Abstracts

Progressive myoclonus epilepsy of Unverricht-Lundborg type is an autosomal recessive disorder characterized by tonic-clonic seizures, myoclonus, and neurological decline. Lamotrogine (LTG) has been reported to be beneficial in the treatment of myoclonus, such as in juvenile myoclonic epilepsy (JME). We report the first known case of genetically proven Unverricht-Lundborg Disease in which progressively disabling myoclonus developed in association with LTG and subsequently improved with cessation of this therapy. A case review of the inpatient and outpatient medical records including chart documentation, EEGs with and without prolonged video monitoring, and laboratory tests was performed in a nineteen-year-old man with genetically proven progressive myoclonic epilepsy of the Unverricht-Lundborg type. A subsequent review of medical literature of antiepileptic drug therapies for progressive myoclonic epilepsies (PME) was performed. A nineteen-year-old Caucasian man developed seizures at the age of twelve characterized by a focal visual aura lasting 15-60 seconds followed by secondarily generalized tonic clonic seizures. Valproic acid (VPA) monotherapy was initiated with control of his seizures. He subsequently developed increasingly frequent tonic-clonic seizures and myoclonus, at which time LTG was initiated as adjunctive therapy with VPA. This resulted in control of tonic-clonic seizures, but not myoclonus. Over the next seven months LTG therapy was increased to a maximum of 900mg/day. Over that time period myoclonus intensified in frequency and duration, eventually leading to inability to ambulate and requiring hospitalization. During this period zonesamide (ZNS) and clonezepam was added with no change in frequency or intensity of myoclonus. Serial prolonged EEGs during his hospitalization exhibited increased frequency of generalized polyspike and wave discharges. LTG therapy was gradually tapered and finally discontinued, with dramatic cessation of disabling myoclonus. Progressive myoclonic epilepsy of Unverricht-Lundborg type typically begins between the ages of six to fifteen. Progressive neurological decline includes clinical symptoms of seizures, dysarthria, cognitive dysfunction, and ataxia. Most patients live well into adulthood with the average onset of disability 5 years after diagnosis. Myoclonus in this disorder is often refractory to conventional therapies. Therapies for PME have included a broad spectrum of anticonvulsants, N-acetylcysteine, and baclofen. Although case reports document LTG as an effective therapy for treatment of myoclonus in JME, no medical documentation exists regarding use of LTG therapy in PME. Given the rarity of patients with PME, controlled trials to assess the impact of antiepileptic drug therapy are frequently impractical in these disorders. In our patient, increasing dosages of LTG induced disabling myoclonus which rapidly improved following cessation of therapy with LTG.