Pallidal deep brain stimulation for patients with myoclonus-dystonia without SGCE mutations.

BACKGROUND: Pallidal deep brain stimulation (GPi-DBS) is effective for treating myoclonus and dystonia caused by SGCE mutations (DYT-SGCE, DYT11). However, it is unknown whether GPi-DBS is effective for the treatment of myoclonus-dystonia which is not associated with the SGCE gene mutations. In this study, we investigated the efficacy of GPi-DBS in treating myoclonus-dystonia in SGCE mutation-negative cases. METHODS: Three patients with myoclonus-dystonia without SGCE mutations who underwent GPi-DBS were evaluated preoperatively and 6 months postoperatively using the Unified Myoclonus Rating Scale (UMRS) and Fahn-Marsden Dystonia Rating Scale (FMDRS) for myoclonus and dystonia, respectively. In two of the three patients, myoclonus was more evident during action. Myoclonus was predominant at rest in the other patient, and he was unaware of his dystonia symptoms. The results were compared with those of the four DYT-SGCE cases. RESULTS: The mean UMRS score in patients with myoclonus-dystonia without SGCE mutations improved from 61.7 to 33.7 pre- and postoperatively, respectively, and the mean FMDRS score improved from 7.2 to 4.5. However, the degree of improvement in myoclonus-dystonia in patients without SGCE mutations was inferior to that in patients with DYT-SGCE (the UMRS score improved by 45% and 69%, respectively). CONCLUSIONS: GPi-DBS is effective for treating myoclonus-dystonia in patients with and without SGCE mutations. GPi-DBS should be considered as a treatment option for myoclonus-dystonia without SGCE mutations.

Knee Buckling as an Atypical Adverse Effect of Clozapine: A Case Report.

Clozapine has become a widely popular and effective medication in the treatment of refractory schizophrenia and refractory bipolar disorder. Although the use of clozapine proves to be an effective resort, it has to be closely monitored due to its narrow therapeutic range and multiple dangerous adverse effects. In rare cases, clozapine has been known to cause an antagonistic myoclonic jerk that leads to knee buckling. Here, we present the case of a 29-year-old female who is being treated for schizoaffective disorder, bipolar, manic type, who reported two instances of knee buckling associated with falls while taking clozapine.

Diabetic striatopathy and other acute onset de novo movement disorders in hyperglycemia.

BACKGROUND AND AIMS: Acute onset de novo movement disorder is an increasingly recognized, yet undereported complication of diabetes. Hyperglycemia can give rise to a range of different movement disorders, hemichorea-hemiballism being the commonest. This article delves into the current knowledge about this condition, its diverse presentations, ongoing debates regarding its underlying mechanisms, disparities between clinical and radiological findings, and challenges related to its management. METHODS: PubMed and Google Scholar were searched with the following key terms- "diabetes", "striatopathy", "hyperglycemia", "striatum", "basal ganglia", "movement disorder", "involuntary movement". Case reports, systematic reviews, meta-analysis, and narrative reviews published in English literature related to the topic of interest from January 1, 1950, to October 20, 2023, were retrieved. The references cited in the chosen articles were also examined, and those considered relevant were included in the review. RESULTS: Diabetic striatopathy is the prototype of movement disorders associated with hyperglycemia with its characteristic neuroimaging feature (contralateral striatal hyperdensitity on computed tomography or hyperintensity on T1-weighted magnetic resonance imaging). Risk factors for diabetic striatopathy includes Asian ethnicity, female gender, prolonged poor glycemic control, and concurrent retinopathy. Several hypotheses have been proposed to explain the pathophysiology of movement disorders induced by hyperglycemia. These hypotheses are not mutually exclusive; instead, they represent interconnected pathways contributing to the development of this unique condition. While the most prominent clinical feature of diabetic striatopathy is a movement disorder, its phenotypic expression has been found to extend to other manifestations, including stroke, seizures, and cognitive and behavioral symptoms. Fortunately, the prognosis for diabetic striatopathy is generally excellent, with complete resolution achievable through the use of anti-hyperglycemic therapy alone or in combination with neuroleptic medications. CONCLUSION: Hyperglycemia is the commonest cause of acute onset de novo movement disorders presenting to a range of medical specialists. So, it is of utmost importance that the physicians irrespective of their speciality remain aware of this clinical entity and check blood glucose at presentation before ordering any other investigations. Prompt clinical diagnosis of this condition and implementation of intensive glycemic control can yield significant benefits for patients.

Association of abnormal explicit sense of agency with cerebellar impairment in myoclonus-dystonia.

