Why does dystonia fascinate and challenge neurology?

Dystonia is probably the most nebulous of neurological terms. Neurologists use the term for a vast array of neurological diseases. Dystonia also crops up as part of many complex neurological syndromes. Worse still, neurologists also use the name dystonia as a symptom. All quite confusing and perplexing for the lay observer.

Public Domain, Link
Public Domain, Link

No wonder dystonia defies simple definitions. Take the National Institute of Neurological Disorders and Stroke (NINDS) definition which labels dystonia as “a disorder characterized by involuntary muscle contractions that cause slow repetitive movements or abnormal postures“. Then compare it with the NHS Choices definition which sees dystonia as “a medical term for a range of movement disorders that cause muscle spasms and contractions“. We must accept the flexibility of dystonia as both a disorder, and a range of disorders. The defining feature of dystonia however is simple enough-abnormal muscle postures and contractions.

By Katomin at the English language Wikipedia, CC BY-SA 3.0, Link
By Katomin at the English language Wikipedia, CC BY-SA 3.0, Link

The complexity in the definition is just a tip of the iceberg of the things that neurologists find fascinating about dystonia. Here are 5 big reasons why dystonia excites and challenges neurologists.

1. Dystonia is a very visible disorder

Rogers Hartmann at TEDxSMU from tedxsmu on Vimeo.

The abnormal postures that typify dystonia are observable, and the neurologist can describe and define the disorder (or disorders!). This is not the case with many neurological disorders such as migraine, which rely entirely on a history, or epilepsy, which rely heavily on eyewitness accounts. The abnormal postures in dystonia are often very dramatic, and sometimes literally defy description. To help ‘decode’ complex dystonia, neurologists often make video recordings of their patients and send to dystonia experts. And dystonia experts present their own video recordings at neurology conferences, to teach the less initiated of course, but also to flaunt their well-earned expertise.

2. Dystonia is both hereditary and acquired

Von James Heilman, MD - Eigenes Werk, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=9445214
Von James Heilman, MDEigenes Werk, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=9445214

Many types of dystonia are hereditary. Myoclonus-dystonia and dopa-responsive dystonia (DRD) for example are caused by well-defined genetic mutations. Dystonia is however also frequently acquired, for example as an adverse effect of antidepressant, antipsychotic, and anti-epileptic drugs. Neurologists go to great lengths to sort out what type of dystonia their patients have, bristling with anticipation that the next genetic blood test they send off will clinch the diagnosis. It doesn’t seem to matter that this is often hope trumping experience.

3. Dystonia manifests in a multitude of ways

By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below)Bartleby.com: Gray's Anatomy, Plate 1194, Public Domain, Link
By Henry Vandyke CarterHenry Gray (1918) Anatomy of the Human Body (See “Book” section below)Bartleby.com: Gray’s Anatomy, Plate 1194, Public Domain, Link

Dystonia may be localised such as with blepharospasm (excessive eyelid twitching), hemifacial spasm, Meige’s syndrome, and cervical dystonia (torticollis). At the same time, dystonia may be generalised as in Wilson’s disease, neuroferritinopathy, and neuroacanthocytosis. Dystonic symptoms often manifest spontaneously, but they may only be task-specific such as in writers cramp and musician’s dystonia. A further way dystonia crops up is as an ally of other movement disorders, as we see with dystonic tremor.

4. Dystonia is a rapidly evolving field

Bootstrap DNA by Charles Jencks, 2003. Mira66 on Flikr. https://www.flickr.com/photos/21804434@N02/3707633630
Bootstrap DNA by Charles Jencks, 2003. Mira66 on Flikr. https://www.flickr.com/photos/21804434@N02/3707633630

Unlike some neurological specialities that are stuck with age-old diseases, dystonia experts regularly describe new dystonia syndromes and genetic mutations, filling up an already crowded taxonomy. An example is the ever-expanding genetic mutations that cause primary dystonia, starting from DYT 1 to DYT 21, and still counting. The field of non-genetic dystonia is also expanding with new disorders such as Watchmaker’s dystonia. Well-established dystonia syndromes also surprise neurologists by manifesting in completely unexpected ways. Recent examples of these new phenotypes are foot drop dystonia resulting from parkin (PARK2) mutation. Neurologists also get excited when they come across known, but rare, presentations of dystonic syndromes such as this recent report on feeding dystonia in chorea-acanthocytosis. 

