Syncope

Question 1

Questions to ask for syncope prodrome

Answer 1

Cardiac: Chest pain, dyspnoea, palpitations, no warning

CNS: Aura, headache, dysarthria, limb weakness

Precipitants (drugs, alcohol, activity)

Recent head trauma (days or weeks earlier!)

Question 2

Questions to ask about during the syncope episode

Answer 2

Pulse

Jerking, incontinence (not specific to epilepsy)

Tongue-biting (pathognomonic of epilepsy)

Duration (seconds –> vasovagal, cardiac; minutes: epilepsy)

Happened before? (uniform suggests epilepsy) –> when did they start/FHx/changes in frequency

Question 3

Questions to ask about syncope recovery

Answer 3

Rapid: Vasovagal, cardiac

Confusion/drowsiness/memory loss: Metabolic, neurological

Question 4

Effect of syncope on driving - cause identified and treated/low risk of recurrence

Answer 4

4 weeks off

Question 5

Effect of syncope on driving - unidentified cause

Answer 5

6 months off

1 seizure-free year

Question 6

Non-syncopal causes of LoC

Answer 6

Intoxication

Head trauma

Hypoglycaemia

Epileptic seizure

Non-epileptic (psychogenic) seizure

Question 7

Definition of syncope

Answer 7

Loss of consciousness due to cerebral hypoperfusion

Question 8

Syncopal causes of LoC

Answer 8

Reflex: Vasovagal syncope, carotid sinus hypersensitivity

Cardiac: Arrhythmias (Usually bradycardias, heart block, sick sinus syndrome); Outflow obstruction (HOCM, Aortic stenosis)

Orthostatic: Drugs (anti-hypertensives, anti-sympathetics), dehydration

Cerebrovascular (rare): Vertebrobasilar insufficiency, aortic dissection, subclavian steal

Question 9

Precipitating factors for vasovagal syncope

Answer 9

3 Ps:

Postural

Provoked (e.g. fear)

Prodrome

Question 10

Main causes of syncope in young patients

Answer 10

Vasovagal (with prodrome)

Question 11

Main causes of syncope in middle-aged patients

Answer 11

Vasovagal syncope

Cardiac arrhythmia (2ry to IHD)

Question 12

Main causes of syncope in elderly patients

Answer 12

Orthostatic hypotension

ACEi/diuretics: Vasodilation + reduced blood volume

Beta blockers: Inability to produce reflex tachycardia

Alpha blockers (e.g. prostate)/Ca blockers: inability to vasoconstrict

(Cardiac arrhythmia less common because would’ve succumbed to atherosclerosis-related death)

Question 13

DDx for syncope without warning

Answer 13

Cardiac cause more likely, cerebrovascular (but rare)

Question 14

Syncope following standing up

Answer 14

Vasovagal, orthostatic more likely

Question 15

Syncope following vigorous arm activity

Answer 15

Subclavian steal more likely

Question 16

Syncope following head turning/shaving

Answer 16

Carotid sinus hypersensitivity

Question 17

Syncope following exercise

Answer 17

Cardiac pathology: AS, Long Q-T channelopathy, HOCM

FHx of sudden death is key!

Question 18

Significant PMHx for syncope

Answer 18

Diabetes: Predisposal to vascular disease, hypos, dehydration, autonomic dysf(x)

Cardiac disease: Predisposes to arrhythmias

Peripheral vascular disease: Ask about claudication

Epilepsy: Is this a typical seizure? Has frequency changed

Psychiatric illness: Psychogenic seizures more common, panichattacks and hyperventilation

Anaemia: Recent bleeding, blood transfusion, haematological problems

Question 19

Medications commonly resulting in AV block

Answer 19

Amiodarone, adenosine

Beta blockers

Non-dihydropiridine Ca blockers (e.g. verapamil)

Question 20

Non-cardiac significant DHx

Answer 20

Insulin (but NOT metformin)

Vasodilators

Antidepressants

Anticoagulants (risk of subdural haemorrhage)

Recreational drugs

Question 21

Non-drug causes of first and second degree heart block

Answer 21

Increased vagal tone/athletes

Acute myocarditis

Ischaemic heart disease

Hypokalaemia

Question 22

Non-drug causes of complete heart block

Answer 22

Idiopathic (fibrosis of conduction tissue)

Congenital

IHD/MI

Surgery/trauma

Aortic stenosis

Question 23

Examination for syncope

Answer 23

Tongue: Sings of biting

Mouth: Signs of dehydration

Head: Signs of trauma

Carotids: Bruits indicating stenosis

Heart: Murmurs, pulse irregularities

Neuro: Peripheral neuropathy, post-ictal neurological recovery

Question 24

Investigations for syncope

Answer 24

ECG: Heart rhythms/conduction, 24-hr if necessary

LSBP: Orthostatic hypotension

U+Es: Dehydration, electrolyte abnormalities

Capillary blood glucose: Exclude hypoglycaemia

Question 25

Rhythms associated with sick sinus syndrome

Answer 25

Sinus bradycardia

Paroxysmal tachycardia (junctional)

Sinus pauses/atrial standstill

Junctional escape rhythms (bradycardic)

Question 26

Junctional escape rhythm rate

Answer 26

50 bpm

Question 27

Ventricular escape rhythm rate

Answer 27

30 bpm

Question 28

Accelerated idioventricular tachycardia

Answer 28

Ventricular escape rhythm similar in appearance to VT but rate <120bpm –> associated with acute MI

Question 29

Definition of Stokes-Adams attacks

Answer 29

Transient LoC due to loss of CO (ie. pulseless) from a cardiac arrhythmia (aka cardiogenic syncope)

Usually complete heart block or sinoatrial disease (sick sinus syndrome)

Question 30

Clinical features of Stokes-Adams attacks

Answer 30

No trigger/change in posture

No prodrome

No pulse + pale appearance

Twitching may occur from cerebral anoxia if prolonged (usually lasts seconds)

After recover pt is flushed as well-oxygenated blood from pulmonary circulation is pumped round

Question 31

Main anticonvulsant drugs

Answer 31

Valproate

Lamotrigine

Carbamazpine

Phenytoin

Question 32

Interactions of carbamazepine and phenytoin

Answer 32

Oral contraceptive pill and warfarin (via P450 system)

Question 33

ECG findings Brugada syndrome

Answer 33

RBBB

Saddle-shaped ST elevation in V1-V3

Question 34

Pathophysiology of Brugada syndrome

Answer 34

Na channel mutation