Abstracts

Rationale: Classification of epileptic seizures and epilepsy syndromes as either focal or generalized is a fundamental and early part in the diagnostic process and is generally fairly easily accomplished. The differentiation between focal and generalised epilepsy has considerable implications for therapy. However,in some patients,this differentiation may not be straightforward, with mixed features of both generalized and focal epilepsy. This report describes a series of different types of possible “dual” epilepsy. Methods: We present a case series of patients referred to the Epilepsy Centre at Beaumont Hospital, Dublin, for further evaluation of difficult refractory epilepsy, who on close analysis turned out to have features of dual epilepsy. These include patients with true dual or co-existing epilepsy,patients with IGE and incidental focal abnormalities on MRI, patients with IGE and focal EEG abnormalities,and patients with myoclonus in the setting of focal epilepsy. Results: Patient 1 is a 24 year-old lady with a remote history of partial epilepsy in childhood, with poorly controlled tonic-clonic seizures on a variety of narrow spectrum drugs. She described an internal feeling of jerkiness, and video EEG monitoring revealed focal spikes and generalized spike and wave, with a generalized onset to a typical convulsive seizure. This patient has a history of remote and remitted partial epilepsy, and active idiopathic generalized epilepsy (IGE). Patient 2 is a 26 year-old female referred by the neurosurgery department with refractory tonic-clonic seizures and a right temporal arachnoid cyst on MRI brain imaging. Clinical and EEG evaluation was consistent with IGE,and she obtained significant improvement in seizure control with a change to a broad-spectrum anti-epileptic drug. The cyst on imaging was judged to be incidental to her epilepsy. Patient 3 was a 25 year-old female admitted for video EEG monitoring because of refractory epilepsy. She described an “aura” of a “fuzziness” in the brain, and an auditory disturbance of a feeling of “sounds speeding up”. Video EEG showed changes consistent with IGE. Thus she was felt to have IGE with focal clinical features. There was significant improvement following weaning of carbamazepine. Patient 4 is a 25 year-old lady with a known long-standing right temporal low grade oligodendroglioma, nocturnal partial seizures, and early morning myoclonic jerks with generalized abnormalities on EEG, all clarified by the use of video EEG monitoring. This patient had true active dual epilepsy. Conclusions: Dual epilepsy represents a small but challenging group of patients with often difficult to control seizures, and a perplexing presentation. Diagnosis may be difficult and is usually best defined by in-patient continuous video EEG monitoring. Appropriate changes to broad spectrum drugs and careful weaning of narrow spectrum agents may provide substantial gains in seizure control and quality of life. It is well to remember that such patients do exist, and that they can unwittingly defy our classification system.