Deep Brain Stimulation for Status Dystonicus: A Case Series and Review of the Literature

Severe Acute Motor Exacerbations (SAME) across Metabolic, Developmental and Genetic Disorders

Acute presentation of severe motor disorders is a diagnostic and management challenge. We define severe acute motor exacerbations (SAME) as acute/subacute motor symptoms that persist for hours-to-days with a severity that compromise vital signs (temperature, breath, and heart rate) and bulbar function (swallowing/dysphagia). Phenomenology includes dystonia, choreoathetosis, combined movement disorders, weakness, and hemiplegic attacks. SAME can develop in diverse diseases and can be preceded by triggers or catabolic states. Recent descriptions of SAME in complex neurodevelopmental and epileptic encephalopathies have broadened appreciation of this presentation beyond inborn errors of metabolism. A high degree of clinical suspicion is required to identify appropriately targeted investigations and management. We conducted a comprehensive literature analysis of etiologies. Reported triggers are described and classified as per pathophysiological mechanism. A video of six cases displaying multiple SAME with diverse outcomes is provided. We identified 50 different conditions that manifest SAME, some associated with developmental regression. Etiologies include disorders of metabolism: energy substrate, amino acids, complex molecules, vitamins/cofactors, minerals, and neurotransmitters/synaptic vesicle cycling. Non-metabolic neurodegenerative and genetic disorders that present with movement disorders and epilepsy can additionally manifest SAME. A limited number of triggers are grouped here, together with an approach to investigations and general management strategies. Several neurogenetic and neurometabolic disorders manifest SAME. Identifying triggers can help in certain cases narrow the differential diagnosis and guide the expeditious application of targeted therapies to minimize adverse developmental and neurological consequences. This process may inform pathogenesis and eventually improve our understanding of the mechanisms that lead to the development of SAME. © 2024 International Parkinson and Movement Disorder Society.

Deep brain stimulation for pediatric pantothenate kinase-associated neurodegeneration with status dystonicus: A case report and literature review

BACKGROUND

Pantothenate kinase-associated neurodegeneration (PKAN) is a type of inherited metabolic disorder caused by mutation in the PANK2 gene. The metabolic disorder mainly affects the basal ganglia region and eventually manifests as dystonia. For patients of dystonia, their dystonic symptom may progress to life-threatening emergency--status dystonicus.

OBJECTIVE

We described a case of a child with PKAN who had developed status dystonicus and was successfully treated with deep brain stimulation (DBS). Based on this rare condition, we analysed the clinical features of PKAN with status dystonicus and reviewed the reasonable management process of this condition.

CONCLUSION

This case confirmed the rationality of choosing DBS for the treatment of status dystonicus. Meanwhile, we found that children with classic PKAN have a cluster of risk factors for developing status dystonicus. Once children diagnosed with similar neurodegenerative diseases are under status dystonicus, DBS can be active considered because it has showed high control rate of this emergent condition.

The role of genetics in the treatment of dystonia with deep brain stimulation: Systematic review and Meta-analysis

BACKGROUND

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions that lead to involuntary postures or repetitive movements. Genetic mutations are being increasingly recognized as a cause of dystonia. Deep brain stimulation (DBS) is one of the limited treatment options available. However, there are varying reports on its efficacy in genetic dystonias. This systematic review of the characteristics of genetic dystonias treated with DBS and their outcomes aims to aid in the evaluation of eligibility for such treatment.

METHODS

We performed a PUBMED search of all papers related to genetic dystonias and DBS up until April 2022. In addition to performing a systematic review, we also performed a meta-analysis to assess the role of the mutation on DBS response. We included cases that had a confirmed genetic mutation and DBS along with pre-and post-operative BFMDRS.

RESULTS

Ninety-one reports met our inclusion criteria and from them, 235 cases were analyzed. Based on our analysis DYT-TOR1A dystonia had the best evidence for DBS response and Rapid-Onset Dystonia Parkinsonism was among the least responsive to DBS.

CONCLUSION

While our report supports the role of genetics in DBS selection and response, it is limited by the rarity of the individual genetic conditions, the reliance on case reports and case series, and the limited ability to obtain genetic testing on a large scale in real-time as opposed to retrospectively as in many cases.

Deep Brain Stimulation for Refractory Status Dystonicus in Children: Multicenter Case Series and Systematic Review

OBJECTIVE

We sought to better understand the workflow, outcomes, and complications of deep brain stimulation (DBS) for pediatric status dystonicus (SD). We present a systematic review, alongside a multicenter case series of pediatric patients with SD treated with DBS.

