A Practical Approach to The Diagnosis and Evaluation of Seizures
Prof. Dr. Alaa H. Alwan TUCOM/ 2015Three basic questions
1. Is it a seizure? If so, what kind? 2. What caused it? 3. What should be done?Seizure
A seizure is a set of clinical symptoms associated with abnormal electrical activity in neurons in the cortex of the brain. The clinical characteristics of a seizure are the result of the area of the brain that is abnormally stimulated. Epilepsy is a clinical condition in which there are multiple seizures that are unprovoked.Types of seizures
Generalized seizures Focal (or partial seizures)Generalized seizures
Generalized seizures arise from both sides of the brain simultaneously. Motor activity is symmetrical and alteration of consciousness occurs. Ex. Primary generalized seizures (grand mal) Absence seizures (petit mal) Myoclonic seizures, atonic seizuresFocal (Partial seizures)
Arise from one area of the cortex and may spread to involve adjacent areas or distant areas Examples: Simple partial seizures Symptoms are referable to the area of the brain involved, no alteration of consciousness Complex partial seizures Partial seizures with alteration of consciousness Partial seizures with secondary generalization Partial seizure at onset (aura) followed by generalized convulsive activity
Seizure like episodes
Syncope Syncopal seizures may have tonic stiffening, clonic jerking and/or post-ictal confusion Parasomnias Sleepwalking, night terrors Hyperventilation Stereotypies/Tics Staring spellsDiagnosis is largely based on the history of the event*
Precipitating factors Position, activity, intercurrent illness, medications Description of the episode Eye movements, body movements, one sided or both sides, loss of consciousness or alteration of consciousness, incontinence, duration, aftereffects Predisposing factors Past medical history, recent illness or neurological symptoms, family history *Is it a seizure, if so what kind?Etiology of Seizure
Symptomatic seizures Acute/subacute Metabolic causes Hypoglycemia, hypo or hypernatremia, hypocalemia Intoxications/ toxins (lead) Infectious/Inflammatory Meningitis, encephalitis, sepsis Post-infectious or autoimmune causes Fever* Trauma Vascular accidentsSymptomatic seizures, part 2
Chronic/ Progressive Remote insults Perinatal asphyxia or vascular insult Past head injury Developmental brain abnormalities Agenesis of the corpus callosum, schizencephaly, cortical dysplasia Inborn errors of metabolism Storage disorders, amino acid disorders, organic acid disorders Neurocutaneous disorders Cerebral degenerative diseasesIdiopathic seizures
The cause of the seizure can not be determined by conventional testing or Seizures of genetic origin in which seizures are the only manifestation. This category may comprise as much as 60% of all childhood seizure disorders.Determining the cause of a child’s seizure(s) * History Associated symptoms, intercurrent illness, recent medications, exposures (drugs,toxins, pets), past medical history ( birth history, developmental history, family history) Examination Fever or other abnormal vital signs Head size, skin abnormalities (hypo/hyperpigmented areas) ,menigismus, asymmetry of the face or the extremities, enlarged organs, dysmorphic features Alteration of mental status, cranial nerve abnormalities, motor tone or strength or reflex changes, gait abnormalities,ataxia, sensory abnormalities. *What caused it?
Diagnostic Studies
Bloodwork - electrolytes, Ca, glucose Urine- toxicology, amino acid and organic acid measurement* EEG Useful for evaluating interictal abnormalities Occasionally useful for determining nature of a clinical symptom (absence seizures, tics or other frequent movements) Helpful in predicting recurrence of seizures. A normal EEG does not exclude a diagnosis of seizure.Diagnostic studies #2
Ambulatory EEG Allows for Ictal recording- ie, EEG activity during a suspected episode Drawbacks- technical, availability, depends on patient/parent to indicate when the episodes are occurring Videotelemetry Simultaneous recording of EEG and video of patient. Can be done as a day procedure or as inpatient Episodes must occur with some frequencyDiagnostic Studies#3
Imaging procedures CTT is not the procedure of choice but is appropriate in emergencies, especially trauma MRI is the imaging procedure of choice Abnormal neurological examination Focal seizure activity Focal findings on EEG PET scanning is a specialized procedure done in limited circumstances (usually as part of evaluation of intractable seizures or when a surgical treatment is proposed.Treatment Decisions*
The decision to treat depends on evaluation of risks and benefits Risk of subsequent seizures Risk of treatment Particular circumstances of patient *What to do about it?Risks of further seizures
Risk of a second seizure is 20-30% if: Examination, EEG and CTT (imaging study) is normal (and careful review of history discloses no other events) Exceptions: Absence seizures. Myoclonic seizures Risk of a second seizure if EEG is abnormal is 60% Risk of a third seizure is 70%Risk of having another seizure
Most seizures do not produce injury to the brain. Seizures in a bad place- bath, driving a car, climbing, riding a bicycle etc. Prolonged seizure which can lead to hypoxia or secondary complications. Sudden unexplained death- a very rare complication of seizures, particularly in children.
