syncope
Table of Contents
syncope / near syncope
see also:
Introduction
- syncope and near syncope are one of the most common presentations to the ED and need to be differentiated from a primary seizure event (seizure activity may be secondary to the syncopal event if there is prolonged reduced blood supply to the brain)
- in the elderly they are particularly concerning, not only because of the higher incidence of potentially life threatening causes but also in the high morbidity and mortality associated with falls such as fracture neck of femur (#NOF), head injury in the adult patient, fractured ribs, etc, not to mention the significant subsequent loss of confidence walking.
- while many are due to benign conditions (especially in the younger population) such as vasovagal events and cough/micturition syncope there are a wide range of not so benign conditions that need to be considered including:
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- acute blood loss (eg. upper GIT bleeding, ectopic pregnancy, both of which may initially be occult)
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- mnemonic for ECG clues to potentially deadly arrhythmias causing syncope:
- A2
- acute coronary syndrome
- Arrythmogenic Right Ventricular Dysplasia (ARVD) - Tinv V1-3 and prolonged S upstroke V1-3
- B2
- blocks - trifascicular, Mobitz, etc
- Brugada syndrome - RBBB with ST elevation in V1-2 with RSR' pattern in young people
- C
- cardiomyopathy - hypertrophic cardiomyopathy (HCM or HOCM)
- W
- WPW eg. AF with variable width QRS
- QT
- prolonged QTc - measure manually and check nomogram
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- persistent decreased cognitive function following the collapse suggests:
- ongoing hypotension
- hypoglycaemia
- post-ictal state - this should resolve over an hour or so
- drug overdose
- mechanical intracranial event such as subarachnoid haemorrhage (SAH), stroke (CVA), other types of intracranial haemorrhage such as subdural, although these tend not to have a sudden syncopal event but gradual deterioration
- decreased cognition with cerebellar signs (may initially be subtle), vertigo or occipital blindness should suggest a posterior circulation stroke
- infective intracranial event such as meningitis, although, again, these tend not to have a sudden syncopal event but gradual deterioration
Mx of the child / adolescent with syncope
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- pre-excitation syndromes including WPW - PR < 120msec, Delta wave causing wide QRS with discordant ST-T change, +/- negative Delta wave causing “pseudo-Q wave”, or a prominent R wave in V1-3 which can mimic posterior AMI
- Brugada syndrome - RBBB (maybe incomplete), ST elevation in R V1-3 leads - may be coved or saddle-back morphology
- hypertrophic cardiomyopathy (HCM or HOCM) - LVH +/- narrow & deep Q waves in the lateral leads duration of < 40 ms
- Arrythmogenic Right Ventricular Dysplasia (ARVD) - T inv V1-3, epsilon wave, wide S
Mx of the older adult with syncope
- history, medication history (is the patient on anticoagulants, etc), and examination (is there evidence of acute stroke?) to ascertain potential cause and exclude any injuries due to a fall
- targeted investigation which should also include:
- blood sugar level
- vital signs - is the patient hypotense or septic?
- 12 lead ECG
- look for evidence of heart block or sick sinus syndrome
- look for evidence of a tachyarrhythmia
- could the patient have had a silent infarct?
- cardiac conditions outlined under the paediatric causes above - as these may present in adult life
- cardiac monitor whilst in ED
- baseline bloods:
- FBE, U&E
- consider troponin, Ca,Mg,PO4 if possible primary cardiac arrhythmia
- HCG if woman of child bearing age
- Group and Hold if possible acute blood loss
- blood cultures, serum lactate, LFTs, lipase, CRP, CXR, urinalysis, etc if sepsis is likely
- urgent CT brain if ongoing decreased cognition, meningism, focal neurology or sudden onset headache
- urgent FAST USS for intrabdominal bleeding, and also assessment of possible abdominal aortic aneurysm (AAA) if hypotension or abdominal pain are features
- consider admission for 12-24hrs of cardiac monitoring if possible primary cardiac arrhythmia
- pre-syncope or syncope in the older adult occurring whilst sitting without other symptoms
- this suggests a cardiac arrythmia cause and the patient should be considered for 24 hour cardiac monitoring if no other cause found
- consider also post-prandial transient hypotension due to blood flow being redirected to GIT after a meal
Syncope and falls in the elderly
- an ever increasing problem compounded by increasing number of elderly population and overzealous Rx of hypertension
- elderly usually do not have recall of a syncopal event causing a fall
- the elderly require a low suspicion for important cardiac or neurologic causes, in particular:
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- if an elderly patient requires admission for the episode of syncope:
- if clinical features of PE (eg. RR > 20, BP < 110, HR > 100), known active cancer, or probable or PH DVT then test for PE
- note that patients with alternative causes for syncope still had a 12% probability of having a PE causing the syncope and their PEs they tend to be more proximal and life-threatening
- if no clinical features PE/DVT/active cancer, then probability of “occult PE” is around 5% and if you believe the mortality benefit of anticoagulation is 3.2% or more which is probably the case, then we should consider testing with D-Dimer
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- carotid sinus syncope
- cardiac arrhythmias
- postural hypotension (orthostatic hypotension) due to medications, dehydration (which most elderly have), and autonomic dysfunction and autonomic neuropathy
- post-prandial hypotension
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- an older adult without history of true vasovagal syncope / neurocardiogenic syncope is very unlikely to have a first vasovagal syncope and a search for other causes is important
syncope.txt · Last modified: 2026/06/24 06:19 by gary1