biology

Opsoclonus myoclonus syndrome

Opsoclonus myoclonus syndrome is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Opsoclonus myoclonus syndrome rather than just read about it. In short: Opsoclonus myoclonus syndrome (OMS), also known as opsoclonus-myoclonus-ataxia (OMA), is a rare neurological disorder of unknown cause which appears to be the result of an autoimmune process involving the nervous system. It is an extremely rare condition, affecting as few as 1 in 10,000,000 people per year.

Key takeaways

Opsoclonus myoclonus syndrome belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Opsoclonus myoclonus syndrome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Opsoclonus myoclonus syndrome from memory before moving on to harder problems.

Reference excerpt

Opsoclonus myoclonus syndrome (OMS), also known as opsoclonus-myoclonus-ataxia (OMA), is a rare neurological disorder of unknown cause which appears to be the result of an autoimmune process involving the nervous system. It is an extremely rare condition, affecting as few as 1 in 10,000,000 people per year. It affects 2 to 3% of children with neuroblastoma and has been reported to occur with celiac disease and diseases of neurologic and autonomic dysfunction.

Signs and symptoms Symptoms include:

opsoclonus (rapid, involuntary, multivectorial (horizontal and vertical), unpredictable, conjugate fast eye movements without intersaccadic [quick rotation of the eyes] intervals) myoclonus (brief, involuntary twitching of a muscle or a group of muscles) cerebellar ataxia, both truncal and appendicular aphasia (a language disorder in which there is an impairment of speech and of comprehension of speech, caused by brain damage) mutism (a language disorder in which a person does not speak despite evidence of speech ability in the past, often part of a larger neurological or psychiatric disorder) lethargy irritability or malaise drooling strabismus (a condition in which the eyes are not properly aligned with each other) vomiting sleep disturbances emotional disturbances (including fits of rage) About half of all OMS cases occur in association with neuroblastoma (a cancer of the sympathetic nervous system usually occurring in infants and children).

Disease course and clinical subtypes In most cases, OMS starts with an acute flare-up of physical symptoms within days or weeks, but some less obvious symptoms such as irritability and malaise may begin weeks or months earlier.

Cause In children, most cases are associated with neuroblastoma and most of the others are suspected to be associated with a low-grade neuroblastoma that spontaneously regressed before detection. In adults, most cases are associated with breast carcinoma or small-cell lung carcinoma. It is one of the few paraneoplastic (meaning 'indirectly caused by cancer') syndromes that occurs in both children and adults, although the mechanism of immune dysfunction underlying the adult syndrome is probably quite different. It is hypothesized that a viral infection (perhaps St. Louis encephalitis, Chikungunya, Epstein-Barr, Coxsackie B, enterovirus, or just a flu) causes the remaining cases, though a direct connection has not been proven. Rare cases of Opsoclonus myoclonus syndrome associated with Lyme disease have also been reported. OMS is not generally considered an infectious disease. OMS is not passed on genetically.

Diagnosis Because OMS is so rare and occurs at an average age of 19 months (6 to 36 months), a diagnosis can be slow. Some cases have been diagnosed as having been caused by a virus. After a diagnosis of OMS is made, an associated neuroblastoma is discovered in half of cases, with median delay of 3 months. The interictal EEG pattern is usually normal.

Treatment

There is no known definitive cure for OMS. However, several drugs have proven to be effective in their treatment. Some of medication used to treat the symptoms are:

ACTH has shown improvements in symptoms but can result in an incomplete recovery with residual deficits. Corticosteroids (such as prednisone or methylprednisolone) used at high dosages (500 mg - 2 g per day intravenously for a course of 3 to 5 days) can accelerate regression of symptoms. Subsequent very gradual tapering with pills generally follows. Most patients require high doses for months to years before tapering. Intravenous Immunoglobulins (IVIg) are often used with varying results. Several other immunosuppressive drugs, such as cyclophosphamide and azathioprine, may be helpful in some cases. Chemotherapy for neuroblastoma may be effective, although data is contradictory and unconvincing at this point in time. Rituximab has been used with encouraging results. Other medications are used to treat symptoms without influencing the nature of the disease (symptomatic treatment): Trazodone can be useful against irritability and sleep problems Additional treatment options include plasmapheresis for severe, steroid-unresponsive relapses. The National Organization for Rare Disorders (NORD) recommends FLAIR therapy consisting of a three-agent protocol involving front-loaded high-dose ACTH, IVIg, and rituximab that was developed by the National Pediatric Myoclonus Center, and has the best-documented outcomes. Almost all patients (80-90%) show improvement with this treatment and the relapse rate appears to be about 20%. A more detailed summary of current treatment options can be found at Treatment Options The following medications should probably be avoided:

Midazolam - Can cause irritability. Melatonin - Is known to stimulate the immune system. Also, see "An Innovative Approach to the Problem of Sedating Children with Opsoclonus-Myoclonus Syndrome". Pranzatelli Abstracts. for more details

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Opsoclonus myoclonus syndrome

Start with the simplest possible case. Write down what Opsoclonus myoclonus syndrome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Opsoclonus myoclonus syndrome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Opsoclonus myoclonus syndrome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Opsoclonus myoclonus syndrome

In research: Opsoclonus myoclonus syndrome appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Opsoclonus myoclonus syndrome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Opsoclonus myoclonus syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Autoimmune diseases, Neurological disorders, Rare syndromes, so understanding it makes those chapters shorter.
In everyday life: Look for Opsoclonus myoclonus syndrome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Opsoclonus myoclonus syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Opsoclonus myoclonus syndrome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Opsoclonus myoclonus syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Opsoclonus myoclonus syndrome in simple terms?

Why does Opsoclonus myoclonus syndrome matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Opsoclonus myoclonus syndrome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Opsoclonus myoclonus syndrome.