Chapter 15 -syncope

Question 1

What is syncope?

Answer 1

• Sudden transient loss of consciousness with associated floppy syndrome (loss of postural tone accompanied by a rapid return to baseline)
• Wide range of life-threatening to benign
• Risk factors: known cerebral vascular disease, HTN, cardiac medications, CAD (highest risk of mortality from syncope)
• Increase mortality associated with age, CHF, CAD
• no mortality from vasovagal, orthostatic or medication induced syncope unless patient suffers trauma/injury

Pathophysiology: bilateral hemispheric dysfunction or RAS dysfunction. Majority from acute hypo-perfusion, can be local such as due to cerebral vasoconstriction SAH or systemic hypovolemia i.e. diarrhea

Question 2

12 critical causes of syncope?

Answer 2

Drop in cerebral perfusion pressure of more than 35% to have syncope.

DIMS:

1) drugs/toxins, 2)ischemia(TIA, CVA)/cardiac,
3) metabolic (hypoglycemia)
4) structural/neuro

Critical causes:
MI
arrhythmia 
thoracic aortic dissection 
critical AS
HOCM
pericardial tamponade
AAA
PE
Subarachnoid bleed
Toxin mediated
Severe hypovolemic shock 
Ruptured ectopic pregnancy 

Critical causes based on pathophysiology:
1) pump failure with heart
MI
VT/Vf
dissection 
critical AS 
HOCM
hypovolemia causes (AAA, toxic, 
2) problem with brain
severe hemorrhage, SAH, stroke in the brain)

Question 3

Describe the San Francisco Syncope rule?

Answer 3

5 pts:

1) Hx of CHF
2) Hematocrit <30% (anemic patient have impaired oxygen delivery)
3) Abnormal ECG (arhythmia, prolonged QT, electrical cardiac history)
4) SOB on history
5) sBP <90 at triage

If 1 or more of these points: high risk for bad cause of syncope - think about admission

Question 4

What are red flags that require admission in syncope?

Answer 4

Absolute:

1) CP - i..e maybe MI
2) unexplained SOB - i.e. cardiac, dysrhythmia cause
3) Hx of significant CHF or valvular disease - (i.e. AS) predispose to dysrhythmia that cause syncope
4) abnormal ECG: patients with ECG evidence of ventricular dysrhythmia, ischemia, significantly prolonged QT intervals, or new BBB

Relative red flags for admission:

1) age >45
2) pre-exsting CV disease or congenital heart disease
3) FH of sudden death (brugada, HOCM)
4) serious co-morbidities such as diabetes
5) exertional syncope: HOCM, critical AS