Syncope

What is the definition of syncope?

Transient loss of consciousness due to global cerebral hypoperfusion, followed by spontaneous recovery.

What is the pathophysiology of syncope?

Sudden drop in cerebral blood flow from cardiac, reflex (vasovagal), or orthostatic mechanisms.

What are the major types of syncope?

• Cardiac

• Vasovagal (reflex)

• Orthostatic

• Neurologic

• Psychogenic

What are high-yield differentials for syncope?

• Seizure

• TIA

• Vasovagal

• Cardiac arrhythmia

• Orthostatic hypotension

What symptoms may precede syncope?

• Dizziness

• Vertigo

• Palpitations

• Nausea

• Weakness

What symptoms may NOT precede syncope?

Syncope may occur without prodrome.

What symptoms suggest seizure rather than syncope?

• Tongue biting

• Postictal confusion

• Prolonged unconsciousness

• Tonic-clonic movements

What symptoms suggest cardiac syncope?

• Sudden collapse without prodrome

• Palpitations

• Exertional syncope

• Family history of sudden death

What symptoms suggest vasovagal syncope?

• Nausea

• Warmth

• Sweating

• Emotional stress

• Prolonged standing

What symptoms suggest orthostatic syncope?

• Occurs when standing

• Lightheadedness

• Dehydration

• Medication-related

What physical exam findings may occur in syncope?

• Orthostatic hypotension

• Arrhythmias

• Murmurs

• Neurologic deficits (if alternative diagnosis)

What is orthostatic hypotension?

Drop in SBP ≥20 mmHg or DBP ≥10 mmHg within 3 minutes of standing

What laboratory studies are used in syncope evaluation?

• CBC

• CMP

• Magnesium

• Phosphorus

• Urine drug screen

What imaging may be used in syncope evaluation?

Head CT (rule out neurologic causes)

What cardiac testing is used in syncope evaluation?

• ECG

• Echocardiogram

• Telemetry

• Holter monitor (outpatient)

What ECG findings may suggest cardiac syncope?

• Arrhythmias

• Heart block

• QT prolongation

• Ischemic changes

What echo findings may suggest cardiac syncope?

• Structural heart disease

• Valvular disease

• Reduced EF

What additional testing may be used for syncope?

Orthostatic blood pressures

What is the management disposition for syncope?

Treat underlying cause

When should syncope patients be admitted?

• Cardiac suspicion

• Abnormal ECG

• Structural heart disease

• Recurrent syncope

• Injury during syncope

• High-risk features

What inpatient monitoring is recommended?

Telemetry

What outpatient monitoring may be used?

Holter monitor if inpatient telemetry is negative.

What complications can occur from syncope?

• Falls

• Trauma

• Underlying cardiac arrhythmia

• Missed seizure diagnosis

What prevention strategies reduce syncope risk?

• Hydration

• Avoid triggers

• Medication review

• Slow positional changes

What is the classic presentation of vasovagal syncope?

Prodrome of nausea, warmth, and lightheadedness followed by brief loss of consciousness

What condition most closely mimics syncope with transient LOC?

Seizure