METHODS

We collected individual data regarding treatment, stimulation parameters, and dystonia severity for a multicenter case series (n = 8) and all previously published cases (n = 77). Data for case series were used to create probabilistic voxelwise maps of stimulated tissue associated with dystonia improvement.

RESULTS

In our institutional series, DBS was implanted a mean of 25 days after SD onset. Programming began a mean of 1.6 days after surgery. All 8 patients in our case series and 73 of 74 reported patients in the systematic review had resolution of their SD with DBS, most within 2 to 4 weeks of surgery. Mean follow-up for patients in the case series was 16 months. DBS target for all patients in the case series and 68 of 77 in our systematic review was the globus pallidus pars interna (GPi). In our case series, stimulation of the posterior-ventrolateral GPi was associated with improved dystonia. Mean dystonia improvement was 32% and 51% in our institutional series and systematic review, respectively. Mortality was 4% in the review, which is lower than reported for treatment with pharmacotherapy alone (10-12.5%).

INTERPRETATION

DBS is a feasible intervention with potential to reverse refractory pediatric SD and improve survival. More work is needed to increase awareness of DBS in this setting, so that it can be implemented in a timely manner. ANN NEUROL 2023.

Long-Term Outcomes of Idiopathic and Acquired Dystonia After Pallidal Deep Brain Stimulation: A Case Series

BACKGROUND

Among dystonia patients receiving globus pallidus internus (GPi) deep brain stimulation (DBS), long-term outcomes remain to be established. To report the long-term outcomes of GPi DBS in a patient cohort with idiopathic and acquired dystonia.

METHODS

In this long-term follow-up cohort, there were 4 patients with idiopathic dystonia and 2 patients with acquired dystonia. The Burke-Fahn-Marsden Dystonia Rating Scale was used to evaluate 6 consecutive patients preoperatively and at 6 months, 12 months, and the last follow-up. The relationship between etiology and clinical improvement was analyzed. Stimulation parameters were evaluated for similarities and differences among these patients.

RESULTS

The mean follow-up of our cohort was 65.3 months (median 40.5 months). The average improvement in the Burke-Fahn-Marsden Dystonia Rating Scale (mean ± SEM) were 56% ± 7.6, 67% ± 6.8 and 66% ± 9.7 at 6 months, 12 months, and the last follow-up, respectively. There was greater improvement during the long-term follow-up in the 4 patients with idiopathic dystonia than in the 2 patients with acquired dystonia. The 2 most ventral electrodes (contact 0 and 1) were activated in all 11 leads in this cohort. The average stimulation intensity, pulse width and frequency were 2.0 ± 0.24 mA, 252 ± 43 μs, and 99 ± 6.0 Hz, respectively.

CONCLUSIONS

Isolated dystonia, either monogenic or idiopathic, usually responds better to GPi DBS than to acquired dystonia. Selection of patients by dystonia etiology, accurate placement of DBS leads in GPi targets, and proper stimulation programming are crucial to achieve better long-term outcomes.

Long-Term Outcomes of Deep Brain Stimulation for Pediatric Dystonia

BACKGROUND

Deep brain stimulation (DBS) has been utilized for over two decades to treat medication-refractory dystonia in children. Short-term benefit has been demonstrated for inherited, isolated, and idiopathic cases, with less efficacy in heredodegenerative and acquired dystonia. The ongoing publication of long-term outcomes warrants a critical assessment of available information as pediatric patients are expected to live most of their lives with these implants.

SUMMARY

We performed a review of the literature for data describing motor and neuropsychiatric outcomes, in addition to complications, 5 or more years after DBS placement in patients undergoing DBS surgery for dystonia at an age younger than 21. We identified 20 articles including individual data on long-term motor outcomes after DBS for a total of 78 patients. In addition, we found five articles reporting long-term outcomes after DBS in 9 patients with status dystonicus. Most patients were implanted within the globus pallidus internus, with only a few cases targeting the subthalamic nucleus and ventrolateral posterior nucleus of the thalamus. The average follow-up was 8.5 years, with a range of up to 22 years. Long-term outcomes showed a sustained motor benefit, with median Burke-Fahn-Marsden dystonia rating score improvement ranging from 2.5% to 93.2% in different dystonia subtypes. Patients with inherited, isolated, and idiopathic dystonias had greater improvement than those with heredodegenerative and acquired dystonias. Sustained improvements in quality of life were also reported, without the development of significant cognitive or psychiatric comorbidities. Late adverse events tended to be hardware-related, with minimal stimulation-induced effects.

KEY MESSAGES

While data regarding long-term outcomes is somewhat limited, particularly with regards to neuropsychiatric outcomes and adverse events, improvement in motor outcomes appears to be preserved more than 5 years after DBS placement.

