Rasmussen encephalitis: Response to early immunotherapy in a case of immune-mediated encephalitis

Role of Early Intravenous Immunoglobulins in Halting Clinical and Radiographic Disease Progression in Rasmussen Encephalitis

BACKGROUND

Rasmussen encephalitis (RE) is a rare progressive presumed autoimmune disorder characterized by pharmacoresistant epilepsy and progressive motor and cognitive deterioration. Despite immunomodulation, more than half of the patients with RE ultimately require functional hemispherotomy. In this study, we evaluated the potential beneficial effects of early initiation of immunomodulation in slowing disease progression and preventing the need for surgical interventions.

METHODS

A retrospective chart review over a 10-year period was conducted at the American University of Beirut Medical Center to identify patients with RE. Data were collected on seizure characteristics, neurological deficits, electroencephalography, brain magnetic resonance imaging results (including volumetric analyses for an objective assessment of radiographic progression), and treatment modalities.

RESULTS

Seven patients met the inclusion criteria for RE. All patients received intravenous immunoglobulins (IVIGs) as soon as the diagnosis was entertained. Five patients with only monthly to weekly seizures at the time of IVIG initiation had favorable outcomes without resorting to surgery, along with a relative preservation of the gray matter volumes in the affected cerebral hemispheres. Motor strength was preserved in those patients, and three were seizure free at their last follow-up visit. The two patients who required hemispherotomy were already severely hemiparetic and experiencing daily seizures at the time of IVIG initiation.

CONCLUSIONS

Our data suggest that the early initiation of IVIG as soon as a diagnosis of RE is suspected, and particularly before the appearance of motor deficits and intractable seizures, can maximize the beneficial effects of immunomodulation in terms of controlling seizures and reducing the rate of cerebral atrophy.

Immunomodulation With Azathioprine Therapy in Rasmussen Syndrome: A Multimodal Evaluation

OBJECTIVE

To verify safety and efficacy of the corticosteroid-sparing drug azathioprine (AZA) in Rasmussen syndrome (RS), we retrospectively analyzed a cohort of patients with RS recruited in a single pediatric neuroscience center.

METHODS

We compared outcomes in 30 patients with RS who received AZA with 23 patients who were not treated with this drug. We used a multimodal approach to correlate therapy with clinical features (seizures, epilepsia partialis continua [EPC], hemiparesis) and neuroimaging markers of progressive brain atrophy.

RESULTS

AZA was well tolerated; only 1 patient discontinued treatment due to pancytopenia. In 27 of 30 patients receiving AZA, all of whom were corticosteroid responders, corticosteroid therapy could be weaned or reduced without worsening of seizures in 89%. Patients receiving AZA had a lower prevalence of EPC (42% vs 67% in controls) and hemiparesis (64% vs 92%, respectively). Cox regression showed for the AZA group compared to controls a delayed time to (1) EPC (≈2 years, exp[B] = 0.295, 95% confidence interval [CI] 0.108-0.807; p = 0.017), (2) hemiparesis (≈1 year, exp[B] = 0.315, 95% CI 0.137-0.724; p = 0.007), and (3) surgery (≈2 years, exp[B] = 2.068, 95% CI 1.012-4.227; p = 0.046). However, there were no group differences in cognitive decline over time (IQ change per year) or in hemispheric gray matter atrophy on serial MRI scans.

CONCLUSION

AZA treatment appears to slow clinical progression of RS in steroid responders; this will give the greatest advantage in patients in the early stages of the disease in whom surgical decision-making may require further time.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that for pediatric patients with RS AZA is well tolerated and slows hemiparesis and appearance of EPC.

An immunotherapy effect analysis in Rasmussen encephalitis

Background

Immune-mediated mechanisms substantially contribute to the Rasmussen encephalitis (RE) pathology, but for unknown reasons, immunotherapy is generally ineffective in patients who have already developed intractable epilepsy; overall laboratory data regarding the effect of immunotherapy on patients with RE are limited. We analyzed multiple samples from seven differently treated children with RE and evaluated the effects of immunotherapies on neuroinflammation. Immunotherapy was introduced to all patients at the time of intractable epilepsy and they all had to undergo hemispherothomy.

Methods

Immunohistochemistry, flow cytometry, Luminex multiplex bead and enzyme-linked immunosorbent assay techniques were combined to determine: 1) inflammatory changes and lymphocyte subpopulations in 45 brain tissues; 2) lymphocyte subpopulations and the levels of 12 chemokines/cytokines in 24 cerebrospinal fluid (CSF) samples and 30 blood samples; and 3) the dynamics of these parameters in four RE patients from whom multiple samples were collected.

Results

Sustained T cell-targeted therapy with cyclophosphamide, natalizumab, alemtuzumab, and intrathecal methotrexate (ITMTX), but not with azathioprine, substantially reduced inflammation in brain tissues. Despite the therapy, the distributions of CD8⁺ T cells and the levels of C-X-C motif ligand (CXCL) 10, CXCL13, and B cell activating factor (BAFF) in patients’ CSF remained increased compared to controls. A therapeutic approach combining alemtuzumab and ITMTX was the most effective in producing simultaneous reductions in histopathological inflammatory findings and in the numbers of activated CD8⁺ T cells in the brain tissue, as well as in the overall CD8⁺ T cell population and chemokine/cytokine production in the CSF.

Conclusions

We provide evidence that various T cell-targeted immunotherapies reduced inflammation in the brains of RE patients. The observation that intractable epilepsy persisted in all of the patients suggests a relative independence of seizure activity on the presence of T cells in the brain later in the disease course. Thus, new therapeutic targets must be identified. CXCL10, CXCL13 and BAFF levels were substantially increased in CSF from all patients and their significance in RE pathology remains to be addressed.

Efficacy and tolerability of mycophenolate mofetil in a pediatric Rasmussen syndrome

Rasmussen syndrome (RS) is a chronic encephalopathy with uncertain etiology and immune-mediated pathogenesis. The only definitive treatment is represented by functional hemispherectomy. We describe the case of a 6.5-year-old female patient who developed several episodes of focal, unilateral clonic seizures. Following laboratory and instrumental investigations, the patient was diagnosed as having RS. A treatment with corticosteroids, intravenous immunoglobulin, and the antiseizure medication (carbamazepine and levetiracetam) did not completely control the seizures. Therefore, the patient was treated with mycophenolate mofetil (MMF), showing a good clinical response, with reduction of the seizures, and stability of the radiological findings. This case suggests the potential utility of MMF in the immune approach to RS.

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Rasmussen encephalitis (RE) is an immune-mediated disease of unknown etiology.

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Current definitive treatment for RE is represented by hemispherectomy.

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The immune approach of RE has been performed with several agents.

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In this case, mycophenolate mofetil was successfully used in a patient with RE.

A Case Series of Adult-Onset Rasmussen's Encephalitis: Diagnostic and Therapeutic Challenges

Rasmussen’s encephalitis (RE) is a rare neurologic disorder characterized by progressive cerebral hemiatrophy and medically refractory epilepsy. The majority of current literature on this topic is focused on the pediatric population. In this case series, we will review three cases of adult-onset RE, as defined by fulfillment of the 2005 Bien criteria. The diagnostic challenge of characterizing this rare disease will be highlighted by the extensive serum, CSF, and pathologic sampling in all three patients. MR imaging and EEG data will be examined over time to characterize hallmark findings as well as progression. In addition, we will review the various forms of therapy attempted in these three patients, namely anti-epileptic drug therapy and immunomodulatory therapy. We will also utilize this case series to critically evaluate the broader context of atypical presentations of this disease and the value of current diagnostic criteria.