Development of Hippocampal Atrophy: A Serial Magnetic Resonance Imaging Study in a Patient Who Developed Epilepsy After Generalized Status Epilepticus

Abstract

Summary:Purpose: To investigate changes in hippocampal volume.Methods: We used serial magnetic resonance imaging (MRI) in a patient who developed chronic epilepsy after having generalized tonic-clonic status epilepticus (SE). Five MRI investigations were performed during SE and a 58-month follow-up period. Hippocampal volumetric measurements and coregistration of scans were performed to detect hippocampal atrophy.Results: During status both mesiotemporal regions returned a high signal on T,-weighted images. Two months after the onset of SE, bilateral hippocampal atrophy was detected. Further progressive hippocampal atrophy was detected in the subsequent 58 months by both hippocampal volumetric measurements and coregistration of scans. Conclusions: Our findings suggest that hippocampal atrophy is a process that may continue after the end of the SE. Key Words: Status epilepticus-Encephalitis-HippocampusSerial magnetic resonance imaging.Status epilepticus (SE) can be associated with hippocampal atrophy (1). However, whether chronic epilepsy is associated with progressive hippocampal atrophy is not known. With serial magnetic resonance imaging (MRI), this question can be addressed. With serial MRI scans, changes occurring in the brain over time can be monitored. Coregistration and substraction of serial MRI scans may help clinicians detect subtle changes (2-4). The hippocampal volume can be quantified on MRI images (5). We performed a serial MRI study for almost 5 years to investigate hippocampal volume changes in a patient who developed chronic epilepsy after having tonic-clonic SE. CASE REPORTA 30-year-old woman developed generalized tonicclonic SE in September 1991 after having low-grade fever for 1 week. Two days after onset of SE, cerebrospinal fluid (CSF) examination showed pleocytosis of 72 cells/ pl, normal blood sugar, and oligoclonal bands against HSV1. The serum HSVl antibody titer increased from 20 to 160 during the third to fourth weeks of the illness.Chest radiograph and results of brain computed tomography (CT), and intravenous digital substraction angiography (DSA) and muscle biopsy were normal. SE persisted for 2 weeks despite intensive therapy including intravenous thiopentone. Two months after the onset of the illness, the patient was well enough to begin neurorehabilitation, but she had developed memory deficits and habitual epilepsy with frequent secondarily generalized seizures that remained refractory to medical treatment. The seizure semiology was compatible with frontal onset with secondary spread to the temporal lobes. There was evidence of continuing neuropsychological decline; her score on the Warrington recognition test for words and faces decreased from 46/50 and 46/50, respectively, to 37/50 and 35/50 in the 4 years after her illness. The IQ (79) was unchanged.

Hippocampal Sclerosis: Development in Adult Life

“…These cases are interpreted as evidence of hippocampal injury rather than the natural history of a disease such as focal encephalitis. Wieshmann et al [17] reported bilateral increased T 2 signal in an adult after prolonged generalized seizures. Hippocampal atrophy was present bilaterally at 2 months and progressive bilateral atrophy subsequently occurred.…”

Recurrent seizures do not cause hippocampal damage

“…Clinically, there is also considerable evidence that several forms of status epilepticus including convulsive tonicclonic status are associated with significant brain damage. Such lesions may be detected using neuropathological methods [7] but also through tailored imaging studies such as quantitative MRI [17,19,26]. However, the answer to the question whether milder forms of status or repetitive isolated seizures that are associated with different pathophysiological processes do also cause structural brain damage remains elusive.…”

The Cost-Effective Use of 18F-FDG PET in the Presurgical Evaluation of Medically Refractory Focal Epilepsy

“…The sensitivity of 18 F-FDG PET in extratemporal lobe epilepsy (ETLE) is generally reported to be less than that in TLE, but 30%-50% of patients with ETLE are successfully localized-including some patients with a normal MRI in whom the PET findings are critical to allowing that patient to proceed to surgery (8,9,20,21). However, despite this information, the evidence for the cost-effectiveness of 18 F-FDG PET in the presurgical evaluation continues to be questioned by several authors and funding organizations (8,(22)(23)(24)(25)(26).…”