Opsoclonus-myoclonus-ataxia syndrome in children

Brain Volumes in Opsoclonus-Myoclonus Ataxia Syndrome: A Longitudinal Study

INTRODUCTION

Little is known about the longitudinal trajectory of brain growth in children with opsoclonus-myoclonus ataxia syndrome. We performed a longitudinal evaluation of brain volumes in pediatric opsoclonus-myoclonus ataxia syndrome patients compared with age- and sex-matched healthy children.

PATIENTS AND METHODS

This longitudinal case-control study included brain magnetic resonance imaging (MRI) scans from consecutive pediatric opsoclonus-myoclonus ataxia syndrome patients (2009-2020) and age- and sex-matched healthy control children. FreeSurfer analysis provided automatic volumetry of the brain. Paired t tests were performed on the curvature of growth trajectories, with Bonferroni correction.

RESULTS

A total of 14 opsoclonus-myoclonus ataxia syndrome patients (12 female) and 474 healthy control children (406 female) were included. Curvature of the growth trajectories of the cerebral white and gray matter, cerebellar white and gray matter, and brainstem differed significantly between opsoclonus-myoclonus ataxia syndrome patients and healthy control children (cerebral white matter, P = .01; cerebral gray matter, P = .01; cerebellar white matter, P < .001; cerebellar gray matter, P = .049; brainstem, P < .01).

DISCUSSION/CONCLUSION

We found abnormal brain maturation in the supratentorial brain, brainstem, and cerebellum in children with opsoclonus-myoclonus ataxia syndrome.

Benign paraspinal ganglioneuroma with paraneoplastic opsoclonus myoclonus syndrome

Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare immune-mediated movement disorder occurring as a paraneoplastic manifestation of neuroblastic tumours (NTs), especially neuroblastoma in infancy. Ganglioneuroma (GN), the benign tumour in the spectrum, is rarely associated with OMAS. We report the case of a child in her second year of life presenting with acute onset of progressive paraplegia and OMAS. MRI showed diffuse and infiltrating left paraspinal mass from T3-T9 levels with differentials of neuroblastoma or ganglioneuroblastoma. Histopathological and immunohistochemistry examination of the excised tumour showed maturing GN. The OMAS was managed with intravenous immunoglobulin and steroids. In the 6-month follow-up, the child has a residual motor weakness with myelomalacia in neuroimaging. The case report substantiates the occurrence of OMAS as paraneoplastic manifestation in NTs, including benign, in children younger than 2 years with a female predilection.

Five Years Follow-up of Opsoclonus-Myoclonus-Ataxia Syndrome-Associated Neurogenic Tumors in Children

AIM

 Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare autoimmune disorder. Approximately half of the cases are associated with neuroblastoma in children. This study's aim is to review management of our cases with OMAS-associated neuroblastoma for treatment approach as well as long-term follow-up.

METHODS

 Age at onset of symptoms and tumor diagnosis, tumor location, histopathology, stage, chemotherapy, OMAS protocol, surgery, and follow-up period were evaluated retrospectively in six patients between 2007 and 2022.

RESULTS

 Mean age of onset of OMAS findings was 13.5 months and mean age at tumor diagnosis was 15.1 months. Tumor was located at thorax in three patients and surrenal in others. Four patients underwent primary surgery. Histopathological diagnosis was ganglioneuroblastoma in three, neuroblastoma in two, and undifferentiated neuroblastoma in one. One patient was considered as stage 1 and rest of them as stage 2. Chemotherapy was provided in five cases. The OMAS protocol was applied to five patients. Our protocol is intravenous immunoglobulin (IVIG) 1 g/kg/d for 2 consecutive days once a month and dexamethasone for 5 days (20 mg/m2/d for 1-2 days, 10 mg/m2/d for 3-4 days, and 5 mg/m2/d for the fifth day) once a month, alternatively by 2-week intervals. Patients were followed up for a mean of 8.1 years. Neuropsychiatric sequelae were detected in two patients.

CONCLUSION

 In tumor-related cases, alternating use of corticosteroid and IVIG for suppression of autoimmunity as the OMAS protocol, total excision of the tumor as soon as possible, and chemotherapeutics in selected patients seem to be related to resolution of acute problems, long-term sequelae, and severity.

