What are the initial orders and common causes for an inpatient syncope workup?

Inpatient Syncope Workup: Initial Orders and Common Causes

The initial evaluation of a patient presenting with syncope should include a careful history, physical examination including orthostatic blood pressure measurements, and a 12-lead electrocardiogram (ECG). 1, 2

Initial Orders for Inpatient Syncope Workup

Essential Initial Orders

• Complete history focusing on circumstances before the attack (position, activity, predisposing factors, precipitating events) 1, 2
• Physical examination with attention to cardiovascular system 2
• Orthostatic blood pressure measurements in lying, sitting, and standing positions 1, 2
• 12-lead ECG 1, 2

Targeted Laboratory Tests (Based on Clinical Suspicion)

• CBC/hematocrit (if volume depletion or blood loss suspected) 2
• Basic metabolic panel (if dehydration or metabolic disorder suspected) 2
• Cardiac biomarkers (BNP, troponin) only if cardiac cause suspected 2
• Avoid routine comprehensive laboratory testing without specific indications 2, 3

Additional Testing Based on Initial Findings

• Echocardiography when structural heart disease is suspected 1, 2
• Cardiac monitoring when arrhythmic syncope is suspected 1, 2
• Exercise stress testing for syncope during or after exertion 2
• Tilt-table testing for suspected vasovagal syncope 2
• Carotid sinus massage in patients over 40 years (if appropriate) 1, 2

Common Causes of Syncope

Neurally-Mediated (Reflex) Syncope

• Vasovagal syncope (triggered by fear, pain, emotional distress, prolonged standing) 1
• Situational syncope (during/after urination, defecation, cough, swallowing) 1
• Carotid sinus hypersensitivity 2

Orthostatic Hypotension

• Medication-induced (antihypertensives, antidepressants, diuretics) 1, 2
• Volume depletion 2
• Autonomic dysfunction 1, 2
• Post-prandial (after meals) 1

Cardiac Causes

• Arrhythmias 1, 2, 4
  • Bradyarrhythmias (sinus bradycardia, AV blocks, pacemaker malfunction) 1
  • Tachyarrhythmias (SVT, VT) 1
• Structural heart disease 2
  • Valvular disease (aortic stenosis, hypertrophic cardiomyopathy) 2
  • Ischemic heart disease 1
• Channelopathies (Brugada syndrome, long QT syndrome) 4

Cerebrovascular Causes (Rare)

• Subclavian steal syndrome (with arm exercise) 1
• Vertebrobasilar TIA (extremely rare cause of true syncope) 5

Risk Stratification

High-Risk Features (Consider Admission)

• Abnormal ECG findings 1, 2
• History of heart failure or structural heart disease 2
• Low blood pressure (systolic BP <90 mmHg) 2
• Age >60 years 2
• Syncope during exertion or in supine position 2
• Absence of prodromal symptoms 2
• Family history of sudden cardiac death 2

Low-Risk Features (Consider Outpatient Management)

• Younger age 2
• No known cardiac disease 2
• Normal ECG 2
• Syncope only when standing 1, 2
• Clear prodromal symptoms 2
• Specific situational triggers 2

Common Pitfalls to Avoid

• Failing to distinguish syncope from non-syncopal causes of transient loss of consciousness 2
• Ordering brain imaging studies (CT/MRI) without specific neurological indications 2
• Performing comprehensive laboratory testing without clinical indication 2, 3
• Overlooking medication effects as potential contributors to syncope 2
• Neglecting orthostatic hypotension as a potential cause 2

Remember that the diagnostic yield of extensive testing is low in patients without concerning features on initial evaluation 3. A targeted approach based on clinical findings is more effective than a standardized workup for all patients with suspected syncope 3.