Learning Objectives - Syncope

Question 1

Define syncope.

Answer 1

Sudden and brief LOC associated with a loss of postural tone from which recovery is spontaneous

Question 2

The pathophysiology of all forms of syncope consist of…

Answer 2

…sudden decreases in, or brief cessations of, cerebral blood flow.

Question 3

List 9 common cardiac causes of syncope.

Answer 3

Obstructive cardiac disease:

1. Valvular heart disease
2. Hypertrophic cardiomyopathy
3. Pulmonary HTN
4. Massive PE
5. Cardiac tamponade
6. Atrial myxoma

Arrhythmias:

7. Brady (sinus node dysfunction, AV block)
8. Tachy (atrial, ventricular)

Ischemia:
9. CAD (ACS with severe impairment of CO or arrhythmias)

Question 4

List 7 non-cardiac causes of syncope.

Answer 4

Peripheral vascular or circulatory dysfunction

1. Neurocardiogenic (vasovagal) syncope
2. Orthostasis (drugs, volume contraction, or autonomic dysfunction)

CNS Disorder

3. TIA/stroke (uncommon causes, as lesions would need to be bilateral)
4. Seizure (not true syncope, but may present like syncope)

Metabolic Derangement

5. Hypoglycemia
6. Potassium/magnesium/calcium disorders -> arrhythmia -> syncope
7. Hyponatremia -> seizure

Question 5

Define orthostatic hypotension.

Answer 5

Drop in systolic BP of 20+ OR diastolic BP of 10+ OR increased HR 30+ within 3 minutes of an upright tilt, or the inability to stand long enough for vitals 2/2 symptoms

Question 6

DDx - orthostatic hypotension?

Answer 6

Medications
Hypovolemia
Cardiac insufficiency
Diabetic neuropathy

Question 7

Work-up for syncope?

Answer 7

1. EKG (arrhythmia, ischemia, other abnormalities)
2. CXR (if chest pain, SOB, crackles)
3. Cardiac enzymes (r/o MI)
4. TSH (r/o hyperthyroidism -> arrhythmia)

Main goal - distinguish cardiac from non-cardiac

5. BMP ONLY if indicated
6. Echo (diagnostic assessment of valvular disease, AF, chamber size, peak RV pressure, hypertrophy, pericardial disease, left atrial thrombus)
7. Holter
8. CT/EEG/EP

DO NOT ORDER BRAIN IMAGING in simple witnessed syncope and a normal neuro exam

Question 8

Explain how atrial fibrillation may lead to syncope.

Answer 8

Loss of atrial mechanical function, irregular ventricular response, and high HR -> reduced diastolic filling, SV, CO

Aortic and mitral stenosis magnify these consequences.

Question 9

What are the important aspects of the history in a patient with syncope?

Answer 9

HPI: # syncopal episodes, LOC, head trauma, associated symptoms (pallor, diaphoresis, lightheadedness, nausea, dimming of vision), emotional stress/pain/fear preceding, postural changes
PMHx: cardiac history
Medications

Question 10

What are the important aspects of the physical in a patient with syncope?

Answer 10

Mental status
Vitals, orthostatics
Murmurs, bruits, HR/rhythm
Lung sounds