Non-motor aspects in dystonia are now well recognized. The sense of agency, which refers to the experience of controlling one's own actions, has been scarcely studied in dystonia, even though its disturbances can contribute to movement disorders. Among various brain structures, the cerebral cortex, the cerebellum, and the basal ganglia are involved in shaping the sense of agency. In myoclonus dystonia, resulting from a dysfunction of the motor network, an altered sense of agency may contribute to the clinical phenotype of the condition. In this study, we compared the explicit and implicit sense of agency in patients with myoclonus dystonia caused by a pathogenic variant of SGCE (DYT-SGCE) and control participants. We utilized behavioural tasks to assess the sense of agency and performed neuroimaging analyses, including structural, resting-state functional connectivity, and dynamic causal modelling, to explore the relevant brain regions involved in the sense of agency. Additionally, we examined the relationship between behavioural performance, symptom severity, and neuroimaging findings. We compared 19 patients with DYT-SGCE and 24 healthy volunteers. Our findings revealed that patients with myoclonus-dystonia exhibited a specific impairment in explicit sense of agency, particularly when implicit motor learning was involved. However, their implicit sense of agency remained intact. These patients also displayed grey-matter abnormalities in the motor cerebellum, as well as increased functional connectivity between the cerebellum and pre-supplementary motor area. Dynamic causal modelling analysis further identified reduced inhibitory effects of the cerebellum on the pre-supplementary motor area, decreased excitatory effects of the pre-supplementary motor area on the cerebellum, and increased self-inhibition within the pre-supplementary motor area. Importantly, both cerebellar grey-matter alterations and functional connectivity abnormalities between the cerebellum and pre-supplementary motor area were found to correlate with explicit sense of agency impairment. Increased self-inhibition within the pre-supplementary motor area was associated with less severe myoclonus symptoms. These findings highlight the disruption of higher-level cognitive processes in patients with myoclonus-dystonia, further expanding the spectrum of neurological and psychiatric dysfunction already identified in this disorder.

Diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging in pediatric opsoclonus myoclonus ataxia syndrome presenting with neuroblastoma.

BACKGROUND: Early precision diagnosis and effective treatment of opsoclonus myoclonus ataxia syndrome (OMAS) patients presenting with neuroblastoma can prevent serious neurological outcomes. OBJECTIVE: To assess the diagnostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging in pediatric OMAS with neuroblastoma. MATERIALS AND METHODS: A retrospective evaluation of 45 patients diagnosed with OMAS who underwent 18F-FDG PET/CT was performed. A univariate analysis was performed to compare clinical characteristics between OMAS with and without neuroblastoma. Univariate and multivariate logistic regression analyses were applied to identify independent risk factors for OMAS with neuroblastoma and to develop the clinical model. Finally, independent risk factors and PET/CT were fitted to build the combined model for the diagnosis of OMAS with neuroblastoma and presented as a nomogram. Receiver operating characteristic curve, decision curve, and calibration curve analyses were conducted to evaluate the performance of the models. RESULTS: Among 45 patients, 27 were PET/CT-positive, 23/27 lesions were neuroblastoma, and four were false positives. One of the false positive patients was confirmed to be adrenal reactive hyperplasia by postoperative pathology, and the symptoms of OMAS disappeared in the remaining three cases during clinical follow-up. The average maximal standardized uptake value of PET/CT-positive lesions was 2.6. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT were 100%, 81.8%, 85.2%, 100%, and 91.1%, respectively. Age at diagnosis, lactate dehydrogenase, and neuron-specific enolase showed statistically significant differences between OMAS with and without neuroblastoma. Lactate dehydrogenase was identified as the independent risk factor to develop the clinical model, and the clinical model demonstrated an area under the curve (AUC) of 0.82 for the diagnosis of OMAS with neuroblastoma, with an AUC as high as 0.91 when combined with PET/CT. The decision curve analysis and calibration curve demonstrated that the nomogram had good consistency and clinical usefulness. CONCLUSION: In patients with OMAS, 18F-FDG PET/CT has a high diagnostic accuracy in detecting tumors of the neuroblastoma, especially when combined with the independent risk factor serum lactate dehydrogenase.

COVID 19 and myoclonus, do hemodialysis patients have more risk?

We discuss two recent cases from our hospital in which two patients with ESKD receiving periodical hemodialysis (HD) and SarS-Cov-2 infection suffered movement disorders, being the onset related to the HD sessions in both. First case is a 78 year-old woman who is admitted with generalized myoclonic status epilepticus and second case is a 46 year-old male who starts repeatedly suffering myoclonus during his hemodialysis sessions on day +10 after testing positive (asymptomatic infection). There are two main hypotheses when it comes to myoclonus and CNS disorders in COVID19, post-hypoxic origin and inmunomediated postinfectious origin. We wonder if they could both be interacting in patients with kidney disease, and especially in those who receive hemodialysis, maximizing the risk of suffering this type of disorders.

