12 Syncope

12.1 Note

12.1.1 H&P

*** Denied HA, diaphoresis, n/v, cold or warm sensation, CP, SOB, palpitations, deja vu, jamais vu, blurry vision or lightheadedness prior to the episode. No witnessed cyanosis while unconscious, tongue bite/laceration, incontinence, limb twitching or seizure-like activity. Following the episode, the pt was not confused and had normal/baseline mentation.

12.1.2 A&P

Syncope
- Calgary Score (VVS)
    - ≥ -2 suggests vasovagal syncope
- EGSYS score
    - < 3 makes cardiac syncope *less* likely
- History: prodromal Sx? dehydration? infectious Sx? deconditioning/malnutrition?
- Medication review: *** anti-HTNs, diuretics, vasodilators, antipsychotics, anti-depressants, EtOH, opiates
- Labs:
    - beta-HCG (if +, consider ectopic pregnancy)
    - Trop, BNP (if indicated)
- EKG
    - try to exclude BLOWHard conditions
- TTE
- Telemetry
  - Outpatient: consider mobile cardiac outpatient telemetry (MCOT)
- Orthostatics
- Any concerning features to suggest adrenal insufficiency?
- Consider autonomics consult if indicated
- PT/OT
- Consider home safety evaluation

Orthostatic hypotension
- Encouraged to rise from resting position gradually, avoid standing motionless (even if still, tense leg mm.)
- Compression waist high stocking (30-40 mmHg)
- Abdominal binder
- Increase salt consumption 6-10 g/d
- Encouraged water intake 2-3 L/d
- If Sx persist despite the above interventions, consider fludrocortisone
    - Alternative pharmacotherapy: midodrine

12.2 4 General Causes

Reflex-mediated
- Vasovagal (most common cause)
- Situational, e.g. coughing, micturition, etc.
- Carotid sinus hypersentivity
Cardiac
- arrhythmia, e.g. SSS, VT, AV block, etc.
- obstruction, e.g. severe AS, HCM, PE, etc.
- massive MI
Orthostatic
- intravascular volume depletion (e.g. dehydration, blood loss) vs. abnml autonomic reflexes
Neuro
- Central → brain steam lesions, Parkinson disease, Lewy body dementia, Parkinsonism, Shy-Drager syndrome
- Peripheral → pure autonomic failure, diabetic neuropathy

Seizure-like activity with Syncope

Pts w/ LOC d/t syncope can have brief (< 15 seconds) of brief asymmetric or symmetric myoclonic or tonic-clonic movements (not a seizure!). Typically occurs within 10 seconds after LOC, but not before.

12.3 Mimics

Seizures
- History:
  - head turning during the event (seizure > syncope; +LR for seizure 14)
  - unusual posturing during the event (seizure > syncope; +LR 13)
  - urinary incontinence (+LR 6.7)
  - absence of presyncope (+LR 5.6)
- Exam:
  - tongue laceration (+LR 16)
  - no recall of unusual behaviors before LOC (+LR 4)

flowchart TD
    A[LOC episode] --> B(Prolonged Confusion)
    A --> C(Rapidly regain awareness)
    B -->D[Seizure<br>post-ictal confusion]
    C -->E[Syncope]

Figure 12.1: Time to regain of consciousness/awareness after an LOC episode can be useful to differentiate seizures (post-ictal confusion) and syncope.

Stroke
hypOglycemia
Rare
- subclavian steal syndrome
- vertebrobasilar TIA
- SAH

12.4 Reflex-mediated Syncope

Common precipitants:
- pain/emotion/fear
- warm/hot environment
- afferent visceral stimuli, e.g. distended stomach or bladder
- pressure on carotid sinus baroreceptor, e.g. a tight collared shirt while turning the neck
Prodromal Sx
- Cause: efferent vagal component of the reflex leads to autonomic symptoms
- History: HA, sweating, a sense of cold or warmth, n/v, abdominal discomfort, or urge to defecate
Vasovagal syncope
- usually initiated by prolonged sitting or standing → ~ 500-800 mL of blood remains in the distensible vv. below the ♥

12.4.1 Vasovagal Syncope Score (Calgary Score)

Vasovagal syncope is suggested if score ≥ -2

fig: — Grading for Vasovagal Syncope Score (Calgary Score)

12.5 Cardiac Syncope

Etiology: a marked ↓ in CO due to cardiopulmonary disease, such as arrhythmia, structural heart disease, or PE → cerebral hypOperfusion
History
- may occur at rest, in the supine position, or during effort when the pt is unable to ↑ CO to meet the increased demand
- may be preceded by CP, SOB, or palpitations
- may have witnessed cyanosis while unconscious

12.5.1 EGSYS Score

Score range: -2 to 12
Higher score → ↑ likelihood of cardiac syncope
EGSYS < 3, suggests low likelihood of cardiac syncope

12.5.2 Things to rule-out on ECG

4 cardiac conditions to look for on ECG in all patients presenting with syncope (BLOWHard) Source:

Brugada
LOng QT
WPW
HCM/LVH

12.5.3 Orthostatic hypOtension

Great overview on orthostatic hypotension
Performing orthostatics
- baseline: check BP, HR after pt lying down for at least 5 minutes
- after 1 minute of standing
- after 3 minutes of standing
Interpreting orthostatics
- positive for orthostasis if ↓ SBP of of ≥ 20 mmHg or ↓ DBP of ≥ 10 mmHg
  - for HTN pts, a ↓ of SBP ≥ 30 mmHg may be a more appropriate criteria ¹
- HR response
  - if HR ↑ by < 15 bpm after standing → suggests neurogenic orthostatic hypOtension
  - if HR ↑ by > 20 bpm after standing → suggests volume depletion
  - if HR ↑ by > 30 bpm after standing → suggests postural orthostatic tachycardia syndrome (POTS)
    - POTS usually presents with typical orthstatic Sx, but do not meet BP criteria for orthostasis, i.e. little/no ↓ in BP w/ postural ∆

12.6 Clinical Pearls

In a pt presenting with syncope and elevated \(\beta\)-hCG, think about ectopic pregnancy as possible underlying cause
In a pt presenting with syncope and associated severe HA, think about SAH or intracranial hemorrhage
In a pt presenting with syncope and neuro deficits, think about stroke/TIA or intracranial bleed
In a young pt presenting with syncope during exercise, think about anomalous coronary artery
- normally, folks will complain of syncope after exercise
Orthostatic hypOtension causes the postural instability in pts w/ Parkinsonism
Shy-Drager syndrome: Parkinsonism predominantly w/ orthostasis

Freeman R, Wieling W, Axelrod FB, et al. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011;21(2):69-72. doi:10.1007/s10286-011-0119-5 ↩︎