Deep Brain Stimulation for Tremor and Dystonia

Deep brain stimulation (DBS) is the most commonly used surgical treatment for drug-refractory movement disorders such as tremor and dystonia. Appropriate patient selection along with target selection is important to ensure optimal outcome without complications. This review summarizes the recent literature regarding the mechanism of action, indications, outcome, and complications of DBS in tremor and dystonia. A comparison with other modalities of surgical interventions is discussed along with a note of the recent advances in technology. Future research needs to be directed to understand the underlying etiopathogenesis of the disease and the way in which DBS modulates the intracranial abnormal networks.

Deep brain stimulation versus pallidotomy for status dystonicus: a single-center case series

OBJECTIVE

First-line pharmacological therapies have shown limited efficacy in status dystonicus (SD), while surgery is increasingly reported as remediable in refractory cases. In this context, there is no evidence regarding which neurosurgical approach is the safest and most effective. The aim of this study was to assess the clinical outcomes and surgery-related complications of globus pallidus internus deep brain stimulation (GPi DBS) and pallidotomy for the treatment of drug-resistant SD.

METHODS

The authors reviewed the records of patients with drug-resistant SD who had undergone GPi DBS or pallidotomy at their institution between 2003 and 2017. The severity of the dystonia was evaluated using the Barry-Albright Dystonia (BAD) Scale. Surgical procedures were performed bilaterally in all cases.

RESULTS

Fourteen patients were eligible for inclusion in the study. After surgery, the mean follow-up was 40.6 ± 30 months. DBS ended the dystonic storm in 87.5% of cases (7/8), while pallidotomy had a success rate of 83.3% (5/6). No significant differences were observed between the two techniques in terms of failure rates (risk difference DBS vs pallidotomy -0.03, 95% CI -0.36 to 0.30), SD mean resolution time (DBS 34.8 ± 19 days, pallidotomy 21.8 ± 20.2 days, p > 0.05), or BAD scores at each postoperative follow-up (p > 0.05). The long-term hardware complication rate after DBS was 37.5%, whereas no surgery-related complications were noted following pallidotomy.

CONCLUSIONS

The study data suggest that DBS and pallidotomy are equally safe and effective therapies for drug-resistant SD. The choice between the two techniques should be tailored on a case-by-case basis, depending on factors such as the etiology and evolution pattern of the underlying dystonia and the clinical conditions at the moment of SD onset. Given the limitation of the low statistical power of this study, further multicentric investigations are needed to confirm its findings.

KMT2B-related disorders: expansion of the phenotypic spectrum and long-term efficacy of deep brain stimulation

Heterozygous mutations in KMT2B are associated with an early-onset, progressive and often complex dystonia (DYT28). Key characteristics of typical disease include focal motor features at disease presentation, evolving through a caudocranial pattern into generalized dystonia, with prominent oromandibular, laryngeal and cervical involvement. Although KMT2B-related disease is emerging as one of the most common causes of early-onset genetic dystonia, much remains to be understood about the full spectrum of the disease. We describe a cohort of 53 patients with KMT2B mutations, with detailed delineation of their clinical phenotype and molecular genetic features. We report new disease presentations, including atypical patterns of dystonia evolution and a subgroup of patients with a non-dystonic neurodevelopmental phenotype. In addition to the previously reported systemic features, our study has identified co-morbidities, including the risk of status dystonicus, intrauterine growth retardation, and endocrinopathies. Analysis of this study cohort (n = 53) in tandem with published cases (n = 80) revealed that patients with chromosomal deletions and protein truncating variants had a significantly higher burden of systemic disease (with earlier onset of dystonia) than those with missense variants. Eighteen individuals had detailed longitudinal data available after insertion of deep brain stimulation for medically refractory dystonia. Median age at deep brain stimulation was 11.5 years (range: 4.5-37.0 years). Follow-up after deep brain stimulation ranged from 0.25 to 22 years. Significant improvement of motor function and disability (as assessed by the Burke Fahn Marsden's Dystonia Rating Scales, BFMDRS-M and BFMDRS-D) was evident at 6 months, 1 year and last follow-up (motor, P = 0.001, P = 0.004, and P = 0.012; disability, P = 0.009, P = 0.002 and P = 0.012). At 1 year post-deep brain stimulation, >50% of subjects showed BFMDRS-M and BFMDRS-D improvements of >30%. In the long-term deep brain stimulation cohort (deep brain stimulation inserted for >5 years, n = 8), improvement of >30% was maintained in 5/8 and 3/8 subjects for the BFMDRS-M and BFMDRS-D, respectively. The greatest BFMDRS-M improvements were observed for trunk (53.2%) and cervical (50.5%) dystonia, with less clinical impact on laryngeal dystonia. Improvements in gait dystonia decreased from 20.9% at 1 year to 16.2% at last assessment; no patient maintained a fully independent gait. Reduction of BFMDRS-D was maintained for swallowing (52.9%). Five patients developed mild parkinsonism following deep brain stimulation. KMT2B-related disease comprises an expanding continuum from infancy to adulthood, with early evidence of genotype-phenotype correlations. Except for laryngeal dysphonia, deep brain stimulation provides a significant improvement in quality of life and function with sustained clinical benefit depending on symptoms distribution.

