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Seizures
Presentation by
Delin Wang
Samir Patel
Introduction
 A seizure is a paroxysmal event due to abnormal, excessive,
hypersynchronous discharges from an aggregate of CNS neurons.
 Depending on the distribution of discharges, various manifestations
can occur
 About 5 – 10 % of the population will have at least one seizure
 The highest incidence occurs in early childhood and late adulthood.
Introduction
 Epilepsy is a condition in which a person has recurrent seizures due to a
chronic, underlying process.
 The incidence of epilepsy is approximately 0.3 – 0.5 % in different
populations throughout the world
 The prevalence of epilepsy has been estimated at 5 – 10 persons per 1000.
 Status epilepticus
 Greater than 30 minutes of continuous seizure activity or recurrent
seizures without full recovery between episodes
 Practically, a seizure lasting > 5 minutes should be treated as status
epilepticus
Classification of seizures
 Partial seizures
 Simple partial seizures (with motor, sensory, autonomic, or psychic
signs)
 Complex partial seizures
 Partial seizures with secondary generalization
 Primarily generalized seizures
 Absence (petit mal)
 Tonic-clonic (grand mal)
 Tonic
 Atonic
 Myoclonic
 Unclassified seizures (e.g. neonatal seizures, infantile spasms)
Partial seizures
 Partial seizures occur within discrete regions of the brain
 Simple partial seizure
 Consciousness is not impaired
 Features
 Focal motor symptoms (eg, hand jerking)
 “Jacksonian march” – the spread of seizure activity over a
progressively larger region of motor cortex
 E. g. abnormal motor movements begin in a very restricted
region such as fingers and gradually progress to include a larger
portion of the extremity
 Todd’s paralysis – localized paresis that last minutes to many hours
in the involved region following the seizure
Partial seizures
 Simple partial seizures
 Features (continued)
 Somatosensory symptoms (eg, paresthesias or tingling)
 Vision (eg, flashing lights)
 Hearing (eg. buzzing)
 Olfaction (eg, burning rubber or kerosene)
 Equilibrium (sensation of falling or vertigo)
 Autonomic function (sensation of epigastric rising, flushing,
sweating, pupillary dilation)
 Psychic symptoms (eg, déjà vu, jamais vu, hallucinations, illusions
that objects are growing smaller or larger)
 If the above symptoms precede a complex partial or secondarily
generalized seizure, they serve as a warning, or aura.
Partial seizures
 Complex partial seizure
 Consciousness is impaired
 It frequently begins with an aura (i.e., a simple partial seizure) that is
stereotypic for the patient
 The start of the ictal phase is often a sudden behavioral arrest or
motionless start
 This marks the onset of the period of amnesia
 The behavioral arrest is usually accompanied by automatisms
 Automatism are involuntary, automatic behaviors that have a
wide range of manifestations
 Examples include chewing, lip smacking, swallowing, or more
elaborate behaviors such as a display of emotion or running
Partial seizures
 Complex partial seizures
 The patient is typically confused following the seizure
 It may take from seconds up to an hour to have full recovery of
consciousness
 Examination immediately following the seizure may show an
anterograde amnesia
 In cases involving the dominant hemisphere, a postictal aphasia
can occur
Partial seizures with secondary generalization
 Partial seizures can spread to involve both cerebral hemispheres and
produce a generalized seizure
 Usually, the tonic-clonic type
 It is often difficult to distinguish from a primary generalized tonic-clonic
seizure
 A careful history that identifies a preceding aura would help
differentiate the secondary generalization from the generalized
seizures
Generalized seizures
 Generalized seizures arise from both cerebral hemispheres simultaneously
 Absence seizures (Petit mal)
 Characterized by sudden, brief lapses of consciousness without loss of
postural control
 Lasts for only seconds
 Consciousness returns as suddenly as it was lost
 No postictal confusion
 May be accompanied by subtle, bilateral motor signs
 E.g. rapid blinking of the eyelids, chewing movements, or smallamplitude, clonic movements of the hands
Generalized seizures
 Absence seizures
 Usually begin in childhood (ages 4 – 8) or early adolescence
 Main seizure type in 15 – 20% of children with epilepsy
 First clue to absence seizure is often unexplained “daydreaming” and a
decline in school performance recognized by a teacher
 Respond well to treatment with specific anticonvulsants
 About 60 – 70% of patients will have a spontaneous remission during
adolescence
Generalized seizures
 Atypical absence seizures
 The loss of consciousness is usually of longer duration and less abrupt
in onset and cessation
 Accompanied by more obvious motor signs
 Usually associated with diffuse or multifocal structural abnormalities
of the brain
 Thus may have other signs of neurologic dysfunction such as
mental retardation
 Less responsive to anticonvulsants compared to typical absence
seizures
Generalized seizures
 Tonic-clonic seizures (Grand mal)
 The most common seizure type resulting from metabolic
derangements
 Usually begins abruptly without warning
 Initial phase is usually tonic contraction of muscles throughout the
body
 Tonic contraction of the muscles of expiration and the larynx at the
onset will produce a loud moan or “ictal cry.”