Myoclonus-Dystonia Plus Syndrome With Early-Onset Multiple Cerebral Cavernous Malformation Type 1 and Growth Hormone Deficiency Associated With Novel 7q21.13-q21.3 Deletion: A Pediatric Case Report.

Myoclonus-dystonia syndrome (MDS) presents with both rapid myoclonus and dystonia, which is caused by mutations in the sarcoglycan (SGCE) gene. However, its complications and management remain unclear. Here, we report a case involving a girl with MDS due to a 7q21.13-q21.3 microdeletion complicated by early-onset multiple cerebral cavernous malformations (CCMs). The patient presented with myoclonus and dystonia at two and eight years of age, respectively. In addition to MDS, the patient developed growth hormone (GH) deficiency and mild intellectual disability. Magnetic resonance imaging of the brain showed multiple CCMs. Array-based comparative genomic hybridization revealed 7q21.13-21.3 microdeletion. The deletion size was 4.11 Mb, which included SCGE and KRIT1. After the introduction of zonisamide, both myoclonus and dystonia showed improvement, and GH therapy led to an increase in patient height. In cases of MDS, multiple early-onset CCMs and GH deficiency may occur; moreover, careful follow-up management may be necessary.

Myoclonus and Dystonia as Recurrent Presenting Features in Patients with the SCA21-Associated TMEM240 p.Pro170Leu Variant.

Background: Spinocerebellar ataxia 21 (SCA21) is a rare neurological disorder caused by heterozygous variants in TMEM240. A growing, yet still limited number of reports suggested that hyperkinetic movements should be considered a defining component of the disease. Case Series: We describe two newly identified families harboring the recurrent pathogenic TMEM240 p.Pro170Leu variant. Both index patients and the mother of the first proband developed movement disorders, manifesting as myoclonic dystonia and action-induced dystonia without co-occurring ataxia in one case, and pancerebellar syndrome complicated by action-induced dystonia in the other. We reviewed the literature on TMEM240 variants linked to hyperkinetic disorders, comparing our cases to described phenotypes. Discussion: Adding to prior preliminary observations, our series highlights the relevance of hyperkinetic movements as clinically meaningful features of SCA21. TMEM240 mutation should be included in the differential diagnosis of myoclonic dystonia and ataxia-dystonia syndromes.

Irregular Tremulous Movements and Infrequent Seizures: A Clinical-Electrophysiological Diagnosis of Benign Adult Familial Myoclonus Epilepsy.

We report a case involving a 31-year-old male without any known precipitating injuries presenting with involuntary finger movements and rare seizures. There was a noted family history of tremulous movements. Yet the characteristics of his finger movements were irregular and not typical of essential tremor (ET). Electrophysiological examinations, including video EEG, showed no epileptic discharges, and brain MRI results were normal. However, somatosensory evoked potentials (SEP) revealed the presence of giant SEP, and a positive cortical (C)-reflex was observed, leading to a clinical diagnosis of benign adult familial myoclonus epilepsy (BAFME). Management with valproic acid and perampanel resulted in a significant reduction of symptoms. This case highlights the necessity of considering BAFME in the differential diagnosis for atypical tremorous finger movements, especially with a relevant family history, and the critical role of electrophysiological findings indicative of cortical hyperexcitability.

Paraneoplastic movement disorders.

Paraneoplastic movement disorders are diverse autoimmune neurological illnesses occurring in the context of systemic cancer, either in isolation or as part of a multifocal neurological disease. Movement phenomena may be ataxic, hypokinetic (parkinsonian), or hyperkinetic (myoclonus, chorea, or other dyskinetic disorders). Some disorders mimic neurodegenerative or hereditary illnesses. The subacute onset and coexisting nonclassic features of paraneoplastic disorders aid distinction. Paraneoplastic autoantibodies provide further information regarding differentiating cancer association, disease course, and treatment responses. A woman with cerebellar ataxia could have metabotropic glutamate receptor 1 autoimmunity, in the setting of Hodgkin lymphoma, a mild neurological phenotype and response to immunotherapy. A different woman, also with cerebellar ataxia, could have Purkinje cytoplasmic antibody type 1 (anti-Yo), accompanying ovarian adenocarcinoma, a rapidly progressive phenotype and persistent disabling deficits despite immune therapy. The list of antibody biomarkers is growing year-on-year, each with its own ideal specimen type for detection (serum or CSF), accompanying neurological manifestations, cancer association, treatment response, and prognosis. Therefore, a profile-based approach to screening both serum and CSF is recommended. Immune therapy trials are generally undertaken, and include one or more of corticosteroids, IVIg, plasma exchange, rituximab, or cyclophosphamide. Symptomatic therapies can also be employed for hyperkinetic disorders.

