Rasmussen's Encephalitis with Faciobrachial Dystonic Attacks and Bilateral Hemispheric Involvement.

To the Editor: Rasmussen's encephalitis (RE) is a rare but devastating unihemispheric brain disorder, usually affecting children and characterized by intractable seizures and progressive neurological deficits.[1] Characteristic magnetic resonance imaging (MRI) finding of RE is progressive unihemispheric focal cortical atrophy. Bilateral RE is very uncommon. Here, we report an RE patient with faciobrachial dystonic attacks and bilateral brain atrophy but without seizures.

A 15-year-old boy presented with progressive left hemiparesis at Department of Neurology, Peking Union Medical College Hospital in November 2013, which appeared at the age of 13. One and a half years ago, the patient suffered from left arm weakness. Half a year later, he had weakness of left leg and slurred speech. The symptoms progressed gradually. Cerebrospinal fluid (CSF) tests were normal. Fifteen months after onset, a 24-h electroencephalography (EEG) was unremarkable, and brain MRI showed atrophy in the right insular cortex, caudate, putamen, and cerebral crus with high signals in the corona radiata on T2-weighted and fluid-attenuated inversion recovery images. Physical examination found dysphasia. Muscle tone in the left limbs was high, and strength was 4/5. Ankle clonus and Babinski sign were positive in the left side. Blood tests showed normal leukocyte and platelet counts. Liver and renal function and erythrosedimentation were normal. Anti-neuronal antibodies and antibodies for herpes simplex virus, rubella virus, Cytomegalovirus, toxoplasma, and Epstein–Barr virus were negative. Repeated CSF analysis was normal. Voltage-gated potassium channel complexes (VGKCs) including leucine-rich glioma inactivated-1 (LgI1) antibodies in serum and CSF were negative. In November 2013, MRI showed atrophy in the right hemisphere without contrast enhancement [Figure 1a]. Repeated EEG showed less sleep spindles and vertex sharp waves on right hemisphere without epileptiform potentials or persistent delta activity [Figure 1c and 1d]. Brain biopsy was recommended. Histological examinations revealed focal chronic inflammatory changes characterized by predominantly CD3+ T-cells scattered in the parenchyma and clustered around small blood vessels with microglial activation. According to the diagnostic criteria in the 2005 European Consensus Statement,[1] RE was diagnosed, and intravenous immunoglobulins and methylprednisolone were recommended, but the patient and his family refused due to economic reasons.

Figure 1

(a) Axial fluid-attenuated inversion recovery images at 18 months after onset showed atrophy in the right caudate and putamen, high signals in the white matter. (b) Axial fluid-attenuated inversion recovery at 32 months after onset demonstrated the progression of atrophy in the right caudate and putamen, progressive gliosis of the white matter. (c and d) Electroencephalography at 18 months after onset showed less and lower amplitude K-complex and sleep spindles on right hemisphere during sleep.

During the follow-up, the patient's neurological deficits progressed, and he developed faciobrachial dystonic attacks 2 years later, which demonstrated as paroxysmal unilateral involuntary movements of the left arm and face, lasting about 5 min and occurring several times a day. He did not lose consciousness or drop during the attacks. In December 2014, repeated MRI demonstrated progressive right hemispheric atrophy, enlargement of bilateral frontal horn, and atrophy in the left insular, perisylvian cortex, and caudate [Figure 1b]. His neurological function declined during the initial 34 months. He had aphasia and spastic quadriplegia. Frequency of faciobrachial dystonic attacks increased to dozens of time. After that period, the patient passed into a stage with a stable neurological deficit. Since both imaging features and focal deficits implicated bilateral hemispheric involvement, he was diagnosed bilateral RE.

There is debate about whether faciobrachial dystonic attacks were movement disorder or seizures.[2] Faciobrachial dystonic attacks were often seen in limbic encephalitis associated with positive VGKC/LgI1 antibodies.[3] In this case, the attacks were more likely movement disorder rather than seizures. No loss of consciousness or drop occurred during the attacks, and ictal EEG showed no epileptiform changes. The duration of the attacks lasted about 5 min, which was much more suggestive of hemidystonia, while faciobrachial dystonic seizures are very brief, usually lasting < 3 s.[4] Another feature of this case was that the neuroimaging showed predominant basal ganglia involvement with putaminal and caudate atrophy, which could explain the extrapyramidal manifestations such as dystonia and dysphasia. The faciobrachial dystonic attacks of the right arm and face might be associated with the prominent atrophy of the head of left caudate nucleus.

This case demonstrated that the manifestation of epilepsy can be timely dissociated from the inflammatory and degenerative features of RE,[5] confirming that seizures are not an obligatory presenting symptom of RE. Epilepsy might be relatively rare in RE presented with dystonia.

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