SYNCOPE

Transient LOC with loss of postural tone, rapid onset, short duration, spontaneous full recovery — due to global cerebral hypoperfusion

SYMPTOMS / ASSOCIATED SX

  • Sudden LOC with fall; rapid, complete recovery (distinguishes from seizure/AMS)

  • Prodrome: lightheadedness, diaphoresis, nausea, visual dimming (vasovagal) — or NO prodrome (cardiac)

  • Palpitations or chest pain before LOC (cardiac); positional (orthostatic); exertional (HCM, AS)

  • Post-event confusion >1 min suggests seizure; brief myoclonic jerks may occur in cardiac syncope

DENIES

  • Chest pain/dyspnea (ACS, PE, aortic dissection)

  • Thunderclap headache (SAH)

  • Focal neurologic deficit after event (stroke/TIA)

  • Prolonged post-ictal period, tongue bite, incontinence (seizure)

SOCIAL HISTORY

  • Alcohol, stimulant use; recent illness, vomiting, diarrhea (volume depletion)

  • Family history of sudden cardiac death, channelopathy (Brugada, LQTS), HCM

MAIN ETIOLOGY

  • Reflex/vasovagal (~50%): triggered by pain, fear, prolonged standing, heat, Valsalva

  • Orthostatic hypotension (~10–15%): volume depletion, medications, autonomic failure

  • Cardiac (~10–15%): arrhythmia (VT, SSS, high-degree AV block, SVT); structural (AS, HCM, PE, tamponade)

  • Unknown (~25–40%): extensive workup often unrevealing

MOST COMMON DDX

  • Seizure (post-ictal confusion >5 min, tongue laceration, incontinence, EEG)

  • Hypoglycemia (fingerstick; no rapid recovery without glucose)

  • TIA/stroke (focal deficit persists, neuroimaging)

  • Psychogenic pseudosyncope (no hemodynamic change, eyes closed — tilt table)

  • Carotid sinus hypersensitivity (head turning, shaving; carotid massage)

  • Acute intoxication (tox screen)

DATA

  • ECG ×12 lead immediately (AV block, delta wave, Brugada, epsilon wave, QTc >500ms, ST changes)

  • Orthostatic VS ×3; fingerstick glucose; BMP; CBC

  • Troponin; BNP if HF suspected

  • Echo if structural heart disease suspected

  • Continuous telemetry monitoring

  • CT head if head trauma or focal deficit; CT-PA if PE suspected

  • SFSR (CHESS) and ROSE rule for risk stratification

HOME MEDS

  • QT-prolonging agents — hold; QTc review (azithromycin, antipsychotics, methadone, ondansetron)

  • Antihypertensives/diuretics — hold if orthostatic

  • Nitrates/alpha-blockers — hold if orthostatic syncope

Plan

  • f/u orthostatics (change of >20/10)

    • d/c contributing meds;  midodrine 5-20mg TID during waking hours and upright,

  • IVF PRN - now s/p ***

  • trend daily labs

  • K >4, Mg >2

  • on telemetry

  • if Orthostatic Hypotension, IV/PO hydration, Hold/reduce BP meds,Slow position changes,Compression stockings

  • if c/f cardiac etiology (arrythmia.structural heart disease) consult cardiology consider Holter Monitor, echo, and tx underlying

  • if Reflex / Vasovagal Trigger avoidance (heat, prolonged standing)

  • if Situational Syncope Identify trigger (micturition/cough/defecation/swallow) tx if possible

  • if Volume Loss / Hemorrhage IVF, CBC trend q6–12h if bleeding, Type & screen transfuse if needed TX underlying issue

  • if neurological, contact neurology

  • if Medication / Substance Hold offending meds, Reduce polypharmacy, ox screen if indicated

  • PT/OT to follow and eval ( orthostatic)

RED FLAGS

  • Exertional syncope — always pathological (HCM, AS, ARVD, channelopathy)

  • Syncope + chest pain, dyspnea, or palpitations

  • New ECG abnormality: Brugada, LBBB, delta wave, epsilon wave, QTc >500ms

  • Known structural heart disease (EF <35%, severe AS, HCM)

  • Age >60 with no clear benign trigger

  • Syncope while supine — always cardiac until proven otherwise

  • Hemodynamic instability at presentation

SENIOR IM RESIDENT PEARLS

  • SFSR (CHESS): HF history, Hct <30%, abnormal ECG, SBP <90 at triage, Shortness of breath → admit if any present

  • ROSE rule adds BNP >300 and fecal occult blood — outperforms SFSR in some studies

  • Vasovagal most common overall; cardiac most dangerous — rule out cardiac first

  • Brief myoclonic jerks occur in ~90% of cardiac syncope — do NOT diagnose seizure without EEG

  • Common mistake: attributing syncope to "dehydration" without ruling out cardiac etiology

  • QTc >500ms significantly increases TdP risk — review ALL QT-prolonging meds; correct K/Mg

  • Common mistake: discharging syncope without driving restriction counseling — document in chart