Do most generalized seizures present with a loss of consciousness?

Loss of Consciousness in Generalized Seizures

Yes, most generalized seizures present with loss of consciousness, as generalized seizures affect large areas or both sides of the brain simultaneously, typically resulting in altered consciousness. 1

Types of Generalized Seizures and Consciousness

• Generalized tonic-clonic seizures affect large areas or both sides of the brain and manifest as full-body rhythmic jerking with alterations in consciousness 1
• During generalized seizures, abnormal increased activity in subcortical structures (cerebellum, basal ganglia, brainstem, and thalamus), along with decreased activity in the association cortex, contributes to impaired consciousness 2
• Unlike focal seizures which may or may not impair awareness, generalized seizures typically involve loss of consciousness as they rapidly affect both hemispheres 1

Mechanisms of Loss of Consciousness

• Complete loss of consciousness occurs when epileptic activity involves both cortical and subcortical structures, as in tonic-clonic seizures and absence seizures 3
• Neuroimaging and electrophysiology studies show that involvement of the bilateral thalamus and upper brainstem leads to selective impairment of frontoparietal association cortices and midline 'default mode' networks, resulting in ictal loss of consciousness 3
• During generalization, the most consistent blood flow increases occur in the superior medial cerebellum, thalamus, and basal ganglia, which correlate with impaired consciousness 2

Clinical Manifestations and Recognition

• Generalized tonic-clonic seizures typically present with:

  • Full-body rhythmic jerking movements 1
  • Loss of consciousness that coincides with the onset of tonic-clonic movements 1
  • Prolonged tonic-clonic movements (longer than those seen in syncope) 1
  • Post-ictal confusion lasting more than a few minutes 1
  • Tongue biting (particularly on the lateral sides) 1
  • Aching muscles after the event 1

• Distinguishing features from syncope:

  • In epilepsy, loss of consciousness coincides with the onset of movements, while in syncope, movements occur after loss of consciousness 1
  • Epileptic movements are typically symmetrical and synchronous, while syncopal movements are often asymmetrical and asynchronous 1
  • Duration of loss of consciousness is typically longer in seizures (mean 74-90 seconds) compared to syncope (usually <30 seconds) 1

Important Considerations for Management

• First aid providers should activate EMS for individuals with:

  • First-time seizure
  • Seizures lasting >5 minutes
  • Multiple seizures without return to baseline mental status between episodes
  • Seizures with traumatic injuries or difficulty breathing
  • Seizures in special populations (infants <6 months, pregnant individuals)
  • Failure to return to baseline within 5-10 minutes after seizure activity stops 1

• During a seizure with loss of consciousness, first aid providers should:

  • Help the person to the ground
  • Place the person in the recovery position
  • Clear the area around them to prevent injury
  • Stay with the person throughout the seizure 1

• Important cautions:

  • Do not restrain the person having a seizure 1
  • Do not put anything in the mouth or give food, liquids, or oral medicines during a seizure or when consciousness is decreased 1