Subacute sclerosing panencephalitis presenting with unilateral periodic myoclonic jerks.

BACKGROUND: Subacute sclerosing panencephalitis (SSPE) is a rare complication of measles virus infection. The disease is characterized by behavioural abnormalities, intellectual deterioration, motor weakness, and generalized myoclonic jerks progressing to coma and death in one to two years in 80% of the cases. The myoclonic jerks are associated with characteristic generalized slow periodic complexes on electroencephalography (EEG). The symptoms and signs of SSPE are frequently quite variable. The clinical course is equally variable and difficult to predict. The characteristic periodic myoclonus can rarely occur unilaterally particularly in the early stages of the disease. As well, the periodic EEG complexes have been reported unilaterally in up to 3% of cases. CASE REPORT: A 12-year-old boy, who was seen at a later stage with atypical manifestation of myoclonic body jerks confined entirely unilaterally, combined with contralateral periodic EEG complexes. One could assume clinically that the more diseased hemisphere was responsible for generating the jerks. However, brain magnetic resonance imaging revealed asymmetric hemispheric changes suggesting that the less neurologically damaged hemisphere is responsible for generating the unilateral myoclonic jerks. This has led to the interpretation that the more severely damaged hemisphere has lost the neuronal connectivity required to generate these periodic myoclonic jerks. CONCLUSIONS: Subacute sclerosing panencephalitis may have asymmetric hemispheric involvement, not only early, but also in the advanced stages of the disease, which can result in unilateral periodic myoclonic jerks.

Topiramate for the treatment of infants with early myoclonic encephalopathy.

OBJECTIVE: Early myoclonic encephalopathy (EME) is a rare epileptic syndrome characterized by neonatal onset of severe recurrent seizures of multiple types often resistant to antiepileptic drugs (AEDs). Topiramate (TPM) is a new AED, which has a wide spectrum of antiepileptic activities suggesting a potentially valuable therapeutic profile. There is limited clinical data available on TPM use in infants and our aim is to report our experience with TPM for the treatment of infants with intractable seizures secondary to EME. METHODS: Prospective, open label, add on trial of TPM in treating a series of infants with EME at King Faisal Specialist Hospital and Research Centre and King Abdul-Aziz University Hospital, Jeddah, Kingdom of Saudi Arabia between June 1999 and March 2002. Topiramate was started at 12.5 mg/day and was increased by doubling the dose every week until the minimum effective dose was reached (seizure free outcome) or up to a maximum of 10 mg/kg/day. RESULTS: Four consecutive infants (2 males and 2 females) were included. In addition to daily seizures, they all had global hypotonia, developmental delay, and progressive microcephaly. The syndrome was cryptogenic in 3, and one had nonketotic hyperglycinemia. Initial electroencephalograms showed generalized epileptic burst suppression pattern. Infants were tried on multiple AEDs (6-11, mean 7.5) with no success. Topiramate was added at age 5-12 months (mean 9) reaching a maximum dose of 5.5-10 mg/kg/day (mean 7.6). The infants were then followed for up to 19 months (mean 13.5). After introducing TPM, one infant became completely seizure free and 3 had significant (>50%) seizure reduction. Electroencephalograms in 3 infants showed marked improvement. One infant had weight loss that resulted in discontinuing the drug after 6 months. Follow-up renal ultrasound findings were normal in all infants. CONCLUSION: Topiramate is effective and safe in treating infants with intractable epilepsy secondary to EME.