Inherited epileptic disorder characterized by
myoclonic jerks, generalized tonic-clonic seizures and, sometimes absence seizures
shortly after awakening. Normal intelligence and onset around adolescence are characteristic.
Juvenile Myoclonic Epilepsy of Janz; Impulsive Petit Mal.
1:1000-2000 in the general population. JME represents 5
to 10% of all epileptic patients, but the condition probably is
underdiagnosed. A slight prevalence among females has been reported in some
(not all) studies.
Exact mode of inheritance is not clear. One
third of JME patients have a positive family history of epilepsy. Some
authors reported association with human leukocyte antigen of chromosome 6
(not confirmed by other studies).
Microscopic brain alterations (dystopic neurons in
stratum moleculare, white matter, hippocampus, and cerebellar cortex) have
been observed. Exact cause of this disorder remains unknown.
Based on clinical grounds. Video electroencephalogram (EEG) monitoring of
typical seizures is the standard criterion (but not necessary to establish
the diagnosis). The diagnosis should be suspected in patients with myoclonic
jerks favored by reproducible precipitating factors. Sleep-deprived EEG with
activation procedures (hyperventilation, photic stimulation) is the most
useful test in clinical practice.
The disorder usually begins in adolescence and is
characterized by absence seizures in early age. As the child ages, it is followed by myoclonic jerks in the morning
(1-9 years later) and then grand mal seizures (a few years later). Patients
are normally intelligent and do not lose consciousness during myoclonic
jerks. Precipitating factors include sleep deprivation, psychological
stress, alcohol use, and menses. Physical examination is normal.
Check anticonvulsant therapy
(including doses of antiepileptics) and continue normal therapy until the
morning of anesthesia and surgery. Premedication, preferably with a
benzodiazepine, is mandatory to reduce preoperative stress (stress is a
precipitating factor of seizures in this syndrome).
No specific anesthetic considerations
with this medical condition.
Avoid anesthetic agents known to be
associated with seizure activity or stimulation. Administration of an
intravenous anticonvulsant for prolonged surgical procedures or after large
blood loss must be considered.
Frontal Lobe Epilepsy: Characterized by recurrent seizures
originating in the frontal lobes, often partial with or without secondary
generalization; usually symptomatic of other disorders, either congenital
(cortical dysgenesis, gliosis, or vascular malformations) or acquired
(neoplasms, head trauma, infections, and anoxia). One rare variant is
genetically transmitted as an autosomal dominant trait.
Bai D, Alonso ME, Medina MT, et al: Juvenile myoclonic epilepsy: Linkage
to chromosome 6p12 in Mexico families. Am J Med Genet
Canevini MP, Mai R, Di Marco C: Juvenile myoclonic epilepsy of Janz:
Clinical observations in 60 patients. Seizure
Wheless JW, Kim HL: Adolescent seizures and epilepsy syndromes. Epilepsia 43(suppl