Calcineurin Inhibitor Use and Myoclonus Association. Is There a Clinical Implication?

Background: Calcineurin Inhibitors (CNIs) play a pivotal role in anti rejection therapy for transplant patients. Neurotoxicity is a known side effect that usually manifests as encephalopathy but myoclonus has also been described. Perioperative myoclonus as a manifestation of neurotoxicity, has not been well studied. Methods: We retrospectively reviewed data from 842,762 patients from the Nationwide Inpatient Sample (NIS) database from January 2011 to December 2014. Of those records we compared 56,423 patients requiring CNIs and undergoing Heart Transplant (HT) with 786,339 patients undergoing Coronary Artery Bypass Graft (CABG) surgery as controls. The objective was to study the rates of myoclonus in patients undergoing cardiac surgery, especially those requiring CNIs, and study the outcome of those patients with myoclonus. The NIS database from January 2011 to December 2014 was the source for the analysis. Patients with underlying epilepsy or hypo-ischemic encephalopathy based on ICD-9-CM codes were excluded from the study. Results: A total of 147 patients (0.26%) were found to have myoclonus in the HT group versus 338 patients (0.04%) in the CABG group, p < 0.0001. No differences in the demographics were seen except for kidney disease which was higher in the HT group. The difference remained statistically significant after adjusting for confounders. Patients with myoclonus in both groups were more likely to have acute kidney injury and have a prolonged length of stay. Only patients with myoclonus in the CABG group had higher rates of discharge disposition to a nursing home and higher rates of in-Hospital mortality. A trend towards higher in-Hospital mortality was found in patients with myoclonus in the HT group. Conclusion: In this study we have compared the rate of myoclonus found in HT patients versus CABG patients. We have identified calcineurin inhibitors as potentially contributing to myoclonus due to its neurotoxic effects. The study also suggests that other disease processes like renal failure may also have an impact on the rate of myoclonus even in the absence of calcineurin inhibitors. Higher rates of myoclonus were seen in patients undergoing HT when compared to patients undergoing CABG, suggesting that CNIs may increase the risk for myoclonus. Myoclonus may be a clinical indicator of patient overall health including a more permeable blood brain barrier. In-Hospital mortality was higher in patients with myoclonus undergoing CABG and a trend towards significance in the HT group suggesting that it may be a marker of poor prognosis. More studies are needed to corroborate our findings.

Opsoclonus-Myoclonus Syndrome Post-Vaccination and Viral Illness

Opsoclonus-myoclonus syndrome is a rare condition with dyskinesia of eye movements and myoclonic movements of the trunk and limbs. It is linked to malignancies, infections and other conditions. We present a case of post-vaccination opsoclonus-myoclonus syndrome. We believe that our patient also experienced a viral illness post-vaccination and prior to the development of opsoclonus-myoclonus. The vaccination in combination with the viral illness potentiated the immune mechanism thought to be noted in this condition. This was supported by her recovery after receiving immunotherapy.

Progressive Myoclonus Epilepsies:PME's in the New Millennium

Description： The progressive myoclonus epilepsies （PME＇s） comprise a large group of genetically determined disorders characterized by myoclonus, generalized tonic-clonic seizures, cerebellar dysfunction and variable degrees of cognitive impairment.

Case Report: Propriospinal Myoclonus

This report presents a case of propriospinal myoclonus (PSM) in a previously fit and well female patient who presented with truncal jerking movements when relaxed. Propriospinal myoclonus is a rare condition, of which 80% of the aetiology is idiopathic. It is characterised by involuntary jerking movements of the trunk due to spreading activity via intrinsic propriospinal pathways along the spinal cord. Polymyography is mandatory in the diagnosis of priopriospinal myoclonus however in discerning the differential diagnoses it is inferior to magnetic resonance diffusion tensor imaging. The management of propriospinal myoclonus is dependent on aetiology. Clonazepam has been shown to be effective in the treatment of idiopathic PSM for symptomatic relief.

A rare complication of measles infection presented with subacute sclerosing panencephalitis: Report of two cases in India

Rationale:Subacute sclerosing panencephalitis(SSPE)is a progressive neurological disorder caused by persistent measles virus infection.SSPE predominantly affects children and adolescents.The symptoms usually develop 6-15 years after measles infection and ultimately leading to death in many cases.Patient concerns:Patient 1 presented with cognitive decline and myoclonus and the Patient 2 presented with diminution of vision with myoclonic jerks.Diagnosis:Based on the clinical features with a characteristic electroencephalogram pattern and the presence of a high titer of anti-measles IgG in serum and cerebrospinal fluid,these patients were diagnosed as SSPE.Interventions:Antiepileptics were started for controlling myoclonus along with supportive treatment.Outcomes:Both patients were discharged on antiepileptics and supportive care.Lessons:Whenever there are unusual clinical manifestations with unknown vaccination status,SSPE can be suspected and the cerebrospinal fluid should be examined for anti-measles antibodies.Our case study also highlights the importance of universal coverage of measles vaccination.To reduce the incidence of measles and associated deaths,it is important to maintain a high level of immunization coverage for the measles vaccine and to strengthen all the integral components of the national immunization program.

