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Neurology
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EDUCATION
Emory Pediatric Neurology Teaching Syllabus
Emory University School of Medicine
Atlanta, Georgia U.S.A, 404-727-5756
Neonatal and Febrile Seizures
Prepared by Philip J. Holt, M.D. for the:
6th Annual Georgia Epilepsy Symposium
November 3, 2001
Conditions with Seizures Outside the Epilepsy Classifications
- Single Seizure
- Neonatal Seizures
- Febrile Seizures
- Status Epilepticus
Neonatal & Febrile Seizures
- Common Pediatric Occurrences
- Medically Controversial
- Evolution of Understanding
- Life long Implications
Neonatal Seizures: Definition & Diagnosis
- Seizures that occur in the 1st month of life
- Premature Infants up to 44 weeks gestation
- Incidence 1.5 to 3.5 per 1000 live births
- Any abnormal, repetitive, and stereotypical behavior is suspect for seizures
- All, repetitive, and stereotypical behaviors are suspect for non-seizure
Types of Neonatal Seizures
- Subtle or Fragmentary Seizures
- Tonic Seizures
- Multifocal Clonic Seizures
- Focal Clonic Seizures
- Myoclonic Seizures
Subtle or Fragmentary Seizures: Motor Automatisms
- Repetitive facial movements
- Rhythmic eye movements
- Sustained eye deviation or fixation of gaze
- Chewing movements
- Rowing or Peddling Movements
Tonic Seizures
- Sustained flexion or extension of Axial or appendicular muscle groups
- Decerebrate posturing
- Dystonic posturing
- Focal tonic head or eye turning
- Variable response to AED Rx
- Low correlation to EEG
Multifocal & Focal Clonic Seizures
- Rhythmic movements of muscle groups
- Rapid twitch followed by a slow relaxation
- May involve face, tongue, limbs, diaphragm
- Focal clonic seizures can be caused by focal or generalized CNS insults
- Generalized clonic seizures preceded by focal clonic seizures
Myoclonic Seizures
- Rapid isolated jerks of single extremity, multifocal, or generalized
- Lacks the slow phase of clonic seizures
- Need EEG confirmation to exclude segmental release myoclonus
- Myoclonus is also a symptom of encephalopathy in preterm and term infants
- Occurs in sleep in healthy infants
Non-Seizure Symptoms that Mimic Seizures
- Jitteriness
- Rapid symmetric to-and-fro motion
- Stopped by holding or changing position of the extremity
- Tremulousness
- slow rhythmic movements
- occur awake and asleep
- normal and abnormal infants
- Shuddering or "Quaking"
EEG in Neonatal Seizures
- Frequently have abnormal backgrounds
- Seizure discharges have evolution of frequency, voltage & field
- EEG monitoring show seizures last 10 seconds to >30 minutes and recur on average every 5 to 8 minutes
- Periodic Lateralized Epileptiform Discharges (PLEDs)
- Electroclinical disassociation: Clinical seizure activity does not always correspond to the seizure discharges on EEG
Etiology of Neonatal Seizures
- Hypoxic-ischemic Encephalopathy
- Structural: Hemorrhage, malformation, tumor
- Metabolic: glucose, electrolytes, Ca++, AAs
- Infection: bacterial, TORCH, herpes
- Drugs: exposure or withdrawal
- Inheritable Dz: Incontinentia pigmenti, Zellweger’s, Neurocutaneous dz, Pyridoxine Dependency, Five Day Fits
Asphyxia (HIE)
- Intrauterine, delivery and postnatal causes
- PO2 < 40 mm Hg & pH < 7.0
- Low 10, 15, or 20 minute APGAR score
- Neonatal Encephalopathy
- Seizures
- Abnormal arousal: hyper-alert or obtunded
- Abnormal tone: hypertonia or hypotonia
- Feeding or respiratory difficulties
Neonatal Stroke
- Often unremarkable L&D with normal APGARS
- Routine first 12 to 48+ hours
- Focal seizures
- Focal hemorrhage on CT
- Coagulation defect or Inflammatory reaction is likely cause
- Hemiparesis, partial seizures and normal IQ
Treatment of Neonatal Seizures
- Treat the underlying condition (glucose, Ca++, Na+, anti-infectives)
- Phenobarbital 20 mg/kg loading dose
- Phenobarbital 10-20 mg/kg repeatedly
- Phenytoin 20 mg/kg or Fosphenytoin 20mg/kg P.E.
