Seizures & Epilepsy Flashcards

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1
Q

Seizure

Definition

A

Transient event that includes symptoms and/or signs of abnormal excessive hypersynchronous activity in the brain.

A seizure is a symptom and one must search for underlying cause, acute or chronic

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2
Q

Epilepsy

Definition

A

A disease of the brain defined by any of the following conditions:

Two unprovoked (or reflex) seizures occurring > 24 h apart

OR

One unprovoked (or reflex) seizure and a 60% likelihoood of a recurrent sz

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3
Q

Provoked Seizures

A

Seizures can be provoked by many causes including:

  • Acute head trauma
  • CNS infection
  • Hypoxia/Ischemia
  • Acute metabolic causes
    • Hypo/Hypernatremia
    • Hypomagnesemia
    • Uremia
    • Hepatic failure
  • Toxins
    • Drugs (tricyclics, neuroleptics, etc.)
    • Alcohol withdrawal
    • Recreational drug
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4
Q

Epilepsy

Etiologies

A

Causes of epilepsy include the following:

  • Genetic
  • Structural processes
    • Past parenchymal injury
    • Tumors
    • Cortical malformations
    • Vascular malformations
    • Cerebrovascular disease
    • Hippocampal sclerosis
  • Unknown
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5
Q

Seizures and Epilepsy

Pathophysiology

A
  • Glutamate ⇒ major excitatory neurotransmitter
  • GABA ⇒ major inhibitory neurotransmitter in the brain.
  • Seizures result from an imbalance between excitation and inhibition, with either too little inhibition or too much excitation
  • Epilepsy is caused by the bursting behavior of an epileptic neuronal aggregate
  • Abnormal neurons display prolonged depolarization with repetitive sodium dependent action potentials which is called a paroxysmal depolarization shift.
  • At the time of a seizure, this discharge spreads into the neighboring areas with propagation to the other areas of the brain
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6
Q

Seizure Triggers

A

Causes of decreased threshold to have a seizure:

  • Stress, emotion
  • Sleep/sleep deprivation
  • Fever/illness
  • Medications, metabolic disturbance
  • Hyperventilation (absence seizures)
  • Reflex seizures – 4-7% prevalence in epilepsy
    • Visual stimuli: strobe lights, visual patterns
    • Musicogenic: specific songs, genres of music, tones
    • Reading, eating, calculating
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7
Q

Epilepsy

Epidemiology

A
  • Cumulative epilepsy incidence: 4.4% (~1 in 23 people) by age 85
  • Adults: ~75% epilepsy with focal seizures
  • Children: ~55% epilepsy with focal seizures
  • Mortality long-term is twice that of general population overall
  • Up to 1%/year for patients with uncontrolled seizures
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8
Q

Epilepsy

Morbidity

A

Morbidity is significant and can be due to all of the following:

  • Traumatic injuries
  • Underemployment
  • Antiepileptic drug side effects
  • Cognitive dysfunction
  • Neuropsychiatric comorbidities higher prevalence over non-epilepsy population:
    • ADHD, depression, anxiety, sleep disorders, migraine
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9
Q

Simple

Partial Seizures

A

Partial: seizures starting in one area of the brain

Simple (no loss of consciousness or memory)

  • Sensory: visual, olfactory, gustatory, vertiginous
  • Motor: focal motor without march, focal motor with march (Jacksonian), postural
  • Sensory-Motor
  • Psychic (abnormal thoughts or perceptions): Dysphasic, dysmnesic, cognitive, illusions, structured hallucination
    • Dysmnesic = inability to learn simple new skills in spite of an ability to perform complex skills learnt before the onset of the disorder
  • Autonomic (heat, nausea, flushing, etc.): epigastric sensation, pallor, sweating, flushing, piloerection, pupillary dilation
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10
Q

Complex

Partial Seizures

A

Partial: seizures starting in one area of the brain

Complex: consciousness or memory impaired

  • With or without aura (warning)
  • With or without automatisms
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11
Q

Secondarily Generalized Seizures

A
  • Begins focally, with or without focal neurological symptoms
  • Becomes generalized
  • Variable symmetry, intensity, and duration of tonic (stiffening) and clonic (jerking) phases
  • Typical duration 1-3 minutes
  • Postictal confusion, somnolence, with or without transient focal deficit
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12
Q

Generalized Seizures

A

Seizures starting in both sides of the brain at the same time

  • Absence
  • Myoclonic
  • Clonic
  • Tonic
  • Tonic-Clonic
  • Atonic
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13
Q

Unclassifiable Seizures

A
  • Complex Partial Seizures
  • Impaired consciousness
  • Clinical manifestations vary with site of origin and degree of spread
    • Presence and nature of aura
    • Automatisms
    • Other motor activity
  • Duration typically < 2 minutes
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14
Q

