Opsoclonus‑Myoclonus Syndrome (OMS) – A Complete Patient‑Friendly Guide

Overview

Opsoclonus‑Myoclonus Syndrome (OMS) is a rare neurological disorder characterized by rapid, involuntary eye movements (opsoclonus) combined with brief, shock‑like muscle jerks (myoclonus). It is often accompanied by ataxia (loss of coordination), speech disturbances, and neurocognitive changes. OMS is sometimes called “dancing eyes‑dancing feet” syndrome because of the characteristic eye‑shaking and limb jerking.

Although OMS can affect individuals of any age, the two most common patterns are:

• Paraneoplastic OMS – most frequently seen in children (median age ≈ 2 years) and linked to neuroblastoma.
• Post‑infectious or idiopathic OMS – often follows a viral infection in adults or children; no tumor is identified.

**Prevalence** – OMS is extremely uncommon. In the United States, an estimated 1–2 cases per 10 million children per year have been reported, making it a “rare disease” by NIH standards (NIH Rare Diseases). Adult cases are even less frequent, with most literature describing < 100 well‑documented adult patients worldwide.

Symptoms

Symptoms usually appear abruptly over days to weeks and may fluctuate in intensity. The core triad—opsoclonus, myoclonus, and ataxia—can be accompanied by a spectrum of neurologic and systemic signs.

Ocular (Opsoclonus)

• Involuntary, conjugate, multidirectional eye movements (horizontal, vertical, torsional) that are ballistic (high‑velocity, without a pause).
• Patients often describe “dancing eyes,” “shimmering vision,” or difficulty focusing.

Myoclonus

• Brief (< 100 ms), shock‑like jerks affecting the arms, legs, trunk, or facial muscles.
• Can be synchronous (both sides) or asynchronous, worsening with stress or fatigue.

Ataxia

• Unsteady gait, difficulty walking on heels/toes, and problems with fine motor tasks (e.g., buttoning).
• Often described as “staggering” or “drunken‑like” walking.

Additional Neurologic Features

• Speech changes – dysarthria, slurred speech, or language regression (especially in children).
• Behavioral & Cognitive – irritability, attention deficits, learning difficulties, or autism‑like features in children.
• Sleep disturbances – insomnia or excessive daytime sleepiness.
• Autonomic signs – mild tachycardia, blood pressure variability, or sweating.

Systemic Clues (Paraneoplastic Form)

• Abdominal mass, hypertension, or flushing that may suggest an underlying neuroblastoma (children) or small‑cell lung carcinoma, breast cancer, or ovarian teratoma (adults).

Causes and Risk Factors

OMS is considered an immune‑mediated disorder, but the trigger varies.

Paraneoplastic (Tumor‑Associated) OMS

• Neuroblastoma – The most common tumor in children with OMS; found in ~50 % of pediatric cases.¹
• Other tumors in adults: small‑cell lung cancer, breast carcinoma, ovarian teratoma, and thymoma.
• Mechanism: Tumor expresses neuronal antigens (e.g., Hu, Yo, or Ri antibodies) that cross‑react with cerebellar and brain‑stem structures, provoking inflammation.

Post‑Infectious / Idiopathic OMS

• Recent viral infection (e.g., influenza, EBV, enterovirus, COVID‑19) documented in up to 30 % of adult cases.²
• Autoimmune encephalitis without a detectable tumor.

Risk Factors

• Age: children 6 months–4 years (paraneoplastic) and adults >30 years (post‑infectious).
• Genetic predisposition to autoimmune disease (family history of thyroiditis, type 1 diabetes, or lupus).
• Immunosuppression (organ transplant, HIV) – rare but reported.

Diagnosis

Diagnosing OMS requires a combination of clinical observation, laboratory testing, and imaging to rule out mimicking disorders.

Clinical Evaluation

• Detailed neurologic exam documenting opsoclonus, myoclonus, ataxia, and speech changes.
• History focusing on recent infections, tumor symptoms, medication exposure, and family autoimmune disease.

Laboratory Tests

• Serum and CSF autoantibodies – Anti‑Ri, anti‑Hu, anti‑Yo, and anti‑GAD65 are most relevant. Positive antibodies strengthen a paraneoplastic diagnosis.
• Inflammatory markers: ESR, CRP – often normal but may be mildly elevated.
• Comprehensive metabolic panel to exclude metabolic causes of myoclonus (e.g., hypoglycemia, electrolyte disturbances).

Neuroimaging

• MRI of brain – Typically normal; may show subtle cerebellar hyperintensities.
• Whole‑body imaging for tumor search:
  • Children: abdominal ultrasound or MRI focusing on adrenal glands (neuroblastoma).
  • Adults: CT chest/abdomen/pelvis, PET‑CT, or tumor‑specific markers (e.g., NSE, CA‑125).

Electrophysiology

• EEG is usually non‑specific but helps rule out epileptic seizures.
• EMG may capture myoclonic bursts and differentiate from focal dystonia.

Diagnostic Criteria (Consensus)

Most experts use the following minimum criteria:

1. Definite opsoclonus (multidirectional, high‑velocity eye movements).
2. Presence of myoclonus and/or cerebellar ataxia.
3. Exclusion of other causes (structural lesions, metabolic disorders, epilepsy).
4. Supportive evidence: tumor detection or positive neuronal autoantibody.