Post-mortem histopathology of a pediatric brain after bilateral DBS of GPI for status dystonicus: case report and review of the literature

PURPOSE

To investigate the effects of deep brain stimulation (DBS) electrodes on the brain of a dystonic pediatric patient submitted to bilateral DBS of the globus pallidus internus (GPI).

METHODS

An 8-year-old male patient underwent bilateral DBS of GPI for status dystonicus. He died 2 months later due to multiorgan failure triggered by bacterial pneumonia. A post-mortem pathological study of the brain was done.

RESULTS

At visual inspection, no grossly apparent softening, hemorrhage, or necrosis of the brain adjacent to the DBS lead tracts was detected. High-power microscopic examination of the tissue surrounding the electrode trajectories showed lymphocyte infiltration, astrocytic gliosis, microglia, macrophages, and clusters of multinucleate giant cells. Significant astrocytosis was confirmed by GFAP staining in the electrode site. The T cell lymphocyte activity was overexpressed with activated macrophages detected with CD3, CD20, CD45, and CD68 stains respectively. There was no gliosis or leukocyte infiltration away from the surgical tracks of the electrodes.

CONCLUSION

This is the first post-mortem examination of a child's brain after bilateral DBS of GPI. The comparison with adult post-mortem reports showed no significant differences and confirms the safety of DBS implantation in the pediatric population too.

Secondary Worsening Following DYT1 Dystonia Deep Brain Stimulation: A Multi-country Cohort

Objective: To reveal clinical characteristics of suboptimal responses to deep brain stimulation (DBS) in a multi-country DYT1 dystonia cohort. Methods: In this multi-country multi-center retrospective study, we analyzed the clinical data of DYT1 patients who experienced suboptimal responses to DBS defined as <30% improvement in dystonia scales at the last follow-up compared with baseline. We used a literature-driven historical cohort of 112 DYT1 patients for comparison. Results: Approximately 8% of our study cohort (11 out of 132) experienced suboptimal responses to DBS. Compared with the historical cohort, the multi-country cohort with suboptimal responses had a significantly younger age at onset (mean, 7.0 vs. 8.4 years; p = 0.025) and younger age at DBS (mean, 12.0 vs. 18.6 years; p = 0.019). Additionally, cranial involvement was more common in the multi-country cohort (before DBS, 64% vs. 45%, p = 0.074; before or after DBS, 91% vs. 47%, p = 0.001). Mean motor improvement at the last follow-up from baseline were 0% and 66% for the multi-country and historical cohorts, respectively. All 11 patients of the multi-country cohort had generalization of dystonia within 2.5 years after disease onset. All patients experienced dystonia improvement of >30% postoperatively; however, secondary worsening of dystonia commenced between 6 months and 3 years following DBS. The improvement at the last follow-up was less than 30% despite optimally-placed leads, a trial of multiple programming settings, and additional DBS surgeries in all patients. The on-/off-stimulation comparison at the long-term follow-up demonstrated beneficial effects of DBS despite missing the threshold of 30% improvement over baseline. Conclusion: Approximately 8% of patients represent a more aggressive phenotype of DYT1 dystonia characterized by younger age at onset, faster disease progression, and cranial involvement, which seems to be associated with long-term suboptimal responses to DBS (e.g., secondary worsening). This information could be useful for both clinicians and patients in clinical decision making and patient counseling before and following DBS implantations. Patients with this phenotype may have different neuroplasticity, neurogenetics, or possibly distinct neurophysiology.

Prestatus and status dystonicus in children and adolescents

AIM

To critically analyse the management of status dystonicus and prestatus dystonicus in children and adolescents, in order to examine clinical features, acute management, and risk of relapse in a paediatric cohort.

METHOD

Clinical, demographic, and therapeutic features were analysed according to disease severity. Risk of subsequent relapse was estimated through Kaplan-Meier curves.

