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Syncope

Sarah Myers

Background

  • Definition: abrupt, transient loss of consciousness with rapid & spontaneous recovery  
  • Presyncope – symptoms occurring before syncope including lightheadedness, tunnel vision/other visual disturbances

Classification

  • Cardiac syncope 
  • Tachyarrhythmias: VT, SVT 
  • Bradyarrhythmias: sinus node dysfunction, AV blocks (high grade) 
  • Structural: Aortic Stenosis, HCM, cardiac tamponade, congenital anomalies, masses/tumors 
  • Vascular: Pulmonary embolism, aortic dissection, severe pHTN 
  • Noncardiac syncope
  • Reflex mediated
    • Vasovagal; most common form of reflex mediated syncope
      • Can occur sitting/standing or with trigger (stress, pain, medical settings)
      • Classically has prodrome of nausea, diaphoresis, tunnel vision followed by hypotension and/or bradycardia
    • Situational (micturition/defecation/coughing)
    • Carotid sinus sensitivity syndrome
  • Orthostatic
    • Medications (diuretics, nitrates/CCB/alpha blockers, TCAs)
    • Volume depletion (hemorrhage, dehydration)
    • Autonomic dysfunction

Differential diagnosis

  • Seizure, stroke, metabolic derangements, Intoxication/withdrawal, hypoglycemia, head trauma
    • With rare exceptions, these do not result In complete LOC with spontaneous recovery

Evaluation

  • History and physical are essential for evaluation of a syncopal event 
  • Characteristics associated with cardiac syncope 
    • Male, >60, known structural/ischemic heart disease, brief/no prodrome, syncope while supine/at rest or during exercise, family hx of SCD/premature death, abnormal exam 
  • Characteristics associated with noncardiac syncope
    • Younger age, syncope while standing or with positional changes, prodrome (nausea, vomiting, warmth), specific triggers, previous episodes that have been similar  

Workup

  • EKG on all patients with syncope, monitor those who are admitted on telemetry
  • CBC, CMP, troponin, BNP (If cardiac cause suspected), POC glucose, UDS, orthostatic VS
  • EEG and neuroimaging if concern for seizure activity or focal neuro deficit  
  • TTE and consider stress testing particularly in exertional syncope  

Management

  • Cardiac: managed as indicated based on pathology 

  • If arrhythmia is suspected but not captured on admission, consider discharge with event monitor  

  • Noncardiac

  • Reflex

    • Vasovagal- consider tilt table testing If recurrent or diagnosis not clear
    • Situational- mainly avoiding triggers
    • Carotid sinus syndrome- may require PPM

  • Orthostatic

    • Medication related
      • Appropriate to hold potentially offending medications (diuretics, vasodilators) during evaluation
      • Monitor for worsening supine hypertension, arrhythmias, or heart failure when holding
    • Volume depletion; resuscitate as appropriate
    • Autonomic dysfunction: see autonomics section

  • Driving: TN law does not require any MD to inform the state of TLOC 

    • Should still recommend patients not drive while work-up ongoing. Document all conversations about driving with patients