People are often confused by the term “parkinsonism” and how it relates to terms like Parkinson’s disease, atypical parkinsonism, Parkinson’s plus syndromes, Lewy body dementia, Parkinson’s disease dementia, drug-induced parkinsonism and vascular parkinsonism. Here’s a brief summary of what all of these terms mean!
Parkinsonism refers to a constellation of symptoms including some or all of the following symptoms: tremors, impairment of fine motor skills (writing, buttoning, etc), stiffness or rigidity of the muscles, bradykinesia or slowness of movement, soft voice (hypophonia), postural instability (imbalance), shuffling gait or walking, and stooped posture.
Parkinson's disease (PD) is the most common cause of parkinsonism. PD refers to the neurodegenerative disorder caused by the degeneration of dopamine-producing neurons (brain cells) in the region of the brain known as the substantia nigra (among other changes). Someone does not typically exhibit clear symptoms of PD until they’ve lost ~80% of the brain cells in this region! This is an important point so remember it for later.
Atypical parkinsonism (synonymous with Parkinson’s-plus syndromes) refers to a group of disorders that share many of the symptoms of PD but have additional features that distinguish them from PD. These disorders include progressive supranuclear palsy (PSP), multiple system atrophy (MSA), corticobasal degeneration (CBD), and others, and they typically do not respond well to the typical treatments for PD. Look for upcoming blog posts about these individual disorders but here’s a little information in the meantime about how they differ from PD.
- PSP is typically characterized by difficulty with balance, usually early in the course of the disease leading to significant falls. There is difficulty with eye movement, especially looking up and down, dystonia (abnormal postures of limbs), and cognitive decline.
- MSA has several subtypes, all caused by the degeneration of several different areas of the brain, leading to a range of symptoms that can include parkinsonism, severe autonomic dysfunction (significant swings in blood pressure, heart rate, regulation of blood vessel dilation, abnormalities in sweating, early erectile dysfunction, significant constipation, bladder dysfunction, occasionally breathing difficulty due to tightness of the airways leading to “stridor”) and cerebellar ataxia (incoordination of limbs and torso, slurred speech).
- CBD is a rare disorder that leads to a range of symptoms that can include parkinsonism, dystonia (abnormal postures of limbs), cognitive decline, inability to control actions of limbs (“alien limb syndrome”), and apraxia (inability to perform certain movements/gestures despite having the physical ability to do so).
Many people ask, “How can I tell which one I have? They all sound so similar.” I always like to give the (very simplified) example of pasta: you can have noodles, ricotta, mozzarella, and a red sauce. What am I making? It could be a variety of things! For example, if I put down a layer of flat noodles, then a layer of ricotta, and then a layer of sauce and repeat this several times and top it with mozzarella, what do I have? Lasagna! What if I take large tubular noodles and stuff them with meat sauce and ricotta and top it with mozzarella. Now I have manicotti! Shells stuffed with ricotta and topped with sauce and mozzarella? Stuffed shells! It’s all the SAME ingredients - but it’s the SHAPE of the noodles and how you put the ingredients together that dictates what the dish is. Same is true for the atypical parkinsonism syndromes - it’s all how you the signs and symptoms (ingredients) are put together that determines what the diagnosis (dish) is.
Lewy body dementia (LBD) refers to two different disorders on the same spectrum: Dementia with Lewy Bodies (DLB) and Parkinson’s disease with dementia (PDD).
- DLB refers to onset of significant cognitive impairment (dementia) and parkinsonism within one year of each other. Typically, the cognitive issues are the more severe of the two and are often the first symptoms to arise.
- PDD refers to the onset of significant cognitive impairment (dementia) at least one year after a clear diagnosis of PD. It could be twenty years between onset of PD and dementia but PD is clearly the first.
The dementia component is often less characterized by memory trouble (though this can certainly be a feature) and moreso by changes in spatial awareness, executive function (ability to do multi-step directions, plan ahead, multitask, etc). Those with LBD will also have issues with hallucinations (seeing/hearing/feeling things that are not really there), illusions (mistaking one item for another such as seeing a cord and thinking it’s a snake), delusions (believing things that are not true), and paranoia. Visual hallucinations (those that are seen) can include lines or colors or more “formed” objects such as children or other people or animals. Two common delusions seen in LBD are Othello syndrome, where a patient believes their spouse is cheating despite having NO evidence to support this, and Capgras syndrome, where a patient believes that people very close to them (spouse, child, close caregiver, etc) has been replaced by one or more exact replicas.
So, we reviewed earlier that PD is due to the loss of brain cells that produce the chemical dopamine. Well, what if you block the effects of dopamine with a drug? Then you might develop drug-induced parkinsonism. This can be caused by medications such as certain antipsychotics (e.g. haldol, risperidone, ziprasidone, aripiprazole, lurasidone, high doses of quetiapine, etc), anti-nausea medications (e.g. metoclopramide, promethazine). Blockade of the effects of dopamine can result in a syndrome that looks like PD but does not result from underlying degeneration of brain cells and thus can be reversible if the offending medications are reduced or stopped. It’s important to remember that 1) doses of these medications that someone may have tolerated in the past may cause symptoms of parkinsonism at any time, 2) in general, older patients may be more sensitive to these side effects, and 3) sometimes, these medications can “unmask” underlying degeneration of dopamine brain cells. Remember earlier when I said that you had to lose ~80% of the dopamine brain cells in the brain region called the substantia nigra before you have symptoms of PD? Well, what if you’d lost 50%? No symptoms of PD unless you take a medication that blocks some dopamine and now you have effectively blocked/lost enough dopamine to have symptoms of PD. This doesn’t mean that you will someday go on to develop PD - we all lose some dopamine brain cells as we get older - it’s just a matter of whether we lose enough in our lifetime!
Lastly, is vascular parkinsonism. This simply refers to people who have some symptoms that look like PD that are not due to degeneration of the dopamine brain cells. In this case, the symptoms are related to damage to some of the same regions of the brain that are affected in PD due to problems such as strokes, atherosclerosis, and other disorders of the vascular system in the brain.
I hope this very brief overview helps clarify the terms used to describe the various types of parkinsonism. Let us know if you want to hear more or have additional thoughts for topics to cover in the future!
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