Seizure Classification, Seizure Classification, Status Epilepticus Classification, Status Epilepticus Classification,

and Emergent EEGand Emergent EEG

J. Stephen Huff, MD, FACEPJ. Stephen Huff, MD, FACEPEmergency Medicine and NeurologyEmergency Medicine and NeurologyUniversity of Virginia Health SystemUniversity of Virginia Health System

Charlottesville, Virginia Charlottesville, Virginia

J. Stephen Huff, MD

A 72 year old woman is brought to the ED by EMS after having altered behavior and inability to speak. She was preparing for bed when peculiar behavior was noted. The patient is unable to speak and is having unusual jerking movements.

J. Stephen Huff, MD

The patient has no history of seizures. There is a history of stroke two years previously with residual mild right sided hemiparesis. There is no history of trauma. The patient has a history of hypertension for which she takes a diuretic.

J. Stephen Huff, MD

On physical exam, her vital signs are blood pressure 120/80, pulse 90, respiratory rate 14, temperature 99, pulse oximetry 98% saturated on supplemental oxygen. She appears alert, eyes open, but is unable to speak. She does look towards the examiner when asked questions. The right side of the patient’s face, torso, and right upper extremity are having a continuous rhythmic motion.

J. Stephen Huff, MD

Cranial nerves appear intact with the exception of facial twitching. The patient does not follow commands. Deep tendon reflexes are difficult to obtain because of movements.

J. Stephen Huff, MD

Is this a seizure? What type? Status?Is this a seizure? What type? Status?

QuickTime™ and aSorenson Video decompressorare needed to see this picture.

J. Stephen Huff, MD

QuestionsQuestions

• Is the patient having a seizure? What type?• What is a classification of seizure types?• What is status epilepticus and when is

status epilepticus a medical emergency?• When is an EEG indicated in the

emergency department?

J. Stephen Huff, MD

Differential diagnosis of recurrent movementsDifferential diagnosis of recurrent movements

• Repetitive abnormal posturing (extensor, flexor)Repetitive abnormal posturing (extensor, flexor)• TetanusTetanus• Neuroleptic malignant syndromeNeuroleptic malignant syndrome• Rigors due to sepsisRigors due to sepsis• Myoclonic jerksMyoclonic jerks• TremorsTremors• Hemiballism / involuntary movementsHemiballism / involuntary movements• Nonepileptic (psychogenic) seizuresNonepileptic (psychogenic) seizures

J. Stephen Huff, MD

Basic classification of seizure typesBasic classification of seizure types

• Partial or general?• If partial

– motor– sensory– special sensory– psychic

• Modifiers for localization

J. Stephen Huff, MD

Basic classification of seizure typesBasic classification of seizure types

Simple implies:

– consciousness not impaired

– simple motor seizure

Complex implies:

– consciousness impaired

– complex partial seizure

J. Stephen Huff, MD

Basic classification of seizure typesBasic classification of seizure types

Generalized implies:

– All areas of cortex involved

– Consciousness impaired

Convulsive implies:

– Generalized motor activity

– Tonic-clonic

– Phasic

J. Stephen Huff, MD

Generalized seizuresGeneralized seizures

• Primarily generalized-all areas of cortex activated at once

– Absence / petit mal

– Myoclonic seizures

• Secondarily generalized-one area of cortex activated then spreads

J. Stephen Huff, MD

Secondarily generalized seizuresSecondarily generalized seizures

• Implies a focus of abnormality

– Tumor

– Old stroke• Most common type of generalized

seizures in adults• Generalization often occurs too rapidly

to appreciate at bedside

J. Stephen Huff, MD

Seizure descriptionSeizure description

• Include any aura• Include any initial motor

manifestations• Include description of tonic phase if

present• Include description of clonic phase• Include level of consciousness

J. Stephen Huff, MD

Seizure descriptionSeizure description

Our patient in video example:Our patient in video example:

Partial motor status epilepticus with Partial motor status epilepticus with complex symptomatologycomplex symptomatology

J. Stephen Huff, MD

What is status epilepticus?

WHO - “enduring epileptic condition”WHO - “enduring epileptic condition”

Traditional definitions:Traditional definitions:

– 30 minutes continuous seizures30 minutes continuous seizures

– Series of seizures without return Series of seizures without return to full consciousness to full consciousness

betweenbetween

J. Stephen Huff, MD

What is status epilepticus?What is status epilepticus?

• Simple status epilepticus Simple status epilepticus (consciousness preserved):(consciousness preserved):

• simple motor status epilepticus simple motor status epilepticus

• sensory status epilepticussensory status epilepticus

• aphasic status epilepticusaphasic status epilepticus

• Nonconvulsive status epilepticusNonconvulsive status epilepticus (consciousness impaired; twilight or fugue):(consciousness impaired; twilight or fugue):

• petit mal statuspetit mal status

• complex partial status epilepticuscomplex partial status epilepticus

J. Stephen Huff, MD

What is status epilepticus? Part 2What is status epilepticus? Part 2

• Overt generalized convulsive status epilepticus Overt generalized convulsive status epilepticus (continuous convulsive activity and intermittent (continuous convulsive activity and intermittent convulsive activity without regaining full convulsive activity without regaining full consciousness):consciousness):

– Convulsive (tonic-clonic) / tonic / clonicConvulsive (tonic-clonic) / tonic / clonic– Myoclonic Myoclonic

• Subtle generalized convulsive status epilepticus Subtle generalized convulsive status epilepticus (following generalized convulsive status epilepticus (following generalized convulsive status epilepticus with or without motor activity)with or without motor activity)

J. Stephen Huff, MD

Types of status epilepticusTypes of status epilepticus

As many types of status epilepticus as As many types of status epilepticus as there are seizure types:there are seizure types:

– Generalized tonic-clonic statusGeneralized tonic-clonic status

– Absence/petit mal statusAbsence/petit mal status

– Complex partial statusComplex partial status

J. Stephen Huff, MD

Why is status an emergency?Why is status an emergency?

