Opsoclonus myoclonus syndrome
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: José Eduardo Riceto Loyola Junior, M.D.[2]
Synonyms and keywords:
Overview
Opsoclonus myoclonus syndrome (OMS) is a rare neurological disorder, which can be very heterogenous, presenting itself with many different symptoms such as opsoclonus and/or myoclonus - which name the syndrome, but also ataxia, behavioral and/or sleep disturbances. It is believed to be caused by an immune system dysfunction, either induced by infection or paraneoplastic etiologies.
Historical Perspective
- Opsoclonus myoclonus syndrome was first described in 1962 by M. Kinsbourne, who presented a series of six cases of children with ataxia, myoclonus and opsoclonus.
- The syndrome was named as "myoclonic encephalopathy", but has also been called as "dancing eye syndrome".[1] Recently it has been more often referred to as opsoclonus myoclonus syndrome.
Classification
- There is no established system for the classification of opsoclonus myoclonus syndrome.
Pathophysiology
- The pathogenesis of opsoclonus myoclonus syndrome is characterized by neuroinflammation involving dysregulated B cells. It is believed that loss of tolerance and autoantibody production causes the neurological damage seen in the disease.
- Cerebrospinal fluid studies have shown B cell recruitment to the brain via CXCL13/CXCR5 and CXCL10/ CXCR3 ligand/receptor pairs[2]. The B cell activating factor plays a role increasing B cell survivability and there may be seen intrathecal production of oligoclonal bands.[3]
- There are two theories about the cause of the disease:
- Dysfunction of the Purkinje cells in the cerebellar vermis leading to disinhibition of the oculomotor neurons of the fastigial nucleus of the cerebellum.
- Disinhibition of burst neurons, which are mostly under inhibition from omnipause cells, causing saccadic eye movements.[4]
- It is not known if the triggers that causes opsoclonus myoclonus syndrome and those that causes relapses of the disease are the same or if they affect the same region of the brain.[3]
- There is no obvious gene/mutation associated with the development of opsoclonus myoclonus syndrome.[4]
- On microscopic histopathological analysis, gliosis and inflammation in the cerebellar vermis are characteristic findings of opsoclonus myoclonus syndrome.[4]
Clinical Features
- Opsoclonus myoclonus syndrome (also often called: “dancing eyes-dancing feet” syndrome) is a rare syndrome of unknown etiology that presents with the following features:[4]
- Opsoclonus,
- Myoclonic jerks,
- Behavioral disturbances
- Ataxia.
- The cause is not yet known but the accepted hypothesis is that it is an autoimmune, inflammatory reaction which damages the central nervous system. It is theorized that I can be triggered by either a paraneoplastic (being associated with neuroblastoma in children) or an infectious etiology.[4]
- In children it is associated neuroblastoma in approximately half of cases.[4] In this age group it also presents with gait ataxia, dysarthria, drooling, irritability, vomiting, and insomnia.[3]
- It has a relapse-remitting course. Symptoms may vary in duration during relapses and the remission period is also variable, but usually the relapses last at least 48-72h.[3]
- Children affected by the disease may not be fully asymptomatic between the episodes of the disease, persisting with significant speech and language deficits, sleep and some behavioral changes.[3]
- Most patients have no detectable antibody, but a few patients presenting with neuroblastoma do have anti-neuronal and anti-Purkinje cell antibodies.[4]
- Children with neuroblastoma and opsoclonus myoclonus syndrome usually have a better prognosis for their neuroblastomas as they are in more differentiated stages.[1]
Differentiating Opsoclonus Myoclonus syndrome from other Diseases
- Opsoclonus myoclonus syndrome must be differentiated from acute inflammatory cerebellar ataxia, which can be differentiated by the type of eye movement, rapid recovery without treatment and absence of irritability.[5]
Epidemiology and Demographics
- The prevalence of opsoclonus myoclonus syndrome is approximately 1 per 1,000,000 individuals worldwide.
Age
- Opsoclonus myoclonus syndrome is more commonly observed among patients aged 18 months old and may occur up to 5-6 years old.[6]
- Relapses of the disease may affect adults.