Epileptic Myoclonus

A
  • Brief, shock-like jerk of a muscle or group of muscles, usually < 50 ms
  • Differentiate from benign, nonepileptic myoclonus (e.g., while falling asleep)
  • EEG: Generalized 4-6 Hz polyspike-wave discharges
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15
Q

Typical Absence Seizures

A
  • Brief staring spells (“petit mal”) with impairment of awareness
  • 3-20 seconds
  • Sudden-onset and sudden-resolution
  • Often provoked by hyperventilation
  • Onset typically between 4-14 years of age
  • Often resolve by 18 years of age
  • Normal development and intelligence
  • EEG: Generalized 3 Hz spike-wave discharges
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16
Q

Atypical Absence Seizures

A
  • Brief staring spells with variably reduced responsiveness
  • 5-30 seconds
  • Gradual (seconds) onset and resolution
  • Generally not provoked by hyperventilation
  • Onset typically after 6 years of age
  • Often in children with global cognitive impairment
  • EEG: Generalized slow spike-wave complexes (<2.5 Hz)
  • Patients often also have Atonic and Tonic seizures
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17
Q

Tonic Seizures and Atonic Seizures

A
  • Tonic seizures
    • Symmetric, tonic muscle contraction of extremities with tonic flexion of waist and neck
    • Duration: 2-20 seconds
    • EEG – Sudden attenuation with generalized, low-voltage fast activity (most common) or generalized polyspike-wave
  • Atonic seizures
    • Sudden loss of postural tone
    • When severe often results in falls
    • When milder produces head nods or jaw drops
    • Consciousness usually impaired
    • Duration: usually seconds, rarely more than 1 minute
    • EEG – sudden diffuse attenuation or generalized polyspike-wave
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18
Q

2017 ILAE Classification of Seizures

A
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19
Q

Focal Seizures

A

Originate within networks limited to one hemisphere

May be localized or could be widely distributed

20
Q

Generalized Seizures

A

Originate at some point within and rapidly engage bilaterally distributed networks

Can include cortical and subcortical structures but not necessarily the entire cortex

21
Q

Seizures of Unknown Origin

A
  • Can be motor or non-motor
  • Most important use is for tonic-clonic seizures for which the beginning was obscured
  • Epileptic spasms and behavior arrest are other possible seizure types of unknown onset
  • Epileptic spasms may require detailed video-EEG monitoring to clarify the nature of onset
  • Important because a focal onset may correspond to a treatable focal pathology
  • An unknown-onset behavior arrest seizure could represent a focal impaired awareness behavior arrest seizure or an absence seizure
  • A seizure might be unclassified due to inadequate information or inability to place the seizure in other categories
  • If an event is not clearly a seizure, then it should not be called an unclassified seizure; rather, this classification is reserved for unusual events likely to be seizures, but not otherwise characterized
22
Q

Aware vs Impaired Awareness

A
  • During a focal aware seizure, consciousness will be intact
  • Implies the ability of the person having the seizure to later verify retained awareness
  • Awareness specifically refers to awareness during a seizure, and not to awareness of whether a seizure has occurred
  • Awareness may be impaired without being fully absent
  • If awareness of the event is impaired for any portion of the seizure, then seizure classified as a focal seizure with impaired awareness
23
Q

Absence Seizures

vs

Focal Impaired Aware Seizure

A
24
Q

Elements of Consciousness

A
  • Awareness of ongoing activities
  • Memory for time during the event
  • Responsiveness to verbal or nonverbal stimuli
  • Sense of self as being distinct from others
25
Q

Common Seizure Symptoms

A
  • Cognitive – aphasia; attention impairment; déjà vu; memory impairment, neglect; responsiveness impairment
  • Emotional or affective – agitation; anger; anxiety, crying; fear, laughing; paranoia
  • Autonomic – bradycardia or tachycardia; flushing; hyper or hypoventilation; GI symptoms (nausea or vomiting); piloerection; erection
  • Automatisms – aggression; eye-blinking; head-nodding; pelvic thrusting; vocalization/speech; undressing; walking.
  • Motor – dysarthria; dystonic; incoordination; “Jacksonian; paralysis; paresis
  • Sensory – auditory; gustatory; hot-cold sensations; olfactory; somatosensory; vestibular; visual
  • Laterality – left; right; or bilateral
26
Q

Epilepsies and Epileptic Syndromes

1989 ILAE Classification

A
  • Localization related (Partial, Focal, Local) Epilepsies and Syndromes
    • Idiopathic (with age related onset)
    • Symptomatic
    • Cryptogenic
  • Generalized Epilepsies and Syndromes
    • Idiopathic
    • Cryptogenic or Symptomatic
    • Symptomatic
  • Epilepsies and syndromes undetermined as to whether they are focal or generalized
  • Special syndromes
27
Q