 Respirations are impaired, secretions pool in the oropharynx, and
cyanosis develops
Generalized seizures
 Tonic-clonic seizures
 Tonic phase:
 Contraction of the jaw muscles may cause biting of the tongue
 A marked enhancement of sympathetic tone leads to increases in
heart rate, blood pressure, and pupillary size
 After 10-20 s, tonic phase typically evolves into the clonic phase
 Clonic phase is produced by the superimposition of periods of
muscle relaxation on the tonic muscle contraction
 The periods of relaxation progressively increase until the end of
the ictal phase
 The postictal phase is characterized by
 Unresponsiveness, muscular flaccidity, and excessive salivation
that can cause stridorous breathing and partial airway obstruction
 Bladder or bowel incontinence may occur at this point
Generalized seizures
 Tonic-clonic seizures (Grand mal)
 Patients gradually regain consciousness over minutes to hours
 During this transition there is typically a period of postictal confusion
 Patients may have complaints of headache, fatigue, and muscle ache
that can last for many hours
 The duration of impaired consciousness in the postictal phase can be
extremely long (i.e. many hours) in patients with
 Prolonged seizures or
 Underlying CNS diseases such as alcoholic cerebral atrophy
Generalized seizures
 Atonic seizures
 Characterized by sudden loss of postural muscle tone lasting 1 – 2
seconds
 Consciousness is briefly impaired
 Usually no postictal confusion
 A very brief seizure may cause only a quick head drop or nodding
movement
 A longer seizure will cause the patient to collapse
 There is a substantial risk of direct head injury with the fall
Generalized seizures
 Myoclonic seizures
 Myoclonus is a sudden and brief muscle contraction that may involve
one part of the body or the entire body
 A normal, common physiologic form of myoclonus is the sudden
jerking movement observed while falling asleep
 Pathologic myoclonus is most commonly seen in association with
 Metabolic disorders
 Degenerative CNS diseases
 Anoxic brain injury
Etiology of seizures
 Seizures are a result of a shift in the normal balance of excitation and
inhibition within the CNS.
 Causes of seizures include
 CNS infections
 Fever
 Hypoxic brain injury
 Stroke (ischemic or hemorrhagic)
 Tumors
 Head injury
 Eclampsia
 Hyperthyroidism
 Congenital brain malformations
 Genetics (phenylketonuria, Sturge – Weber, tuberous sclerosis, etc.)
 Toxic metabolic (porphyria, uremia, liver failure)
Etiology of seizures
 Causes (continued)
 Drug withdrawl (alcohol, barbiturates, benzodiazepine, AEDS)
 Drug intoxication (TCAs, cocaine, amphetamine)
 Electrolyte abnormalities
 Hyponatremia
 Hypocalcemia
 Hypomagnesemia
 Hypoglycemia/hyperglycemia
 For patients with a known seizure disorder with an increasing seizure
frequency
 Consider anticonvulsive medication noncompliance, subtherapeutic
anticonvulsant levels, or any infection
Differential diagnosis
 Alternate diagnoses that may mimic seizures include:
 Syncope, especially convulsive syncope in which seizure-like motor
activity is observed
 Pseudoseizures
 Toxic-metabolic encephalopathy
 Tremors, dyskinesias
 Nonepileptic myoclonus following a hypoxic event
 Rigors
Initial approach
• If pts present shortly after a seizure pay
attention to:
– vital signs
– Respiratory, and cardiovascular support,
– resuming seizure medication if any,
– life threatening conditions such as CNS infection,
metabolic derangement or drug toxicity.
• If patient is not acutely ill focus on history
Diagnosis
The primary tool for seizure assessment is the history
-age at onset
-Risk factors such as family hx, prior history of stroke, history of febrile seizures,
genetic disorders.
-Developmental delays (i.e mental retardation, cerebral palsy, attention deficit,
memory difficulties, and learning disorders)
-behavior profile
-psychoses, anxiety disorders, and eating disorders
-Preictal and postictal symptoms
-health at seizure onset, including fever, vomiting, diarrhea, or illness exposure.
•
any witness should be interviewed if the patient is in ictal or postictal phase.
