Symptomatic palatal myoclonus as a rare manifestation of neuro-behcet́s disease: A case report

Palatal myoclonus (PM), also known as palatal tremor (PT) (Caviness, 2019), is a rare disorder of rhythmic soft palate contractions, sometimes producing audible clicks. It occurs as essential palatal tremor (EPT) or symptomatic palatal tremor (SPT), the latter usually linked to lesions in the dentato-rubro-olivary pathway (Guillain–Mollaret triangle) (Deuschl et al., 1994).

Behçet’s disease (BD) is a chronic, relapsing, multisystem inflammatory disorder that may involve the CNS as Neuro-Behçet’s disease (NBD) typically presenting as meningoencephalitis with brainstem predilection (Akman-Demir et al., 1999, Kidd, 2017).

Movement disorders in NBD are uncommon; palatal tremor is exceptionally rare.

A 30-year-old man reported recurrent abdominal pain and diarrhea for seven years, later developing polyarticular pain, oral/genital aphthae, and sensory disturbances. He experienced bilateral acoustic clicks, more pronounced on the right, and rhythmic palatal movements at 2–3 Hz (Video 1). Speech and swallowing were intact. Neurological exam confirmed palatal myoclonus without other brainstem signs.

MRI showed no lesions or olivary hypertrophy. EMG demonstrated asynchronous contractions of the right palatopharyngeal muscle (Fig. 1); EEG was normal. Whole-exome sequencing revealed no pathogenic variants. The patient met BD diagnostic criteria; HLA-B51 was negative. Treatment with colchicine, corticosteroids, and azathioprine improved systemic symptoms, but palatal tremor persisted.

Fig. 1.

Bilateral palatopharyngeal electromyography. The palatopharyngeus muscles exhibited increased insertional activity and asynchronous involuntary motor activity. The right palatopharyngeus muscle at rest displayed brief bursts characteristic of positive myoclonus. No other abnormalities were observed.

Palatal tremor (PT) is a rare movement disorder characterized by rhythmic contractions of the soft palate, classified as either essential (EPT) or symptomatic (SPT), with the latter typically resulting from structural lesions within the dentato-rubro-olivary pathway (Caviness, 2019, Deuschl et al., 1994). Common etiologies of SPT include ischemic, demyelinating, neoplastic, traumatic, infectious, and inflammatory processes affecting the brainstem (Bhattacharjee, 2020). Although Behçet’s disease (BD) primarily involves mucocutaneous and vascular systems, it may rarely affect the central nervous system as Neuro-Behçet’s disease (NBD) (Akman-Demir et al., 1999, Kidd, 2017), which can present atypically with movement disorders.

In this case, despite normal MRI and EEG, clinical features and partial response to immunosuppression support NBD-related brainstem involvement. Persistent tremor may reflect irreversible damage or subclinical inflammation.

Despite an unremarkable brain MRI and EEG, other movement disorders or epileptic phenomena were excluded. Additionally, the constellation of clinical findings and the partial response to immunosuppressive therapy—along with the persistence of palatal tremor—suggest underlying inflammatory involvement of the brainstem or a probable irreversible brainstem injury. However, this interpretation must be made cautiously due to the absence of confirmatory imaging findings. This case highlights the importance of considering neuro-Behçet’s disease (NBD) in patients presenting with atypical movement disorders and systemic inflammatory features, even in the absence of abnormalities on conventional neuroimaging.

This case report has limitations: Lack of confirmatory neuroimaging: No structural abnormalities were detected on MRI, which limits the ability to correlate symptoms with anatomical lesions. Incomplete exclusion of alternative diagnoses: Although genetic testing and clinical evaluation were performed, other rare causes of palatal tremor may not have been fully ruled out. This a single case report, so findings may not be generalizable and should be interpreted within the context of broader clinical evidence.

This study was reviewed and approved by Fundación Valle del Lilís Institutional Review Board. The patient provided informed consent to participate in this report, and consented to the publishing of all images, clinical data, and other data included in the manuscript. The patient has provided written informed consent for the publication of this case report and any accompanying images.The data associated with the study has not been deposited into a publicly available repository. The authors do not have permission to share data.

Declaration of generative AI and AI-assisted technologies in the writing process

During the preparation of this work the author(s) used ChatGPT to translate and improve the readability and language of the manuscript. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the publication.

Author contribution

AHJ, PH and OJL made substantial contributions to the conception and design of the work and interpretation of data. QPV and CE contributed to the acquisition and interpretation of data for the work and writing of the manuscript. QPV and SABI contributed to the interpretation of the data, writing process, review, and edition of the manuscript. All authors contributed to the article and approved the submitted version.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplementary data

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