Background

Acute movement disorders are infrequent manifestations of central nervous system demyelination. Our purpose is to highlight an extremely unusual relapse presentation in an MS patient with highly active disease.

Objectives

Non-applicable......................................................................................

Methods

Non-applicable......................................................................................

Results

We present the case of a 26-year-old female patient, diagnosed with Relapsing-Remitting MS at age 16. She was initially non-compliant with disease-modifying therapies and clinical follow up, experiencing multiple relapses during an eight-year period. She resumed follow-up at our institution in 2018, following two episodes of cervical myelitis without clinical motor involvement. Her neurological examination was noticeable for vertical non-fatigable nystagmus, asymmetric left-predominant hyperreflexia, and truncal ataxia. Re-baseline MRI performed in 2019 revealed multiple T2 lesions involving infratentorial, spinal cord, juxtacortical, and periventricular regions, none of which showed gadolinium enhancement. She was started on dimethyl fumarate 240mg bid in March 2020 with adherence.

The patient consulted our MS outpatient clinic in May 2020, because of a 4-day history of continuous involuntary wavelike movements localized to the right side of her face. The patient’s spouse reported that the movements were unremitting during sleep. A video recording of this manifestation was obtained. Neurological examination at this time revealed continuous right-sided facial myokymia, more prominent around the orbicular and peri-labial muscles, not influenced by voluntary activity. There was no concurrent hemifacial spasm. Brain MRI documented a new hyperintense T2/FLAIR non-enhancing lesion in the pontine tegmentum, adjacent to the traject of the facial nerve and multiple gadolinium-enhancing lesions in the supratentorial compartment. The patient was offered intravenous methylprednisolone treatment but denied. She subsequently experienced full recovery within 3 weeks, with no abnormal facial movements detected at clinical reevaluation one-month later.

Conclusions

We described the case of an MS patient with a highly active disease course, presenting with continuous hemifacial wavelike movements related to a pontine demyelinating lesion. Although infrequent, strictly unilateral facial myokymia is a possible presentation of infratentorial MS relapse.