Neuroscience Clerkship

 

 

SEIZURE AND SYNCOPE

 

Brief loss of consciousness is a common situation. Such a symptom can signify benign as well as potentially life threatening disorders. Both syncope and seizure can result in a brief episode of loss of consciousness. It is critical to first differentiate them apart, as their evaluation, differential diagnosis and treatment are markedly different.

Definitions

Syncope is the sudden but temporary loss of consciousness caused from insufficient blood supply to the brain.

Seizure is an alterations in brain functions due to abnormal electrical activity; attacks may range in severity from a brief loss of consciousness to several minutes of generalized convulsions.

 
  SEIZURE SYNCOPE
ONSET


Sudden loss of consciousness

      OR

Preceding Aura (may include):

Focal sensory phenomena

Focal motor phenomena

Sensation of fear

Olfactory hallucinations

Gustatory hallucinations

Other emotional sensations


P
rogressive light-headedness

Dimming of vision

Faintness

Nausea

Pallor

Diaphoresis

DURING

Loss of consciousness with tonic clonic movements

         OR

Isolated motor findings

         OR

Altered consciousness (awake but unresponsiveness or poorly responsive to the environment)

Usually flaccid

Loss of consciousness

Unresponsiveness but may have stiffening/jerking movements, especially if hypoperfusion is prolonged

LENGTH

Typical seizure (actual ictal period) is 30 sec - 2 minutes

Loss of consciousness rarely more than 15 sec

POSTURE

Can occur in any position

More common in upright position

EXERTION

Not related to exertion

May be related to exertion

AFTER

Post-ictal state

Confusion, disorientation and/or agitation

May last 30 min to 2 hours; may last longer in the elderly

Full lucidity with return of consciousness usually immediately (typically under 30 sec)

OTHER

All of the following favor seizure:

Urinary incontinence

Tongue biting

Multiple bruises on the extremities

All of the following favor syncope:

History of prior fainting to emotional stimuli (e.g., sight of blood)

Palpitations

History of cardiac disease

Bradycardia

Abnormal EKG