Syncope

Question 1

What are the 3 types of reflex syncope?

Answer 1

Vasovagal
Situational
Carotid sinus syncope

Question 2

Describe how a vasovagal syncope would present?

Answer 2

Vasovagal (fainting) – Occurs due to reflex bradycardia and peripheral vasodilation provoked by emotion, pain or stress. Can occur due to standing too long but will not occur whilst lying down. Often preceded by pre-syncopal symptoms such as nausea, pallor, narrowing of visual fields and sweating. Brief clonic jerking of the limbs may occur due to cerebral hypoperfusion but no tonic/clonic sequence. Urinary incontinence is uncommon and no tongue biting. Usually lasting a few minutes and recovery is rapid without any post ictal phase.

Question 3

What is situational syncope?

Answer 3

Situation Syncope – as vasovagal but with a clear precipitating trigger such as cough, effort, or micturition.

Question 4

What is carotid sinus syncope?

Answer 4

Carotid sinus syncope – hypersensitive baroreceptors causing excessive reflex bradycardia and vasodilation with minimal stimulation.

Question 5

What is orthostatic syncope?

Answer 5

Postural hypotension

Question 6

What are the 4 classes of causes of orthostatic hypotension

Answer 6

Primary autonomic failure e.g. Parkinson’s and Lewy body dementia
Secondary autonomic failure e.g. diabetes, amyloidosis, and uraemia.
Drug induced e.g. diuretics, alcohol, and vasodilators
Volume depletion – haemorrhage, diarrhoea, and sepsis etc.

Question 7

What can cause cardiac syncope?

Answer 7

Arrhythmias – bradycardias (Sinus node dysfunction, AV conduction disorder or tachycardias (supraventricular or ventricular)
Structural – valvular, myocardial infarction, hypertrophic obstructive cardiomyopathy Others – PE

Question 8

What is a stokes-Adams attack?

Answer 8

Transient arrhythmias e.g. bradycardia due to complete heart block causes reduced cardiac output and LOC. The patient usually falls to the ground often without any warning except palpitations, on the floor patient is pale, with a slow or absent pulse. Patients recover in seconds as with vasovagal attacks. Anoxic jerks can also occur.

Question 9

List some causes of sycope other than vagal induced, arrhythmias and epilepsy?

Answer 9

Hypoglycaemia
Vertigo
Anxiety
Drop attacks – leg weakness, hydrocephalus, cataplexy or narcolepsy

Question 10

How would epilepsy present differently to syncope?

Answer 10

Presentation suggestive of this include attacks whilst asleep or lying down, aura, identifiable triggers, altered breathing, cyanosis, typical tonic-clonic movements, incontinence of urine, tongue biting, prolonged post-ictal drowsiness and confusion, amnesia and transient focal paralysis.

Question 11

What investigations should/can be done in someone presenting with syncope?

Answer 11

Measure standing and lying BP – systolic fall >20 or diastolic >10 or decrease in systolic < 90 is considered diagnostic 
ECG including 24 hours ECG
Carotid sinus massage 
Echo if indicated
Tilt table test 
FBC, U&amp;E, Mg, Ca, glucose
Neurological
Most important thing is a collateral history

Question 12

Name some drugs which increase the risk of syncope?

Answer 12

Dopamine antagonists, nitrates and Ca Channel blockers all increase the risk of syncope