10.8 Syncope

Question 1

Define syncope

Answer 1

frequently untrue
- A transient loss of consciousness, usually leading to falling.
- The onset of syncope is relatively rapid, and the subsequent recovery is spontaneous, complete and usually prompt.
not always true = variable

Question 2

Clinical features of syncope

Answer 2

Warning signs
- Hyperventilation
- facial pallor, followed by yawning, sighing and tachy
- sweating, restlessness, salivation, pupillary dilation

Question 3

Syncope pathophysiology

Answer 3

Postural Hypotension
Baroreceptor reflex:
- If your blood pressure falls (for example when you stand up), baroreceptors trigger a sympathetic response which arises from the medulla.
- A considerable portion of this response consists of constriction of the blood supply to the gut. (Splenic circulation)

Question 4

Syncope vs Epilepsy

Answer 4

• syncope do have jerks and is not a sign of seizure
• look a duration of jerks (<10sec)
• eye also roll in vasovagal syncope
• Incontinence of urine/faeces favours diagnosis of epilepsy
• Biting of tongue favours diagnosis of epilepsy
• Headache (a migraine) afterwards favours diagnosis of epilepsy
• Feeling stiff and sore favours diagnosis of epilepsy

Question 5

Causes of syncope

Answer 5

1. Vasovagal event
- Young

2. Cardiac Cause: reduced cardiac output
- Old
- Arrhythmias:
• ventricular (VF VT) or
• heart block, with ventricular escape rhythm;
• sick sinus syndrome.
- Cardiac output obstruction eg Aortic Stenosis

3. Very rare: hereditary arrhythmias: warning sign is syncope associated with exercise

4. Postural Hypotension
- Complaint: dizziness on standing upright/ walking around as opposed to lying flat
- If severe, prolonged →→→ syncope

5. Functional
- Functional Neurological Symptom Disorder
- “Clinical findings provide evidence of incompatibility between the symptom and recognized neurological or medical conditions”.

Question 6

Causes of low BP

Answer 6

1. Medicines for lowering BP
2. Autonomic dysfunction
   - Neuropathies (Diabetes; GBS (AIDP); Porphyria)
   - Parkinson’s disease and similar conditions (multisystem atrophy (MSA)).
3. Normal low diastolic in teenager is 65 mmHg

Question 7

Misconception / controversies related to syncope
Can stroke &TIA causes blackout?

Answer 7

• Stroke, TIA: virtually never
  (SAH may cause/Large stroke may cause but obvious neurological deficit)