SYNCOPE What to do when the lights go out . . .

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SYNCOPEWhat to do when the lights go out . . .

• Peter Rogers, R2
• Academic Half Day
• Jan. 28, 2003

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Objectives

• Define syncope and differentiate from other
  causes of altered LOC
• Review pathophysiology and outline an approach
• Determine important points for history,physical
  exam and investigation in the ED
• Review cases

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Definition

• A transient loss of consciousness accompanied by
  an inability to maintain postural tone
• Resolves spontaneously without intervention
• Duration seconds - minutes
• Presyncope refers to a prodromal state that
  terminates prior to LOC

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Epidemiology

• In the US . . .
• 3 of ED visits
• 6 of admissions
• Costs 750 million annually
• Common in elderly
• CAD
• Polypharmacy
• Neuropathies
• Autonomic instability
• Incidence lt 0.1 in children

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Mortality / Morbidity

• Mortality at 1 year . . .
• 20-30 if cardiac
• 2-6 if etiology unknown
• Major potential for morbidity
• Head injury
• Lacerations
• Extremity fractures

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Pathophysiology 101

• Syncope is caused by impaired cerebral perfusion
• The brain is very sensitive to glucose and oxygen
  levels requiring a blood flow of 55ml/100g brain
  tissue/minute

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Pathophysiology 102

• Syncope will result if
• blood flow is less than 20ml/100g/min
• if it stops for 3-5 seconds
• Can be due to
• I. regional hypoperfusion
• II. systemic hypotension

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I. Regional Hypoperfusion

• Cerebral vasoconstriction
• hyperventilation
• Cerebrovascular disease
• CVA
• Vascular steal syndromes
• subclavian steal

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Cerebrovascular

• Vertebrobasilar insufficiency may block blood
  flow to the Reticular Activating System (RAS) in
  the brainstem
• Prodrome /- cranial nerve findings
• Bilateral cerebral cortex occlusion

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Subclavian Steal

• Stenosis of subclavian artery proximal to
  vertebral artery
• Usually L side
• Use of ipsilateral arm steals blood

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II. Systemic Hypotension

• Mechanical obstruction to cardiac output
• aortic stenosis
• Cardiac arrhythmia
• heart block
• Hypovolemia
• hemorrhage, dehydration
• Dysfunctional vasoregulatory reflexes
• orthostatic hypotension

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Cardiogenic Syncope

• 18 of Syncope
• 1 year mortality 30!!
• 24 of these SCD
• 2 main mechanisms
• Arrhythmias
• Mechanical obstruction

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Arrhythmias

• Most common cardiac cause
• lt 10 sec
• Usually sudden with no prodrome
• Unrelated to posture or exertion

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Arrhythmias

• Tachyarrhythmias
• V-Tach
• Torsades de points
• Rarely SVT
• Long QT syndrome
• Bradyarrhythmias
• Sick sinus
• Blocks
• Pacemaker malfunction

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Mechanical Obstruction

• Often exertional - beware athletes
• Right-sided outflow obstruction
• Pulmonary stenosis
• PE
• Left-sided outflow obstruction
• Aortic stenosis
• Hypertrophic obstructive cardiomyopathy
• Aortic dissection
• Cardiac tamponade

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Dysfunctional Vasoregulatory Reflexes??

• 3/4 systemic blood flow is contained in the
  venous bed
• Decreased CO if there is any interference with
  venous return
• usually prevented by vasoconstriction, increased
  HR and muscle contraction
• Syncope may result if these regulatory measures
  fail

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Vasomotor Syncope

• aka orthostatic/postural hypotension
• Most common type esp. elderly
• Blunted baroreceptor response which results in
  failure of cardiac compensation following
  hypotension
• i.e. increased vagal tone

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Vasomotor Syncope

• Decreased vasomotor tone
• Bradbury-Eggleston Syndrome
• Shy-Drager Syndrome
• Neuropathies
• Decreased intravascular volume
• Hemorrhage
• Dehydration
• Sepsis

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Vasovagal Syncope

• aka faint, swoon
• PPT by emotional/noxious stimuli
• Common in younger people
• ?familial
• Initial stimulus effects catechol. release ?
  HR, BP, SVR
• ? sympathetic tone sensed by vasomotor center in
  medulla, which ? parasympathetic tone

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Vasovagal

• Can be prevented/reversed with supine position
  and elevation of legs
• Less common in elderly because ofdecreased vagal
  tone and decreased B-adrenergic contractility

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Vasovagal Syncope

• Several subtypes
• Cough
• Micturition
• Defecation
• Postprandial
• Carotid Sinus Syncope

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Carotid Sinus Syncope

• Sensitive to stretch
• 10 of population are hypersensitive
• Results in ? vagal tone
• Turning head, tight collar
• Usually elderly men

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Finally The Main Event

• Loss of muscle tone and loss ofconsciousness
  lead to collapse
• Usually motionless with relaxed skeletal muscles
• May have mild clonic limb jerks, especially if
  longer period of anoxia
• Pulse weak, BP low, breathing shallow
• Duration seconds minutes

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Post Syncope

• Once horizontal there is no gravity impeding
  blood flow to the brain
• Rapid and spontaneous recovery
• Few residual symptoms - may feel weak
• Will likely recur if patient rises quickly
• May have neurologic complications ifprolonged
  cerebral ischemia

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History

• Prodrome
• Associated symptoms
• Activity prior to event
• Position of patient
• Witnesses
• Duration rate of recovery
• Seizure?
• Trauma?

