Seizures & Epilepsy Flashcards
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
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
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
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
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
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
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
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
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
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
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
12
Q
Generalized Seizures
A
Seizures starting in both sides of the brain at the same time
- Absence
- Myoclonic
- Clonic
- Tonic
- Tonic-Clonic
- Atonic
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
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
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
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
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
18
Q
2017 ILAE Classification of Seizures
A
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
Common Seizure Symptoms
* **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
Epilepsies and Epileptic Syndromes
1989 ILAE Classification
* **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
Epilepsy Syndromes
Overview
*Grouping of patients that share similar:*
* Seizure type(s)
* Age of onset
* Natural history/Prognosis
* EEG patterns
* Genetics
* Response to treatment
28
Epilepsies and Epileptic Syndromes
Revision of Classification
* _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
Electroclinical Syndromes / Epilepsies
* **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
Epilepsy Syndromes by Age
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
Distinctive Constellations
* 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
Structural-Metabolic
Epilepsies
* Cortical malformations
* Neurocutaneous syndromes
* Neoplasms
* Infections
* Trauma
* Vascular malformations
* Perinatal insults
* Stroke
33
Epileptic Seizures Conditions
| (Not dx as a form of epilepsy)
* Benign neonatal seizures
* Febrile seizures
34
Electroencephalogram
| (EEG)
**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
Seizure
Differential Diagnoses
* **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
Non-epileptic Events
vs
Epileptic Seizures
37
New-onset Seizure
Evaluation
* **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
Recurrent Seizure
Risk
* **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
Anti-Seizure Medication (ASM)
Guidelines
* 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
New-Onset Focal Epilepsy
Initial therapy
* Oxcarbazepine / Carbamazepine/ Phenytoin
* Levetiracetam
* Lamotrigine
* Topiramate
41
New-Onset Generalized Epilepsy
Initial therapy
* Valproate (not in a young woman due to teratogenicity)
* Levetiracetam
* Lamotrigine
* Topiramate / Zonisamide
42
Anti-Seizure Meds
Memorable Side Effects
* **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
Status Epilepticus (SE)
Definition
**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
Status Epilepticus (SE)
Subtypes
* **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
Convulsive Status Epilepticus
Therapy
* **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
Refractory Epilepsy
**Failure of two anti-seizure medications at therapeutic doses**
Not failed due to side effects
47
Epilepsy
Other Therapeutic Approaches
* Resective surgery
* Ketogenic diet
* Neurostimulation
* RNS (Responsive nerve stimulation)
* VNS (Vagus nerve stimulation)
* DBS (Deep brain stimulation)