[Opsoclonus-myoclonus syndrome associated with West Nile virus]

Opsoclonus is oculomotor dyskinesia characterized by rapid, repetitive conjugate eye movements that are involuntary, arrhythmic, chaotic, and multidirectional (horizontal, vertical, and torsional components). Most common cause of the symptom is paraneoplastic process. It is combined with myoclonus usually with the development of opsoclonus-myoclonus syndrome. Viral etiology is one of the possible causes of the of this syndrome, which is presented in the following case. A 26-year-old man was admitted to an infectious hospital suspected by encephalitis. After a 2-day febrile fever the patient developed balance problem, nausea, vomiting, tremors in the limbs and head, sensations of jerking of eyeballs. The neurological examination revealed opsoclonus, myoclonic jerking in the limbs, neck and trunk muscles, severe static and dynamic ataxia, there was no consciousness changes or altered mental stature. Cerebrospinal fluid examination revealed a pleocytosis (24 cells), increased protein levels (1.1 g/l). MRI of the brain was normal. After excluding of typical neuroinfections the patient was tested for West Nile fever. Elevated titers of IgG and IgM for West Nile fever virus were detected, as well as positive PCR for virus RNA in the cerebrospinal fluid. Patient was treated by acyclovir, an antibiotic and dexamethasone but severe neurological symptoms were persisted for 2 weeks with inability of sitting and walking. Then the symptoms gradually began to improve, rehabilitation was included with total recovery during the next 2 months. The doctors should be aware for possibility of neuroinvasive form of West Nile fever as the etiology of opsoclonus-myoclonus syndrome.

Nonspecific Gastrointestinal Symptoms as the First Sign of Ganglioneuroblastoma Intermixed-Case Report and Literature Review

Nonspecific gastrointestinal symptoms remain a problem for pediatricians because, out of a thousand trivial cases, there are rare diseases that require in-depth diagnostics and extensive knowledge to identify them. These complaints may be caused by a neoplastic process. We present the case of a 5-year-old boy whose diagnostic pathway lasted about 3 months. He was admitted to hospital due to severe abdominal pain. Physical examination revealed a bloated, hard, and painful abdomen. In the standing X-ray, the features of intestinal obstruction were visualized. An ultrasound examination showed a possible malignant lesion in the location of the left adrenal gland. After the surgical removal of the pathological mass and histopathological examination, the diagnosis of ganglioneuroblastoma intermixed was made. This tumor, along with neuroblastoma, ganglioneuroma, and ganglioneuroblastoma nodular, belongs to neuroblastic tumors (NTs), which originate from primitive cells of the sympathetic nervous system. NTs are quite rare, but they are still the majority of extracranial solid tumors in children, and their symptoms often appear relatively late when the neoplastic process is already advanced. The purpose of this review is to present current information about ganglioneuroblastoma, with a special emphasis on nonspecific gastrointestinal symptoms as first sign of this tumor and its diagnostics.

Diagnosis and Treatment of Paraneoplastic Neurologic Syndromes

Paraneoplastic antibody syndromes result from the anti-tumor antibody response against normal antigens ectopically expressed by tumor cells. Although this antibody response plays an important role in helping clear a nascent or established tumor, the engagement of antigens expressed in healthy tissues can lead to complex clinical syndromes with challenging diagnosis and management. The majority of known paraneoplastic antibody syndromes have been found to affect the central and peripheral nervous system. The present review provides an update on the pathophysiology of paraneoplastic neurologic syndromes, as well as recommendations for their diagnosis and treatment.

Paraneoplastic Neurological Syndromes of the Central Nervous System: Pathophysiology, Diagnosis, and Treatment

Paraneoplastic neurological syndromes (PNS) include any symptomatic and non-metastatic neurological manifestations associated with a neoplasm. PNS associated with antibodies against intracellular antigens, known as "high-risk" antibodies, show frequent association with underlying cancer. PNS associated with antibodies against neural surface antigens, known as "intermediate- or low-risk" antibodies, are less frequently associated with cancer. In this narrative review, we will focus on PNS of the central nervous system (CNS). Clinicians should have a high index of suspicion with acute/subacute encephalopathies to achieve a prompt diagnosis and treatment. PNS of the CNS exhibit a range of overlapping "high-risk" clinical syndromes, including but not limited to latent and overt rapidly progressive cerebellar syndrome, opsoclonus-myoclonus-ataxia syndrome, paraneoplastic (and limbic) encephalitis/encephalomyelitis, and stiff-person spectrum disorders. Some of these phenotypes may also arise from recent anti-cancer treatments, namely immune-checkpoint inhibitors and CAR T-cell therapies, as a consequence of boosting of the immune system against cancer cells. Here, we highlight the clinical features of PNS of the CNS, their associated tumors and antibodies, and the diagnostic and therapeutic strategies. The potential and the advance of this review consists on a broad description on how the field of PNS of the CNS is constantly expanding with newly discovered antibodies and syndromes. Standardized diagnostic criteria and disease biomarkers are fundamental to quickly recognize PNS to allow prompt treatment initiation, thus improving the long-term outcome of these conditions.