-precipitating events such as toxins, head trauma, systemic diseases, illicit drug or
alcohol use
-change in sleep pattern (eg sleep apnea)
-dietary pattern
Diagnosis
• Physical Examination
• Signs of Fever help diagnose febrile seizures
• Neck stiffness for meningitis
• Complete neurological examination
– Focal deficits, mental deficiency, stroke, cerebral palsy
• Careful examination of the skin for Café-au-lait spots, adenoma
sebaceum and hypopigmented spots (tuberous sclerosis), or portwine stain (Sturge–Weber).
• Signs such as automatisms, facial and extremity twitching, eye
deviation, mental status changes( ie confusion, amnesia, postictal
phase), changes in respiration
• Look for signs of head trauma, use of alcohol or illicit drugs.
• Auscultation of heart and carotid arteries may identify any heart
abnormality that predisposes to Cerebrovascular disease.
Diagnosis
Laboratory and Radiological Exams
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Blood tests
– Electrolytes (hyponatremia), glucose (hypoglycemia), blood urea nitrogen
[BUN], creatinine, calcium (hypocalcemia), magnesium (hypomagnesemia)
– especially indicated for age 6 mo or younger; continued illness; history of
vomiting, diarrhea, or dehydration
Toxicology screening in case of drug or substance abuse
Lumbar puncture i.e. meningitis
Elevated Prolactin and creatine kinase levels
EEG: All patients who have possible seizure disorder
-Abnormal, repetitive, rhythmic activity having an abrupt onset and
termination establishes the diagnosis, but the absence does not rule out
seizure disorder.
-Diagnostic in only 30-50% of first time seizure victims
-Accuracy improves to 90% with repetitive testing.
- Used also to classify seizure disorders and aiding in selection of
medications; for example episodic generalized spike-wave activity is
usually seen in patients with typical absence seizure.
-The clinical presentation should serve as a guide regarding who needs
an EEG.
Diagnosis
Brain imaging: almost all patients with new onset seizures should have a
brain study to determine whether there is an underlying structural
problem
– Exception to this rule is children who have clear history and
examination suggestive of benign, generalized seizure disorder such as
absence seizure.
– CT: limited largely to head trauma, and in acute setting
– MRI is prefered over CT: Identify any lesions such as tumors, vascular
malformations, or stroke
• Used best for prolonged postictal paralysis, persistent neurologic
abnormality, age younger than 12 months, abnormal EEG
Treatment
A)Treatment of underlying conditions that cause or contribute to the
seizures
-Reversal of any metabolic disturbances.
-Stopping any medications that may lower the seizure threshold (i.e
beta lactams, tramadol, antidepressants, antipsychotics, lithium,
barbiturates, benzos etc)
-Seizures caused by structural CNS lesion such as brain tumor,
vascular malformation, or brain abscess should be treated
accordingly. .
B) Avoidance of precipitating factors
-sleep deprivation
-illicit drugs such as cocaine
-alcohol intake
-stress
Treatment
C) Suppression with antiepileptic medications
• When to initiate
– Patient with recurrent seizures of unknown etiology or known cause
that cannot be reversed. Not indicated after a single unprovoked
seizure.
• Recurrence rate ranges from 31%-71% in the 1st 12 months after the initial
seizure.
• Antiepileptic drugs
– Older medications such as phenytoin, valporic acid, carbamazepine, and
ethosuximide are generally used as 1st line therapy for most seizure
disorders and most new ones are used as add-on or alternative therapy.
– Efficacy, convenience of dosing, and side effects are factors that
influence the choice of initial medication.
– Almost all of the commonly used drugs can cause similar dose-related
side effects such as sedation, ataxia, and diplopia
– Initiation and monitoring of therapy
• Careful education about the approach to therapy
• Most drugs need to be introduced slowly to minimize side effects.
• Monitoring of serum drug levels is very important especially for compliance and
Treatment
Treatment
Status Epilepticus
Treatment
D) Nonpharmacological treatments
1. Surgery
-approximately 20% of patients are resistant to medical therapy
- severing of the corpus callosum or temporal lobe resection, results in 80%
seizure-free outcomes for specific epilepsy types.
- Candidates for surgery should have recurrent uncontrolled seizures, focal EEGs,
and consistent focal abnormalities on neuroimaging
2. VNS (vagal nerve stimulation)
-treatment option used to treat refractory partial-onset epilepsy who are not
candidates for resection brain surgery
-involves placement of a bipolar electrode on the midcervical portion of left vagus
nerve. The electrode is connected to a small, subcutaneous generator located in
the infraclavicular region and is programmed to deliver intermittent electrical
pulses to the vagus nerve.
-This has shown to increase seizure threshold, but the precise mechanism of
action is unknown. Shown to reduce seizures in about 40% of patients.