RESULTS

Thirty-four patients (eight females, 26 males) experiencing 63 episodes of acute dystonia exacerbations at a tertiary referral Italian hospital were identified. Mean age at status dystonicus presentation was 9 years 11 months (11y at inclusion in the study). Onset of dystonia dated back to infancy in most cases. Fourteen patients experienced two or more episodes. Infections were the most common trigger (48%). Benzodiazepines were the most commonly used drugs for acute management. Stereotactic pallidotomy was performed in six cases during status dystonicus, and in two additional patients it was electively performed after medical management. The probability of survival free from status dystonicus relapses was 78% after 4 months and 61% after 27 months.

INTERPRETATION

Dystonia exacerbations are potentially life-threating emergencies, with a considerable risk of relapse. Nevertheless, no obvious factors for relapse risk stratification exist. Pallidotomy is a feasible option in medical refractory status dystonicus for patients with limited deep brain stimulation applicability, but the risk of recurrence is elevated.

WHAT THIS PAPER ADDS

Acute exacerbations may affect up to 10% of children with dystonia. Infections are the most common precipitant factor. In about 30% of the cases, intensive care unit admission is needed. Subsequent relapses are common, reaching 25% risk at 1 year. Pallidotomy can be considered in medical-refractory cases with no deep brain stimulation applicability.

Ablative brain surgery: an overview

Background: Ablative therapies have been used for the treatment of neurological disorders for many years. They have been used both for creating therapeutic lesions within dysfunctional brain circuits and to destroy intracranial tumors and space-occupying masses. Despite the introduction of new effective drugs and neuromodulative techniques, which became more popular and subsequently caused brain ablation techniques to fall out favor, recent technological advances have led to the resurgence of lesioning with an improved safety profile. Currently, the four main ablative techniques that are used for ablative brain surgery are radiofrequency thermoablation, stereotactic radiosurgery, laser interstitial thermal therapy and magnetic resonance-guided focused ultrasound thermal ablation. Object: To review the physical principles underlying brain ablative therapies and to describe their use for neurological disorders. Methods: The literature regarding the neurosurgical applications of brain ablative therapies has been reviewed. Results: Ablative treatments have been used for several neurological disorders, including movement disorders, psychiatric disorders, chronic pain, drug-resistant epilepsy and brain tumors. Conclusions: There are several ongoing efforts to use novel ablative therapies directed towards the brain. The recent development of techniques that allow for precise targeting, accurate delivery of thermal doses and real-time visualization of induced tissue damage during the procedure have resulted in novel techniques for cerebral ablation such as magnetic resonance-guided focused ultrasound or laser interstitial thermal therapy. However, older techniques such as radiofrequency thermal ablation or stereotactic radiosurgery still have a pivotal role in the management of a variety of neurological disorders.

Current therapies and therapeutic decision making for childhood-onset movement disorders

Movement disorders differ in children to adults. First, neurodevelopmental movement disorders such as tics and stereotypies are more prevalent than parkinsonism, and second, there is a genomic revolution which is now explaining many early-onset dystonic syndromes. We outline an approach to children with movement disorders starting with defining the movement phenomenology, determining the level of functional impairment due to abnormal movements, and screening for comorbid psychiatric conditions and cognitive impairments which often contribute more to disability than the movements themselves. The rapid improvement in our understanding of the etiology of movement disorders has resulted in an increasing focus on precision medicine, targeting treatable conditions and defining modifiable disease processes. We profile some of the key disease-modifying therapies in metabolic, neurotransmitter, inflammatory, and autoimmune conditions and the increasing focus on gene or cellular therapies. When no disease-modifying therapies are possible, symptomatic therapies are often all that is available. These classically target dopaminergic, cholinergic, alpha-adrenergic, or GABAergic neurochemistry. Increasing interest in neuromodulation has highlighted that some clinical syndromes respond better to DBS, and further highlights the importance of "disease-specific" therapies with a future focus on individualized therapies according to the genomic findings or disease pathways that are disrupted. We summarize some pragmatic applications of symptomatic therapies, neuromodulation techniques, and some rehabilitative interventions and provide a contemporary overview of treatment in childhood-onset movement disorders. © 2019 International Parkinson and Movement Disorder Society.

Deep brain stimulation for pediatric dystonia: a meta-analysis with individual participant data

AIM

We performed a meta-analysis with individual participant data of deep brain stimulation (DBS) for dystonia in children and young people.

