Download Febrile Seizures Febrile convulsions, the most common seizure

Febrile Seizures
Febrile convulsions, the most common seizure disorder during
childhood.Febrile seizures are age dependent and are rare
before 9 mo and after 5 yr of ageIt is initially generalized and
tonic-clonic in nature, lasts a few seconds and rarely up to 15
min A febrile seizure is described as complex or complicated
when the duration is >15 min,when repeated convulsions occur
within 24 hr, or when focal seizure activity or focal findings are
present during the postictal period.During the acute evaluation,
a physician's most important responsibility is to determine the
cause of the fever and to rule out meningitis or encephalitis. If
any doubt exists about the possibility of meningitis, a lumbar
puncture with examination of the cerebrospinal fluid (CSF) is
indicated. A lumbar puncture should be strongly considered in
children <12 mo of age and considered in those 12–18 mo of age,
especially if seizures are complex or sensorium remains clouded
after a short postictal periodAside from glucose determination,
laboratory testing such as serum electrolytes and toxicology
screening should be ordered based on individual clinical
circumstances such as evidence of dehydration
Partial Seizures
Partial seizures account for a large proportion of childhood
seizures, up to 40% in some series. Partial seizures may be
classified as simple or complex; consciousness is maintained
with simple seizures and is impaired in patients with complex
seizures.
SIMPLE PARTIAL SEIZURES (SPS).
Motor activity is the most common symptom of SPS. The
movements are characterized by asynchronous clonic or tonic
movements, and they tend to involve the face, neck, and
extremities. Versive seizures consisting of head turning and
conjugate eye movements are particularly common in SPS.
Automatisms do not occur with SPS, but some patients
complain of aura (chest discomfort, headache), which may be
the only manifestation of a seizure.
COMPLEX PARTIAL SEIZURES (CPS).
A CPS may begin with a simple partial seizure with or without
an aura, followed by impaired consciousness; conversely, the
onset of the CPS may coincide with an altered state of
consciousness. An aura consisting of vague, unpleasant
feelings, epigastric discomfort, or fear is present in
approximately one third of children with SPS and CPS. The
presence of an aura always indicates a focal onset of the seizure.
BENIGN PARTIAL EPILEPSY WITH
CENTROTEMPORAL SPIKES (BPEC).
BPEC is a common type of partial epilepsy in childhood and
has an excellent prognosis. The clinical features, EEG findings
(rolandic foci), and lack of a neuropathologic lesion are
characteristic and readily separate BPEC from CPS. BPEC
occurs between the ages of 2 and 14 yr and has a peak age of
onset of 9–10 yr
Generalized Seizures
ABSENCE SEIZURES.
Simple (typical) absence (petit mal) seizures are characterized
by a sudden cessation of motor activity or speech with a blank
facial expression and flickering of the eyelids. These seizures,
which are uncommon before age 5 yr, are more prevalent in
girls, are never associated with an aura, rarely persist longer
than 30 sec, and are not associated with a postictal state. These
features tend to differentiate absence seizures from complex
partial seizures. Children with absence seizures may
experience countless seizures daily, whereas complex partial
seizures are usually less frequent. Patients do not lose body
tone, but their head may fall forward slightly. Immediately
after the seizure, patients resume preseizure activity with no
indication of postictal impairment. Automatic behavior
frequently accompanies simple absence seizures.
Hyperventilation for 3–4 min routinely produces an absence
seizure. The EEG shows a typical 3/sec spike and generalized
wave discharge. Complex (atypical) absence seizures have
associated motor components consisting of myoclonic
movement of the face, fingers, or extremities and, on occasion,
loss of body tone. These seizures produce atypical EEG spike
and wave discharges at 2–2.5/sec.
GENERALIZED TONIC-CLONIC SEIZURES.
These seizures are common and may follow a partial seizure
with a focal onset (second generalization) or occur de novo.
They may be associated with an aura, suggesting a focal origin
of the epileptiform discharge. It is important to inquire about
the presence of an aura, because its presence and site of origin
may indicate the area of pathology. Patients suddenly lose
consciousness and, in some cases, emit a shrill, piercing cry.
Their eyes roll back, their entire body musculature undergoes
tonic contractions, and they rapidly become cyanotic in
association with apnea. The clonic phase of the seizure is
heralded by rhythmic clonic contractions alternating with
relaxation of all muscle groups. The clonic phase slows toward
the end of the seizure, which usually persists for a few minutes,
and patients often sigh as the seizure comes to an abrupt stop.
During the seizure, children may bite their tongue but rarely
vomit. Loss of sphincter control, particularly the bladder, is
common during a generalized tonic-clonic seizure.
