General Discussion

Seizures are the most common pediatric neurologic disorder, with 4% to 10% of children suffering at least one seizure in the first 16 years of life. The incidence is highest in children younger than 3 years of age and decreases with increasing age. A seizure is defined as a transient, involuntary alteration of consciousness, behavior, motor activity, sensation, or autonomic function caused by a paroxysmal electrical discharge of neurons in the brain. A postictal period of decreased responsiveness usually follows most seizures, and the duration of the postictal period is proportional to the duration of seizure activity. Epilepsy describes a condition of susceptibility to recurrent seizures. Status epilepticus refers to continuous or recurrent seizure activity lasting longer than 30 minutes without recovery of consciousness.

Classification systems have been developed to standardize the terminology used to describe seizure activity. Two overall seizure types exist: partial and generalized. Partial seizures originate in one cerebral hemisphere. Partial seizures are further subdivided based on whether they result in an altered level of consciousness. A simple partial seizure has no impairment of consciousness and most commonly manifests as abnormal motor activity. Autonomic, somatosensory, and psychic symptoms can also occur. A complex partial seizure occurs when an alteration of consciousness is present. An aura consisting of abnormal perception or hallucination often precedes this type of seizure. Both simple and complex partial seizures may ultimately become generalized.

A generalized seizure involves both cerebral hemispheres and may involve a depressed level of consciousness. Generalized seizures are either convulsive, with bilateral motor activity, or nonconvulsive. Types of generalized seizures include tonic-clonic (also known as grand mal), tonic, clonic, myoclonic, atonic-akinetic (drop attacks), or absence (petit mal).

The immature neonatal brain is more excitable than that of an older child and is more susceptible to seizure activity. However, the resulting seizures may be subtle and difficult to discern from other normal newborn movements or activities. Lip smacking, eye deviations, or apneic episodes may be the only manifestations of seizure activity in this age group.

A seizure represents a clinical symptom of an underlying pathologic process with many possible causes. These causes are outlined below. When a child presents with a seizure, every effort should be made to determine the cause. It is important to differentiate between a seizure and other nonepileptic conditions that may mimic seizure activity.

The topic of febrile seizures is reviewed in Chapter 17.

Medications and Toxins Associated with Seizures

Analgesics

Anticonvulsants (from withdrawal)

• Carbamazepine

• Phenytoin

Cellular Asphyxiants

Drugs of Abuse

• γ-Hydroxybutyratic acid (GHB)

Envenomations

Heavy Metals

Plants, Herbs, and Natural Products

• Ephedra

• Gyromitra esculenta mushroom

• Nicotine

• Water hemlock

Psychiatric Medications

• Buproprion

• Cyclic antidepressants

• Selective serotonin reuptake inhibitors (SSRIs)

Rodenticides

Withdrawal

Miscellaneous

Causes of Seizures

Infectious

Neurologic, Congenital, or Developmental

Metabolic

• Inborn errors of metabolism

• Pyridoxine deficiency

Obstetric (Eclampsia)

Oncologic

Traumatic or Vascular

• Cerebral contusion

• Cerebrovascular accident

• Child abuse

• Head trauma

• Intracranial hemorrhage

Toxicologic (See Medications and Toxins Associated with Seizures)

Idiopathic (60%–70%) or Epilepsy

Differential Diagnosis of Seizures

Disorders with Altered Consciousness

• Apnea and syncope

• Breath-holding spells

• Cardiac dysrhythmias

• Migraine

Paroxysmal Movement Disorders

Sleep Disorders

Psychological Disorders

• Anorexia nervosa

• Attention deficit hyperactivity disorder

• Bulimia nervosa

• Conversion disorder

• Hyperventilation

• Hysteria

• Panic attacks

Gastroesophageal Reflux (Sandifer Syndrome)

Key Historical Features

Events immediately before the onset of the episode

Thorough description of the seizure

• Duration

• Movements

• Loss of consciousness

• Cyanosis

• Eye findings

• Presence of an aura

• Tonque biting

• Incontinence

• Length of the postictal period

• Post-seizure neurologic abnormalities

Precipitating factors

• Trauma

• Ingestions

• Fever

• Recent immunizations

History of seizure disorder, including:

• Age of onset

• Frequency of seizures

• Whether the recent seizure was different from previous seizures

• Medications being taken for seizures

• Compliance with medication regimen

• Any recent medication changes

• Identified triggers for seizures such as sleep deprivation, flashing lights, hyperventilation

Maternal exposures

Birth history and perinatal complications

Medical history, especially:

• Neurologic disease

• Presence of ventriculoperitoneal shunt

• Developmental delay

Cognitive behavioral history, especially:

• Motor and speech milestones

• Sudden loss of speech, activity, attention

• Developmental delay

Family history, especially family history of seizures

Social history, especially risk for child abuse or neglect

Travel history

Key Physical Findings

Suggested Work-up of Pediatric Seizures

Laboratory testing for a child who has an afebrile seizure should be guided by the history and physical examination and should attempt to elucidate a treatable cause of seizure activity.

Bedside glucose test	To evaluate for hypoglycemia
Specific drug level(s)	Should be obtained in patients who are taking anticonvulsant medications
Electrolytes, calcium, magnesium	Indicated in patients with a history of diabetes or metabolic disorder, dehydration, excess free water intake, prolonged seizure, an altered level of consciousness, and those younger than 6 months because of an increased risk of electrolyte disturbances
Complete blood count (CBC)	If an infectious cause of the seizure is suspected
Toxicology screen	If toxin exposure is suspected
Lumbar puncture	Should be considered in patients with meningeal signs, altered mental status, a prolonged postictal period, a petechial rash, or in neonatal seizures
Brain computed tomography (CT)	Should be performed in patients with: • A history of trauma • Neurocutaneous disease • Ventriculoperitoneal shunt • Exposure to cysticercosis • Evidence of increased intracranial pressure (ICP) • Focal seizure activity • Focal neurologic deficits • Prolonged postictal period

Should be considered in patients with:

• Hypercoagulable states such as sickle cell disease or with oral contraceptive use

• Bleeding disorder

• Immunocompromised state such as Human immunodeficiency virus (HIV) or malignancy

Outpatient electroencelphalography (EEG) Indicated for children with a first-time unprovoked nonfebrile seizure

Additional Work-up of Pediatric Seizures

Blood amino acids, lactate, pyruvate, ammonia, and urine organic acids	If an inborn error of metabolism is suspected
Emergent EEG	For patients in whom the diagnosis of nonconvulsive status epilepticus is suspected or in those with refractory seizure activity
Magnetic resonance imaging (MRI)	More sensitive than a cranial CT scan for the detection of certain tumors and vascular malformations
HIV test	If HIV infection is suspected