Gender
- Girls are slightly more affected with opsoclonus myoclonus syndrome than boys.[6]
Race
- There is no racial predilection for opsoclonus myoclonus syndrome.[4]
Risk Factors
- There are no risk factors associated with the development of opsoclonus myoclonus syndrome.
Natural History, Complications and Prognosis
- The majority of patients with opsoclonus myoclonus syndrome present with a relapse-remitting form of the disease.
- Early clinical features begin mostly at 18 months of age, and include myoclonus, opsoclonus, irritability and ataxia.[7]
- If left untreated, the neurological deficits of patients with opsoclonus myoclonus syndrome may remain more severe and affect neurological development through childhood and teenage years.[1]
- Prognosis is generally poor, as the patients with opsoclonus myoclonus syndrome usually remain with developmental delays and severe learning difficulties.[1]
- Adult opsoclonus myoclonus syndrome can occur as a paraneoplastic syndrome in association with small cell lung cancer or breast cancer, half of the cases being idiopathic and parainfectious.[1]
Diagnosis
Diagnostic Criteria
- The diagnosis of opsoclonus myoclonus syndrome is made when at least 3 of the following 4 diagnostic criteria are met:[8]
- Rare type of cancer that affects the nerve (neuroblastoma)
- Uncontrolled eye movement (opsoclonus)
- A movement disorder with sudden muscle contractions (myoclonus) and/or lack of coordination (ataxia)
- Behavioral and/or sleep disturbance
Symptoms
- Opsoclonus myoclonus syndrome presents in a relapse-remitting manner.
- There are acute and chronic symptoms.
- The classic symptoms are mostly seen in acute disease and they are:[6]
- Myoclonus,
- Opsoclonus,
- Ataxia.
- The symptoms presenting in the chronic disease may be a residual opsoclonus and abnormalities of eye movement which may be elicited by re-fixating from near to far or squeezing the eyelids shut. Hypometric saccades and smooth eye pursuit movements can remain abnormal for years. Children may also remain not as coordinated as their peers. Expressive language is generally more affected than receptive language, and cognitive deficits may become more evident in teenagers.[7]
Physical Examination
- Physical examination may be remarkable for:
- Ataxia: children present with an acute or subacute form of ataxia, losing the ability to walk and/or sit over a period ranging from one day to a few weeks, accompanied by severe irritability and myoclonus, being the first diagnosis proposed for most children often post-infectious acute cerebellar ataxia of childhood.[7]
- Opsoclonus: must be differentiated from nystagmus, which is present in most acute cerebellar ataxias. Opsoclonus is multidirectional, conjugate, non-phasic and fast in contrast with nystagmus, which is phasic, may be conjugated, unidirectional.[7]
- Myoclonus: ranges from polymyoclonia to coarse multifocal jerks, and may be persistent and exacerbated by emotional distress and movement.[7]
- Behavioral changes: development regression and personality change may also be seen.[7]
Laboratory Findings
- There are no specific laboratory markers associated with opsoclonus myoclonus syndrome.[9]
- In adults with OMS, a blood exam may show Hu anti-neuronal nuclear antibodies (anti-Hu) but not in children.[8]
- In some patients cerebrospinal fluid evaluation is necessary to detect neuroinflammation. These studies should include oligoclonal bands (with paired serum sample), aiming to detect antibodies in the CSF. [6]
- Flow cytometry of the lymphocytes using immunophenotyping may find an increased frequency of CSF CD 19+ B cells, which is a biomarker of opsoclonus myoclonus disease activity.[6]
- Atypical cases may warrant autoantibodies tests in some children, but this is not cost-effective.[6]
Imaging Findings
- Opsoclonus myoclonus syndrome may present with neuroblastoma in half of the cases (one author reported 80% of the cases), though only 2-3% of neuroblastoma present with opsoclonus myoclonus syndrome.[7]
- In the evaluation of a child with opsoclonus myoclonus syndrome, it is usually performed either a CT scan with contrast or MRI with gadolinium of the neck, chest, abdomen, and pelvis[6] as neuroblastomas can arise from sympathetic nervous system, being most frequent in the abdomen (2/3 of the cases) and thorax (20% of the cases)[10]
- On CT scans, the neuroblastoma is heterogeneous with calcifications being commonly seen. Usually the tumor insinuates itself beneath the aorta and lifting it off the vertebral column.[10]
- MRIs are superior to all other exams on detecting neuroblastomas and shows the tumor being heterogenous and iso to hypo intense on T1, and hyper intense on T2, with cystic/necrotic areas being easily identifiable.[6]
- On adults, the most associated neoplasms are small cell lung cancer, breast carcinoma, and ovarian teratoma[11], and PET scans are done to evaluate for occult tumors.[6]
Other Diagnostic Studies
- There are no other diagnostic studies that may be used to diagnose opsoclonus myoclonus syndrome.
