Rasmussen encephalitis

Press C, Wallace A, Chapman KE. The Janus-faced nature of Rasmussen’s Encephalitis. Semin Pediatr Neurol. 2014 Jun;21(2):129-36.

Rasmussen encephalitis (RE) is an inflammatory unilateral progressive medically refractory epilepsy associated with hemiparesis, cognitive dysfunction, and hemispheric atrophy. Here, we present 2 cases from our institution that demonstrate the dual nature of RE in 2 similarly aged children. Overall, 2 types of RE have been described: type 1 has a short prodromal phase and more explosive onset and type 2 has a longer prodromal of partial seizures followed by hemiparesis and atrophy. Younger patients are more likely to fit into the type 1 presentation and have been described as more likely to have dual pathology. Perhaps the patients with a more acute onset are more likely to have a dual pathology as is found in our 2 cases. We review the typical findings in RE and discuss current treatment options, highlighting new experimental treatments.

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Olson HE, Lechpammer M, Prabhu SP, Ciarlini PD, Poduri A, Gooty VD, Anjum MW,
Gorman MP, Loddenkemper T. Clinical application and evaluation of the Bien diagnostic criteria for Rasmussen encephalitis. Epilepsia. 2013 Oct;54(10):1753-60.

The 2005 Bien clinical diagnostic criteria for RE have reasonably high sensitivity and specificity and good clinical-pathologic correlation in most cases. We suggest modification of the criteria to allow inclusion of cases with well-described but less common features. Specifically we suggest making the diagnosis in the absence of epilepsia partialis continua (EPC) or clear progression of focal cortical deficits or MRI findings if biopsy is positive and two of the A criteria are met (B3 plus two of three A criteria). This would improve the sensitivity of the criteria.

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Takahashi Y, Yamazaki E, Mine J, Kubota Y, Imai K, Mogami Y, Baba K, Matsuda
K, Oguni H, Sugai K, Ohtsuka Y, Fujiwara T, Inoue Y. Immunomodulatory therapy
versus surgery for Rasmussen syndrome in early childhood. Brain Dev. 2013

We examined seizure, cognitive, and motor outcomes in patients with Rasmussen syndrome or Rasmussen encephalitis (RS), after recent initiation of immunomodulatory therapies. Among 53 patients with a diagnosis of RS referred from all over Japan, 49 patients (male 22, female 27) with symptoms and findings characteristic of RS were evaluated. Regular intravenous immunoglobulin (IVIg) therapy was administered at a dose of 100mg/kg/day, etc. Regular steroid pulse therapy was conducted with methylprednisolone at a dose of 30mg/kg/day (children) or 1000mg/day (adults) for 3days. Tacrolimus was given at an initial dose of 0.1mg/kg/day (children). Mean onset age was 8.7±10.5years. Seizure-free rate was 71% after treatment by functional hemispherectomy (FH), and response rate for seizures was 81% by regular steroid pulse therapy, 42% by tacrolimus therapy, and 23% by regular IVIg therapy. Rate of patients with IQ higher than 80 (R80) was 50% by regular steroid pulse therapy, 43% by regular IVIg therapy, 29% by tacrolimus therapy, and 0% by FH. R80 after regular steroid pulse therapy was 100% in patients without MRI lesions, and 37% in those with advanced MRI lesions. Improvement of motor function (paresis) was observed only by immunomodulatory therapy. Motor function was aggravated in 100% of patients treated by FH, 62% by regular IVIg, and 10% by regular steroid pulse therapy. We suggest a new treatment strategy for RS using early immunomodulatory therapy: initiation of regular steroid pulse therapy after early diagnosis indicated by biomarkers, then switching to tacrolimus therapy after several months.

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Granata T, Andermann F. Rasmussen encephalitis. Handb Clin Neurol. 2013;111:511-9.

Rasmussen encephalitis (RE) is a rare, inflammatory, and possibly immuno-mediated disease that typically affects one hemisphere. The two cardinal symptoms are progressive neurological deficits and intractable seizures, often in the form of epilepsia partialis continua and recurring epileptic status. Distinctive MRI features include progressive unilateral focal cortical atrophy and gray or white matter high-signal changes with basal ganglion involvement. Histopathology is characterized by brain inflammation dominated by T cells, microglial activation, and microglial nodules, followed by neuronal loss and astrogliosis. The diagnosis of RE, which may be particularly challenging in the initial stages, is based on clinical and laboratory findings. The diagnosis requires the exclusion of other causes of epilepsia partialis continua, and other cerebral focal inflammatory diseases. The treatment of RE is often demanding: antiepileptic drugs are of limited effect, whereas the surgical exclusion of the affected hemisphere offers a very high chance of seizure freedom but at the price of irreversible neurological deficits. By contrast, long-term immunotherapy may delay hemispheric tissue loss and neurological deficits, but has a lesser effect on total seizure burden. Given that the severity of symptoms varies among different patients and phases, the therapeutic strategy, including medical and surgical options, must be tailored to the need of each patient.

Children’s and Emory users, request article from Emily Lawson. 

Mastrangelo M, Mariani R, Menichella A. Eponym: Rasmussen syndrome. Eur J
Pediatr. 2010 Aug;169(8):919-24.

Rasmussen’s syndrome (RS) is a rare acquired progressive inflammatory encephalopathy characterized by drug-resistant partial seizures and cognitive deterioration resulting from a gradual impairment and a subsequent atrophy of a single brain hemisphere. It was firstly described by Theodore Rasmussen in 1958. The original etiopathogenic hypothesis of a chronic viral infection no longer holds. Today, the presumed mechanism is a complex autoimmune process comprising an active role of both cytotoxic T lymphocytes and circulating autoantibodies, activating the subunit 3 of the ionotropic glutamate receptor (GluR3Ab). Several medical options, such as antiepileptic drugs and immunomodulatory therapies, deserve consideration to face epileptic manifestations and to slow neurologic regression. Yet, all these therapies turn out to be almost always just temporizing measures. Surgical disconnection of the affected hemisphere (“functional hemispherectomy”) is the best therapeutic choice to achieve the arrest of the disease, a good seizure control, the block of neurologic decline, and the improvement of patient’s quality of life.

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More PubMed results on Rasmussen encephalitis.

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