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She went right funny

• 70 experience a prodrome
• Pallor, diaphoresis
• Nausea or vomiting
• Faintness, dizziness
• Blurring/dimming vision, constriction of visual
  fields, paralysis of voluntary lateral gaze, EOM
  fixed
• Yawning, ringing in ears
• Parasthesias

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Red Flags

• Chest pain
• Dyspnea
• Back pain
• Palpitations
• Focal CNS deficits
• worst headache ever

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Medications

• ß blockers
• Diuretics
• Digoxin
• Antipsychotics
• Antidepressants
• Phenothiazines
• Alcohol
• Antidysrhythmics
• Antiparkinsonism drugs

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Physical Exam

• ABCs!!!
• Vitals with postural changes
• Fever
• Volume status
• CVS
• CNS
• Abdomen
• Dont forget trauma

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Orthostatic Vitals

• Recumbent for 5 minutes prior
• Stand at least 2 minutes
• Significant changes include
• Systolic ? 20 mm Hg
• Diastolic ? 10 mm Hg
• Heart rate ? 20 bpm
• High false positive rate in elderly (drop but
  asymptomatic)

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Carotid Sinus Massage??

• Used to Dx Carotid sinus syncope
• Start on right 5-15 sec
• Measure vitals, wait 2 min, repeat L
• Positive response
• gt 3 sec asystole
• SBP drop gt 50 mm Hg
• Beware bruits or CVA

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Ddx of Altered LOC

• Hypoglycemia
• Migraine
• Narcolepsy
• Drugs / alcohol
• Psychiatric illness
• Malingering
• Seizure
• Intracranial lesion

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Seizure??

• Aura
• More sudden onset
• /- tonic/clonic movements
• Tongue biting
• Incontinence
• Duration typically longer
• Postictal confusion
• Injury common
• Syncope and seizure may occur together if the
  patient is prevented from lying down

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Workup

• 40-60 nondiagnostic
• Often extensive, out of fear of missing BAD
  THINGS
• Hx PE should diagnose 50-60 of patients

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BAD THINGS

• AMI
• PE
• Aortic dissection
• Cardiac tamponade
• Tension pneumothorax
• AAA
• SAH
• Ectopic pregnancy

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Workup

• All patients warrant
• EKG
• FOB
• glucose
• Often done but rarely useful
• CBC, lytes, BUN, Cr, Mg, Ca
• Cardiac enzymes
• Urinalysis
• ?-HCG

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Workup

• Cardiac monitor
• Head CT
• CXR
• Abd ultrasound

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Disposition

• Discharge home if
• Cause benign
• vasovagal
• Cause determined and treated
• hypovolemia
• F/U with family doctor essential
• esp. regarding medications

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Consult?

• Refer the following
• Hx of CHF or arrhythmias
• Sx of CHF
• Sx suggestive of ACS or red flags
• EKG abnormality
• These also might make you nervous
• Age gt 60
• Hx of CAD
• FHx of sudden cardiac death
• Exertional syncope in a younger patient

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Ann Emerg Med 294, 1997

• Martin et al used the following to predict 1-year
  risk of SCD or ventricular arrhythmia
• Abnormal EKG
• Age gt 45
• Hx of ventricular arrhythmia
• Hx of CHF

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Specialist Workup

• EST
• Holter
• Echocardiogram
• Tilt table testing

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Case 1

• 25 yo famale medical student
• Collapsed during Medicine Rounds on 4NA
• Nurse couldnt find a pulse 999
• PMHx
• Nil no meds

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Upon awakening . . .

• Found herself in ED on monitor
• Described autonomic prodrome
• forgot to eat breakfast
• gave blood yesterday
• Dx -gt vasomotor syncope

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Case 2

• 61 yo Internist
• c/o blacking out while skiing
• No prodrome
• PMHx
• ?IHD
• Went 15 minutes on EST!!

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Case 2

• Initial workup nil
• Head CT nil
• Holter
• runs of ventricular tachycardia
• Cath
• 3 vessel disease

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Case 3

• 36 yo female
• Blacked out ? duration
• No prodrome
• Headache x 48h
• I think its a migraine
• But . . . No Hx of migraines

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Case 3

• CT head
• SAH

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Bottom Line

• Syncope is a common event
• A symptom, not a diagnosis!!
• Usually benign, but missed events can be
  catastrophic
• Biggest yield from Hx, PE, EKG
• Diagnostic in 50-80 of cases

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Questions?