Neurology

Evaluation of First Nonfebrile Seizure

 

Introduction

Seizures are a common yet frightening problem in pediatric populations. The majority of children with epilepsy have normal neurologic examinations and imaging studies.  Therefore a careful and detailed history is paramount for an accurate diagnosis.

 

Definition

Seizure: a single convulsive episode or multiple such episodes within 24 hrs with return to consciousness between the episodes.

Seizure types included

  1. Partial (simple, complex, or partial with secondary generalization)
  2. Generalized tonic-clonic
  3. Tonic

Seizure types excluded

  1. Seizure due to obvious causes, such as fever, CNS trauma, infection, tumor, metabolic imbalances
  2. Absence, myoclonic, and atonic seizures (often difficult to recognize unless they become repetitive)
  3. Neonatal seizures (≤28 days of life)

 

Key Considerations

  1. Is this a true seizure?
  2. Is there a stimulus for the seizure?
  3. What is the likelihood of seizure recurrence or development into chronic epilepsy?
  4. What are the risks/benefits of antiepileptic drug (AED) therapy

 

Differential Diagnosis of a Seizure-like Episode

  1. Infants (<2 years old): breath-holding spells, GERD, dystonia, paroxysmal torticollis, cyclic vomiting, infantile spasms
  2. Childhood (>2 years old): migraine, syncope (cough syncope, long QT), narcolepsy-cataplexy, paroxysmal dyskinesia/benign paroxysmal vertigo, hyperventilation, pseudoseizure/psychogenic seizure, startle disease, night terrors

 

Evaluation

  1. History
    1. Relevant HPI: description of event (setting/environment-are events specific to a certain time of day or location), focal/generalized (specific description of limb movements, opening/closing of eyes and mouth), duration, aura/pre-ictal events, postictal state, autonomic instability, incontinence, automatisms, activity/behavior immediately before, during and after the seizure
    2. Medical history: seizure-like events, psychiatric disorders
    3. Medications
    4. Family history
    5. Development/milestones
    6. Behavior
    7. Recent illnesses/exposures at seizure onset
    8. State screening results
  1. Physical examination
    1. Neurologic: focal deficits, mental status
    2. Ophthalmic: congenital defects, retinal changes associated with neurocutaneous/neurodegenerative disorders, signs of infection
    3. Abdominal: HSM may indicate a storage disorder
    4. Cardiac: decreased cardiac output may mimic complex partial seizure presentation
    5. Skin: as above, some neurocutaneous disorders may be associated with epilepsy (TS, Sturge-Weber, NF, linear nevus syndrome, Ito; Wood lamp examination may be useful
  1. Labs/studies
    1. Blood chemistries (especially glucose): useful only if history or clinical findings are suggestive (vomiting, diarrhea, dehydration, continued altered mental status)
    2. Toxicology screen: useful if have any suspicion of drug exposure/abuse
    3. Lumbar puncture: NOT useful routinely, useful only in very young children (<6 mo) with persistent altered mental status of unknown cause
    4. EEG: very useful in characterizing seizure type, location, and predicting risk of recurrence; highest yield of abnormalities within 24-48 hrs but also may show post-ictal slowing which complicates interpretation; outpatient EEG may be arranged; sleep versus awake EEG is often useful since seizures may only occur in one state
    5. Neuroimaging (CT or MRI): first seizure should NOT be a sole indication for neuroimaging; if imaging is needed, MRI is preferred because of increased sensitivity, especially for progressive lesions (tumors, vascular malformations, cortical dysplasia); emergent imaging is recommended at any age if a child has prolonged post-ictal focal deficit (Todd’s paresis), or fails to return to baseline after several hours post-seizure; non-urgent imaging is recommended if child has cognitive/motor deficits w/o known cause, abnormal neurologic exam, focal seizure, abnormal EEG that does not represent a benign seizure of childhood, children < 1 year old
    6. EKG: long QT syndrome can often mimic seizure-like presentation, including an aura

 

References

  1. Vining E.P. Freeman J.M. Management of nonfebrile seizures. Pediatrics in Rev. 1986
  2. Haslam R.H. Nonfebrile seizures. Pediatrics in Rev. 1997
  3. Hirtz D. et al. Practice Parameter: Evaluation a first nonfebrile seizure in children. Neurology September 2000
  4. Riviello J.J. et al. Practice parameter: diagnostic assessment of the child with status epilepticus (an evidence-based review): Report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology 2006
  5. Tekgul H. The Current Etiologic Profile and Neurodevelopmental Outcome of Seizures in Term Newborn Infants.  Pediatrics April 2006
  6. American Academy of Neurology Diagnostic Assessment of the Child with Status Epilepsy Neurology 2006