What is the workup and treatment for syncope (fainting)?

Workup and Treatment for Syncope

The initial evaluation of syncope must include a detailed history, physical examination, orthostatic blood pressure measurements, and standard ECG, which will establish the diagnosis in most patients without requiring extensive testing. 1

Initial Diagnostic Approach

History Taking

Focus on these specific elements:

• Position and activity when syncope occurred (supine, sitting, standing, during/after exercise)
• Predisposing factors: crowded places, prolonged standing, post-prandial period
• Precipitating events: fear, pain, neck movements
• Prodromal symptoms: nausea, vomiting, sweating, feeling cold, blurred vision
• Eyewitness account: manner of falling, skin color, duration of unconsciousness, breathing pattern, movements
• Post-event symptoms: confusion, muscle aches, injury, chest pain, incontinence
• Background information: family history of sudden death, cardiac disease, neurological conditions, medications

Physical Examination

• Cardiovascular assessment including orthostatic blood pressure measurements
• Neurological examination
• Carotid sinus massage (in patients >40 years with syncope of unknown origin)

Initial Testing

• Standard 12-lead ECG
• Orthostatic blood pressure measurements (supine and standing)

Diagnostic Classification

Based on the initial evaluation, syncope can be classified into:

1. Neurally-mediated (reflex) syncope:

   • Vasovagal syncope (common faint)
   • Carotid sinus syncope
   • Situational syncope (cough, micturition, defecation, etc.)

2. Orthostatic hypotension:

   • Primary or secondary autonomic failure
   • Drug-induced
   • Volume depletion

3. Cardiac syncope:

   • Arrhythmias (bradyarrhythmias, tachyarrhythmias)
   • Structural heart disease (valvular, cardiomyopathy, etc.)
   • Pulmonary embolism/hypertension

Further Diagnostic Testing

For Suspected Cardiac Syncope:

• Echocardiography
• Prolonged ECG monitoring (Holter, external loop recorder)
• Implantable loop recorder for recurrent unexplained episodes
• Electrophysiological studies if non-diagnostic

For Suspected Neurally-Mediated Syncope:

• Tilt table testing
• Carotid sinus massage (if not done initially)
• Implantable loop recorder for recurrent episodes

For Suspected Orthostatic Hypotension:

• Detailed orthostatic vital sign measurements
• Autonomic function testing

Treatment Approach

Neurally-Mediated Syncope:

1. Patient education and reassurance
2. Volume expansion strategies:
   • Increased salt intake
   • Adequate fluid intake (2-2.5 liters daily)
   • Head-up tilt sleeping (>10°)
3. Physical counterpressure maneuvers for patients with prodromal symptoms:
   • Leg crossing with muscle tensing
   • Hand gripping
   • Arm tensing
4. Pharmacological options for refractory cases:
   • Fludrocortisone (0.1-0.2 mg daily)
   • Midodrine for frequent recurrent episodes
5. Cardiac pacing only for:
   • Documented cardioinhibitory carotid sinus syndrome
   • Cardioinhibitory vasovagal syncope with >5 attacks per year or severe physical injury and age >40

Orthostatic Hypotension:

1. Discontinuation of hypotensive medications when possible
2. Volume expansion as above
3. Pharmacological treatment:
   • Fludrocortisone
   • Midodrine
   • Desmopressin for specific cases

Cardiac Syncope:

1. Arrhythmias:
   • Pacemaker for bradyarrhythmias
   • Antiarrhythmic drugs or ablation for tachyarrhythmias
   • ICD for ventricular arrhythmias with risk of sudden death
2. Structural heart disease:
   • Specific treatment based on underlying condition

Special Considerations

• Unexplained syncope: Consider implantable loop recorder for recurrent episodes
• Psychiatric assessment: Necessary when syncope is associated with multiple somatic complaints
• High-risk settings: More aggressive treatment for patients in occupations like commercial drivers, pilots
• Elderly patients: More cautious approach to volume expansion with cardiovascular comorbidities

Common Pitfalls to Avoid

1. Overuse of diagnostic tests without proper initial evaluation
2. Misdiagnosis of seizures as syncope (look for post-ictal confusion, tongue biting)
3. Overlooking medication-induced syncope (review all medications)
4. Premature cardiac pacing without adequate documentation of bradyarrhythmia
5. Failure to identify life-threatening causes of syncope (structural heart disease, arrhythmias)

Following this algorithmic approach will lead to accurate diagnosis and appropriate treatment in the majority of syncope cases, reducing morbidity and improving quality of life.