Clinical characteristics and outcomes of adults with multifocal epilepsy

Multifocal epilepsy is an important subtype of epilepsy, but it is sometimes difficult to recognise in general clinical practice. Distinguishing (uni)focal from multifocal drug resistant epilepsy is important when considering surgical resection. The presence of multiple discrete autonomous epileptogenic zones may limit surgical options to neuromodulation or palliative resection. We describe the clinical characteristics and outcomes of a cohort of patients with multifocal epilepsy diagnosed by video-EEG monitoring.

Patients with probable and possible multifocal epilepsy were identified from an Epilepsy Monitoring Unit database during a 9-year period. Clinical characteristics and long term outcomes are described.

We identified 30 patients- 19 with possible and 11 with probable multifocal epilepsy based on clinical assessment and video-EEG findings. The aetiology of epilepsy was structural or of unknown cause in the majority. Prior to video-EEG monitoring, clinical assessment including ascertainment of seizure semiology or routine EEG suggested multifocal epilepsy in only 13.3% of patients. Over 95% had ongoing drug resistant seizures at last follow up. One patient died from sudden unexpected death in epilepsy over the 9-year study interval.

This study highlights that multifocal epilepsy is often not recognised or diagnosed in the outpatient setting. Typically it is a diagnosis made after video-EEG monitoring. In our experience multifocal epilepsy is usually drug-resistant and often highly refractory. Recognising patients with multifocal epilepsy as a more treatment-resistant subgroup within focal epilepsy is important for counselling and management considerations.