EMCrit.org

Syncope

From Greek meaning pause

In seconds preceding LOC there is a loss of lateral gaze, possibly dizziness

Vascular/Cardiac-rhythmic, obstructive, metabolic, meds

Vasomotor-consider AAA, ectopic, and other sources of occult bleeding

Cardiac-if exercise induced, think IHSS, valvular disorder, or subclavian steal

            Stokes-Adams:  heart block, syncope, vertigo

Cough, micturition, post-prandial

Place pregnant women in LLR

High risk if >60 y/o or Cardiac history

CHF on exam assoc. c high risk

12 Lead EKG (even in the young for prolonged QT and Brugada), consider CBC or guiac and pregnancy test. 

Admit high risk or young pts c syncope during exercise

(ACEP Clinical Guidelines)

Neurally Mediated

Syncope associated with inappropriate vasodilatation, bradycardia or both.

a. Vasovagal syncope is often associated with a sensation of increased warmth and may be accompanied by nausea. It may occur after exposure to an unexpected or unpleasant sight, sound or smell, fear, severe pain, emotional distress and instrumentation. It may also occur in association with prolonged standing or kneeling in a crowded or warm place or on exertion (all three latter scenarios may also be due to autonomic failure)

b. Situational syncope occurs during or immediately after coughing, micturition, defecation or swallowing. Syncope associated with throat or facial pain, however, may be due to glossopharyngeal or trigeminal neuralgia

c. Carotid sinus syncope can be associated with neck pressure (shaving, tight collar) or head turning

Orthostatic Syncope

Occurs when there is documented hypotension associated with syncopal or presyncopal symptoms. According to ECS guidelines, orthostatic blood pressures are recommended to be taken after five minutes of being supine.  A decrease of more than 20mm Hg in the systolic pressure is considered abnormal as is a drop in pressure below 90mm Hg independent of the development of symptoms.

Neurologic Syncope

Neurologic causes of apparent syncope include seizures, TIAs, migraine headaches and subclavian steal syndrome. Confusion after "syncope" that lasts more than five minutes, tongue biting, incontinence, epileptic aura suggest this diagnosis. A significant differential in the blood pressure of the two arms suggests subclavian steal

Cardiac-Related Syncope

The major categories of cardiac disease associated with syncope are ischemia, valvular and arrhythmic.

QT syndrome suggested by notched or bifid T waves in V2-V4

Risk Stratification for Syncope Martin et al

252 derivation, 374 validation

• Age greater than 45 y/o

• History of Vent dysrhythmias

• History of CHF

• Abnormal EKG

No risk one year mortality 1.1% 27.3% with three or more risk factors (Ann Emerg Med 1997Apr 29(4)459)

All patients with positive CTs in one study had a witnessed seizure or an alteration of their neurologic exam (Ann Intern Med 1997 Jun 15;126(12):989-996)

Eur Heart J 2003 24;811-819

• Age>65

• Cardiovascular Disease

  • Previous clinical or lab dx of structural heart dis, valvular dis, and primary myocardial dis

  • Previous Hx of CHF

  • Previous Dx or clinical evidence of PVD

  • Previous Dx of stroke or TIA

• Syncope without a prodrome (drop syncope)

• Abnormal EKG

  • A-fib, a-flutter, SVT, MFAT, frequent PVC, sustained or non-sustained V-tach or paced rhythms

  • Mobitz types I and II, 3rd degree and bundle branch blocks

  • Left axis deviation, LVH, old MI

  • ST-T abnormality c/w myocardial ischemia

If you had 2 or more, much higher mortality

ACEP

Level B

A hx of CHF or ventricular arrhythmias
Associated CP or symptoms c/w ACS
Evidence of CHF or valvular heart dis. on physical exam
ECG findings of ischemia, BBB, prolonged QT or arrhythmia
Level C
Age older than 60 years
Hx of CAD or congenital heart diseases
Family Hx of sudden death
Exertional syncope in younger patients
 

