Syncope Flashcards
What is syncope?
sudden, transient LOC, with rapid + spontaneous recovery thought to be secondary to cerebral hypoperfusion
What are the 3 subtypes of syncope?
Cardiac: arrhythmogenic + myocardial
Non-cardiac e.g. Reflex (neurally mediated) + Orthostatic
List 6 causes of arrhythmogenic syncope
Sick sinus syndrome
Ventricular tachycardia
AV block
Supraventricular arrhythmias
Adams-Stokes syndrome
Torsades de pointes
List 9 causes of myocardial syncope
Massive MI
Aortic stenosis
Mitral valve prolapse
Atherosclerotic cardiovascular diseases
PE
Pulmonary HTN
HOCM
Severe asymmetric septal hypertrophy
Cardiac tamponade
List 3 types of reflex syncope
Vasovagal (neurocardiogenic)
Situational
Carotid sinus syndrome
List 5 causes of Vasovagal Syncope
Prolonged standing
Emotional stress, e.g. fear, sight of blood
Pain/ injury
Heat exposure
Idiopathic
List 5 triggers for situational syncope
Cough
Swallow
Laughing
Defecation
Micturition (common in prostatic hyperplasia)
What causes carotid sinus syncope?
Pressure on carotid sinuses (e.g. during a massage, when shaving, tightening a necktie)
What is the Vasovagal response?
Hemodynamic response to a trigger (e.g., stress) of the vagus nerve, resulting in a decrease in SNS tone simultaneous with PNS tone increase.
Increased PNS activity results in a drop in HR, BP + heart contractility.
Can lead to fainting (vasovagal syncope).
Describe the mechanisms of orthostatic syncope
Mostly orthostatic hypotension
Postural tachycardia syndrome (POTS): orthostasis with tachycardia + no hypotension
When does postural tachycardia syndrome often occur?
Following other medical conditions (e.g., pregnancy, trauma, surgery, viral illness)
List 6 causes of orthostatic hypotension
Hypovolemia: dehydration, hemorrhage, diuretics, diarrhoea
Meds: BB’s, alpha blockers, CCBs
Neurogenic: Diabetic neuropathy, Parkinson disease
What is the most common cause of syncope?
Reflex syncope (all ages)
Orthostatic + cardiac become progressively more common in older patients.
List 7 prodromal symptoms of vasovagal syncope
Impairment of senses
Nausea
Pallor
Warmth
Diaphoresis
Lightheadedness
Hyperventilation
List 3 prodromal symptoms of orthostatic syncope
Lightheadedness
Nausea
Dizziness
How does cardiac syncope often present?
Without any prodrome, i.e. a sudden fall, which may be accompanied by injuries resulting from a lack of protective reflexes.
Describe Syncope
Rapid onset LOC
Accompanied by complete loss of muscle tone
Last secs to mins followed by spontaneous recovery
What movement can occur in vasovagal syncope?
Brief myoclonus (NOT suggestive of epilepsy)
Describe initial evaluation of patients presenting with syncope
Cardio examination
LSBP + HR
ECG for all patients
In which circumstances are no further investigations required for syncope?
If typical features, no postural drop + a normal ECG
What readings are suggestive of orthostatic syncope?
Symptomatic fall in SBP >20 mmHg
or
DBP >10 mmHg
or
Decrease in SBP < 90mmHg
What bloods may be taken in suspected syncope to identify cause of syncope?
Hb: anaemia
U+Es: dehydration
Serum cortisol: adrenal insufficiency
Glucose: DM/ hypoglycaemia
Cardiac enzymes: MI
D-dimer: PE
Which investigations are indicated in cardiogenic syncope?
Imaging (e.g. TTE, CTA)
Lab studies (e.g. cardiac enzymes)
Cardiac rhythm monitoring
Which investigation can be performed to help confirm noncardiogenic syncope?
Tilt-table test
Describe conservative measures for syncope
Increase fluid (2–3L/day) + sodium intake (6–9g salt/day) unless CI
Medication adjustment: discontinue/ decrease dosage of offending/ contributing drugs (e.g., diuretics, antihypertensives).
Instruct patients to avoid/ anticipate triggers.
Advise patients with prodrome to lie down when prodrome is detected (to avoid injuries from falls).
Describe management of vasovagal syncope
Conservative Mx
If Sx persist, consider:
Midodrine or fludrocortisone
+/-
Orthostatic training
Describe management of situational syncope
Conservative Mx
Avoidance of triggers where possible
Describe management of carotid sinus syndrome
Conservative Mx
Avoid triggers, e.g. tight-collared clothing.
Describe management of orthostatic syncope
Conservative measures
Compression stockings
Counter-pressure manoeuvres (if prodromal)
Head up tilt sleeping
Consider Midodrine if Sx persist
Describe management of cardiogenic syncope
Refer to cardiology
Mx may involve: pacing, anti-arrhythmics, ICD, catheter ablation
Give 3 features of autonomic neuropathy in diabetics
- Postural hypotension
- Loss of respiratory arrhythmia
- Erectile dysfunction
