostatic hypotension

- Occurs within 15 secs of standing
- Mismatch between CO and PVR
- Compensatory increase in HR
- Supine Hypertension uncommon
- Caused by volume depletion, vasodilatation, or decreased CO

19

Neurogenic/Autonomic orthostatic hypo

- Occurs within 3 mins of standing
- Sympathetic vasoconstrictor (autonomic) failure
- Usually NO compensatory increase in HR
- Supine Hypertension common
- Caused by central neurodegenerative disorders and peripheral neuropathies

20

predisposing factors of NOH

Postprandial, elderly

21

Presyncope symptoms

- Commonly in neurogenic orthostatic hypotension
- Caused by hypoperfusion/ischemia of various structures
- dizziness, lightheadedness, weakness, fatigue, and visual/auditory disturbances, headache, cognitive slowing

22

Dx studies for NOH

- Tilt table test
- HR (parasympathetic) and BP (sympathetic) response to Valsalva
- Thermoregulatory sweat response (sympathetic cholinergic)

23

Tx of NOH

- Remove reversible causes
- Patient education: staged moves from supine to upright, isometric counter measures, raising head of bed, warn about hypotension after meals
- Optimize intravascular volume with fluid and salt intake

24

Which type get prodromal symptoms?

neurally mediated syncope (vasovagal)

25

Which type get presyncope sx?

neurogenic orthostatic hypotension

26

Central neurodegenerative disorders that cause orthostatic hypotension

Alzheimer's, Lewy Bodies disorders (Parkinson's, dementia), stroke

27

Peripheral neurodegenerative diseases that cause orthostatic hypotension

DM, amyloidosis, spinal cord injury