Treatment
Medical Therapy
- There is no treatment for [disease name]; the mainstay of therapy is supportive care.
- The mainstay of therapy for [disease name] is [medical therapy 1] and [medical therapy 2].
- [Medical therapy 1] acts by [mechanism of action 1].
- Response to [medical therapy 1] can be monitored with [test/physical finding/imaging] every [frequency/duration].
Surgery
- Surgery is the mainstay of therapy for [disease name].
- [Surgical procedure] in conjunction with [chemotherapy/radiation] is the most common approach to the treatment of [disease name].
- [Surgical procedure] can only be performed for patients with [disease stage] [disease name].
Prevention
- There are no primary preventive measures available for [disease name].
- Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].
- Once diagnosed and successfully treated, patients with [disease name] are followed-up every [duration]. Follow-up testing includes [test 1], [test 2], and [test 3].
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Blaes, Franz, and Backialakshmi Dharmalingam. "Childhood opsoclonus-myoclonus syndrome: diagnosis and treatment." Expert review of neurotherapeutics 16.6 (2016): 641-648.
- ↑ Pranzatelli MR, Tate ED, McGee NR, Travelstead AL, Ranso- hoff RM, Ness JM, et al. Key role of CXCL13/CXCR5 axis for cerebrospinal fluid B cell recruitment in pediatric OMS. J Neuroimmunol 2012;243:81–8.
- ↑ 3.0 3.1 3.2 3.3 3.4 Pranzatelli, Michael R., and Elizabeth D. Tate. "Trends and tenets in relapsing and progressive opsoclonus-myoclonus syndrome." Brain and Development 38.5 (2016): 439-448.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 "American Academy of Ophthalmology - Opsoclonus Myoclonus Syndrome". American Academy of Ophthalmology. 07/04/2020. Check date values in:
|date=(help) - ↑ "ORPHANET - Opsoclonus-Myoclonus Syndrome". ORPHANET. 07/04/2020. Check date values in:
|date=(help) - ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 "NORD - National Organization for Rare Diseases - Opsoclonus-Myoclonus Syndrome". NORD. 07/04/2020. Check date values in:
|date=(help) - ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Matthay, Katherine K., et al. "Opsoclonus myoclonus syndrome in neuroblastoma a report from a workshop on the dancing eyes syndrome at the advances in neuroblastoma meeting in Genoa, Italy, 2004." Cancer letters 228.1-2 (2005): 275-282.
- ↑ 8.0 8.1 "Genetic and Rare Diseases Information Center - Opsoclonus Myoclonus Syndrome". GARD. 07/04/2020. Check date values in:
|date=(help) - ↑ Pike M. Opsoclonus-myoclonus syndrome. Handb Clin Neurol 2013;112:1209–11.
- ↑ 10.0 10.1 "Radiopaedia - Neuroblastomas". Radiopaedia.org. 07/04/2020. Check date values in:
|date=(help) - ↑ Oh, Sun-Young, Ji-Soo Kim, and Marianne Dieterich. "Update on opsoclonus–myoclonus syndrome in adults." Journal of neurology 266.6 (2019): 1541-1548.