Risk of treatment
Medication side effects Severe- liver failure, aplastic anemia, severe allergic reaction (Stevens-Johnson syndrome) Decreased alertness, personality/behavior changes, weight loss/gain Social stigmaTreatment
Discuss risks and benefits with patient and parent based on available statisticsIf 1st seizure with lower risk of recurrence, consider no treatment. Use of rectal valium as a “rescue measure”If decision to treat, choose a medication based on seizure type, age of patient and side effect profile.Monotherapy is generally preferable, especially in first line treatment.Anticonvulsant medications
Generalized seizures Divalproex sodium Zonisamide Topiramate Lamotrigine Levetiracetam Rufinamide Ethosuximide*Partial Seizures Carbamazepine Oxycarbazepine Zonisamide Topiramate Levetiracetam Lamotrigine Phenytoin Phenobarbital*
Other Treatment Alternatives
Dietary treatment Ketogenic diet Modified Atkins diet Surgical treatment Vagal nerve stimulator Surgical removal of seizure focusHistorical Clues
Precipitating factorsSeizures may be precipitated by flashing lights, hyperventilation, illness or being overtired (stress?)Syncope is precipitated by standing up, being overheated, sight of blood, frightening eventState of alertness- syncope doesn’t occur in sleep, Seizures may occur in sleep or wakefulness. Parasomnias only occur in sleep.Further historical cues
Position- seizures may occur in any position, syncope usually occurs when sitting or standing Eye movements- eyes are usually closed or partially open during a syncopal episode, more likely to be open during a seizure. The presence of deviation of the eyes to one side or another suggests a partial seizure. Seizures that affect one side of the body more than the other are likely to be focal in origin. Syncopal episodes are usually symmetrical.
Staring vs. Absence vs. Partial Complex seizures
Staring spells are more apt to occur when the patient is passive, listening to a teacher, or parent or watching TV. They can be of indeterminate length and are interruptible by voice or touch. Absence seizures can occur in the midst of activity, usually brief 10-20 seconds. There may be eye blinking/fluttering or subtle head movements. The patient recovers very quickly. Incontinence may occur. Partial complex seizures are usually 1-2 minutes in length, and can not be interrupted. There are often stereotypic movements and postictal confusion is common.Generalized seizures vs Partial Seizures
Generalized seizures have sudden onset without warning. Motor symptoms are symmetrical. Postictal state is common when there is convulsive activity but not for absence or myoclonic seizures Partial seizures may begin with localized symptoms that the patient is aware of (aura) and may have asymmetric motor symptoms. Postictal state is common, even without convulsive activity.Algorithm
AlgorithmInitial Event
History- eyewitness report if possible
Physical Examination
EEG, imaging study if EEG focal
If isolated event, no treatment or Rectal valium
If multiple episodes discuss medication
Normal
Abnormal
Probable seizure
Other
Another lecture
EEG,Imaging study, consider more emergent evaluation
Neonatal seizures
Subtle seizures Deviation of the eyes Eyelids are flickering Swimming or pedaling movements Apnoeic spells Tonic Clonic Myoclonic Seldom tonic clonic seizuresAetiology of neonatal seizures
Perinatal: HIE Metabolic Hypoglycemia, hypocalcemia hypomagnesemia OtherInfections Structural abnormalities
Treatment of neonatal seizures
Optimize ventilation, cardiac output, BP, glucose, electrolytes and pH. Treat the underlying disease Intravenous line is essential Treat the seizures promptly and vigorously Phenobarbitone PhenytoinFebrile seizures
Definition: Seizure in children between the age of 6 months and 3-4(5) years in association with fever but without evidence of an intracranial infection Majority occurs before the age of 3 years Average age of onset: 18 months to 22 months Boys more than girlsPathophysiology
Seizure threshold is low in children Susceptible to infections i.e urti, LRTI Possible role of endogenous pyrogens IL1 May increase neuronal activity Probable role of cytokines2 Types