CLINICAL CLUES TO CAUSE OF SYNCOPE

The following list was adapted from Jeff Mann

Jeff Mann's Clues to Syncope

1. Sudden syncope at rest when non-erect suggests a cardiac arrhythmia or atrial myxoma

2. Sudden syncope on exertion suggests aortic stenosis, hypertrophic obstructive cardiomyopathy

3. Preceding "lightheadedness" prodrome with sweating and nausea when erect that has a slow, progressive onset suggests vasovagal syncope (orthostatic hypotension would not likely have the sweating and nausea and is another cause of syncope preceded with lightheadedness)

4. Preceding palpitations suggests a cardiac arrhythmia

5. Preceding or accompanying dyspnea suggests pulmonary embolism (PE), tension pneumothorax, cardiac tamponade and air embolism

6. Preceding chest pain suggests myocardial ischemia, PE, cardiac tamponade, dissecting aneurysm, and mitral valve prolapse

7. Preceding or accompanying back pain suggests dissecting aortic aneurysm or leaking abdominal aortic aneurysm

8. Preceding or accompanying abdominal pain suggests a leaking abdominal aneurysm or ectopic pregnancy

9. Occurring when turning head side to side, shaving or with neck compression suggests carotid sinus syncope

10. Occurring when exercising an upper arm suggests subclavian steal syndrome

11. Occurring during (or immediately after) coughing, laughing, vomiting, swallowing, urination, defecation, combing hair or stretching suggests situational syncope

12. Occurring after prolonged standing suggests vasovagal syncope

13. Occurring after an emotional upset suggests either vasovagal syncope, prolonged QT syndrome or torsades de pointes

14. Recent illicit drug use suggests a cardiac arrhythmia, air or foreign body embolism

15. Syncope associated with a sudden headache suggests a subarachnoid hemorrhage

16. Recent neurologic symptoms suggests a brain stem stroke, vertebrobasilar insufficiency, basilar migraine, carotid or vertebral artery aneurysm or aortic dissection

17. Recent vaginal insufflation suggests an air embolism

18. Recent black stools suggest a GI bleed

19. Recent fluid loss (vomiting, diarrhea, sweating) or poor intake suggest hypovolemia and orthostatic hypotension or Addisonian crisis

20. Postprandial syncope is associated with a recent meal

21. Polypharmacy or sildenafil suggest orthostatic hypotension as a cause of syncope

22. A history of known cardiac ischemia or structural heart disease suggests a cardiac arrhythmia or a drug-induced arrhythmia or cardiac valvular dysfunction

23. A history of a mechanical heart valve can be associated with syncope caused by valve-related thrombosis

24. Cancer, obesity, pregnancy, recent surgery or trauma, prolonged bed rest and prior thromboembolic events suggest the presence of a pulmonary embolism as the cause of syncope.

25. A history of autonomic dysfunction manifested by impotence, anhydrosis, sphincter dysfunction can be associated with orthostatic hypotension-related syncope.

The most accurate decision rule in the derivation set gave two points if the patient reported waking with a cut tongue, and one point each if there was a report of abnormal behavior, loss of consciousness with emotional stress, post-ictal confusion, head turning to one side during loss of consciousness, or prodromal deja vu or jamais vu; two points each were deducted for any reported presyncope, loss of consciousness with prolonged standing or sitting, or diaphoresis prior to an episode. (J Am Coll Card 40(1):142, July 2002)

San Francisco Syncope Rule Derivation Set only (Annals 2004, Feb. 43:2) There were 684 visits for syncope, and 79 of these visits resulted in patients' experiencing serious outcomes. Of the 50 predictor variables considered, 26 were associated with a serious outcome on univariate analysis. A rule that considers patients with an abnormal ECG, a complaint of shortness of breath, hematocrit less than 30%, systolic blood pressure less than 90 mm Hg, or a history of congestive heart failure has 96% (95% confidence interval [CI] 92% to 100%) sensitivity and 62% (95% CI 58% to 66%) specificity. If applied to this cohort, the rule has the potential to decrease the admission rate by 10%.

(Ann Emerg Med 2006;47(5):448)

failed in revalidation (Ann emerg med 2008;52:151)