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Seizures and Epilepsy

Seizures occur at all ages. The term "seizure" designates a clinical event that represents dysfunction of the central nervous system (CNS) and may signal a serious underlying abnormality; however, more often in children the seizures result from a transient disturbance of brain function seizures, epilepsy, sezures, epelepsy

Epidemiology and classification of seizure types

The ages of greatest risk for nonfebrile seizures are during infancy, childhood, and adolescence. The annual incidence rate from birth to 20 years of age is 0.56 per 1000.The two primary forms of epilepsy are generalized seizures and partial seizures.

Partial seizures

Partial seizures are the most common form of epilepsy in

Simple partial seizures (SPS)

SPS are most commonly focal, asynchronous, clonic or tonic motor movements, such as forced deviation of the head and eyes to

An SPS typically is short-lived, rarely persisting longer than 10 to 20 seconds, and the child remains conscious and is able to verbalize throughout the seizure. The EEG characteristically shows unilateral spikes or sharp waves in the

Complex partial seizures (CPS)

CPS initially may be similar in appearance to an SPS, but they are followed by impairment of consciousness. CPS may begin with a loss of consciousness. The average duration of a

Aura signals the onset of a seizure in 30% of children who have CPS, with the child

 

International Classification of Epileptic Seizures

Partial Seizures

--Simple partial (consciousness retained)

–Complex partial (consciousness impaired)

– Partial seizure with secondary generalization

Generalized Seizures

--Absence seizures

--Myoclonic seizures

--Clonic seizures

--Tonic seizures

--Tonic-clonic seizures

--Atonic seizures

Unclassified Seizures

 

Generalized Seizures

Simple absence seizures usually have their onset at 5 to 6 years of age and are characterized by brief (5-20 sec) lapses in consciousness, speech, or motor activity. Absence seizures are not accompanied by an aura or a postictal drowsiness, but

Pathophysiology of epilepsy

The etiology of most seizures in children remains unknown.

The acute onset of seizures may result from head injury, CNS infection (meningitis, encephalitis), cerebrovascular diseases (infarction, arteriovenous malformation, hemorrhage, venous thrombosis), toxins (lead), brain tumor, specific epilepsy syndromes, genetic/hereditary diseases (Down syndrome,

Hypoxic-ischemic encephalopathy is the most common cause of seizures in the newborn, which

Pyridoxine dependency may be the cause of seizures that begin shortly after

Metabolic encephalopathies commonly are associated with seizures in the newborn. A urea cycle abnormality or a disorder of amino acid metabolism may

Structural abnormalities of the brain and congenital disorders of neuronal migration play an important role in the causation of epilepsy. Simple febrile seizures are not a

Diagnosis

A presumptive diagnosis of epilepsy generally is made from a history of spontaneous recurrent seizures and physical examination findings. The parent usually can give a good account of the seizure and

Management of nonfebrile seizures

Anticonvulsant medication

Anticonvulsants are initiated following absence (typical or atypical) seizures, myoclonic seizures, and infantile spasms because the risk of recurrence is 

 

Common Anticonvulsant Drugs

Drug

Seizure Type

Oral Dose

Serum Level mcg/mL

Side Effects and Toxicities

Carbamazepine (Tegretol)

 

Partial epilepsy

Tonic-clonic

Begin 10 mg/kg/d. Increase by 5 mg/kg/d every wk to 20-30 mg/kg/d in 2 or 3 divided doses

4-12

Dizziness, drowsiness, diplopia, liver, dysfunction, anemia, leukopenia

Clonazepam (Klonopin)

Myoclonic

Absence

Begin 0.05 mg/kg/d. Increase by 0.05 mg/kg per wk. Maximum, 0.2 mg/kg/d in 2 or 3 divided doses

6.3-56.8

Drowsiness, irritability, drooling, behavioral abnormalities, depression

Ethosuximide (Zarontin)

Absence

Myoclonic

Begin 10 to 20 mg/kg/d in 2 divided doses; may be increased to 50 mg/kg/d

40-160

Drowsiness, nausea, rarely blood dyscrasias

Gabapentin (Neurontin)

Partial epilepsy

Tonic-clonic

Begin 300 mg/d. Increase by 300 mg/d every 3 to 5 days. Maximum 900 to 1200 mg/d in 3 equally divided doses

<2

Somnolence, dizziness. ataxia, headache, tremor, vomiting, nystagmus, fatigue.

Lamotrigine (Lamictal)

Partial epilepsy

Tonic-clonic

Lennox-Gastaut

 

Begin 2 mg/kg/d in 2 equal doses. Increase to maintenance dose of 5 to 15 mg/kg/d.

1-4

Severe skin rashes, drowsiness, headache, blurred vision.

Phenobarbital

Tonic-clonic

Partial epilepsy

3 to 5 mg/kg/d in 1 or 2 divided doses

15-40

Hyperactivity, irritability, short attention span, temper tantrums, altered sleep pattern, Stevens-Johnson syndrome, depression of cognitive function.

Phenytoin (Dilantin)

Partial epilepsy

Tonic-clonic

5 m 6 mg/kg/d in 2 divided doses

10-20

Hirsutism, gum hypertrophy, ataxia, skin rash, Stevens Johnson syndrome.

Primidone (Mysoline)

Tonic-clonic

Partial epilepsy

Myoclonic

Begin 50 mg/d in two divided doses. Gradually increase to 150 to 500 mg/d divided into 3 equal doses.

5-12

Aggressive behavior and personality changes similar to those for phenobarbital.

Sodium valproate (Depakote)

Tonic-clonic

Absence

Myoclonic

Partial epilepsy

Unclassified

Begin 10 mg/kg/d. Increase by 5 to 10 mg/kg per wk. Usual dose, 20 to 60 mg/kg/d in 2 or 3 divided doses.

50-100

Weight gain, alopecia, tremor, hepatotoxicity.

Vigabatrin (Sabril)

Partial epilepsy

Begin 30 to 40 mg/kg/d. Increase by 10 mg/kg per wk. Maximum, 80 to 100 mg/kg/d in 2 equal doses

1.4-14

Agitation, drowsiness, weight gain, dizziness, headache, ataxia.

 

Therapeutic monitoring and routine screening

Some children achieve seizure control with subtherapeutic serum drug levels (eg, carbamazepine); for others, the seizures do not come under control until 

Indications for therapeutic drug monitoring: 1) At the initiation of therapy to ensure