Workup-syncope

(etiology cannot be determined in ~40% of cases) (JAMA 2019;321:2448)

• H&P incl. orthostatic VS have highest yield and most cost effective
• R/o life-threatening dx including: cardiac syncope, severe blood loss, PE, SAH
• History (from Pt and witnesses if available) activity and posture before the incident precipitating factors: exertion (AS, HCMP, PHT), positional ∆ (orthostatic HoTN), stressors such as sight of blood, pain, emotional distress, fatigue, prolonged standing, warm environment, N/V, cough/deglutition/micturition/defecation (neurocardiogenic), head turning or shaving (carotid sinus hypersens.); arm exercise (subclavian steal) sudden onset → cardiac; prodrome (eg, diaphoresis, nausea, blurry vision) → vasovagal associated sx: chest pain, palp., neurologic, postictal, bowel/bladder incontinence, (convulsive activity for <10 sec may occur w/ transient cerebral HoTN & mimic seizure)
• PMH: prior syncope, previous cardiac or neuro dis.; cardiac more likely if >35 y, known structural heart dis., h/o AF, CV prodrome, syncope while supine or exertional, cyanosis
• Medications that may act as precipitants of syncope
• Family history: CMP, SCD, syncope (vasovagal may have genetic component)
• Physical exam VS incl. orthostatics (⊕ if supine → standing results in ≥20 mmHg ↓ SBP or ≥10 ↓ DBP or SBP <90 mmHg w/in 3 min; POTS if ≥30 bpm ↑ HR w/in 10 min), BP in both arms Cardiac: HF (↑ JVP, displ. PMI, S3), murmurs, LVH (S4, LV heave), PHT (RV heave, ↑ P2) Vascular: ✓ for asymmetric pulses, carotid/vert/subclavian bruits; carotid sinus massage to ✓ for carotid hypersens (if no bruits): ⊕ if asystole >3 sec or ↓ SBP >50 mmHg Neurologic exam: focal findings, evidence of tongue biting
• ECG for syncope workups (abnormal in ~50%, but only definitively identifies cause of syncope in <10%)
• Lab: glc, Hb, HCG (pre-menop ♀), ? D-dimer, ? troponin/NT-proBNP (↓ yield w/o other s/s)