Faciobrachial dystonic seizure-like events in a patient with subacute sclerosing panencephalitis

Vikram V Holla; Sudhakar Pushpa Chaithra; Shweta Prasad; Nitish Kamble; Pramod Kumar Pal; Ravi Yadav

doi:10.4103/AOMD.AOMD_41_21

CASE REPORT

Year : 2022 | Volume : 5 | Issue : 2 | Page : 121-124

Faciobrachial dystonic seizure-like events in a patient with subacute sclerosing panencephalitis

Vikram V Holla¹, Sudhakar Pushpa Chaithra¹, Shweta Prasad², Nitish Kamble¹, Pramod Kumar Pal¹, Ravi Yadav¹
¹ Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
² Clinical Neurosciences and Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India

Date of Submission	27-Aug-2021
Date of Decision	24-Nov-2021
Date of Acceptance	31-Dec-2021
Date of Web Publication	04-Jul-2022

Correspondence Address:
Dr. Ravi Yadav
Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru - 560029, Karnataka
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/AOMD.AOMD_41_21

Abstract

Faciobrachial dystonic seizure is a distinctive phenomenology that is considered pathognomonic of leucine-rich glioma-inactivated protein 1 (LGI1) antibody-associated autoimmune limbic encephalitis. However, similar phenomenology has been described with other neurological disorders as well. Here, we report the case of a 26-year-old man with subacute sclerosing panencephalitis who presented with multiple episodes of involuntary movements resembling faciobrachial dystonic seizure. Serum and cerebrospinal fluid autoimmune encephalitis panel, including leucine-rich glioma-inactivated protein 1 antibody, were negative. Classical periodic stereotypical slow wave discharges on the electroencephalogram and raised measles antibody titre in cerebrospinal fluid confirmed the diagnosis of subacute sclerosing panencephalitis.

Keywords: Faciobrachial dystonic seizure, leucine-rich glioma-inactivated protein 1, myoclonus, subacute sclerosing panencephalitis

How to cite this article:
Holla VV, Chaithra SP, Prasad S, Kamble N, Pal PK, Yadav R. Faciobrachial dystonic seizure-like events in a patient with subacute sclerosing panencephalitis. Ann Mov Disord 2022;5:121-4

How to cite this URL:
Holla VV, Chaithra SP, Prasad S, Kamble N, Pal PK, Yadav R. Faciobrachial dystonic seizure-like events in a patient with subacute sclerosing panencephalitis. Ann Mov Disord [serial online] 2022 [cited 2023 May 29];5:121-4. Available from: https://www.aomd.in/text.asp?2022/5/2/0/349812

Introduction

Faciobrachial dystonic seizure (FBDS) is a distinctive phenomenology that is considered pathognomonic of leucine-rich glioma-inactivated 1 (LGI1) antibody-associated autoimmune limbic encephalitis.^[1] It often precedes the onset of limbic encephalitis and is typically brief, frequent, and patterned, often with unilateral dystonic jerky movements involving the arm and ipsilateral face, and occasionally, the leg.^[1],[2],[3] However, similar phenomenology has been described with other neurological disorders; the sudden jerky movements can sometimes be mistaken for myoclonus.^{[2],[4],[5],[6],[7]} In this study, we report the case of a 26-year-old man with subacute sclerosing panencephalitis (SSPE) who presented with multiple episodes of involuntary movements resembling FBDS.

Case report

A 26-year-old man presented with a 3-year history of brief episodes of jerks in the left upper limb, ipsilateral face, and 2 years later in the ipsilateral leg. Each episode lasted for 2–3 seconds. Initially, there were only few episodes in a day, which progressed to two or three episodes per minute at the time of presentation. There were no jerks on the contralateral side, and he had no history of generalized convulsion. The patient used to briefly drag his left leg while walking during the episodes with no falls. In addition, he experienced transient and mild impaired awareness only during the episodes and would immediately regain awareness following the episode. There were no apparent precipitating factors. However, the episodes subsided during sleep. Poor scholastic performance was noted in the past 6 months. He was not immunized since birth. There were no other remarkable past or family history. Ethical approval for this study was waived by the institute’s ethics committee, owing to the retrospective nature of the study. Written informed consent was obtained before recording the video.

On examination, there were regular transient, brief episodes of posturing, predominantly involving the left half of the face and upper and lower limbs, lasting 1–2 seconds and recurring every 15–20 seconds [Video 1, Segments 1–3 [Additional file 1]]. There was elevation of the left upper limb and dragging of the left foot while walking, during the episodes without fall [Video 1, Segment 4]. The patient had mild cognitive impairment. His remaining neurological and other examinations were normal.

