Neurogenic Causes of Syncope

Neurally-Mediated (Reflex) Syncope

The European Society of Cardiology recommends that vasovagal syncope, the most common form of reflex syncope, is triggered by emotional stress, fear, pain, or blood phobia in patients with a history of syncope 1, 3
The American Heart Association notes that carotid sinus syncope occurs when mechanical manipulation of the carotid sinuses triggers the vasovagal reflex, and is more common in older adults 1, 5
Situational syncope is associated with specific scenarios, such as cough or sneeze-induced syncope, gastrointestinal stimulation, micturition syncope, post-exercise syncope, and post-prandial syncope, according to the European Heart Journal 1, 3

The American College of Cardiology defines neurogenic orthostatic hypotension (OH) as a sustained reduction of systolic BP ≥20 mmHg or diastolic BP ≥10 mmHg within 3 minutes of assuming upright posture, and notes that primary autonomic failure syndromes, such as multiple system atrophy and pure autonomic failure, can cause OH 5, 6, 7
The American Autonomic Society notes that secondary autonomic failure syndromes, such as diabetic neuropathy and amyloid neuropathy, can also cause OH 1, 6

The European Federation of Neurological Societies notes that symptoms of neurogenic OH differ from those due to dehydration, drugs, and cardiac/reflex syncope, and include persistent and often progressive generalized weakness, fatigue, visual blurring, cognitive slowing, leg buckling, and "coat hanger" headache 6, 7

The American Heart Association recommends autonomic evaluation to improve diagnostic and prognostic accuracy in patients with Parkinsonism or other central nervous system features, peripheral neuropathies, progressive autonomic dysfunction, postprandial hypotension, or known or suspected neuropathic POTS 6, 7
The European Society of Cardiology notes that neurological evaluation with simultaneous EEG and hemodynamic monitoring during tilt-table testing can help distinguish among syncope, pseudosyncope, and epilepsy 8, 7

The American College of Cardiology recommends non-pharmacological measures, such as acute water ingestion, physical counter-pressure maneuvers, and compression garments, for temporary relief of neurogenic orthostatic hypotension 2
The European Heart Journal notes that midodrine can be beneficial in patients with syncope due to neurogenic OH, and that other options include fludrocortisone, octreotide, indomethacin, or ergotamine 2, 6