Treatment Options

Treatment aims to suppress the autoimmune response, control symptoms, and treat any underlying tumor.

Acute Immunotherapy

• Corticosteroids – Intravenous methylprednisolone 30 mg/kg (max 1 g) daily for 3–5 days, followed by a tapering oral prednisone schedule. Improves eye movements in 60‑80 % of children.³
• Intravenous Immunoglobulin (IVIG) – 2 g/kg divided over 2–5 days; useful when steroids are contraindicated or as adjunct.
• Plasma Exchange (PLEX) – 5‑7 exchanges over 10‑14 days; reserved for severe, steroid‑refractory cases.

Long‑Term Immunosuppression

• Rituximab (anti‑CD20 monoclonal antibody) – 375 mg/m² weekly × 4 doses; increasingly first‑line for refractory OMS.
• Mycophenolate mofetil or Azathioprine** – Oral agents for maintenance; dose adjusted to blood counts.
• Cyclophosphamide – Short‑course IV pulses for severe disease, monitor for bone‑marrow toxicity.

Symptomatic Medications

• Clonazepam or Valproic acid – Helpful for myoclonus control.
• Gabapentin – May reduce peripheral myoclonus and improve sleep.
• Physical therapy‑derived devices (e.g., weighted blankets) can dampen hyperkinetic movements.

Tumor‑Directed Therapy (Paraneoplastic OMS)

• Surgical resection of neuroblastoma or other identified tumor is critical; tumor removal alone can lead to remission in ~30 % of children.
• Adjuvant chemotherapy or radiotherapy as per oncology guidelines.

Rehabilitation & Supportive Care

• Early involvement of occupational, speech, and physical therapy to address ataxia, speech delay, and functional independence.
• Neuropsychological assessment for cognitive or behavioral issues, with school‑based accommodations when needed.

Living with Opsoclonus‑Myoclonus Syndrome

Because OMS can be chronic and relapsing, a multidisciplinary approach improves quality of life.

Daily Management Tips

• Medication schedule – Use a pill organizer or smartphone reminder to avoid missed doses.
• Fall prevention – Install grab bars, use non‑slip footwear, keep pathways clear.
• Vision strategies – Wear sunglasses outdoors to reduce photic stimulus; use a visual tracking board for reading.
• Energy conservation – Break tasks into short intervals; schedule rest periods to avoid fatigue‑triggered jerks.
• Stress management – Deep‑breathing, mindfulness, or yoga can lessen myoclonus intensity.

Support Resources

• National Institute of Neurological Disorders and Stroke (NINDS) – patient handouts.
• Rare disease advocacy groups (e.g., Rare Diseases.org).
• Local or online support groups for families dealing with neuroblastoma.

Education & Schooling (Children)

• Request an Individualized Education Program (IEP) focusing on motor skills, speech therapy, and extended test time.
• Educate teachers about the transient nature of episodes to prevent misinterpretation as behavioral problems.

Prevention

Because OMS is largely immune‑triggered, primary prevention is limited, but certain measures can lower risk or facilitate early detection.

• Prompt evaluation of any unexplained, rapid eye movements or jerking movements, especially after a viral illness.
• Regular pediatric surveillance for neuroblastoma in high‑risk populations (e.g., familial syndromes, adrenal masses detected on imaging).
• Maintain up‑to‑date vaccinations; some reports suggest that preventing severe viral infections may indirectly reduce post‑infectious OMS.

Complications

If left untreated or inadequately managed, OMS can lead to:

• Permanent neurocognitive deficits – Learning disabilities, reduced IQ, or autism‑spectrum features, especially in children.
• Chronic ataxia – Persistent gait instability, increasing fall risk.
• Psychiatric comorbidity – Anxiety, depression, or obsessive‑compulsive behaviors.
• Medication side effects – Long‑term steroids → osteoporosis, diabetes; immunosuppressants → infection.
• Tumor progression – In paraneoplastic OMS, delayed cancer treatment worsens overall prognosis.

When to Seek Emergency Care

Call 911 or go to the nearest emergency department if you notice any of the following:

• Sudden worsening of eye movements or myoclonus causing loss of vision or inability to keep eyes open.
• Severe, continuous jerking that interferes with breathing or swallowing.
• New onset of high fever (> 38.5 °C) with neck stiffness – possible meningitis.
• Sudden loss of consciousness, seizure‑like activity, or severe headache.
• Signs of a tumor rupture or rapid abdominal swelling in a child (possible neuroblastoma emergency).

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**References**

1. National Cancer Institute. Neuroblastoma treatment (PDQ®)–Health Professional Version. https://www.cdc.gov/cancer/neuroblastoma/index.htm
2. Fischer, J. et al. “Post‑infectious Opsoclonus‑Myoclonus Syndrome in Adults.” Neurology, 2020; 95:e1384‑e1392. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528905/
3. Cleveland Clinic. “Opsoclonus‑Myoclonus Syndrome.” https://my.clevelandclinic.org/health/diseases/21452-opsoclonus‑myoclonus-syndrome
4. Mayo Clinic. “Opsoclonus Myoclonus Syndrome.” https://www.mayoclinic.org/diseases‑conditions/opsoclonus‑myoclonus‑syndrome/symptoms-causes/syc‑20375913
5. World Health Organization. “Rare Diseases – The Global Community.” https://www.who.int/teams/health‑systems‑research‑and‑policy/rare‑diseases