PMC8063734_01
Serial axial T2/FLAIR weighted MRI brain in adult onset Rasmussen showing the progression of the condition in: 3 months, 17 months, 24 months, 32 months and 7 years after the disease onset. MRIs show multiple enhancing left hemispheric lesions involving primarily the temporal, parietal, and occipital lobes. Progressive left parietal and occipital cystic encephalomalacia and volume loss are very prominent between 2007 and 2008.
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Brain MRI initially revealed multiple enhancing lesions over the left hemisphere that ultimately evolved to unihemispheric atrophy (Fig. 1).
Histopathology of a brain biopsy in patient with Rasmussen's encephalitis. Panels (a) and (b) show CD3 (T-lymphocytes) around vessels and disperse in the neuropil. Panels (c) and (d) shows the adjacent sections stained for CD20 (B-lymphocytes), which are mostly in the perivascular compartment. Panels (e) and (f) show microglia and macrophages (IBA-1) with perivascular macrophages and activated hypertrophic microglia throughout the brain parenchyma. [(a) and (b) - adjacent sections (200x); (b), (d) and (f) - adjacent sections (400x); e (400x)].
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A brain biopsy showed a prominent lymphocytic infiltrate, CD3 predominant, and activated hypertrophic microglia throughout the brain parenchyma but no evidence of viral inclusions, vasculitis or granulomas (Fig. 2), fulfilling the proposed criteria for Adult-onset RE.
Epilepsy time course and response to therapy in adult-onset Rasmussen encephalitis treated with RNS. The figure illustrates the seizure frequency and the response to anti-seizure medications (ASM), immunotherapy and the RNS system. The lines symbolize the concomitant immunotherapy, while the dots represent the ASM. The bars represent the seizure frequency by the average number of seizures per one month; the clinical seizures, in terms of focal impaired awareness seizures were reported by the patient or the patient's family, are represented with blue bars, while the orange bars symbolize the seizure frequency that obtained from the RNS recordings.
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Although her epilepsy was resistant to ASMs and immunotherapy, seizure frequency stabilized on rituximab monotherapy for a duration of four years (Fig. 3). Unfortunately, the seizure frequency and intensity increased in 2016 despite appropriate B cell depletion (Fig. 3). RNS stimulation therapy was initiated three weeks of post-lead implantation (Fig. 3). After 24 months of RNS system treatment, clinically, the decline in frequency compared to the pre-RNS baseline was > 50%, which coincided with the RNS System electrocorticography (ECoG) data (Fig. 3).
Sagittal head CT topogram showing the location of a left hippocampal depth and left parieto-occipital strip electrodes. ECoG example showing an electrographic seizure arising from the left hippocampal depth (LH3-LH4) [B] and left parieto-occipital strip electrode contacts (LPO1-2) [C].*Tr = therapy.
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Following an eight week course of recovery from the iEEG monitoring, the patient was implanted with RNS (model: RNS-300 M) depth and strip electrodes: a four contact depth electrode targeting the left hippocampus and a four contact strip over the left parieto-occippital lateral neocortex, with center-to-center alignment (Fig. 4).