Treatment
E) Other Management issues.
1. Psychological problems: patients with epilepsy are at risk of developing
a variety of psychiatric problems including depression (20%), anxiety, and
psychosis.
2. Referral: Neurological consultation.
3.Educate on Employment and Driving
4.Family counseling
5. Pregnancy: Seizure frequencies remain unchanged in around 50%,
increase in around 30%, and decrease in 20%.
-overall incidence of fetal abnormalities in childer born to mothers
with epilepsy is 5-6%, compared to 2-3% in healthy mother
-it is recommended that pregnant women with epilepsy be
maintained on effective drug therapy as potential harm for uncontrolled
seizures is higher that the teratogenic effects of the drugs.
Question #1
A mother comes to your office with her previously healthy 8-year-old son
complaining that he is found to have multiple staring episodes. During
those episodes, he is unresponsive to verbal or tactile stimuli and
produces lip-smacking movements. Each of these episodes lasts for a few
minutes. He remains confused for some time after the episode is over. He
has no family history of any seizure disorder. His neurological examination
is unremarkable. EEG performed before and after hyperventilation is
normal. Based on these findings, which of the following is the most likely
diagnosis?
A). Complex partial seizure
B). Typical absence seizure
C). Atypical absence seizure
D). Juvenile myoclonic epilepsy
E). Lennox-Gastault syndrome
Answer: A
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Complex partial seizures are characterized by brief episodes of impaired
consciousness. The patient fails to respond to various stimuli during these
episodes. He may be found to be staring. During these episodes, he shows
automatisms like lip smacking, swallowing or picking movements of the hand.
Each episode lasts for a few minutes and these is a post-ictal confusion state.
EEG is usually normal or may show brief discharges. Hyperventilation neither
precipitates a seizure nor produces any EEG abnormality.
A typical absence seizure is characterized by brief periods of impaired
consciousness. There may be automatisms but there is no post-ictal state.
Each episode typically lasts for seconds. Hyperventilation may precipitate a
seizure as well as it may produce EEG abnormalities typical of absence seizure,
which are generalized 3-Hz spike and wave pattern on a normal background.
An atypical absence seizure lasts longer and EEG shows slow spike and wave
activity with a frequency less than 2.5.
Juvenile myoclonic epilepsy presents in adolescents with unilateral or bilateral
myoclonic jerks. These jerks take place in the morning and may be
precipitated by sleep deprivation.
Lennox-Gastault syndrome is characterized by seizures of multiple types,
impaired cognitive function and slow spike and wave activity on EEG. It
usually presents in childhood.
Question #2
A mother brings her 7-year-old child to her physician complaining
that her son is found to be daydreaming frequently, and his teacher
has noted a recent decline in his school performance. She also
reported that sometimes he stares for few seconds and rolls his
eyes without any reason. He has no family history of any seizure
disorder and his psychomotor development is normal. His
neurological examination is unremarkable. EEG is performed which
shows generalized, symmetrical 3-Hz spike and wave activity on a
normal background. Hyperventilation provokes these
electrographic discharges. Which of the following medications is
the most appropriate to treat this disorder?
A). Phenytoin
B). Phenobarbital
C). Valproic acid
D). Clonazepam
E). Lamotrigine
Answer: C
Absence seizures, also known as petit mal seizures occur in children
aged 4-8 years and usually present with day dreaming episodes and
decline in school performance. Clinically, typical absence seizures
appear as brief staring spells. Patients have no warning or postictal
phase and if engaged in gross motor activity, such as walking, may
stop and stand motionless or may continue to walk. Children are
not responsive during the seizure and have no memory of what
happened during the attack. They are generally unaware that a
seizure has occurred. EEG shows generalized, symmetrical 3-Hz
spike and wave (classic finding), activity on a normal background.
These findings are usually provoked by hyperventilation.
The preferred treatment of absence seizures is ethosuximide or
valproic acid.
Clonazepam or Lamotrigine are alternative agents for the treatment
of absence seizures.
Phenytoin is currently the initial drug of choice for partial seizures.
Phenobarbital is not used for the treatment of absence seizures; it
can be used in primary generalized and partial seizures as an
alternative agent.
References
1.
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6.
Harrison’s Principles of Internal Medicine, 17e. “Chapter 363: Seizures
and Epilepsy.”
Current Medical Diagnosis & Treatment 2010. “Chapter 24. Nervous
System Disorders.”
The Washington Manual of Medical Therapeutics, 33e.
Seizures and Epilepsy, Overview and Classification: eMedicine.com
Current Diagnosis and Treatment in Family Medicine, 2e. “Chapter 9.
Seizures.”
Epilepsy Ontario. www.epilepsyontario.org