Approach to Transient (paroxysmal) loss of consciousness

Episodes of transient (paroxysmal or episodic) loss of consciousness are one of the most common reasons that neurologist are consulted for in practice. This is probably because seizures and epilepsy over the common is conditions and neurologists face and treat. However there are other competing conditions that can cause transient loss of consciousness that need to be considered and differentiated from seizures. The main 3 differential diagnosis for seizures are syncope, hypoglycemia and psychogenic seizures also known as pseudoseizures or nonepileptic events.
As with all transient (paroxysmal) neurological events the clinical assessment relies heavily on the temporal features and sequence of events. Start with open ended questions and let the patient speak, then move to close ended questions to get the details that may be missing. It is useful to ask the patient and witness about of events that preceded the episode, events that occurred during the episode and events that occurred after the episode. 2 additional temporal features are the frequency of the events and the duration of the events.
For features preceding this event asked about palpitations darkening of the vision, rising epigastric sensation, whether they were sitting or standing or whether there was diplopia or vertigo. For features that occurred during tried to determine whether there was complete loss of awareness during the episode? Were the patient’s eyes open during the episode? Was there is tonic stiffening of the muscles? Was there jerking of the limbs? Was there tongue biting or cheek biting? Was the episode accompanied by loss of bowel or bladder function?

Transient (paroxysmal) loss of consciousness, like all paroxysmal events have 5 additional features to enquire about:

  • Frequency of events
  • Duration of events
  • Pre-ictal features (before the event)
  • Ictal features (during the event)
  • Post-ictal (after the event)

Causes of transient (paroxysmal) loss of consciousness:

  • Seizures and epilepsy
  • Syncope
  • Hypoglycemia
  • Non-epileptic attack disorder NEAD (a.k.a. Psychogenic episodes, Pseudoseizures, non-epileptic attacks):
    • Conversion disorder (commonest form), somatization disorder, factitious disorder, malingering.