5. Treatments of dystonia are proliferating

Drugs. Daniel Foster on Flikr. https://www.flickr.com/photos/danielfoster/15097483625
Drugs. Daniel Foster on Flikr. https://www.flickr.com/photos/danielfoster/15097483625

Just as the types of dystonia are burgeoning, so are the treatments. Some interventions are novel, and some have a feel of ‘back to the future’. A few recent examples are treatment of isolated dystonia with zolpidem and selective peripheral denervation for cervical dystonia. Enough to keep the dystonia researchers busy, and to keep their patients feeling valued. Old school treatment such as botulinum toxin however maintain their pride of place. 

Human Genome. Richard Ricciardi on Flikr. https://www.flickr.com/photos/ricricciardi/11622986115
Human Genome. Richard Ricciardi on Flikr. https://www.flickr.com/photos/ricricciardi/11622986115

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For more on dystonia syndromes and treatment, check out:

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Dystonia is a hydra; why not get a concise handle by exploring the dystonia topics in neurochecklists  

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Which are the most reliable neurology reference sources?

Neurology is huge. It consists of diverse subspecialties, each covering several distinct diseases. Neurology is also a rapidly advancing field with cutting-edge diagnostic processes and novel therapeutic approaches. Neurological practice, therefore, depends on reliable and up-to-date resources.

"Interior view of Stockholm Public Library" by Marcus Hansson from Göteborg, Sweden - The best days are not planned. Licensed under CC BY 2.0 via Wikimedia Commons.
Interior view of Stockholm Public Library” by Marcus Hansson from Göteborg, Sweden – The best days are not planned. Licensed under CC BY 2.0 via Wikimedia Commons.

 

I have previously posted on the proven all-time outstanding neurology textbooks, the most helpful and practical neurology guidelines, and the top all-time neurology review articles. These are all very useful, but all struggle keep up with the rapidly evolving progress in neurology; these resources become obsolete very quickly, and updates often go through laborious and slow processes. Neurologists therefore need reliable sources that keep up with new knowledge, and make sense of all the information ‘out there’. What are these dependable neurology reference sites?  Here is a selection.

Neurology-specific reference sites

  1. The NINDS Disorder Index is a library of all neurological disorders listed alphabetically. All sections have information on current research, and provide links to involved organisations. It is an extensive resource, but you would expect this from the world-renown National Association of Neurological Disorders and Stroke.
  2. MedLink Neurology is an extensive resource for a wide variety of neurological diseases. Content requires paid registration. Articles cite references linked to PubMed and indicate the date they were last updated.

General medical sites with neurology sections

  1. Uptodate has a neurology section with a good search function but needs a subscription. It is text intensive.
  2. Medscape has a very good and extensive neurology section listed alphabetically, and it is free!
  3. BMJ Best Practice also lists neurology topics alphabetically but requires access
  4. BMJ Neurology resources page has a few important neurology links
  5. The Cochrane Library is searchable using neurology as search terms; as far as I can see, most if not all, contents are free
  6. Scholarpedia appears to be a growing site with a helpful neuroscience section worth keeping an eye on.
  7. Medline is the go-to resource for current articles on everything medical. It is however difficult to confirm which articles are relevant or reliable
  8. Trip Database is another huge searchable resource including neurology

Specialty-specific neurology reference sites

  1. The Neuromuscular Disease Centre of Washington University has a detailed database of neuromuscular diseases
  2. Brain Infections UK is a useful site for updates on neurological infections but has a research-focus
  3. Radiopaedia is, as expected, an image-intensive site. It is useful because neurologists need to keep on top of the subtle neuro-radiological features of the diseases they treat. And its free.
  4. PsychCentral is a useful resource for mental health diseases, but you should go straight to the resources directory.

Neurology Guidelines resources

  1. American Academy of Neurology (AAN) guidelines is a reliable site for guidelines covering the broad range of neurology
  2. NICE guidelines are the authoritative benchmark for medical practice in the UK and there is extensive coverage of the major neurological conditions
  3. SIGN guidelines are the equivalent of the NICE guidelines in Scotland
  4. Guidelines Central has an extensive library of guidelines and this link is to neurology section

 

Neurochecklists

For the future, neurochecklists is now live. Learn more about it in my blog post What is the secret of neurochecklists?  Check it out and leave some feedback:

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Looking for more? The Queen Square Library resources page of University College London (UCL) Queen Square Library has several helpful links.

 

Any thoughts or suggestions? Please leave a comment.