METHOD

Three databases (PubMed, Embase, and Web of Science) were queried from January 1999 to August 2017 with no language restrictions to identify case studies and cohort studies reporting on pediatric patients (age ≤21y) with dystonia. The primary outcomes were changes in Burke-Fahn-Marsden (BFM) or Barry-Albright Dystonia Scale scores. A mixed-effects regression was used to identify associations between clinical covariates and outcomes.

RESULTS

Of 2509 citations reviewed, 72 articles (321 children) were eligible. At last follow-up (median 12mo, 25th centile=9.0; 75th centile=32.2), 277 (86.3%) patients showed improvement in dystonia, while 66.1 percent showed clinically significant (>20%) BFM Dystonia Rating Scale-motor improvement. On multivariable hierarchical regression, older age at dystonia onset, inherited dystonia without nervous system pathology and idiopathic dystonia (vs inherited with nervous system pathology or acquired dystonia), and truncal involvement indicated a better outcome (p<0.05).

INTERPRETATION

The data suggest that DBS is effective and should be considered in selected children with inherited or idiopathic dystonia.

WHAT THIS PAPER ADDS

Deep brain stimulation is effective in selected children with inherited or idiopathic dystonia.

Frameless robot-assisted pallidal deep brain stimulation surgery in pediatric patients with movement disorders: precision and short-term clinical results

OBJECTIVE

The purpose of this study was to verify the safety and accuracy of the Neuromate stereotactic robot for use in deep brain stimulation (DBS) electrode implantation for the treatment of hyperkinetic movement disorders in childhood and describe the authors' initial clinical results.

METHODS

A prospective evaluation of pediatric patients with dystonia and other hyperkinetic movement disorders was carried out during the 1st year after the start-up of a pediatric DBS unit in Barcelona. Electrodes were implanted bilaterally in the globus pallidus internus (GPi) using the Neuromate robot without the stereotactic frame. The authors calculated the distances between the electrodes and their respective planned trajectories, merging the postoperative CT with the preoperative plan using VoXim software. Clinical outcome was monitored using validated scales for dystonia and myoclonus preoperatively and at 1 month and 6 months postoperatively and by means of a quality-of-life questionnaire for children, administered before surgery and at 6 months' follow-up. We also recorded complications derived from the implantation technique, "hardware," and stimulation.

RESULTS

Six patients aged 7 to 16 years and diagnosed with isolated dystonia ( DYT1 negative) (3 patients), choreo-dystonia related to PDE2A mutation (1 patient), or myoclonus-dystonia syndrome SGCE mutations (2 patients) were evaluated during a period of 6 to 19 months. The average accuracy in the placement of the electrodes was 1.24 mm at the target point. At the 6-month follow-up, patients showed an improvement in the motor (65%) and functional (48%) components of the Burke-Fahn-Marsden Dystonia Rating Scale. Patients with myoclonus and SGCE mutations also showed an improvement in action myoclonus (95%-100%) and in functional tests (50%-75%) according to the Unified Motor-Rating Scale. The Neuro-QOL score revealed inconsistent results, with improvement in motor function and social relationships but worsening in anxiety, cognitive function, and pain. The only surgical complication was medial displacement of the first electrode, which limited intensity of stimulation in the lower contacts, in one case.

CONCLUSIONS

The Neuromate stereotactic robot is an accurate and safe tool for the placement of GPi electrodes in children with hyperkinetic movement disorders.

An unusual surgical indication for cerebral tuberculosis: status dystonicus. Case report

Actual indications for surgery in tuberculosis are limited to obtaining a diagnosis, acquiring tissue for culture studies, treating hydrocephalus, aspiring a brain abscess, and reducing intracranial pressure in patients with multiple tuberculomas. Tuberculosis-related movement disorders are usually treated pharmacologically. We report on a child affected by post-tubercular generalized dystonia, who progressed to status dystonicus (SD) and underwent stereotactic bilateral pallidotomy. After surgery, SD resolved, and drugs were rapidly tapered. The successful reversal of SD and the motor improvement observed in our patient demonstrate the safety, feasibility, and clinical efficacy of pallidotomy in post-tuberculous-meningoencephalitis dystonia and SD.

Surgical treatment of dystonia

INTRODUCTION

Treatment of dystonia should be individualized and tailored to the specific needs of patients. Surgical treatment is an important option in medically refractory cases. Several issues regarding type of the surgical intervention, targets, and predict factors of benefit are still under debate. Areas covered: To date, several clinical trials have proven the benefit and safety of deep brain stimulation (DBS) for inherited and idiopathic isolated dystonia, whereas there is still insufficient evidence in combined and acquired dystonia. The globus pallidus internus (GPi) is the target with the best evidence, but data on the subthalamic nucleus seems also to be promising. Evidence suggests that younger patients with shorter disease duration experience greater benefit following DBS. Pallidotomy and thalamotomy are currently used in subset of carefully selected patients. The development of MRI-guided focused ultrasound might bring new options to ablation approach in dystonia. Expert commentary: GPi-DBS is effective and safe in isolated dystonia and should not be delayed when symptoms compromise quality of life and functionality. Identifying the best candidates to surgery on acquired and combined dystonias is still necessary. New insights about pathophysiology of dystonia and new technological advances will undoubtedly help to tailor surgery and optimize clinical effects.

