Objective: Epilepsy with myoclonic absences is a rare epilepsy syndrome with distinct features and high rates of drug resistance. Identifying this syndrome may help guide treatment decisions. We highlight clinical heterogeneity in this case series and two cases in which corpus callosotomy was performed.
Methods: Medical records were reviewed between 2017 and 2021 to identify demographics, comorbidities, age at onset, EEG findings, diagnostic evaluations, seizure semiologies, seizure frequency, anti-seizure medications, diet therapy and surgical treatments in patients with myoclonic absences.
Results: Ten patients were identified including twins with myoclonic absence status epilepticus. Forty percent had an atonic component, 20% presented with myoclonic absence status epilepticus and 60% had incomplete control of seizures at last follow-up visit. Two patients with epilepsy with myoclonic absences with atonia underwent corpus callosotomy; one patient was seizurefree eight months after surgery and the other had greater than 50% seizure reduction over a five-month period.
Significance: Phenotypic heterogeneity was evident based on seizure semiologies, comorbidities, seizure frequency and response to anti-seizure medications and non-medication treatments. Of patients with an atonic component, 75% did not achieve seizure freedom with medication alone. Corpus callosotomy was performed in two of these patients with encouraging seizure response thus far, however, the efficacy of this treatment should be further evaluated in a larger study.