IM
Generalized Seizure
- Absence
- Myoclonic
- Clonic
- Tonic
- Tonic-clonic
- Atonic
Generalized Seizures (convulsive or non-convulsive)
- Absences
- Myoclonic seizures
- Clonic seizures
- Tonic seizures
- Atonic seizures
Pediatrics
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Involves BOTH hemispheres of the brain
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Always involves loss of consciousness
- Tonic or clonic movements or combination (grand mal)
- Absence (petit mal)
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Myoclonic: Sudden, <100 ms involuntary contraction of muscle(s) or muscle groups
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Clonic: Repetitive, rhythmic myoclonus at 2-3 Hz
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Tonic: Sustained muscle contraction for seconds to minutes
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Generalized tonic-clonic: Bilateral symmetrical tonic contraction, then bilateral clonic contractions
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Atonic: (e.g., drop attacks) Sudden, brief, 1–2 s decrease in tone without preceding myoclonic or tonic event
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Astatic: Loss of posture (=drop) due to atonic, myoclonic, or tonic event
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Infantile Spasm: Axial contraction, may be asymmetric
Generalized Tonic-Clonic Seizures
Typically have no evidence of any localized, regional, or diffuse brain abnormality on history, physical, or neurologic examination; clinical laboratory testing; or imaging studies.
The awake EEG of patients with generalized tonic-clonic seizure may be normal.
In generalized seizure patients, photic stimulation and/or hyperventilation during an EEG may produce spikes or even seizures
Patients may have prodrome, occurring hours or days before a seizure: mood changes, sleep disturbances, lightheadedness, anxiety, irritability, difficulty concentrating.
Patients do not have auras. An aura represents a simple partial seizure/focal aware seizure.
In nocturnal seizures, it may be hard to distinguish a primary generalized seizure from a partial seizure with secondary generalization (focal seizure evolving to a bilateral tonic-clonic seizure).
Phases
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Tonic Phase: 10-20 seconds, begins with flexion of the trunk and elevation and abduction of the elbows. Subsequent extension of the back and neck is followed by extension of arms and legs. Can be accompanied by apnea, which is secondary to laryngeal spasm. Air being forced past the vocal cords causes a cry or groan. The child loses consciousness and falls to the floor.
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Clonic Phase: Clonic convulsive generalized movements. This is because phases of atonia alternate with repeated violent flexor spasms. Each spasm is accompanied by pupillary contraction and dilation. Some patients may bite their tongue or cheek. Voiding may occur at the end of the clonic phase as sphincter muscles relax. The atonic period lasts about 30 seconds. The patient continues to be apneic during this phase.
The convulsion, including tonic and clonic phases, lasts around 1-2 minutes.
Postictal State
- A variable period of decreased consciousness during which the patient becomes quiet and breathing resumes.
- The patient gradually awakens, often after a period of stupor or sleep, and often is confused, with some automatic behavior.
- Headache and muscular pain are common.
- The patient does not recall the seizure itself.