• Ongoing generalized status epilepticus Ongoing generalized status epilepticus • Potential for neuronal damagePotential for neuronal damage• Electrical activity alone is damagingElectrical activity alone is damaging

J. Stephen Huff, MD

Rationale for aggressive treatment in Rationale for aggressive treatment in generalized convulsive status epilepticusgeneralized convulsive status epilepticus

1. The longer generalized convulsive status epilepticus persists, the harder it is to control.

2. Neuronal damage is primarily caused by continuous excitatory activity, not systemic

complications of generalized convulsive status epilepticus.

3. Systemic complications of seizure activity, particularly hyperpyrexia, may exacerbate damage.

4. Every seizure counts in terms of making generalized convulsive status epilepticus more difficult to control and for causing neuronal damage.

J. Stephen Huff, MD

Status epilepticus requiring immediate, Status epilepticus requiring immediate, aggressive treatmentaggressive treatment

• Continuous generalized convulsive activity with Continuous generalized convulsive activity with impaired consciousness lasting greater than 5 min*impaired consciousness lasting greater than 5 min*

• Serial seizures without return to full consciousness Serial seizures without return to full consciousness between seizuresbetween seizures

• SGCSE epilepticus - coma with minimal or no SGCSE epilepticus - coma with minimal or no associated motor activity:associated motor activity:

• Consider if post-ictal state is not improving Consider if post-ictal state is not improving in 20 minutes*in 20 minutes*• May evolve from GSCSEMay evolve from GSCSE

J. Stephen Huff, MD

Status epilepticus that possibly Status epilepticus that possibly benefits from aggressive treatmentbenefits from aggressive treatment

• Evidence of CNS injury from these Evidence of CNS injury from these seizure types is not as clear….seizure types is not as clear….

• Complex partial status epilepticusComplex partial status epilepticus(twilight or fugue state)†(twilight or fugue state)†

† † EEG may be required for diagnosisEEG may be required for diagnosis

J. Stephen Huff, MD

Status Epilepticus Requiring Status Epilepticus Requiring TreatmentTreatment

(Not time critical)(Not time critical)

• Absence status epilepticus Absence status epilepticus

(spike-wave status epilepticus)†(spike-wave status epilepticus)†

• Simple motor status epilepticusSimple motor status epilepticus

(epilepsia partialis continua)†(epilepsia partialis continua)†

† † EEG may be required for diagnosisEEG may be required for diagnosis

J. Stephen Huff, MD

When is an EEG indicated in the ED?When is an EEG indicated in the ED?

• Persistent altered consciousnessPersistent altered consciousness• Refractory generalized convulsive statusRefractory generalized convulsive status• Pharmacologic paralysisPharmacologic paralysis• Viral encephalitisViral encephalitis• Undifferentiated comaUndifferentiated coma• Brain deathBrain death

J. Stephen Huff, MD

When is an EEG indicated in the ED?When is an EEG indicated in the ED?

• Multicenter Study

• Emergency Medicine Seizure Study Group

• EEG uncommonly used-local practice pattern?

J. Stephen Huff, MD

When is an EEG indicated in the ED?When is an EEG indicated in the ED?

Survey of EEG labs shows:Survey of EEG labs shows:

– An average response time of 3 hrsAn average response time of 3 hrs

– Neurology consulted firstNeurology consulted first

– No clear consensus existedNo clear consensus existed

J. Stephen Huff, MD

When is an EEG indicated in the ED?When is an EEG indicated in the ED?

• Most compelling scenario:Most compelling scenario:–Generalized convulsive status epilepticusGeneralized convulsive status epilepticus

• Pharmacologic paralysisPharmacologic paralysis• Consideration of “subtle” statusConsideration of “subtle” status

• Patient not awakening 20-30 minutes Patient not awakening 20-30 minutes after seizure terminationafter seizure termination

J. Stephen Huff, MD

EEG ProblemsEEG Problems

• Artifact / InterferenceArtifact / Interference• Complex interpretation Complex interpretation • High inter-observer variabilityHigh inter-observer variability• Technician intenseTechnician intense

J. Stephen Huff, MD

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J. Stephen Huff, MD

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J. Stephen Huff, MD

J. Stephen Huff, MD

When is an EEG indicated in the ED?When is an EEG indicated in the ED?

• Generalized convulsive status epilepticus– Pharmacologic paralysis– Consideration of “subtle” status

• Patient not awakening 20-30 minutes after seizure termination• Pathway-early neurologic consultation

J. Stephen Huff, MD

Questions?Questions?