Absence seizures vs Focal and generalized tonic-clonic seizures
How to tell Absence seizures and Focal and generalized tonic-clonic seizures apart when a board question makes them look alike.
Absence is brief generalized pause with 3-Hz spike-wave and no postictal state; focal seizures have focal onset/aura; tonic-clonic has convulsion and postictal state.
Side by side
Brief staring spells with impaired awareness, no postictal confusion, provoked by hyperventilation, and generalized 3-Hz spike-and-wave discharges, classically in children.
Focal aware seizures preserve awareness; focal impaired-awareness seizures cause aura/automatisms and postictal confusion; generalized tonic-clonic seizures cause loss of consciousness with tonic then clonic movements and postictal state.
Generalized thalamocortical network oscillations create brief absence events.
Focal seizures begin in one cortical network and may impair awareness or generalize; generalized tonic-clonic seizures involve bilateral networks from onset or spread.
3-Hz spike-and-wave EEG and brief staring without postictal confusion support absence seizure.
Aura, automatisms, focal onset, postictal confusion, or tonic-clonic motor phases support focal or generalized tonic-clonic seizure.
The trap
Staring can occur in absence or focal impaired-awareness seizures, so duration, postictal state, automatisms, and EEG decide.
The repair move
For seizure type, sort awareness, focal features, motor pattern, postictal state, and EEG.
Try a free question
CoreA child has frequent 10-second staring spells during class, provoked by hyperventilation. She immediately resumes activity afterward, and EEG shows generalized 3-Hz spike-and-wave discharges. Which seizure type is most likely?
Show answer and explanation
Answer: A. Absence seizure. Brief staring with immediate recovery and 3-Hz spike-and-wave EEG supports absence seizure.
Why the other choices are tempting
- B. Focal impaired-awareness seizures often have aura, automatisms, and postictal confusion.
- C. Focal aware seizures preserve awareness.
- D. Generalized tonic-clonic seizures have tonic-clonic motor activity and postictal state.
- E. Atonic seizures cause sudden loss of tone.
Flashcards
Tap a card to flip it.
What EEG pattern points to absence seizure?
Generalized 3-Hz spike-and-wave discharges point to absence seizure.
What postictal pattern supports absence seizure?
No postictal confusion supports absence seizure.
Quick answers
What is the fastest way to tell Absence seizures from Focal and generalized tonic-clonic seizures?
Absence is brief generalized pause with 3-Hz spike-wave and no postictal state; focal seizures have focal onset/aura; tonic-clonic has convulsion and postictal state.
What is the key clue for Absence seizures?
Brief staring spells with impaired awareness, no postictal confusion, provoked by hyperventilation, and generalized 3-Hz spike-and-wave discharges, classically in children.
What is the key clue for Focal and generalized tonic-clonic seizures?
Focal aware seizures preserve awareness; focal impaired-awareness seizures cause aura/automatisms and postictal confusion; generalized tonic-clonic seizures cause loss of consciousness with tonic then clonic movements and postictal state.
What is the common trap with Absence seizures vs Focal and generalized tonic-clonic seizures?
Staring can occur in absence or focal impaired-awareness seizures, so duration, postictal state, automatisms, and EEG decide.