Neuroimaging in cerebellar ataxia in childhood: A review

Ataxia is one of the most common pediatric movement disorders and can be caused by a large number of congenital and acquired diseases affecting the cerebellum or the vestibular or sensory system. It is mainly characterized by gait abnormalities, dysmetria, intention tremor, dysdiadochokinesia, dysarthria, and nystagmus. In young children, ataxia may manifest as the inability or refusal to walk. The diagnostic approach begins with a careful clinical history including the temporal evolution of ataxia and the inquiry of additional symptoms, is followed by a meticulous physical examination, and, depending on the results, is complemented by laboratory assays, electroencephalography, nerve conduction velocity, lumbar puncture, toxicology screening, genetic testing, and neuroimaging. Neuroimaging plays a pivotal role in either providing the final diagnosis, narrowing the differential diagnosis, or planning targeted further workup. In this review, we will focus on the most common form of ataxia in childhood, cerebellar ataxia (CA). We will discuss and summarize the neuroimaging findings of either the most common or the most important causes of CA in childhood or present causes of pediatric CA with pathognomonic findings on MRI. The various pediatric CAs will be categorized and presented according to (a) the cause of ataxia (acquired/disruptive vs. inherited/genetic) and (b) the temporal evolution of symptoms (acute/subacute, chronic, progressive, nonprogressive, and recurrent). In addition, several illustrative cases with their key imaging findings will be presented.

Long-term neurological outcomes of children with neuroblastoma with opsoclonus-myoclonus syndrome

BACKGROUND

Neuroblastoma with opsoclonus-myoclonus syndrome (OMS-NB) is a rare disease in children. Few studies of long-term outcome of children with OMS-NB were conducted. This study aimed to review the rate of recovery of neurological symptoms and the long-term neurological outcomes of children with OMS-NB.

METHODS

This study retrospectively assessed 14 children with OMS-NB diagnosed at Peking University First Hospital from May 2011 to November 2019. Demographic data, neurological symptoms, oncological status and treatments were retrospectively reviewed from the records. Neurological sequelae were recorded by clinical and remote follow-up.

RESULTS

During the acute stage, myoclonus and ataxia were observed in all children while opsoclonus was observed in 10/14 children. The median durations of neurological symptoms were 15 months (range, 5-48 months). Approximately 93% (13/14) children revealed neurological sequelae. Significant correlations were as follows: motor retardation with female gender (P<0.001) and residual tumors (P<0.05); language impairment with non-adrenal-gland-located tumors (P<0.05). There were no obvious factors that had a statistical relationship with cognitive disorder or behavioral changes.

CONCLUSIONS

Children with OMS-NB have favorable outcomes in terms of neurological symptoms. Neurological sequelae occurred in almost all children. Children with different features tend to reveal different sequalae. Features of female gender and residual tumors tend to reveal motor retardation while that of non-adrenal-gland-located tumors tend to reveal language impairment.

Acute Movement Disorders in Childhood

Acute-onset movement disorders (MDs) are an increasingly recognized neurological emergency in both adults and children. The spectrum of possible causes is wide, and diagnostic work-up is challenging. In their acute presentation, MDs may represent the prominent symptom or an important diagnostic clue in a broader constellation of neurological and extraneurological signs. The diagnostic approach relies on the definition of the overall clinical syndrome and on the recognition of the prominent MD phenomenology. The recognition of the underlying disorder is crucial since many causes are treatable. In this review, we summarize common and uncommon causes of acute-onset movement disorders, focusing on clinical presentation and appropriate diagnostic investigations. Both acquired (immune-mediated, infectious, vascular, toxic, metabolic) and genetic disorders causing acute MDs are reviewed, in order to provide a useful clinician’s guide to this expanding field of pediatric neurology.