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A child’s first seizure is most often a brief, less than
5 minutes in duration, generalized convulsion that is justifiably
concerning to physicians and parents. The overall incidence of a
single unprovoked seizure approximates 60 per 100,000 persons/year
with a peak incidence in the first year of life approximating 130
per 100,000 persons/year.1 In some instances,
the first seizure is provoked by an underlying acute illness. In
others, it is a manifestation of a chronic syndrome. In about half
of the cases, a seizure recurs and the child meets diagnostic criteria
for epilepsy.2 Accordingly, the evaluation of a
new-onset seizure is centered on identifying its cause and predicting
likelihood of recurrence.
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Broadly, by the initial history and examination, a first seizure
can be categorized into 1 of 3 groups: febrile, acute symptomatic,
and remote symptomatic. Management of febrile seizures is discussed
in Chapter 559, and of status epilepticus (seizure lasting greater
than 5 minutes) in Chapter 561.
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An acute symptomatic seizure is triggered by a recent or ongoing
neurologic insult such as infection, trauma, stroke, or metabolic
disturbance. Examples include seizures in the setting of encephalitis,
head injury, or intoxication. Evaluation of an acute symptomatic
seizure, even if the seizure is brief, is often emergent and guided
by the overall clinical picture. If the history and examination
suggest that a seizure is acutely provoked, then tests typically
include blood tests to diagnose infection or metabolic disturbance,
toxicologic screening, and head computerized tomography (CT) if
trauma or hemorrhage is suspected. Lumbar puncture may also be warranted
if there is suspicion that an intracranial infection caused the
seizure. If after the seizure the patient has not recovered fully,
has persistent focal neurologic deficits, or has not regained baseline
consciousness, testing may be followed by magnetic resonance imaging
(MRI) to evaluate for a structural abnormality, or electroencephalography
(EEG) to evaluate for nonconvulsive seizures (see Chapter 561).
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If the history and examination indicate that a child’s
first seizure occurred without accompanying illness or trauma, and
the child has recovered to his or her usual state of health, the seizure
can be assumed to be remote symptomatic. In contrast to acute symptomatic
seizures, remote symptomatic seizures reflect a chronic underlying
vulnerability to seizure, such as a genetic seizure susceptibility
or a relatively old brain injury. A common example of a remote symptomatic
seizure is one that occurs in a child who had perinatal hypoxic/ischemic
brain injury but did not develop seizures until a few years of age.
In some reports, remote symptomatic seizures are distinguished from
cryptogenic seizure by the presence of neurologic symptoms such
as a static encephalopathy or a brain MRI abnormality in the remote
symptomatic group, and an otherwise normal neurologic picture (normal
neurologic exam, normal development, and normal brain MRI) in the cryptogenic
group.3 However, for practical purposes of first
seizure management, grouping cryptogenic seizures together with
remote symptomatic seizures is useful.
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