Tight clothing and jewelry around the neck should be
loosened, the patient should be placed on one side, and the
neck and jaw should be gently hyperextended to enhance
breathing. The mouth should not be opened forcibly by an
object or by a finger because the patient's teeth may be
dislodged and aspirated, or significant injury to the
oropharyngeal cavity may result. Postictally, children are
initially semicomatose and typically remain in a deep sleep
from 30 min to 2 hr. If patients are examined during the
seizure or immediately postictally, they may demonstrate
truncal ataxia, hyperactive deep tendon reflexes, clonus, and a
Babinski reflex. The postictal phase is often associated with
vomiting and an intense bifrontal headache.
Idiopathic seizure is a term applied when the cause of a
generalized seizure cannot be ascertained. Many factors are
known to precipitate generalized tonic-clonic seizures in
children, including low-grade fever associated with non–
central nervous system infections, excessive fatigue or
emotional stress, and various drugs including psychotropic
medications, theophylline, and methylphenidate, particularly if
the seizures are poorly controlled by anticonvulsant drugs.
MYOCLONIC EPILEPSIES OF CHILDHOOD.
This disorder is characterized by repetitive seizures consisting
of brief, often symmetric muscular contractions with loss of
body tone and falling or slumping forward, which has a
tendency to cause injuries to the face and mouth. Myoclonic
epilepsies include a heterogeneous group of conditions with
multiple causes and variable outcomes. At least five distinct
subgroupings can be identified; these represent the broad
spectrum of myoclonic epilepsies in the pediatric population.
BENZODIAZEPINES.
The benzodiazepines exert anticonvulsant activity by binding
to a specific GABA site that enhances the opening frequency of
the chloride channel without affecting open or burst duration
(see Fig. 593-4 ). The drugs diazepam and lorazepam IV are
used for initial management of status epilepticus. Rectal
diazepam gel has been demonstrated to be an effective and safe
treatment to abort episodes of acute repetitive seizures in
children and is available as Diastat gel in 2.5, 5, and 10 mg
doses for children. Buccal or nasal midazolam is also effective
acutely. Clonazepam is useful for the management of the
Lennox-Gastaut syndrome, myoclonic, akinetic, and absence
seizures.
CARBAMAZEPINE.
This drug is effective for the management of generalized tonicclonic and partial seizures
Significant leukopenia (<1,000 neutrophils/mL3) and
hepatotoxicity may rarely develop, particularly during the initial
3–4 mo of therapy. Therefore, a CBC with differential and AST
and ALT levels should be obtained on a monthly basis during this
period, although serious idiosyncratic drug reactions may
develop despite normal liver function tests results and routine
blood work.
ETHOSUXIMIDE.
Ethosuximide provides its anticonvulsant action by blocking
calcium channels associated with thalamocortical circuitry.
Ethosuximide is an effective drug for the management of
typical absence epilepsy and has a half-life of 60 hr
GABAPENTIN.
This anticonvulsant is used as an add-on drug for patients with
refractory complex partial and secondarily generalized tonicclonic seizures
LAMOTRIGINE.
Lamotrigine is a phenyltriazine compound used as an add-on
drug for the management of complex partial and generalized
tonic-clonic seizures. Lamotrigine is effective as monotherapy
for some children with the Lennox-Gastaut syndrome and
generalized absence seizures
PHENOBARBITAL AND PRIMIDONE.
These are relatively safe anticonvulsants that are particularly
useful for generalized tonic-clonic seizures. Approximately
25% of children undergo severe behavioral changes on these
drugs. Neurologically abnormal children are at greater risk.
Furthermore, there is evidence that phenobarbital may
adversely affect the cognitive performance of children treated
on a long-term basis
PHENYTOIN.
Phenytoin acts by decreasing the sustained repetitive firing of
single neurons by blocking sodium-dependent channels and
decreasing depolarization-dependent calcium uptake.
Phenytoin is used for primary and secondary generalized
tonic-clonic seizures, partial seizures, and status epilepticus
VALPROIC ACID.
Valproic acid is a broad-spectrum anticonvulsant. It acts by
blocking voltage-dependent sodium channels and increases
calcium-dependent potassium conductance. The elimination
half-life is 6–16 hr. This drug is useful for the management of
many seizure types, including generalized tonic-clonic,
absence, atypical absence, and myoclonic seizures. It rarely
induces behavioral changes but is associated with mild
gastrointestinal disturbances, alopecia, tremor, and
hyperphagia. Two rare but serious side effects of valproate are
a Reye-like syndrome and irreversible hepatotoxicity.
ACTH.
This is the preferred drug for the management of infantile
spasms, although the dose and duration of therapy are not
uniform. Prednisone is equally effective