Rasmussen syndrome: an atypical presentation in ten patients

CNS autoimmune response in the MAM/pilocarpine rat model of epileptogenic cortical malformation

The development of seizures in epilepsy syndromes associated with malformations of cortical development (MCDs) has traditionally been attributed to intrinsic cortical alterations resulting from abnormal network excitability. However, recent analyses at single-cell resolution of human brain samples from MCD patients have indicated the possible involvement of adaptive immunity in the pathogenesis of these disorders. By exploiting the MethylAzoxyMethanol (MAM)/pilocarpine (MP) rat model of drug-resistant epilepsy associated with MCD, we show here that the occurrence of status epilepticus and subsequent spontaneous recurrent seizures in the malformed, but not in the normal brain, are associated with the outbreak of a destructive autoimmune response with encephalitis-like features, involving components of both cell-mediated and humoral immune responses. The MP brain is characterized by blood-brain barrier dysfunction, marked and persisting CD8+ T cell invasion of the brain parenchyma, meningeal B cell accumulation, and complement-dependent cytotoxicity mediated by antineuronal antibodies. Furthermore, the therapeutic treatment of MP rats with the immunomodulatory drug fingolimod promotes both antiepileptogenic and neuroprotective effects. Collectively, these data show that the MP rat could serve as a translational model of epileptogenic cortical malformations associated with a central nervous system autoimmune response. This work indicates that a preexisting brain maldevelopment predisposes to a secondary autoimmune response, which acts as a precipitating factor for epilepsy and suggests immune intervention as a therapeutic option to be further explored in epileptic syndromes associated with MCDs.

Cerebral hemiatrophy and hemiparesis following hemiclonic status epilepticus in Dravet syndrome

Dravet syndrome is currently considered as an developmental and epileptic encephalopathy and, recently, mandatory, alert, and exclusionary criteria have been proposed. Here, we describe three patients with Dravet syndrome with the typical early presentation including febrile and afebrile alternating hemiclonic seizures due to loss-of-function SCN1A variants. Subsequently, they developed episodes of febrile focal status epilepticus (SE) associated with hemiparesis and cerebral hemiatrophy with posterior focal seizures, as a consequence of Dravet syndrome. This sequence of events has been previously published in patients with Dravet syndrome and does not contradict the recent classification by the International League Against Epilepsy (ILAE). The ILAE guidance identifies "Focal neurological findings" as alert criteria and "MRI showing a causal focal lesion" as exclusionary criteria for making an initial diagnosis of Dravet syndrome at presentation. Our three patients would correspond to a severe phenotype, similar to the well-known presentation of generalized atrophy following prolonged status epilepticus. Common genetic findings in cases of diffuse and unilateral brain involvement may help explain these clinical presentations. Further genotype-phenotype studies may provide additional insights into this electroclinical behavior.

Bilateral Rasmussen Encephalitis: Good Outcome Following Hemispherotomy

BACKGROUND

Bilateral Rasmussen encephalitis is a rare variant of a debilitating, typically unihemispheric disease with limited treatment options. Few cases with bilateral histopathology have been reported, all with poor seizure control following surgery. Here we report a favorable outcome following hemispherotomy in a four-year-old male with biopsy-confirmed bilateral disease.

CASE

The patient presented with right hemispheric focal seizures with behavioral arrest and over a year progressed to left lower extremity clonic seizures, epilepsia partialis continua, and loss of ambulation, with transient response to steroids and tacrolimus. Histopathology confirmed bilateral disease. The patient developed super-refractory status epilepticus and underwent right functional hemispherotomy 4.5 years after initial presentation. In a 2.5-year follow-up period, an Engel 1D outcome classification was observed with substantially improved quality of life.

CONCLUSION

Previous reports of bilateral Rasmussen encephalitis describe universally poor outcomes, and hemispherotomy is often considered contraindicated. However, hemispherotomy in a patient with bilateral Rasmussen encephalitis may have a good outcome if seizures are unihemispheric.

Atypical Rasmussen's Encephalitis

A three-year-old female patient was admitted to our institution due to subacute fever, intermittent vomiting, persistent bilateral mydriasis after cycloplegia, right central facial palsy, and mild right hemiparesis with hyperreflexia. Brain MRI shows encephalitis in frontal, parietal, insular, and left putamen course and loss of cortical volume and white matter of the entire left hemisphere which are features described in Rasmussen's encephalitis (RE). Therapy with intravenous methylprednisolone bolus was initiated, with adequate clinical response. We consider in this case the diagnosis of atypical RE by imaging criteria in the subacute stage. There are few reports of atypical RE without epilepsy or continuous partial epilepsy. Our purpose is to present a case of a patient with RE images without epilepsy seizures and review the diagnostic and therapeutic approach of RE.

A case of focal cortical dysplasia type IIa with pathologically suspected bilateral Rasmussen syndrome

BACKGROUND

Rasmussen syndrome (RS) is a rare neurological disorder characterized by unilateral chronic inflammation, drug-resistant epilepsy, and progressive neurological and cognitive deterioration. There has been no detailed pathological evaluation or finding, including focal cortical dysplasia, for bilateral RS.

CASE REPORT

A 13-year-old boy presented with status epilepticus with focal to bilateral tonic clonic seizure starting from the left upper limb. At the age of 15, epilepsia partialis continua of the right face and upper extremities appeared, and MRI showed hemispheric abnormal signal intensities with left frontal lobe predominance. Three months later, MRI showed extensive abnormal signal intensities in the right occipitoparietal and left temporal lobes. Tacrolimus was useful in preventing recurrence. Because the seizures were intractable, a corpus callosotomy was performed at 16 years along with a concurrent brain biopsy from the bilateral lateral frontal cortices. We detected dysmorphic neurons in addition to inflammatory changes suspicious for RS, leading to a diagnosis of focal cortical dysplasia (FCD) type Ⅱa and suspected bilateral RS. Total callosotomy and vagus nerve stimulation were not sufficiently effective.

CONCLUSIONS

In bilateral RS, FCD may be present in both cerebral hemispheres. In the current case, an autoimmune response to dysmorphic neurons may have contributed to the pathogenesis of intense inflammation.

Atypical Presentation of Cerebral Palsy and Seizures: A Case Report on Rasmussen's Encephalitis in an Adolescent

Rasmussen's encephalitis is a rare neurological disease first described in 1958 that is characterized by medico-refractory seizures, focal unilateral cerebral inflammation, and deficits such as hemiparesis. While we still do not have a full understanding of this disease, proposed theories behind its etiology include auto-immune manifestations, immune attack by T cells, and malfunctional alterations in genetic expression. It is classically considered a rare childhood malady with a median age of onset of six years, and cases in adolescents and adults are even rarer, representing up to 10% of all cases to date. In this report, we would like to share a rare case of Rasmussen's encephalitis that occurred in an adolescent. Our 17-year-old male patient presented with signs and symptoms beginning at age 14 and was initially diagnosed with cerebral palsy only to later present with additional symptoms and characteristic EEG and MRI findings that ultimately led to a diagnosis of Rasmussen's encephalitis. Thus, with this case report, our intent is twofold: to shed light on an atypical presentation of an already rare disease, even rarer in adolescents and adults, and to underscore the importance of keeping a broad differential when it comes to evaluating a patient with seizures.