Vasovagal Syncope

Medicine > Cardiovascular

Background Knowledge 🧠

Definition

A transient loss of consciousness caused by a temporary drop in blood flow to the brain, often due to a reflex of the involuntary nervous system.
Most common cause of syncope in adults.

Pathophysiology

Overreaction of the parasympathetic nervous system (vagus nerve) leading to bradycardia (slow heart rate) and vasodilation (widening of the blood vessels).
Results in reduced cardiac output and transient cerebral hypoperfusion.

Triggers

Emotional distress: Fear, severe pain, distressing sights.
Standing for long periods.
Heat exposure.
Physical factors: Coughing, urination, swallowing.
After exercise.

Clinical Features 🌡️

Clinical Presentation

Prodromal symptoms:
- Light-headedness
- Nausea
- Feeling warm
- Pallor
- Visual“blackout”
- Sweating
Transient loss of consciousness (often less than a minute).
Recovery is typically rapid but may be associated with transient confusion.

Investigations 🧪

Investigations

Clinical history: Most diagnostic. Collateral history can help determine possible underlying causes.
ECG: To rule out cardiac causes.
Orthostatic blood pressure measurements.
Tilt table test: Diagnostic in some cases.
Holter monitor (ambulatory ECG monitor): If episodic or suspicion of arrhythmia.

Management 🥼

Management

Educate about triggers and early warning signs.
Counterpressure manoeuvres: Leg crossing, handgrip, arm tensing.
Increased salt and fluid intake.
Avoid prolonged standing, especially in hot environments.
Gradual physical training.
Pharmacological: Beta-blockers, fludrocortisone, SSRIs – used in recurrent cases.

Complications

Generally benign but has the potential for injury due to falls.
Recurrent episodes are common.

Key Points

Inappropriate reflex of the parasympathetic nervous system can cause a temporary drop in blood flow to the brain, resulting in a transient loss of consciousness.
Common triggers include emotional distress and standing for long periods.
Typically preceded by prodromal symptoms (light headedness, nausea, feeling warm)

References

Jeanmonod, R., Sahni, D. and Silberman, M. (2023). Vasovagal Episode. [online] PubMed. Available at: https://www.ncbi.nlm.nih.gov/books/NBK470277/.

National Institute for Health and Care Excellence (2010). Introduction | Transient loss of consciousness (‘blackouts’) in over 16s | Guidance | NICE. [online] www.nice.org.uk. Available at: https://www.nice.org.uk/guidance/cg109/chapter/Introduction.

No comments yet 😉

Leave a Reply Cancel reply

You must be logged in to post a comment.

Don't take our word for it

"The stations you provide are strikingly similar to those I came across during my medical school finals (some even verbatim!), and I have tried many other exam platforms. I'm truly grateful for your priceless support throughout my final couple of years at medical school!"

Raza Q 🇬🇧

"It has absolutely everything for medical school, so many histories with detailed differential diagnoses, how to approach emergencies, commonly prescribed drugs..every kind go examination you’ll ever need in osces"

John R 🇬🇧

"Thank you SO MUCH for the amazing educational resource. I’ve tried lots of platforms and books with mock OSCE stations and yours is by far and away the best I’ve tried"

Ed M 🇳🇿

"Get this right away. So helpful for OSCEs but also general clinical learning and understanding. Wish I had brought it sooner"

Emma W 🇬🇧

"Without a doubt, your platform outshines all other OSCE resources currently available. In all honesty, I can confidently attribute my success in securing a distinction in my finals to OSCEstop."

Harish K 🇬🇧

"OSCEstop distinguishes itself from many other platform banks by offering a wealth of questions that mimic the demanding and complex aspects of our finals. This platform played a crucial role in ensuring I was ready for the level of difficulty that awaited me in my final exams."

Natasha W 🇳🇿

😃 More:

📖 Learning notes: 247

🏥 Stations available: 207

🧠 Qbank questions: 2255