see also:

• seizures
• the blood donor who collapses
• vertigo - peripheral vs central

• 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:
  • the shocked hypotensive patient
    • sepsis / septicaemia
    • acute blood loss (eg. upper GIT bleeding, ectopic pregnancy, both of which may initially be occult)
    • dehydration
    • anaphylaxis
    • massive PE
    • air embolism eg. the blood donor who collapses
  • occult PE
    • 2017: PE and syncope - the maths - D-Dimer or no D-Dimer?
  • cardiac arrhythmias
    • 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
        • short QTc
  • subarachnoid haemorrhage (SAH)
  • postural hypotension
• 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
    • air embolism eg. the blood donor who collapses
    • 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

• 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
• vasovagal syncope / neurocardiogenic syncope becomes a much more uncommon cause of syncope as age increases above 35 yrs age and thus the elderly require a low suspicion for other cardiac or neurologic causes, in particular:
  • occult PE
    • 2017: PE and syncope - the maths - D-Dimer or no D-Dimer?
      • 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
  • aortic dissection - do an ADD - an aortic dissection risk assessment tool
  • carotid sinus syncope
    • Carotid sinus massage should be considered in both supine and upright positions whilst cardac monitored as patients with this cause develop 5-10 secs of asystole with often delayed return of BP. These patients do well with cardiac pacemaker.
  • Cardiac arrhythmias
  • orthostatic hypotension due to medications, dehydration (which most elderly have), and age or disease related impaired autonomic systems such autonomic neuropathy and post-prandial hypotension

• RCH guideline - syncope
• ECG patterns NOT to miss in the young person with syncope
  • 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
  • prolonged QTc
  • 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

• 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
      • see https://lifeinthefastlane.com/ecg-library/100-ecgs/quiz-ecg-020/
    • 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
    • eg. elderly with syncope whilst sitting and no cause found