Epilepsy Syndromes

Overview

A

Grouping of patients that share similar:

  • Seizure type(s)
  • Age of onset
  • Natural history/Prognosis
  • EEG patterns
  • Genetics
  • Response to treatment
28
Q

Epilepsies and Epileptic Syndromes

Revision of Classification

A
  • Abandoned terms
    • “Localization-related epilepsy syndromes”
    • “Generalized epilepsy syndromes”
  • Instead syndromes were arranged by age of onset
  • Term changes:
    • Idiopathic → Genetic
      • Genetic means the epilepsy is the direct result of a known or presumed genetic defect(s) in which seizures are the core sx of the disorder
    • Symptomatic → Structural/metabolic
    • Cryptogenic → Unknown cause
29
Q

Electroclinical Syndromes / Epilepsies

A
  • Electroclinical syndromes arranged by age at onset:
    • Neonatal
    • Infantile
    • Childhood
    • Adolescence
    • Adult
  • Distinctive constellations
  • Epilepsies due to structural/metabolic causes
  • Epilepsies of unknown cause
  • Conditions with epileptic seizures that are traditionally not dx as a form of epilepsy
30
Q

Epilepsy Syndromes by Age

A

For reference. Dot not memorize.

  • Neonatal
    • Benign familial neonatal epilepsy
    • Early Myoclonic Encephalopathy
    • Ohtahara syndrome
  • Infantile
    • Epilepsy of Infancy with migrating focal seizures
    • West syndrome
    • Myoclonic epilepsy in infancy (MEI)
    • Benign infantile epilepsy
    • Benign familial infantile epilepsy
    • Dravet Syndrome
    • Myoclonic encephalopathy in nonprogressive disorders
  • Childhood
    • Febrile seizures plus (FS+) (can also start in infancy)
    • Panayiotopoulos syndrome
    • Epilepsy with myoclonic atonic (previously astatic) seizures
    • Benign epilepsy with centrotemporal spikes (BECTS)
    • Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE)
    • Late onset childhood occipital epilepsy (Gastaut type)
    • Epilepsy with myoclonic absences
    • Lennox-Gastaut Syndrome
    • Epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS)
    • Landau-Kleffner syndrome (LKS)
    • Childhood Absence Epilepsy
  • Adolescence - Adult
    • Juvenile absence epilepsy (JAE)
    • Juvenile myoclonic epilepsy (JME)
    • Epilepsy with GTC seizures alone
    • Progressive myoclonus epilepsy (PME)
    • Autosomal dominant epilepsy with auditory features (ADEAF)
    • Other familial temporal lobe epilepsies
  • Less specific-age relationship
    • Familial focal epilepsy with variable foci (childhood to adulthood)
    • Reflex epilepsies
31
Q

Distinctive Constellations

A
  • Clinically distinctive constellations on the basis of specific lesions or other causes
  • May have implications for clinical treatment, particularly surgery
  • Age at presentation is not a defining feature
  • Some specific distinctive constellations include:
    • Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE with HS)
    • Rasmussen syndrome
    • Gelastic seizures with hypothalamic hamartoma
    • Hemiconvulsion-hemiplegia-epilepsy
32
Q

Structural-Metabolic

Epilepsies

A
  • Cortical malformations
  • Neurocutaneous syndromes
  • Neoplasms
  • Infections
  • Trauma
  • Vascular malformations
  • Perinatal insults
  • Stroke
33
Q

Epileptic Seizures Conditions

(Not dx as a form of epilepsy)

A
  • Benign neonatal seizures
  • Febrile seizures
34
Q

Electroencephalogram

(EEG)

A

A recording of the electrical activity of the brain

  • 1st EEG: ~40% likelihood of identifying epileptiform abnormalities in a pt w/ a single unprovoked seizure
    • with repeated EEG, activation procedures, and extended EEG monitoring
    • Activation procedures: capturing sleep, hyperventilation, and photic stimulation
  • Epileptiform discharges in isolation are NOT diagnostic of epilepsy
  • Epileptiform abnormalities on EEG after the first unprovoked seizure raise 2-year recurrence risk to 58% and fulfill current dx criteria for epilepsy
  • Routine EEG may be helpful in guiding initial treatment (focal vs. generalized)
  • Extended video-EEG monitoring beneficial for seizure diagnosis, classification, and localization
35
Q

