Bulbar and Limb Myorhythmia with “Smooch Sign”: A Distinctive Movement Disorder in an Adult Patient with Reversible Anti-NMDA Receptor Encephalitis Associated with an Ovarian Teratoma

Ghosh

Journal of Neuroimmunology

et al. 2020

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is one of the most common causes of autoimmune encephalitis. Both movement disorders and neuropsychiatric manifestations are considered core features of anti-NMDAR encephalitis. Strong clinical suspicion, along with NMDAR antibody positivity in paired sample of serum and cerebrospinal fluid, with supportive MRI changes clinch diagnosis in majority. We herein report a case of a middle-aged woman with subacute behavioral abnormalities, which were so severe that forced her to attempt suicide. Hemichorea and dystonia, which appeared later in course, are not previously reported movement disorders in combination in anti-NMDAR encephalitis. Further, magnetic resonance imaging showed bilateral thalamic hyperintensities with diffusion restriction, which are in turn not described in this entity. After amalgamation of history, especially the presence of neuropsychiatric symptoms, clinical features, physical examination, and investigations, the diagnosis of anti-NMDAR encephalitis could be established. Our case not only highlights that the combination of hemichorea and dystonia can be features of anti-NMDAR encephalitis, but adds novelty by bilateral symmetric thalamic changes.

Section: Discussionmentioning

confidence: 99%

Bilateral thalamic changes in anti-NMDAR encephalitis presenting with hemichorea and dystonia and acute transient psychotic disorder

Ghosh

Journal of Neuroimmunology

et al. 2020

“…The most common cause of myorhythmia is brainstem 3 and thalamic strokes, but it can also be found in patients with autoimmune 4 , 5 and demyelinating disorders, drug or toxin intake, trauma, Listeria rhombencephalitis 6 and Whipple disease where it commonly manifests with oculomasticatory rather than limb myorhythmia. 7 Case reports have also described myorhythmia associated with COVID-19 Acute Hemorrhagic Necrotizing Encephalopathy, 8 brain tumors (i.e.…”

Section: Discussionmentioning

confidence: 99%

Limb myorhythmia treated with chemodenervation: a case report

Saez-Calveras

Bryarly

Salinas

2023

Ther Adv Neurol Disord

We describe a case of limb myorhythmia successfully palliated with botulinum toxin injections. The patient is a 30-year-old male evaluated for abnormal movements of the left lower foot that began after an ankle injury for which the patient underwent Achilles tendon scar tissue debridement without improvement. On examination, he had near-constant involuntary, slow, rhythmic flexion/extension tremor of toes 2–4 that was diminished during active movement. Needle electromyography (EMG) revealed a rhythmic, 2–3 Hz tremor isolated to the flexor digitorum brevis. After failure of medical management with muscle relaxants, gabapentin, and levodopa trials, the patient underwent two EMG-guided chemodenervation procedures with incobotulinum toxin A injections of the left flexor digitorum brevis. At 3-month follow-up, he had achieved a sustained 50% reduction in the intensity of the movements and improved quality of life. Myorhythmia is a rare condition characterized by a repetitive, rhythmic, slow frequency (1–4 Hz) movement affecting the cranial and limb muscles. The most common causes include stroke, demyelinating disorders, drug or toxin intake, trauma, and infections. The management of this condition is very limited with pharmacologic agents such as anticholinergics, antispasmodics, anticonvulsants, or dopaminergic agents showing limited efficacy. The use of botulinum toxin chemodenervation aided by EMG muscle targeting can be a useful therapeutic intervention in cases of medication-refractory regionally distributed myorhythmia involving accessible muscles.

“…It has been frequently reported as oculo-masticatory myorhythmia in the context of Whipple's disease, caused by the infection of the central nervous system by Trophyrema whipplei ( 140 ). Other conditions where myorhythmia has been reported are stroke ( 139 ), anti-NMDA encephalitis ( 141 , 142 ), anti-IgLON5 disease ( 143 ), interferon alpha-2a use ( 144 ), Hashimoto encephalopathy ( 145 ), and X-linked dystonia-parkinsonism ( 146 ). As myorhythmia is often associated with conditions that are potentially treatable, it is important to be familiar with this phenomenology and its differential diagnoses.…”

Section: Tremor In the Setting Additional Neurological Featuresmentioning

confidence: 99%

Tremor Syndromes: An Updated Review

Lenka

Jankovic

2021

Front. Neurol.

Tremor is the most commonly encountered movement disorder in clinical practice. A wide range of pathologies may manifest with tremor either as a presenting or predominant symptom. Considering the marked etiological and phenomenological heterogeneity, it would be desirable to develop a classification of tremors that reflects their underlying pathophysiology. The tremor task force of the International Parkinson Disease and Movement Disorders Society has worked toward this goal and proposed a new classification system. This system has remained a prime topic of scientific communications on tremor in recent times. The new classification is based on two axes: 1. based on the clinical features, history, and tremor characteristics and 2. based on the etiology of tremor. In this article, we discuss the key aspects of the new classification, review various tremor syndromes, highlight some of the controversies in the field of tremor, and share the potential future perspectives.