The phenomenology of the events raised the possibility of either FBDS, typically observed in LGI1 encephalitis, or slow myoclonus of SSPE. Blood investigations and magnetic resonance imaging (MRI) of the brain were normal. In addition, antibody panel for paraneoplastic and autoimmune encephalitis, including LGI1, was negative. Cerebrospinal fluid (CSF) analysis revealed raised protein (72 mg/dl), nil cells, and raised antimeasles IgG antibody titre (1:625). Electroencephalogram (EEG) revealed characteristic jerk-locked, bilaterally synchronous, symmetrical, high-voltage bursts of polyphasic, and stereotyped delta waves that recurred approximately every 15 seconds [Figure 1]. A diagnosis of SSPE was made based on the CSF and EEG findings. The patient was treated with intrathecal interferon alfa-2b and an antiepileptic, with no further worsening at the 6-month follow-up.

Figure 1: EEG of the patient
(A) EEG (double banana longitudinal bipolar montage; page speed, 20 second/page; sensitivity, 50 μV/mm) showing normal background of posterior dominant alpha activity with jerk-locked bilaterally synchronous; symmetrical; and high-voltage bursts of polyphasic, stereotyped delta waves recurring approximately every 15 seconds. (B) EEG tracing with page speed decreased to 1 minute/page, with other settings unchanged to show the periodicity of the complexes. Four complexes are observed in 1-minute trace

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Discussion

We report the case of 26-year-old man who presented with an FBDS-like phenomenology, but investigations revealed a diagnosis of SSPE. FBDS is a pathognomonic finding observed in patients with LGI1 encephalitis. The movements are described as dystonic and jerky and may sometimes mimic a myoclonus. They are brief (3–10 seconds) but occur frequently multiple times a day and are often unilateral but can be bilateral, in which case they are usually asynchronous and almost always involve the arms along with the ipsilateral face in most patients but may affect the legs in some [Video 2 [Additional file 2]]. Transient impairment of awareness is common and is often triggered by heightened emotions, sudden movements, and loud noises. Most patients report a brief tingling sensory aura before and during the episodes. These episodes are not generalized and are often refractory to antiepileptics but responsive to immunotherapy.^[1],[4]

The nature and origin of FBDS have been long debated and supposedly lie in the borderland between epilepsy and movement disorders.^[3] Extremely short duration, alternating pattern, facial involvement, poor response to antiepileptic medication, and basal ganglia signal changes on MRI and hypermetabolism on positron emission tomography support a paroxysmal movement disorder character. However, stereotyped appearance, concomitant impaired awareness, and cortical electrophysiological findings immediately before and during the episode identified by jerk-locked back averaging techniques and accurate electroencephalogram analysis suggest an epileptic nature and cortical origin. However, routine EEG is often normal.

In the present case, the brief, frequent, unilateral, and patterned posturing predominantly involving the face with transient impaired awareness suggested the possibility of FBDS. However, the duration of the episodes were short (1–2 seconds vs >3 seconds in typical FBDS), with periodic and slow myoclonus rather than frank dystonic and jerky movements with no apparent triggers. Our case had characteristic jerk-locked complexes with raised antimeasles antibody titre in CSF, suggesting the possibility of SSPE. Although the slow myoclonus in SSPE is often generalized, it can begin unilaterally and be confused with FBDS.^[7] Moreover, SSPE usually affects the pediatric age group, whereas LGI1 encephalitis often affects adults and the elderly, with a few exceptions.

In addition, phenomenology mimicking FBDS can be observed in other disorders ([Table 1]). The jerky nature of FBDS can be confused with myoclonus, and in the background of rapidly progressive cognitive decline, it can lead to an erroneous diagnosis of Creutzfeldt–Jakob disease.^[6] However the classical myoclonus in Creutzfeldt–Jakob disease is often multifocal, asynchronous, and briefer than FBDS; in addition, it has a typical EEG finding of periodic sharp-wave discharges and classic MRI findings. Furthermore, dystonia-like seizures observed in certain types of insular epilepsies can mimic FBDS and have been reported in N-methyl-d-aspartate encephalitis.^[2],[4] However, strictly unilateral, prolonged dystonia (30–60 seconds), without loss of awareness but with hypersalivation and an ictal EEG correlate, should raise suspicion of insular epilepsy. In addition, hyponatremia and cognitive impairment are unusual. MRI may show an insular lesion and LGI1 serology is expected to be negative. In addition. FBDS has been reported in a patient with cerebral amyloid angiopathy who had negative LGI1 serology both in serum and CSF.^[5]

Table 1: Features differentiating faciobrachial dystonic seizures associated with LGI1 encephalitis from other movements

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In conclusion, although FBDS is considered pathognomonic of LGI1 encephalitis, phenomenology similar to it is rarely observed in other diseases such as SSPE. High clinical suspicion, careful analysis of the phenomenology, and appropriate investigations will help in avoiding an erroneous diagnosis.

Acknowledgement

None

Author contribution

Vikram V Holla contributed in acquisition and interpretation of the data and in writing the first draft of the manuscript. Sudhakar Pushpa Chaithra, Shweta Prasad, Nitish Kamble, Pramod Kumar Pal and Ravi Yadav contributed in interpretation of data and in review and critique of the manuscript.

Ethical compliance statement

Ethical approval for this study was waived by the Institute ethics committee owing to the retrospective nature of the study. Written informed consent of the patient was obtained for the video recording and for online publication and dissemination.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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