Identification of a Novel Homozygous Splice-Site Mutation in SCARB2 that Causes Progressive Myoclonus Epilepsy with or without Renal Failure

Background： Progressive myoclonus epilepsies （PMEs） conaprise a group of rare genetic disorders characterized by action rnyoclonus, epileptic seizures, and ataxia with progressive neurologic decline. Due to clinical and genetic heterogeneity of PMEs, it is difficult to decide which genes are affected. The aim of this study was to report an action myoclonus with or without renal failure syndrome （EPM4） fhmily and summarize the clinical and genetic characteristics of all reported EPM4 patients. Meihods： In the present study, targeted next-generation sequencing （NGS） was applied to screen causative genes in a Chinese PME family. The candidaie variant was further confirmed by cosegregation analysis and further functional analysis, including the reverse transcription polymerase chain reaction and Western blot of the proband＇s muscle. Moreovel, literature data on the clinical and mutational features of all reported EPM4 patients were reviewed. Results： The gene analysis revealed a novel homozygous splicing mutation （c.995-1G〉A） of the SCARB2 gene in two brothers. Further functional analysis revealed that this mutation led to loss function of the SCARB2 protein. The classification of the candidate variant, according to the American College of Medical Genetics and Genomics standards and guidelines and functional analysis, was pathogenic. Therefore, these two brothers were finally diagnostically confirmed as EPM4. Conclusions： These present results suggest the potential for targeted NGS to conduct a more rapid and precise diagnosis for PME patients. A literature review revealed that mutations in the different functional domains of SCARB2 appear to be associated with the phenotype of EPM4.

Beneficiality of combined levetiracetam, clonazepam for myoclonus in MERRF requires further confirmation

To the Editor: With interest, we read the article by Su et al[1] about the antiepileptic drug (AED) treatment of 17 patients with genetically confirmed myoclonic epilepsy with ragged-red fibers (MERRF) syndrome. It was found that monotherapy with either levetiracetam (LEV), clonazepam (CZP), valproic acid (VPA).

Reversible dysphagia due to gabapentin-induced jaw myoclonus

An 89-year-old woman was admitted with a 3-day history of dysphagia and lower jaw twitching. She had a history of hypertension, diabetes mellitus, surgically corrected left proximal humeral fracture, and right C5 dermatome postherpetic neuralgia. The jaw twitching had caused dysphagia with an inability to drink liquids. Physical examination confirmed the persistent lower jaw myoclonus (Supplementary Video;http://links.lww.com/CM9/A48). The patient was fully conscious and had no twitching or nystagmus in any of her other extremities. The results of neurological examination and biochemical analysis (including complete blood profile, electrolyte level, random glucose concentration, renal function test, and liver function test) were all within the normal range. Computed tomography of the brain was unremarkable and an electroencephalogram showed no evidence of seizure. A careful review of her prescribed medications revealed the following: the patient complained of allodynia over the right C5 dermatome around 3 months prior and was prescribed gabapentin. The dosage of gabapentin was increased to 300 mg total dissolved solids (TDS) around 2 months prior. Creatinine levels were normal but her glomerular filtration rate, as estimated by the Cockcroft-Gault equation, was 36 mL/min.[1] Since the patient’s relatives supervised her medication intake, overdosage was not possible. Gabapentin was discontinued and replaced with pregabalin 50 mg BD and the patient was prescribed valium 2 mg TDS transiently. The jaw myoclonus subsided on the second day. After a consultation with a speech therapist, the patient resumed oral intake and remained tolerant of a normal diet. Upon review after 1 month, the patient remained free from jaw myoclonus.