Deep brain stimulation treated dystonia-trajectory via status dystonicus

BACKGROUND

Status dystonicus (SD) is a life-threatening condition.

OBJECTIVE AND METHODS

In a dystonia cohort who developed status dystonicus, we analyzed demographics, background dystonia phenomenology and complexity, trajectory previous to-, via status dystonicus episodes, and evolution following them.

RESULTS

Over 20 years, 40 of 328 dystonia patients who were receiving DBS developed 58 status dystonicus episodes. Dystonia was of pediatric onset (95%), frequently complex, and had additional cognitive and pyramidal impairment (62%) and MRI alterations (82.5%); 40% of episodes occured in adults. Mean disease duration preceding status dystonicus was 10.3 ± 8 years. Evolution time to status dystonicus varied from days to weeks; however, 37.5% of patients exhibited progressive worsening over years. Overall, DBS was efficient in resolving 90% of episodes.

CONCLUSION

Status dystonicus is potentially reversible and a result of heterogeneous conditions with nonuniform underlying physiology. Recognition of the complex phenomenology, morphological alterations, and distinct patterns of evolution, before and after status dystonicus, will help our understanding of these conditions. © 2018 International Parkinson and Movement Disorder Society.

GNAO1 Mutation-Induced Pediatric Dystonic Storm Rescue With Pallidal Deep Brain Stimulation

Dystonic storm or status dystonicus is a life-threatening hyperkinetic movement disorder with biochemical alterations due to the excessive muscle contractions. The medical management can require pediatric intensive care unit admission and a combination of medications while the underlying trigger is managed. Severe cases may require general anesthesia and paralytic agents with intubation and may relapse when these drugs are weaned. Deep brain stimulation of the globus pallidum has been reported to terminate dystonic storm in several pediatric cases. We present a 10-year-old boy with a de novo GNAO1 mutation-induced dystonic storm who required a 2-month pediatric intensive care unit admission and remained refractory to all medical treatments. Deep brain stimulation was performed under general anesthetic without complication. His dyskinetic movements stopped with initiation of stimulation. He was discharged from the pediatric intensive care unit after 4 days. We present prospectively evaluated changes in dystonia symptoms and quality of life for a patient with GNAO1 mutation treated with deep brain stimulation.

Reversal of Status Dystonicus after Relocation of Pallidal Electrodes in DYT6 Generalized Dystonia

Background

DYT6 dystonia can have an unpredictable clinical course and the result of deep brain stimulation (DBS) of the internal part of the globus pallidus (GPi) is known to be less robust than in other forms of autosomal dominant dystonia. Patients who had previous stereotactic surgery with insufficient clinical benefit form a particular challenge with very limited other treatment options available.

Case Report

A pediatric DYT6 patient unexpectedly deteriorated to status dystonicus 1 year after GPi DBS implantation with good initial clinical response. After repositioning the DBS electrodes the status dystonicus resolved.

Discussion

This case study demonstrates that medication‐resistant status dystonicus in DYT6 dystonia can be reversed by relocation of pallidal electrodes. This case highlights that repositioning of DBS electrodes may be considered in patients with status dystonicus, especially when the electrode position is not optimal, even after an initial clinical response to DBS.

Status dystonicus in childhood

PURPOSE OF REVIEW

Dystonia is a common paediatric neurological condition. At its most severe, dystonia may lead to life-threatening complications, a state termed status dystonicus. This review provides an update on the definition, causes, management and outcome of childhood status dystonicus.

RECENT FINDINGS

High-quality studies in childhood status dystonicus are lacking, though an increasing number of case series have been published. Status dystonicus appears to occur more frequently in children compared with adults, with a clear precipitant identified in around two-thirds of cases. Although febrile illness remains the commonest trigger for status dystonicus, unplanned interruption to deep brain stimulation (DBS) is increasingly reported as a precipitant. In parallel with this, neurosurgical intervention for status dystonicus appears to have become more widely used, though optimum timing and patient selection remains unclear. In most cases, a multistaged approach is required; we propose an 'ABCD' approach - Addressing precipitants, Beginning supportive measures, Calibrating sedation and Dystonia specific medications. Outcomes following status dystonicus appear to have slightly improved in recent years, potentially as a consequence of increasing use of DBS, though mortality has remained around 10%.