Seizure

Differential Diagnoses

A
  • Non-epileptic, physiologic events
    • Syncope
    • Hyperventilation / Panic
    • Migraine / Migraine Equivalents
    • Paroxysmal Movement Disorders
    • Sleep Disorders
    • Metabolic Disorders
    • Transient Ischemic Attacks
  • Non-epileptic, psychogenic events
36
Q

Non-epileptic Events

vs

Epileptic Seizures

A
37
Q

New-onset Seizure

Evaluation

A
  • Detailed history of seizure characteristics, epilepsy/seizure risk factors, and possible signs of past seizures
  • Should be part of evaluation
    • EEG - with recording of sleep, photic stimulation, and hyperventilation
      • Sleep deprivation increases the dx yield
    • Brain imaging - MRI best, but CT if no MRI
  • Possibly helpful but not enough evidence to support
    • Bloodwork (glucose, electrolytes, CBC)
    • Lumbar puncture
    • Toxicology
38
Q

Recurrent Seizure

Risk

A
  • 40% after first unprovoked seizure
    • If both EEG and MRI are normal, risk is about 25%
  • Risk of recurrence is 60% after 2nd unprovoked seizure or 1st unprovoked seizure with epileptiform abnormalities on EEG
  • Usually don’t treat after a single unprovoked seizure unless there are specific EEG findings
39
Q

Anti-Seizure Medication (ASM)

Guidelines

A
  • Diagnose seizure types and epileptic syndrome
  • Safest, most specific drug for seizure type
  • Start low, go slow (depending on severity)
  • Use small dose increments in therapeutic zone
  • Newer medications not more effective, but may have more favorable side effect profiles
40
Q

New-Onset Focal Epilepsy

Initial therapy

A
  • Oxcarbazepine / Carbamazepine/ Phenytoin
  • Levetiracetam
  • Lamotrigine
  • Topiramate
41
Q

New-Onset Generalized Epilepsy

Initial therapy

A
  • Valproate (not in a young woman due to teratogenicity)
  • Levetiracetam
  • Lamotrigine
  • Topiramate / Zonisamide
42
Q

Anti-Seizure Meds

Memorable Side Effects

A
  • Oxcarbazepine/Carbamazepine – Hyponatremia
  • Topiramate/Zonisamide – cognitive dysfunction (word finding difficulties), nephrolithiasis, hypohydrosis
  • Lamotrigine, Carbamazepine, Phenytoin, Phenobarbital, Zonisamide – Stevens-Johnson Syndrome
  • Phenytoin – gingival hyperplasia, cerebellar atrophy, peripheral neuropathy
  • Levetiracetam – Depression, Anger/Agitation
  • Felbamate–Hepatic Failure, Aplastic Anemia
  • Valproate- weight gain, tremor, hepatic failure, pancreatitis
43
Q

Status Epilepticus (SE)

Definition

A

Neurologic emergency

Current definition – defined by two time points

  • T1 - time beyond which seizures are likely to be prolonged
    • Tonic-Clonic seizure ⇒ 5 min
    • Focal SE with impaired consciousness ⇒ 10 min
    • Absence SE ⇒ 10-15 min
  • T2 - time beyond which seizures lead to long-term consequences
    • Tonic-Clonic seizure ⇒ 30 min
    • Focal SE with impaired consciousness ⇒ > 60 min
    • Absence SE ⇒ unknown
44
Q

Status Epilepticus (SE)

Subtypes

A
  • Convulsive status epilepticus
    • Repetitive tonic-clonic movements occur
    • Post-ictal state
  • Epilepsia partialis continua
    • Focal neurological deficits and/or motor dysfunction occur
    • AMS is not present
  • Nonconvulsive status epilepticus
    • Continuous or fluctuating mental status changes
      • Possible subtle twitching of face/limbs
      • Unresponsiveness
      • Possible automatisms
    • No definitive criteria for nonconvulsive status epilepticus exists
45
Q

Convulsive Status Epilepticus

Therapy

A
  • ABCs: ensure airway and O2, maintain blood pressure, monitor cardiac function
  • Obtain baseline blood studies and establish IV access
  • Give glucose IV (if low or unable to measure)
  • Administer anticonvulsant drugs
    • Lorazepam 0.1mg/Kg
    • Fosphenytoin 20 mg/Kg
  • If no response, general anesthesia
    • Propofol, midazolam, pentobarbital
  • Obtain additional clinically indicated diagnostic studies once status is controlled
46
Q

Refractory Epilepsy

A

Failure of two anti-seizure medications at therapeutic doses

Not failed due to side effects

47
Q

Epilepsy

Other Therapeutic Approaches

A
  • Resective surgery
  • Ketogenic diet
  • Neurostimulation
    • RNS (Responsive nerve stimulation)
    • VNS (Vagus nerve stimulation)
    • DBS (Deep brain stimulation)