Overview of treatment strategies in paraneoplastic neurological syndromes.

Treatment strategies in paraneoplastic neurological syndromes rely on the three pillars of tumor treatment, immunotherapy, and symptomatic treatment, the first one being by far the most important in the majority of patients and syndromes. Classically, antibodies against extracellular antigens are directly pathogenic, and patients with these syndromes are more responsive to immunomodulatory or immunosuppressive treatments than the ones with antibodies against intracellular targets. This chapter first discusses some general principles of tumor treatment and immunotherapy, followed by a closer look at specific treatment options for different clinical syndromes, focusing on symptomatic treatments.

Paraneoplastic cerebellar and brainstem disorders.

Paraneoplastic cerebellar and brainstem disorders are a heterogeneous group that requires prompt recognition and treatment to help prevent irreversible neurologic injury. Paraneoplastic cerebellar degeneration is best characterized by Yo antibodies in patients with breast or ovarian cancer. Tr (DNER) antibodies in patients with Hodgkin lymphoma can also present with a pure cerebellar syndrome and is one of the few paraneoplastic syndromes found with hematological malignancy. Opsoclonus-myoclonus-ataxia syndrome presents in both pediatric and adult patients with characteristic clinical findings. Other paraneoplastic brainstem syndromes are associated with Ma2 and Hu antibodies, which can cause widespread neurologic dysfunction. The differential for these disorders is broad and also includes pharmacological side effects, infection or postinfectious processes, and neurodegenerative diseases. Although these immune-mediated disorders have been known for many years, mechanisms of pathogenesis are still unclear, and optimal treatment has not been established.

Flapping Tremor: Unraveling Asterixis-A Narrative Review.

Asterixis is a subtype of negative myoclonus characterized by brief, arrhythmic lapses of sustained posture due to involuntary pauses in muscle contraction. We performed a narrative review to characterize further asterixis regarding nomenclature, historical aspects, etiology, pathophysiology, classification, diagnosis, and treatment. Asterixis has been classically used as a synonym for negative myoclonus across the literature and in previous articles. However, it is important to distinguish asterixis from other subtypes of negative myoclonus, for example, epileptic negative myoclonus, because management could change. Asterixis is not specific to any pathophysiological process, but it is more commonly reported in hepatic encephalopathy, renal and respiratory failure, cerebrovascular diseases, as well as associated with drugs that could potentially lead to hyperammonemia, such as valproic acid, carbamazepine, and phenytoin. Asterixis is usually asymptomatic and not spontaneously reported by patients. This highlights the importance of actively searching for this sign in the physical exam of encephalopathic patients because it could indicate an underlying toxic or metabolic cause. Asterixis is usually reversible upon treatment of the underlying cause.

Characteristics of Opsoclonus-Myoclonus Syndrome in Patients of the Largest Pediatric Hospital in Latin America.

BACKGROUND: Opsoclonus-myoclonus syndrome (OMS) is a rare neuroinflammatory disorder characterized by ataxia, opsoclonus, and myoclonus. Clinical diagnosis of OMS has been challenging; therefore, we sought to determine the clinical and treatment profiles of patients with OMS at the largest pediatric hospital in Latin America. METHODS: We analyzed the data of patients diagnosed with OMS between 2010 and 2020 at Pequeno Principe Hospital (Brazil) to determine the corresponding clinical profile more accurately. RESULTS: Of the approximately 50,000 visitors to our pediatric neurology department from 2010 to 2020, 10 patients with OMS were observed. Five nontumor cases included three parainfectious and two idiopathic cases. The median time from symptom onset to diagnosis was 34 days. All patients with diagnostic OMS criteria in the idiopathic, nontumor group underwent whole-exome sequencing, with potentially pathogenic mutations identified in two cases. Nine patients were treated with methylprednisolone pulse, followed by oral steroids; eight received one or more intravenous immunoglobulin treatments; and six received azathioprine and cyclophosphamide. Complete symptomatic recovery was observed in only one patient. CONCLUSIONS: OMS diagnosis remains challenging. Diagnostic suspicion is necessary to improve the management of these patients and allow early immunosuppressive treatment. Paraneoplastic etiology is the most prevalent. In idiopathic patients who do not respond to immunosuppressive treatment, tests, such as whole-exome sequencing, may reveal a differential diagnosis. Genetic alterations that increase the risk of tumors may be an important clue to the pathophysiology of OMS.

