Epileptic Seizures

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Epileptic Seizures Powered By Docstoc
					Classification of Epileptic Seizures (International League Against Epilepsy, ILAE)
                                                 Partial-Onset Seizures                                                                                                                  Generalized-Onset Seizures
Begin in a focal area of cerebral cortex                                                                              Onset recorded simultaneously in both cerebral hemispheres
            Simple Partial                             Complex Partial                  Secondarily Generalized                Absence                  Myoclonic                     Clonic                     Tonic                 Tonic-Clonic                    Atonic
Preserved consciousness                   Consciousness impaired                     Aura                             Brief episodes of         Brief                       Rhythmic                   Sudden-onset tonic        Grand mal seizures         In people with clinically
Aura                                      Aura                                        Evolve into complex            impaired consciousness    Arrhythmic                  Motor                      extension/ flexion of     Several motor              significant neurologic
Lasts for a few seconds → minutes         Lasts for 60 – 90 seconds                     partial seizure               No aura                   Jerking                     Jerking movements           Head                    behaviours                 abnormalities
                                          Followed by brief postictal confusion       Then into generalized          No postictal confusion    Motor movement              With/ without impaired      Trunk                   Generalized tonic          Consists of
                                          May last a few days                           tonic-clonic seizure          Lasts < 20 seconds        Last < 1 second             consciousness               Extremities             extension of extremities      Brief loss of postural
                                            Generalized weakness                    ↑ Prominent amnesia for aura     Few/ no automatisms       Often cluster within a      Can have a focal origin    Several seconds           (few seconds)                  tone
                                            Asthenia                                (with severity)                   Facial automatism       few minutes                 (with/ without impaired    Occur in relation to      Clonic rhythmic               Resulting in
                                            Fatigue                                 Complex partial seizure may       Repetitive blinking     Evolve to clonic seizure    consciousness)              Drowsiness              movements                      falls, injuries
                                          Ictal correlate on EEG (majority)          evolve into generalized tonic-   Precipitating factors      Rhythmic                  Focal origin                Shortly after falling   Prolonged postictal
                                                                                     clonic seizure, or an aura may    Hyperventilation         Jerking movements            Simple partial            asleep                 confusion
                                                                                     evolve into generalized tonic-    Photic stimulation      Not always epileptic in        Complex partial         Just after awaken       No aura
                                                                                     clonic seizure without obvious   Manifestation             origin                      Typical generalized        Associated with other
                                                                                     complex partial seizure           ↓ Performance                                       clonic seizure             neurologic                (Secondarily generalized
Diagnosis                                                                                                                in school                                          Simultaneously involve     abnormalities             tonic-clonic seizure has
Repeated, stereotypic occurrence of the same experience                                                                ↓ Overall attention                                 upper, lower                                         aura) But aura is often
Association with                                                                                                                                                            extremities                                          forgotten (postictal
     Focal EEG changes                                                                                                                                                                                                          amnesia)
     Recurrent auras (leading to a complex partial seizure, secondarily generalized seizure)
Resolution of recurrent clinical phenomena with anticonvulsants is presumptive (but not diagnostic evidence)
Simple Partial Status Epilepticus      Begins with behavioural arrest                                                 Classic ictal EEG          Classic ictal EEG           Classic ictal EEG          Classic ictal EEG        Classic ictal EEG          Classic ictal EEG
Aura > 30 minutes                      Followed by                                                                    3.5Hz generalized          Fast polyspike-and-slow     Bilateral rhythmic         Electrodecremental       Generalized (bilateral)    Electrodecremental
                                         Staring                                                                     spike-and-slow wave        wave complexes              epileptiform discharges    response                 complexes of spikes/       response
                                         Automatisms                                                                 complexes                                                                         ↑ Frequency              polyspikes                 ↑ Frequency
                                          (chewing, lip smacking, mumbling,                                                                                                                             electrographic           Slow waves                 electrographic
                                          fumbling with hands)                                                                                                                                          discharge in β           Epileptiform discharges    discharge in β
                                         Postictal confusion                                                                                                                                           frequency                ↑ Amplitude in frontal     frequency
                                       Originate from Mesial Temporal Lobe                                                                                                                              (beta buzz)              regions                    (beta buzz)
                                       Dystonic posturing                                                                                                                                               ↓ Amplitude                                         ↓ Amplitude
                                       (contralateral upper extremity)                                                                                                                                  (compared to                                        (compared to
                                       Originate from Frontal Lobe                                                                                                                                      background rhythm)                                  background rhythm)
                                       Bizarre motor behaviours
                                        Bicycling posture                                                                                                                                              May evolve into slow                                May evolve into slow
                                        Fencing posture                                                                                                                                                spike-and-wave                                      spike-and-wave
                                       Fast postictal recovery to baseline                                                                                                                              complexes or diffuse                                complexes or diffuse
                                       (appear in clusters of seizures)                                                                                                                                 polyspikes                                          polyspikes

Normal α rhythm – highly suggestive of nonepileptic seizures