Simple febrile seizures Generalise <15min duration Do not recur within 24hrs Complex Prolonged seizures Usually more than one in a 24hr period Or may be focal Indicative of a more serious conditionFebrile seizures
Recurrence 1/3 may have at least one recurrence The younger the age of onset the greater the risk of recurrence Low fever at first seizure Family hx Risk of developing epilepsy 2% (vs 1% in gen pop) Risk increases with: Complex Abnormal neurological stateInvestigation of febrile seizures
Lab investigations, although routine, usually unhelpful, in the evaluation of first time seizure – possible just a Na and GlucoseCT is not warranted in the evaluation of simple febrile convulsions but considered for complex Study of 71 patient with complex seizures None had an intracranial condition requiring treatementRoutine EEG is seldom necessary??LPSimple febrile seizure probable not indicatedProbable those with prolonged post-ictal phaseCurrent recommendation should be routine in the under 12 month groupTreatment of febrile convulsion
Oxygen and supportive care Benzodiazapines Antipyretics Do not appear to prvent recurrence Councel parentsTreatment of Epilepsy
Drug treatment should be regular Simple as possible Minimum of side effects Monotherapy Changes should be made gradually High initial dosages increases side effects Rapid withdrawal carries the risk of provoking status Always calculate the dosage according to the weightTreatment of Epilepsy
Drugs commonly used Carbamazepine Sodium valproate Clonazepam Phenobarbitone Phenytoin Newer drugs Clobazam Oxcarbazepine Gabapentin Vigabatrin LamotrigineTreatment of Epilepsy
Antiepileptics can cause convulsions Benzodiazepines can induce TC seizures in LGS Carbamazepine may exacerbate absence seizures What is used as first line treatment. Absence: Sodium valproate Focal and Generalized TC: Carbamazepine
Status epilepticus (SE) presents in a multitude of forms, dependent on aetiology and patient age (myoclonic, tonic, subtle, tonic-clonic, absence, complex partial etc.) Generalized, tonic-clonic SE (GCSE) is the most common form of SE
Definition
Conventional “textbook” definition of status epilepticus:Single seizure > 30 minutesSeries of seizures > 30 minutes without full recoveryWhy 30 minutes ?
Animal experiments in the 1970s and 1980s had shown that ...… neuronal injury could be demonstrated after 30 min of seizure activity, even while maintaining respiration and circulationNevander G. Ann Neurol 1985;18(3):281-90.More practical: Mechanistic definition
GCSE is a condition which most likely will not terminate rapidly and / or spontaneously GCSE is a condition which requires prompt intervention Lowenstein DH. Epilepsia 1999The longer SE persists, the lower is the likelihood of spontaneous cessation the harder it is to control the higher is the risk of morbidity and mortality
Bleck TP. Epilepsia 1999;40(1):S64-6 The Status Epilepticus Working Party. Arch Dis Child 2000;83(5):415-9.
Typical seizure duration
Children > 5 years: Typical, generalized tonic-clonic seizure lasts < 5 minutes Young children and infants: little data. latsts < 10-15 minutes Reviewed in: Lowenstein DH. It's time to revise the definition of status epilepticus. Epilepsia 1999;40(1):120-2.
Revised Definition
Generalized, convulsive status epilepticus in older children (> 5 years) refers to > 5 minutes of continuous seizure or >2 discrete seizures with incomplete recovery of consciousnessCauses
Fever Medication change Unknown Metabolic Congenital Anoxic Other (trauma, vascular, infection, tumor, drugs)36% 20% 9% 8% 7% 5% 15%
\
Mortality
Adults Children15 to 22% 3 to 15%
Reviewed in: Fountain NB. Epilepsia 2000;41 Suppl 2:S23-30
Mortality
The primary determinant of mortality and morbidity of SE in children is its aetiology With the highest mortality rates caused by an acute neurological condition (infection, trauma, stroke)Mitchell WG. J Child Neurol 2002;17 Suppl 1:S36-43.
Prolonged seizures
Duration of seizureLife threatening systemic changes
Death
Temporary systemic changes