Syncope

Syncope

1. Rapid onset of transient loss of consciousness
2. Inability to maintain postural tone
3. It may be associated with a fall
4. Resolves spontaneously and quickly without intervention

Presyncope (Near-Syncope)

1. Weakness, Dizziness, lightheadedness, or "graying out" of consciousness without loss of postural tone
2. Evaluate Presyncope with the same vigor as Syncope
1. Presyncope has the same risks of adverse events as Syncope

Causes: Neural or Reflex Mediated Syncope (no cardiovascular risk, most common, 45% of cases)

1. Vasovagal Syncope (Vasodepressor Syncope)
2. Situational Syncope
3. Carotid Sinus Syncope
4. Glossopharyngeal neuralgia (uncommon)
5. Trigeminal Neuralgia
6. Hypovolemia
7. Medication-related Syncope (Drug-Induced Syncope, responsible for 5-15% of Syncope causes)
8. Recreational drug use
9. Postural Tachycardia Syndrome (POTS)

• Most common in young female women (associated with chronic Fatigue and Mitral Valve Prolapse)

10. Autonomic failure

Cardiac syncope

• Arrhythmias
• Ventricular Tachycardia
• Sick Sinus Syndrome
• Supraventricular Tachycardia
• Atrioventricular Block (second or third degree)
• Pacemaker malfunction
• Valvular disorders
• Hypertrophic Cardiomyopathy (esp. young patients)
• Aortic Stenosis
• Acute Mitral Valve Regurgitation (i.e. acute MI with papillary Muscle rupture)
• Prosthetic Heart Valve complications (e.g. Thromboembolism, valvular obstruction)

Vascular disorders

• Myocardial Infarction
• Aortic Dissection
• Abdominal Aortic Aneurysm rupture
• Pulmonary Embolism
• Pulmonary Hypertension
• Subarachnoid Hemorrhage
• Subclavian Steal Syndrome

Myocardial disorders

• Hypertrophic Cardiomyopathy
• Atrial myxoma

Examination

• Vital sign
• General
• Cardiovascular examination-murmurs, Carotid bruit, asymmetric pulses
• Abdomen and pelvis exam- pulsatile mass and decreased femoral pulses, pelvic pain, rectal exam

Labs

• Basic Chemistry Panel (Serum Electrolytes including Glucose)
• Hemoglobin or Hematocrit 
• Pregnancy Test (urine HCG)
• Fecal Occult Blood Test 
• Troponin I
• D Dimer if necessary.

Diagnostics

• Electrocardiogram (EKG)
• Continuous cardiac monitoring-telemetry for inpatient

Imaging

• Chest XRay
• Echocardiogram
  
• CT chest with contrast (if Pulmonary Embolism is suspected)
• Imaging related to injuries sustained in a Syncope- fall
• CT Head (usually low yield except indicated by history and physical examination)

Indications for head imaging include:

• Age over 65 years
• Warfarin use
• First Seizure
• Trauma above the clavicles
• Persistent neurological deficit
• Dizziness
• Sudden onset headache (Thunderclap Headaches)

Note: The San Francisco Syncope Rule (CHESS Score) or Canadian syncope risk score are used to evaluate the short-term risk of severe outcomes and may reduce the syncope hospitalization rate.

Management depends on the cause

• Fall precautions
• Telemetry if needed
• Assess ability to tolerate PO
• IV fluids if needed
• Consider intoxication

References

1. Joshi and Dermark (2016) Crit Dec Emerg Med 30(8):3-12
2. Orman and Mattu in Herbert (2016) EM:Rap 16(3): 9-11
3. Orman and Mattu in Herbert (2018) EM:Rap 18(6): 10-11
4. Schauer et al. (2016) Crit Dec Emerg Med 30(9):13-9
5. Kapoor (2000) N Engl J Med 343:1856-62 [PubMed]
6. Brignole (2001) Eur Heart J 22:1256-306 [PubMed]
7. Miller (2005) Am Fam Physician 72:1492-500 [PubMed]
8. Runser (2017) Am Fam Physician 95(3): 303-12 [PubMed]
9. Vermeulen (2007) Stroke 38(4): 1216-21 +PMID: 17322078 [PubMed]