Tag Archives: atypical Parkinsoniann disorders

I like “Parkinson-like.”

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Does anyone like being called “atypical”?  That adjective often conveys a foreign-ness or other-ness, and not in a good way.  If you agree, you will be glad to know that a colleague, Dr. Junaid Siddiqui of the Cleveland Clinic, and I are about to publish an opinion piece entitled, “Time to Retire the Term “Atypical Parkinsonism.”

Over my career as a movement disorders subspecialist, I’ve heard both from professional colleagues and my patients that the term “atypical Parkinsonism” for PSP, CBD, MSA and a few other conditions is unwelcome.  First, it implies that those conditions are simply unusual variants of Parkinson’s disease.  However, they are actually independent diseases at the microscopical, molecular, and clinical levels with some features in common with PD.  A similar problem applies to the term “Parkinson-plus.”  PSP, CBD, and MSA aren’t simply PD with some additional features. 

Yes, those three disease do include some degree of “Parkinsonism,” but that only means that they share a collection of outward slowness, muscle rigidity, impaired balance, and in some cases, tremor. Of course, the Parkinsonism of PSP, CBD, and MSA differ from that of PD.  But that’s not because the first three are atypical versions of the fourth – it’s because they’re fundamentally different diseases.  

That’s the scientific argument, but there’s also an emotional one.  As I mentioned at the outset, no one wants their uncommon disorder to be considered an appendage of some other, more frequent one with superficial similarities.  That would suggest that the uncommon condition is unworthy of its own approaches to support, treatment, and scientific study.  

So, Dr. Siddiqi and I propose replacing the terms “atypical Parkinsonism,” “atypical Parkinsonian disorder,” and “Parkinson-plus disorder” with “Parkinson-like disorder.”  This avoids the implication of inferiority and other-ness without losing the “Parkinson” term familiar to every physician.

The “-like” term has precedent in “Huntington-like disorder,” “polio-like syndrome,” and “stroke-like syndrome,” and that’s only in neurology.  Yes, changing medical language can be a heavy lift, but it’s been done before.  Examples just in movement disorders are Steele-Richardson-Olszewski syndrome to PSP, paralysis agitans to Parkinson’s disease, striatonigral degeneration to MSA-Parkinson, sporadic olivopontocerebellar ataxia to MSA-cerebellar, and corticodentatonigral degeneration to corticobasal degeneration.

Glossary of proposed terminology:

ExistingProposedDefinition/comments
Parkinson’s diseaseParkinson’s diseaseNo change proposed
parkinsonismParkinsonismA group of phenotypic features, not specific disease(s).  The first letter should be upper-case.
ParkinsonismsParkinsonian disorderMultiple members of a group of specific disorders featuring Parkinsonism
Primary parkinsonismPrimary Parkinsonian disorderAny neurodegenerative disorder featuring Parkinsonism as a major component, at least in a majority of cases
Secondary parkinsonismSecondary Parkinsonian disorderAny non-degenerative disorder featuring Parkinsonism in at least some cases or at some point in the illness
Atypical Parkinsonism or typical Parkinsonian disorderParkinson-like disorderReserve “Parkinsonism” for a group of phenotypic features.  Reserve “Parkinson-like” for specific diseases. Replace “Parkinson-plus” with “Parkinson-like disorder” as well.

Our paper will appear in the journal Parkinsonism and Related Disorders in a few days or weeks, at which time I’ll post you a link.  Of course, if the journal itself follows our recommendation to confine the term “Parkinsonism” to a collection of signs and symptoms rather than allowing it to refer to specific diseases, then it will have to change its own name!  But — one step at a time, I always tell my students and patients.

How to diagnose atypical Parkinsonisms

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I’ve been neglecting psp-blog.org for the past two weeks in favor of a project to help general neurologists diagnose PSP and other atypical Parkinsonian disorders (APDs) without having to refer to a movement disorders specialist.  I can hear you saying, “Great idea, but why now?”  Here’s how this started:

I’ve told you about CurePSP’s Centers of Care network.  That’s a group of (now) 32 medical school-based movement disorder centers with a special interest and expertise in PSP, CBD and in many cases, MSA as well.  The network’s mission is to improve the quality and availability of care for these disorders.  One of the problems standing in our way is the long wait for an initial appointment with a movement disorders specialist.  A survey among our own 32 centers showed an average wait of about 4 months.  For rapidly progressive disorders, that’s too long.

One partial solution we discussed is to educate general neurologists to make a confident diagnosis themselves and to institute appropriate management.  Then, the referral to a movement disorders specialist could be simply confirmatory.  Of course, making a diagnosis of any disease means looking for evidence against the competing diagnostic possibilities.  In the case of PSP, the main alternatives (a list called the “differential diagnosis”) are Parkinson’s disease, corticobasal degeneration, multiple system atrophy, and dementia with Lewy bodies. 

Then there’s a long list of less likely disorders that can resemble PSP, at least in some ways, at least in some cases, at least in the early stages.  They can be degenerative like PSP and the other four, but also genetic, infectious, autoimmune, nutritional, vascular, toxic, endocrine, psychiatric, neoplastic (directly related to tumors), and paraneoplastic (indirectly related to tumors).  The list includes 24 disorders that, like PSP, are treatable only at a symptomatic level but also, crucially, 31 with specific treatment to slow, halt or reverse progression of the disease.  All of those 55 are pretty rare as causes of a PSP-like picture, but the 31 with specific treatment must not be overlooked. 

We devised a decision algorithm to help the general neurologist navigate this daunting menu of options.  I can’t “publish” the list here just yet, as we want to submit it, along with an explanatory text, to a good, selective journal, and journals don’t like to accept previously published material.  Besides, we should show it to a few experts from outside of our 13-member writing committee, and of course, the peer review process at the journal could result in major changes.  Plus, the raw list of 55 disorders wouldn’t be that useful without the decision algorithm and the sub-lists of diagnostic features and recommended tests.  I’ll pass it along to you when I can in the next couple of months, but in the meantime, my blog post from March of this year on “PSP mimics” covers 30 of the 55 in a useful degree of detail.