Periodic lateralized epileptiform discharges in multiple sclerosis: a case report.

The occurrence of epileptiform abnormalities on the EEG in patients with multiple sclerosis (MS) is rare. The following case correlates the clinical, EEG, MRI, and single photon emission computed tomographic (SPECT) findings in a patient with a long history of MS and acute onset of focal motor seizures and confusion. Two routine EEGs, brain MRI, and brain SPECT were performed. The patient was a 44-year-old woman with a long history of clinically definite MS of the relapsing-remitting and secondary progressive form with three events of focal motor seizures followed by generalized tonic-clonic seizures and postictal confusion. The first EEG done during admission showed periodic lateralized epileptiform discharges in the right temporal region. Brain MRI done several weeks later showed scattered T2 hyperintensities in several locations, including the periventricular and subcortical white matter bilaterally. Brain SPECT using Tc99-Neurolite demonstrated decreased perfusion on the right parietal and temporal lobes. This case suggests that focal motor seizures and a transient state of altered consciousness can be the result of an exacerbation of MS. The neurophysiologic expression of these clinical manifestations may present as periodic lateralized epileptiform discharges on the EEG and decreased regional perfusion on brain SPECT.