Rasmussen's encephalitis

Rasmussen's encephalitis (RE) is a rare progressive encephalitis that results in intractable seizures, cognitive decline and hemiparesis.

A retrospective review was performed for all patients with RE who had surgery between 1998 and 2020. Sundar et al. collected seizure history, postoperative outcomes, and functional data. Imaging was independently reviewed in a blinded fashion by 2 neurosurgeons and a neuroradiologist.

They analyzed 30 patients with RE who underwent 35 hemispherectomies (5 reoperations). Using Kaplan-Meier analysis, the seizure-freedom rate was 81.5%, 63.6%, and 55.6% at 1, 5, and 10 years after surgery, respectively. Patients with a shorter duration of hemiparesis preoperatively were less likely to be seizure-free at follow-up (P = .011) and more likely to undergo reoperation (P = .004). A shorter duration of epilepsy (P = .026) and preoperative bilateral MRI abnormalities (P = .011) were associated with an increased risk of reoperation. Complete disconnection of the diseased hemisphere on postoperative MRI after the first operation improved seizure freedom (P = .021) and resulted in fewer reoperations (P = .034), and reoperation resulted in seizure freedom in every case.

Obtaining complete disconnection is critical for favorable seizure outcomes from hemispherectomy, and neurosurgeons should have a low threshold to reoperate in patients with RE with recurrent seizures. Rapid progression of motor deficits and bilateral MRI abnormalities may indicate a subpopulation of patients with RE with an increased risk of needing reoperation. Overall, they believe that hemispherectomy is a curative surgery for the majority of patients with RE, with excellent long-term seizure outcomes 1).


From a total of 20 patients surgery was conducted in the left hemisphere in 6 patients and in the right hemisphere in 14. The surgical methods included anatomical hemispherectomy, functional hemispherectomy, hemispherotomy, lesion resection, multilobar resection, selective resection and bipolar electrocoagulation of functional cortexes. The mean follow-up period was 5.45 years (range 3-8). After surgery, 16 patients (80%) were evaluated as being Engel class I. All of the patients had increases in cognitive abilities after surgery except 1 patient with bilateral RE. After surgery, most patients could walk independently, but the fine movement of the hands was lost. Postoperative hydrocephalus was observed in 1 patient after functional hemispherectomy, and there was no death in this series.

Hemispherectomy and hemispherotomy were both confirmed as beneficial procedures in controlling seizures and improving quality of the life in RE cases 2).

A 29-year-old woman presented with a 24-year history of epileptic seizures. Neurological examination showed hemiplegia, homonymous hemianopsia, and right muscular atrophy. Neuropsychological examination demonstrated cognitive disorders. Serial magnetic resonance imaging (MRI) and computed tomography (CT) scans showed progressive encephalatrophy in the left hemisphere and ventriculomegaly in the left lateral ventricle. The Wada test showed that the right hemisphere was dominant for language. A functional hemispherectomy was performed. Postoperatively, no antiepileptic drugs were administered, and the patient remained seizure-free without aggravation of hemiplegia. Over a 2-year follow-up, cognitive functions improved. In an adult patient with RE, a favorable prognosis was achieved after functional hemispherectomy. The safety and efficacy of functional hemispherectomy in patients with RE is highlighted 3).

Sundar SJ, Lu E, Schmidt ES, Kondylis ED, Vegh D, Poturalski MJ, Bulacio JC, Jehi L, Gupta A, Wyllie E, Bingaman WE. Seizure Outcomes and Reoperation in Surgical Rasmussen Encephalitis Patients. Neurosurgery. 2022 May 13. doi: 10.1227/neu.0000000000001958. Epub ahead of print. PMID: 35544031.
Guan Y, Zhou J, Luan G, Liu X. Surgical Treatment of Patients with Rasmussen Encephalitis. Stereotact Funct Neurosurg. 2014 Feb 6;92(2):86-93. [Epub ahead of print] PubMed PMID: 24503650.
Wang Q, Zhu Z, Wang G, Sun L, Qiu J. Functional Hemispherectomy for Adult Rasmussen Encephalitis: A Case Report and Literature Review. Turk Neurosurg. 2019;29(6):945-949. doi: 10.5137/1019-5149.JTN.21188-17.1. PMID: 29091250.
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