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 ID: 697059
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Slide1
Seizures
Presentation by
Delin
Wang
Samir
PatelSlide2
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 seizureThe highest incidence occurs in early childhood and late adulthood.Slide3
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 epilepticusGreater 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 epilepticusSlide4
Classification of seizures
Partial seizures
Simple partial seizures (with motor, sensory, autonomic, or psychic signs)
Complex partial seizuresPartial seizures with secondary generalizationPrimarily generalized seizures
Absence (petit mal)
Tonic-clonic (grand mal)
Tonic
Atonic
Myoclonic
Unclassified seizures (e.g. neonatal seizures, infantile spasms)Slide5
Partial seizures
Partial seizures occur within discrete regions of the brain
Simple partial seizure
Consciousness is not impairedFeaturesFocal 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 seizureSlide6
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.Slide7
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 patientThe start of the ictal phase is often a sudden behavioral arrest or motionless startThis 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 runningSlide8
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 consciousnessExamination immediately following the seizure may show an anterograde amnesia In cases involving the dominant hemisphere, a postictal aphasia can occurSlide9
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 seizureA careful history that identifies a preceding aura would help differentiate the secondary generalization from the generalized seizuresSlide10
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 controlLasts for only secondsConsciousness 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 small-amplitude, clonic movements of the handsSlide11
Generalized seizures
Absence seizures
Usually begin in childhood (ages 4 – 8) or early adolescence
Main seizure type in 15 – 20% of children with epilepsyFirst clue to absence seizure is often unexplained “daydreaming” and a decline in school performance recognized by a teacherRespond well to treatment with specific anticonvulsants
About 60 – 70% of patients will have a spontaneous remission during adolescenceSlide12
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 signsUsually 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 seizuresSlide13
Generalized seizures
Tonic-clonic seizures (Grand mal)
The most common seizure type resulting from metabolic derangements
Usually begins abruptly without warningInitial phase is usually tonic contraction of muscles throughout the bodyTonic 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 developsSlide14
Generalized seizures
Tonic-clonic seizures
Tonic phase:
Contraction of the jaw muscles may cause biting of the tongueA marked enhancement of sympathetic tone leads to increases in heart rate, blood pressure, and pupillary sizeAfter 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 pointSlide15
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 confusionPatients may have complaints of headache, fatigue, and muscle ache that can last for many hoursThe 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 atrophySlide16
Generalized seizures
Atonic seizures
Characterized by sudden loss of postural muscle tone lasting 1 – 2 seconds
Consciousness is briefly impairedUsually no postictal confusionA very brief seizure may cause only a quick head drop or nodding movementA longer seizure will cause the patient to collapse
There is a substantial risk of direct head injury with the fallSlide17
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 asleepPathologic myoclonus is most commonly seen in association withMetabolic disorders
Degenerative CNS diseases
Anoxic brain injurySlide18
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 infectionsFeverHypoxic 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)Slide19
Etiology of seizures
Causes (continued)
Drug withdrawl (alcohol, barbiturates, benzodiazepine, AEDS)
Drug intoxication (TCAs, cocaine, amphetamine)Electrolyte abnormalitiesHyponatremia
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 infectionSlide20
Differential diagnosis
Alternate diagnoses that may mimic seizures include:
Syncope, especially convulsive syncope in which seizure-like motor activity is observed
PseudoseizuresToxic-metabolic encephalopathyTremors, dyskinesiasNonepileptic myoclonus following a hypoxic eventRigorsSlide21
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 historySlide22
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 patternSlide23
Diagnosis
Physical Examination
Signs of Fever help diagnose febrile seizures
Neck stiffness for meningitisComplete neurological examination Focal deficits, mental deficiency, stroke, cerebral palsyCareful examination of the skin for Café-au-lait spots, adenoma sebaceum and hypopigmented spots (tuberous sclerosis), or port-wine 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. Slide24
Diagnosis
Laboratory and Radiological Exams
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 dehydrationToxicology screening in case of drug or substance abuseLumbar 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.
Slide25
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 strokeUsed best for prolonged postictal paralysis, persistent neurologic abnormality, age younger than 12 months, abnormal EEGSlide26
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
-stressSlide27
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 drugsOlder medications such as phenytoin, valporic acid, carbamazepine, and ethosuximide are generally used as 1
st
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 toxicity. Slide28
TreatmentSlide29Slide30Slide31
TreatmentSlide32Slide33
Status EpilepticusSlide34Slide35
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. Slide36
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. Slide37
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 syndromeSlide38
Answer: A
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.Slide39
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).
LamotrigineSlide40
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.Slide41
References
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.comCurrent Diagnosis and Treatment in Family Medicine, 2e. “Chapter 9. Seizures.”
Epilepsy Ontario.
www.epilepsyontario.org