SUMMARY

Future work is needed to inform evidence-based guidelines for the management of status dystonicus. One of many pressing questions is the precise indication, and timing of interventions such as DBS.

Staged pallidotomy: MRI and clinical follow-up in status dystonicus

PURPOSE

We report on a patient affected by Status Distonicus who was treated with Deep Brain Stimulation electrodes implanted in the Globus Pallidus internus (Gpi) and used for serial radiofrequency lesions.

MATERIALS AND METHODS

The evolution of radiofrequency lesions was monitored by post-operative and late Magnetic Resonance Imaging (MRI). After the first lesion the patient did improve, though not in a significant fashion. Therefore, three further radiofrequency lesions were delivered 2, 4 and 6 days respectively after surgery with subsequent improvement of dystonic movements.

RESULTS

MRI scans performed at 8 days, 3 months, and 6 months after surgery showed a diffuse T2-hyperintense and T1-hypointense GPi signal alteration which progressively decreased over time.

CONCLUSION

We confirm that the possibility to stage pallidotomies over time using a couple of new contacts is a safe and efficacious procedure in treating SD patients where the lesions themselves are limited by the appearance of side effects, or in patients showing a poor response to a single lesion. As far as we know, this is the first description of MRI evolution and monitoring of a staged pallidotomy.

Rethinking status dystonicus

Status dystonicus is a movement disorder emergency that has been a source of controversy in terms of terminology, phenomenology, and management since it was first described in 1982. Here we argue that the current use of the term status dystonicus falls well short of the precision needed for either clinical or academic use. We performed a critical review on this topic, describing possible pathophysiological mechanisms and areas of uncertainties. This review also addresses the problems derived by the extreme clinical heterogeneity of this condition, as the lack of an objective criterion useful for the definition, or the fact that status dystonicus may present not only in the context of a known dystonic syndrome. We propose a new possible definition that includes not only dystonia but also other hyperkinetic movements in the wide range of movement disorders that can be seen during an episode. The new definition keeps the term status dystonicus and highlights the fact that this is a medical emergency based on the impairment of bulbar and/or respiratory function requiring hospital admission as the principal feature. Furthermore, the new definition should not consider as necessary unspecific features as patient's condition at baseline, the distribution of dystonia, occurrence of systemic symptoms such as fever or laboratory findings. We hope that this proposal will stimulate the debate on this subject among our peers, further developing a clinical and pathophysiological understanding of status dystonicus. © 2017 International Parkinson and Movement Disorder Society.

Acute Presentation of Nonmotor Symptoms in Parkinson's Disease

There are a few syndromes involving the nonmotor symptoms of Parkinson's disease and other movement disorders that can quickly lead to severe morbidity and mortality, and, as such, need rapid identification and management. Among these are neuroleptic malignant syndrome, serotonin syndrome, dopamine agonist withdrawal syndrome, and dystonic storm. It is important to maintain a high index of suspicion for these disorders as lack of identification can lead to death. Many of these acutely occurring nonmotor syndromes are primarily the result of imbalances in dopaminergic and serotonergic systems due to changes in pharmacologic management of psychiatric disorders or Parkinson's disease. We discuss these acutely occurring nonmotor symptoms in order to raise awareness and also to highlight how these extremes in symptoms may uniquely shed light on the pathophysiology of Parkinson's disease.

Dystonic storm: a practical clinical and video review

Dystonic storm is a frightening hyperkinetic movement disorder emergency. Marked, rapid exacerbation of dystonia requires prompt intervention and admission to the intensive care unit. Clinical features of dystonic storm include fever, tachycardia, tachypnea, hypertension, sweating and autonomic instability, often progressing to bulbar dysfunction with dysarthria, dysphagia and respiratory failure. It is critical to recognize early and differentiate dystonic storm from other hyperkinetic movement disorder emergencies. Dystonic storm usually occurs in patients with known dystonia, such as DYT1 dystonia, Wilson’s disease and dystonic cerebral palsy. Triggers such as infection or medication adjustment are present in about one-third of all events. Due to the significant morbidity and mortality of this disorder, we propose a management algorithm that divides decision making into two periods: the first 24 h, and the next 2–4 weeks. During the first 24 h, supportive therapy should be initiated, and appropriate patients should be identified early as candidates for pallidal deep brain stimulation or intrathecal baclofen. Management in the next 2–4 weeks aims at symptomatic dystonia control and supportive therapies.