Syncope

Differential Diagnosis

  • Cardiac
    • Arrhythmias
      • Tachyarrhythmias (SVT, atrial fibrillation, etc)
      • Bradyarrhythmias (sick sinus syndrome, etc)
      • Pacemaker malfunction
      • WPW, Brugada, Long QT
    • Obstruction
      • Valvular
      • Cardiomyopathy (hypertrophic obstructive)
      • RV outflow (i.e. PE)
    • Pump failure
    • Acute MU
  • Peripheral vascular
    • Hypervolemia (dehydration)
    • Hemorrhage (GI bleed)
    • Anaphylzxis
    • Vasodilation
  • Reflex mediated
    • Vasovagal
    • Situational
    • Carotid sinus sensitivity
  • Neurological
    • Cerebrovascular (carotid stenosis)
    • CVA (ischemic, hemorrhagic)
    • Posterior circulation TIA
    • Subclavian steal
    • Migraine
  • Other
    • Endocrine
    • Hyperventilation
    • Psychogenic
    • Poisoning
    • Rx



 

Hypoperfusion to the brain, either lack of glucose or lack of O2, results in syncope and presyncope.

History and Physical Exam

Obviously the differential diagnosis for this problem is huge, so a complete history and physical must be done.  Always ask about medications, especially antihypertensives and diuretics.  Don’t forget to assess the JVP as well as do a rectal.

Investigations

  • Chemstrip
  • CBCD, lytes
  • Troponin
  • Digitalis level
  • EKG
  • Urinalysis

As an outpatient may consider a Holter monitor and/or Echo.

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