Severe form of intractable epilepsy resulting in
severe learning disabilities and impaired organization of movements. Poor
prognosis: 5% of patients die within 10 years; 50% of affected adults
are completely dependent and less than 20% are independent.
Childhood Epileptic Encephalopathy.
First described in 1770 by Tissot, who reported an
11-year-old boy with frequent drop attacks, myoclonus, and progressive
From 3 to 10% of children with epilepsy. Male
predominance. No racial predominance.
Commonly, there is a history of epilepsy in
the family of children with Lennox-Gastaut syndrome, but no familial case of
this syndrome has been reported.
Unknown even though many favoring factors have
been suggested, such as brain injury at birth, brain infections, genetic
brain diseases (e.g., tuberous sclerosis and inherited metabolic brain
diseases), brain malformations, and West syndrome. Excessive permeability in
the excitatory interhemispheric pathways in the frontal areas might play a
role. Immunogenetic mechanisms may be involved in triggering or maintaining
some cases of Lennox-Gastaut syndrome. One study found a strong association
between Lennox-Gastaut syndrome and the human lymphocyte antigen class I
antigen B7, but a second study did not.
Clinical presentation and characteristic
electroencephalographic (EEG) pattern. The EEG
shows spikes and slow frequency waves of 1.5 to 2.5 Hz. The
background rhythm is slow with multifocal spikes. The maximal voltage area
is usually anterior.
Peak age for onset is between 3 and 5 years
(extremes: 1-10 years). The syndrome consists of the triad of intractable
seizures (tonic seizures, drop attacks, atypical absences), mental
retardation, and characteristic EEG. Affected patients have a large variety
of seizures that occur at any time (day and night). Consciousness may be
only partially affected, and patients may remain rather active but
“distant,” with loss of tone of muscles of the face and neck resulting in
impaired balance or abnormal posture. Severe cases of status epilepticus may
develop. Lennox-Gastaut syndrome may be preceded by infantile spasms (West
syndrome), which worsens the prognosis. Antiepileptic agents are not
effective against this baffling disorder. Felbamate currently seems to be
the only agent with some efficacy.
Proper evaluation of the degree of
epilepsy and the medications used in this situation. No known specific
precautions other than the evaluation of the potential complications
associated with this form of intractable seizure disease. Most patients are
resistant to medications. In patients with frequent seizures, a ketogenic
diet may be considered, and less conventional therapies such as intravenous
immunoglobulin therapy may be worth considering.
No specific anesthetic considerations
except for the importance and the frequency of seizure activities, which may
affect the anesthetic management. Patients may be anxious and uncooperative.
Induction of anesthesia should be performed in conditions adapted to the
behavior of the patient. Use of preoperative sedative medication should be
considered if there are no contraindications from the cardiopulmonary and
intracranial clinical condition.