- Pyridoxine 50 mg
Outcome of Neonatal Seizures
- Influence by etiology comorbid CNS insult
- 15% to 40% mortality (higher mortality in series with EEG confirmed seizures)
- 65% neurologic sequelae in survivors
- Epilepsy in 15% to 30% by age 7 years
- Infantile spasms in the first year of life
- Normal EEG, development, & HC have low risk of seizure recurrence
Febrile Seizures
- Seizure with fever from 6 months to 5 years of age without CNS infection
- Neurologically normal children
- Simple Febrile Seizure: <15 minutes, generalized, occurs once in 24 hours
- Complex Febrile Seizure:>15 minutes, focal, multiple times in 24 hours
- Cause: Genetics
Work-up of Febrile Seizures
- Evaluate source of fever
- If prolonged or repeated consider short term therapy
- Educate family
- Estimate risk of recurrence
- EEG of no value and should not be done
Risk of Recurrence of Febrile Sz
- Less than 1 year of age: 50%
- Greater than 1 year: 20% to 33%
- Short length of fever before seizure
- Low grade fever
- Raises question: Was it really a Febrile Seizure or an unprovoked seizure with a low grade, transient post-ictal temperature elevation?
Treatment of Febrile Seizures Before February 8, 1990
- Phenobarbital debated after first seizure
- Phenobarbital usually prescribed after 2nd FS
- 30% to 50% behavior effect accepted
- Valproic Acid more effective than PB but not used because of toxicity
- Studies with phenytoin and carbamazepine showed no ability to prevent FS
Treatment of Febrile Seizures After February 8, 1990
Farwell et. al. Phenobarbital for febrile seizures: Effects on intelligence and seizure recurrence.
NEJM 322:364-9, 1990.
- Just Do Nothing
- Anti-pyretics of no value and possible risk
- Diazepam prn tried with illness
Diazepam for Febrile Seizures
- Oral diazepam at dose of 0.33 mg/kg q 8 hr during febrile illness
- Rosman et al. NEJM 329:79-84, 1993.
- Unknown if oral lorazepam is better
- Lorazepam v. diazepam v Placebo Status Epilepticus. NEJM 345:631-7,2001.
- Rectal diazepam approved for seizure clusters, used for recurrent and prolonged febrile seizures.
Diastat® dose based on age and weight.
Outcome for Febrile Seizures:
- Nelson: NCPP data : Simple febrile seizures, 2-4% develop epilepsy by age 7
- Annegars et al. NEJM. 316:493-8, 1987
- 687 Children with FS followed to age 25
- Risk of Epilepsy recurrent Simple FS = 2.5%
- Risk increased with number of Complex FS Criteria: 1=7%, 2=17-22%, 3=49%
Febrile Status Epilepticus
Shinnar, Pelock, Berg et. al. Short-term outcomes of children with febrile status epilepticus. Epilepsia. 42(1): 47-53, 2001.
- Neurologically abnormal 20% vs 5%
- Neonatal Seizures 3% vs 0%
- Family History of Epilepsy 11% vs 5%
- Lower Family Hx of FS 15% vs 27%
Febrile Seizures and TLE
Maher J. McLachlan RS. Febrile convulsions. Is seizure duration the most important predictor of temporal lobe epilepsy
- Brain. 118:1521-8, 1995.
- 6 families with 59 individual with FS, 8 with TLE
- 1 of 213 family members with TLE
- No difference in no. Sz, max. Sz/day, age onset
- Mean Duration individuals with TLE=100 minutes vs. No-TLE=9 m (P<0.02)
Hippocampal Sclerosis Revisited
Fisher PD, Sperber EF, Moshé SL. Brain & Development 20:563-573, 1998. (review)
- Retrospective Clin/MRI Studies link FS-MTS
- Prospective Studies do not link FS-MTS
- Adult animal models with induced HS and SZ
- Normal developing animal models SZ no HS
- Abnormal animal models SZ with HS
- Pre-existing pathology + FS relationship to HS
Febrile Seizures and IQ
- Farwell, NEJM 1990: Non-PB Rx group was more normal than the PB Rx group.
- Verity, Greenwood, Golding, Long-Term Intellectual and Behavioral Outcomes of Children with Febrile Convulsions NEJM 338:1723-1728 1998.
- Population based study to age 10
- FS no difference than non-FS patients
- Special Ed: FS <1 yr.=7.5%, >1 yr.=1.5%
Febrile Seizures References:
- Baumann, Duffner, Treatment of Children with Simple Febrile Seizures Pediatr Neurol 23:11-17, 2000.
- Knudsen FU. Febrile Seizures: treatment and prognosis. Epilepsia. 41:2-9, 2000.
- Neurodiagnostic Evaluation of the Child with a First Simple Febrile Seizure, Pediatrics 97:769-75,1996.
- Practice Parameter: Long Term Treatment of the Child with Simple Febrile Seizures. Pediatrics 103:1307-1309, 1999.
- Academy of Pediatrics Policy Statements:http://www.aap.org/policy/
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