Successful Treatment of a Paroxysmal Kinesigenic Dyskinesia Patient with Carbamazepine-Induced Stevens-Johnson Syndrome Using Oxcarbazepine Monotherapy: A Case Report

Paroxysmal kinesigenic dyskinesia (PKD) is a rare condition characterized by abnormal involuntary movements that are precipitated by a sudden movement. PKD is often misdiagnosed with psychogenic movement disorders. Carbamazepine is usually the first choice of medication due to its well-established evidence but could induce Stevens-Johnson syndrome. We report a 21-year-old male patient with PKD referred to our movement disorders clinic after being misdiagnosed with conversion syndrome. PRRT2 gene testing using next-generation sequencing revealed a mutation in c.649dupC p. (Arg217fs). The patient responded well to carbamazepine but had to withdraw the treatment due to carbamazepine-induced Stevens-Johnson syndrome after 3 weeks of medication. Our patient did not respond to trials of levetiracetam and phenytoin but finally responded well to oxcarbazepine. The patient was followed up for 4 years, during which he had no attacks and no side effects. Here, we present a PKD case with carbamazepine-induced Stevens-Johnson syndrome successfully treated with oxcarbazepine despite the risk of cross-reactive skin eruption between these antiepileptics. Careful history taking and examining patient’s attacks are crucial to accurate diagnosis and treatment in PKD patients.

Increased Incidence of Functional (Psychogenic) Movement Disorders in Children and Adults Amidst the COVID-19 Pandemic: A Cross-Sectional Study

Background:Functional (psychogenic) movement disorders (FMDs) are conditions in which affected patients develop abnormal movements that are incongruous with known, organic, movement disorders, often associated with psychological stressors.Methods:In this case series, electronic medical records of all patients who presented to our adult and pediatric tertiary-care movement disorders clinics between March 1 and October 30, 2020 and during the same period in 2019 were reviewed. All patients diagnosed with functional or psychogenic movement disorder were included if they satisfied diagnostic criteria.Results:Among 550 new patients referred for evaluation at our tertiary care movement disorders centers, 45 (8.2%) received a diagnosis of FMD; 75.6% were female, in comparison to the prior year during which time 665 new patients were evaluated and 5.1% were diagnosed with FMD. This represents a 60.1% increase (90.1% in pediatric cohort, 50.9% in adult cohort) in new patients diagnosed with FMD during the COVID-19 pandemic.Conclusions:Within our patient population, there has been increased incidence of FMDs in the setting of the COVID-19 pandemic, possibly reflecting increased psychological and other stressors during this period.

Functional (Psychogenic) Movement Disorders

Functional movement disorders are any type of movement disorder due to a brain network disorder where normal function is possible. The terminology of functional movement disorders has changed; in the recent past, these disorders were most frequently called psychogenic. Characteristics of functional movements include incongruity with a known type of involuntary movement; inconsistency in the pattern, degree, and distribution during the clinical course; improvement with distraction; and possible psychogenic background. While the movements are said to be fully involuntary, there is often some suggestibility. In the case of unilaterally predominant tremor, if the patient is requested to repeat voluntary movements with the intact or less affected hand at a certain pace, the tremor frequency might be replaced by the frequency of the voluntary movement, the phenomenon called entrainment.

Clinical and neural responses to cognitive behavioral therapy for functional tremor

ObjectivesTo evaluate changes in tremor severity and motor/emotion-processing circuits in response to cognitive behavioral therapy (CBT) delivered as treatment for functional tremor (FT), the most common functional movement disorder in adults.MethodsFifteen patients with FT underwent fMRI with motor, basic-emotion, and intense-emotion tasks before and after 12 weeks of CBT. Baseline fMRI was compared to those of 25 healthy controls (HCs). The main clinical endpoint was the tremor score (sum of severity, duration, and incapacitation subscores) adapted from the Rating Scale for Psychogenic Movement Disorders (PMDRS) assessed by a blinded clinician. CBT responders were defined as those with PMDRS score reduction >75%. Anatomic and functional brain images were obtained with a 4T MRI system. Generalized linear model and region-of-interest analyses were used to evaluate before-versus-after treatment-related changes in brain activation.ResultsCBT markedly reduced tremor severity (p < 0.01) with remission/near remission achieved in 73.3% of the cohort. Compared to HCs, in those with FT, a functionally defined fMRI region of interest in the anterior cingulate/paracingulate cortex showed increased activation at baseline and decreased activation after CBT during basic-emotion processing (p = 0.012 for CBT responders). Among CBT responders, the change in anterior cingulate/paracingulate was more significant in those with more severe baseline depression (r = 0.75, p < 0.01).ConclusionsTremor severity improved significantly after CBT. The improvement was associated with changes in the anterior cingulate/paracingulate activity, which may represent a marker of emotional dysregulation in FT and a predictor of treatment response.Classification of evidenceThis study provides Class III evidence that CBT significantly improves tremor severity in patients with functional tremor.

Movement Disorders

This chapter deals with classic Parkinson’s disease and the main variants such as progressive supranuclear palsy, multiple system atrophy, and the corticobasal syndrome. There are details on chorea, particularly Huntington’s disease, chorea-acanthocytosis, McLeod’s syndrome, Sydenham’s chorea, Wilson’s disease. The main varieties of tremor are described as are neurodegeneration with brain iron accumulation. Subsequent parts deal with tics, restless legs syndrome, periodic movements of sleep, and painful legs and moving toes. Several Handles are specified for dystonia and its subdivisions, Lesch-Nyhan syndrome, gait disorders, paroxysmal dyskinesias, stereotypies, psychogenic movement disorders, and myoclonus.