- Prodromal nausea is a common symptom preceding vasovagal syncope due to activation of the autonomic nervous system causing increased parasympathetic tone and vagal stimulation.
- This leads to gastrointestinal symptoms like nausea and sweating, which often appear before transient cerebral hypoperfusion causes loss of consciousness.
- Other symptoms such as palpitations, chest pain, or shortness of breath are less typical and may suggest alternative diagnoses.
- Recognizing prodromal nausea helps differentiate vasovagal syncope from other syncopal causes and guides appropriate management.

Reference: Davidson’s Principles and Practice of Medicine, 23rd Edition, Chapter: Neurological Disorders, Page 476.