A case of Dravet syndrome with focal cortical myoclonus

Background:Dravet syndrome(DS)is a severe epileptic encephalopathy in children dominated by polymorphic seizures.Focal cortical myoclonus indicated on conventional electroencephalogram(EEG)was rarely observed in DS.Case presentation:The child,boy,thirteen months old,suffered from clonic seizures during bathing at two months old.Later he suffered from recurrent afebrile or febrile generalized tonic–clonic seizures often developing into status epilepticus.A genetic analysis of the SCN1A gene revealed a de novo heterozygous frame shift mutation in exon 21(c.3836_c.3837del AT).His myoclonic jerks of unilateral arm occurred spontaneously in response to movement.A spike wave from right central-parietal cortex immediately preceded a left myoclonic muscle activity,while a spike wave from left immediately preceded a right myoclonic muscle activity.The onset of the detected spike preceded the onset of myoclonic muscle activity by 42 ms using jerk-locked back-averaging of electroencephalogram data.The focal cortical myoclonus was not noted when one year old.Conclusions:Focal cortical myoclonus could be a form of seizures during the first year of life in DS,which may broaden the types of seizures of DS and may provide some diagnostic clues for DS.

Case Report:Lance-Adams syndrome:a report of two cases

Chronic post-hypoxic myoclonus, also known as Lance-Adams syndrome (LAS), is a rare complication of successful cardiopulmanry resuscitation often accompanied by action myoclonus and cerebellar ataxia. It is seen in patients who have un-dergone a cardiorespiratory arrest, regained consciousness afterwards, and then developed myoclonus days or weeks after the event. Worldwide, 122 cases have been reported in the literature so far, including 1 case of Chinese. Here we report 2 Chinese LAS patients with detailed neuroimagings. Cranial single photon emission computed tomography (SPECT) of patient 1, a 52-year-old woman, showed a mild hypoperfusion in her left temporal lobe, whereas patient 2, a 54-year-old woman, manifested a mild bilateral decrease of glucose metabolism in the frontal lobes and a mild to moderate decrease of the N-acetyl aspartate (NAA) peak in the bilateral hippocampi by cranial [18F]-fluorodeoxyglucose positron emission tomographic (PET) scan and cranial magnetic resonance spectroscopy (MRS), respectively. We also review the literature on the neuroimaging, pathogenesis, and treatment of LAS.

Compound heterozygous mutations in the neuraminidase 1 gene in type 1 sialidosis: A case report and review of literature

BACKGROUND Type 1 sialidosis,also known as cherry-red spot-myoclonus syndrome,is a rare autosomal recessive lysosomal storage disorder presenting in the second decade of life.The most common symptoms are myoclonus,ataxia and seizure.It is rarely encountered in the Chinese mainland.CASE SUMMARY A 22-year-old male presented with complaints of progressive myoclonus,ataxia and slurred speech,without visual symptoms;the presenting symptoms began at the age of 15-year-old.Whole exome sequencing revealed two pathogenic heterozygous missense variants[c.239C>T(p.P80L)and c.544A>G(p.S182G)in the neuraminidase 1(NEU1)gene],both of which have been identified previously in Asian patients with type 1 sialidosis.All three patients identified in China's Mainland come from three unrelated families,but all three show the NEU1 mutations p.S182G and p.P80L pathogenic variants.Increasing sialidase activity through chaperones is a promising therapeutic target in sialidosis.CONCLUSION Through retrospective analysis and summarizing the clinical and genetic characteristics of type 1 sialidosis,we hope to raise awareness of lysosomal storage disorders among clinicians and minimize the delay in diagnosis.

7例儿童斜视眼阵挛-肌阵挛临床特征及治疗效果分析

目的分析儿童斜视眼阵挛-肌阵挛综合征（OMS）的诊断、治疗及预后。方法回顾性分析2002年1月至2014年12月本院确诊的斜视眼阵挛-肌阵挛综合征7例患儿临床资料，根据是否与神经母细胞瘤（NB）相关，分为伴发NB（NB＋组3例）和不伴发NB（NB-组4例）。NB＋组3例患儿均接受新辅助化疗（环磷酰胺化疗为主）＋手术；两组患儿均接受激素治疗，NB＋组3例、NB-组2例接受免疫球蛋白治疗，两组中各有2例行利妥昔单抗二线治疗。两组患儿随访均〉2年，最后一次随访复查时进行神经系统预后评估。结果（1）7例患儿中4例（4／7）有神经系统后遗症，包括：2例（2／7）患儿实践／语言后遗症，2例（2／7）患儿持续共济失调；1例患儿运动障碍（1／7）；1例患儿同时存在运动，实践／语言后遗症；（2）NB＋组3例患儿2例NB预后良好，1例肿瘤残余。两组患儿间神经系统功能预后差异无统计学意义（P〉0．05）。结论OMS（伴发或不伴发NB）可能是同一种疾病，由于本病少见，需要多学科和多中心合作收集病例积累经验，为提升对OMS的认知，建立标准化诊断步骤和治疗方法提供依据。