Century myoclonus with absences (Jevons syndrome)
(MVA) is a form of abscess epilepsy, characterized by short absence with myoclonia of the eyelids, setting up the eyeballs, expressed photo-sensitivity.
This syndrome was first described by Jeavons in 1977.
Frequency. The exact frequency of the syndrome is unknown. It can occur as an independent nosological form and be included in the structure of such forms as juvenile myoclonic epilepsy, epilepsy with myoclonic absans and some others. According to K.Yu.Mukhina, A.S. Petrukhin 2000, MVA is about 5% of all forms of idiopathic generalized epilepsy. Giannakodimos & Panayiotopoulos (1996) found that MBA is 12.6% among all absence forms of epilepsy.
Genetics. Family cases are uncharacteristic.
Clinic. Attacks begin in 5-6 years, more often boys are sick. The disease is manifested by short absans, at the moment of which the patient turns the eyeballs up, the eyelids make frequent (3-4 times per second) trembling (pathognomonic sign!).
The duration of absences is 2-5 seconds. Characterized by a high frequency of attacks – tens per hour, attacks are increasing on sunny days, when going from a darkened room to light. In such patients photosensitivity is expressed: photophobia, pain in the eyes, tearing in the light. The second type of seizures is generalized tonic-clonic seizures.
Focal symptoms are usually absent in neurological status. However, almost all patients have varying degrees of intellectual-mental disorders, down to the level of moronity.
EEG. The main activity in the background recording is usually saved. The appearance of a generalized polypic-wave activity with a frequency of 3-5 Hz is typical when the eyes are closed and during the light rhythmic stimulation at frequencies of 5-15 Hz.
The EEG clearly reveals an oculographic artifact caused by the deviation of the eyeballs, which immediately precedes the peak-wave activity.
Basic diagnostic criteria. The difficulties of diagnosing this syndrome lie in the fact that very short absences can remain unrecognized, and without video EEG monitoring (including an EMG study with electrodes from M. orbicularis oculi), it is difficult to establish the presence of eyelid myoclonia during an attack. Patients often mistakenly diagnose facial hyperkinesis.
A.S. Petrukhin (2000) identified the following differential diagnostic criteria for MBA:
- the presence of isolated eyelid myoclonia;
- short absence with the establishment of the eyeballs;
- photosensitive nature of the attacks;
- the presence on the EEG of discharges of polypic-wave activity in combination with oculographic
- resistance to monotherapy.
Treatment. MVA is one of the most resistant to treatment forms of absence epilepsy.
Therapy begins with convolux or other valproates, a starting dose of 15 mg / kg / day, with a gradual increase to 50 mg / kg / day, and if necessary, up to 100 mg / kg / day. In the absence of a clinical effect, they switch to combinations of valpro- ty + suxilep or valproate + lamictal. All drugs are used in the maximum tolerated dosages.
Forecast. With the use of polytherapy (basic drugs – valproate) in most cases it is possible to achieve the effect of reducing the frequency of seizures, but complete remission is achieved in less than a third of patients. It is recommended to continue therapy for at least 3.5-4 years from the time of the last attack, as the probability of a relapse is high.