Isolated, chronic, epilepsia partialis continua in an HIV-infected patient

Background: The characteristic clinical feature of epilepsia partialis continua (EPC) is chronic focal myoclonus, usually involving the distal part of one extremity. A variety of pathogenetic factors have been implicated in EPC. In children, the most common cause is Rasmussen encephalitis; in adults, it is vascular disease or tumor involving the sensorimotor cortex. Epileptic seizures are a relatively common manifestation of central nervous system involvement in patients infected with human immunodeficiency virus (HIV), but, to our knowledge, isolated, chronic EPC has not been previously reported. Objective: To describe a case of typical EPC in a patient infected with HIV. Design and Setting: Case report from an epilepsy center. Patient: A 58-year-old man infected with HIV had continuous myoclonus that involved the right arm and was associated with intermittent motor seizures. The electroencephalographic findings were normal at the onset of the symptoms, but left central theta rhythm appeared later. Serial magnetic resonance imaging scans obtained over a 3-month period showed a progressively increasing left rolandic T-2-weighted hypersignal. Histologic study of a stereotactic biopsy specimen demonstrated inflammation characterized by perivascular mononuclear cell infiltration. The only detectable cause was HIV infection. Immunocytochemical tests ruled out JC virus. Neuropsychological testing showed no evidence of cognitive impairment. An electroencephalographic-electromyographic "back-averaging" study showed a reproducible transient left biphasic complex preceding the bursts by about 30 milliseconds on the C3 and F3 electrodes, thus demonstrating that the myoclonus was of cortical origin. High-dose corticosteroid (prednisone, 100 mg/d) and anti-HIV-1 therapy led to marked radiological and clinical improvement. Infection with HIV enhances the risk of seizures, but, to our knowledge, this is the first reported case of "inflammatory" EPC. Conclusions: The present case suggests that the possibility of central nervous system involvement by HIV-1 should be taken into account in the diagnostic workup of patients with EPC. This case also indicates that treatment can be effective.