A rare clinical presentation of COVID 19: opsoclonus-myoclonus ataxia syndrome.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) can have symptoms like many neurological diseases, and one of the rare forms of these presentations is opsoclonus-myoclonus ataxia syndrome (OMAS). The pathogenesis of OMAS in adults has not been clearly elucidated and OMAS can be fatal. CASE PRESENTATION: We present a 71-year-old male patient who was admitted to the emergency department with complaints of involuntary tremor-like movements in his hands, feet and mouth, and speech impediment for three days, and was followed up with COVID-19. The patient was diagnosed with OMAS and clonazepam treatment was started. He died three days later due to respiratory arrest. Our case is the first case diagnosed with COVID-19-associated OMAS in Turkey. DISCUSSION: OMAS has no definitive treatment. Early diagnosis and initiation of corticosteroids and intravenous immunoglobulin (IVIG) therapy, if necessary, can be life-saving. In COVID-19 patients with unexplained clinical findings, awareness of different and rare diseases and a multidisciplinary approach has vital importance.

DHDDS-related disease; biallelic missense novel variant causing major severity with an early-onset epilepsy and hyperkinetic movement disorder.

BACKGROUND: Dehydrodolichyl diphosphate synthase complex is encoded by DHDDS. De novo mutations in this gene are associated with epilepsy, movement disorders, intellectual and motor disabilities. The clinical picture is commonly identified in children and shows variations in terms of age of onset, severity, seizure types, and types of dyskinesia. CASE: we present a case with a infantile- onset epilepsy and severe global developmental delay, caused by a novel, de novo homozygous variant (c.425C > T, p.Thr142Met) in DHDDS. Clinical improvement was achieved with valproate and tetrabenazine treatments in the 2-year-old male patient with drug-resistant epilepsy, hyperkinetic movement disorder and myoclonus. CONCLUSION: Despite being rare, DHDDS-related diseases should be considered in patients with movement disorders, seizures and global developmental delay in infancy in differential diagnosis of patients resembling neuronal ceroid lipofuscinosis or progressive myoclonic epilepsies.

Review of Opsoclonus-Myoclonus Ataxia Syndrome in Pediatric Patients.

Opsoclonus-myoclonus ataxia syndrome (OMAS), also known as Kinsbourne syndrome, is a rare disorder that presents with myoclonus, ataxia, abnormal eye movements, irritability, and sleep disruptions, often in young children. We report a case of an infant barely 6 months old, with no significant past medical history, who presented to the emergency department with tremors, jerking motions of the head and arms, and rapid eye movements. After an extensive workup, she was found to have a neuroblastoma, which was subsequently surgically removed via thoracotomy. Despite an initial improvement in symptoms post-resection, the patient's symptoms recurred. She was subsequently treated with dexamethasone, intravenous immunoglobulin (IVIG), and rituximab. After treatment, the patient was noted to have mild global developmental delays but was otherwise well. This case report highlights the rare occurrence of OMAS in an infant barely 6 months old at diagnosis. Using the PubMed database, a systematic review was conducted to highlight the clinical presentation, diagnosis, and management of OMAS.

Scrub typhus with opsoclonus-myoclonus-ataxia-seizure as primary presentations.

Scrub typhus is a simple acute febrile illness with rash or an eschar, with up to one-fifth of the patients complicated with the nervous system. Hence, certain cases present to physicians with rather a different systemic manifestation and incidentally have been diagnosed with scrub typhus. We present two such cases of scrub typhus with neurological manifestations. The first case was of a 14-year-old boy with no previous history of any comorbidities who presented with bilateral opsoclonus with multifocal spontaneous myoclonus with cerebellar ataxia with a preceding history of fever and acute gastroenteritis. The second case of a 30-year-old gentleman with no previous history of any comorbidities presented to us with generalized tonic-clonic seizures and spontaneous multifocal myoclonus with a preceding history of fever. Both cases had no motor, sensory, cerebellar, or autonomic involvement. The pathophysiology of central nervous system (CNS) infections in scrub typhus is attributed to three major mechanisms of vasculitis, direct invasion, and immune-mediated. CNS involvement in scrub typhus is a significant marker for risk of mortality or morbidity. The most common CNS manifestations in scrub include meningitis, encephalitis, and seizures. Opsoclonus, myoclonus, and parkinsonism are comparatively rare manifestations.Scrub typhus infection must be considered in the differential diagnosis of clinical neurological features with even a remote history of acute febrile illnesses in endemic regions like ours, despite the absence of any eschar, rashes, and unremarkable neuroimaging.