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Episode 2 – Making the Case for a Diagnosis of PDP

  • Authors: George T. Grossberg, MD; Mark F. Lew, MD
  • CME / ABIM MOC Released: 10/20/2022
  • Valid for credit through: 10/20/2023, 11:59 PM EST
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  • Credits Available

    Physicians - maximum of 0.50 AMA PRA Category 1 Credit(s)™

    ABIM Diplomates - maximum of 0.50 ABIM MOC points

    You Are Eligible For

    • Letter of Completion
    • ABIM MOC points

Target Audience and Goal Statement

This activity is intended for neurologists, psychiatrists, and primary care physicians.

The goal of this activity is that learners will be better able to recognize and effectively manage patients with PD psychosis (PDP) and PD dementia (PDD).

Upon completion of this activity, participants will:

  • Have greater competence related to
    • Ability to diagnose PDP
  • Demonstrate greater confidence in their ability to
    • Diagnose PDP


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  • George T. Grossberg, MD

    Professor and Director 
    Division of Geriatric Psychiatry 
    Department of Psychiatry and Behavioral Neuroscience 
    St Louis University School of Medicine 
    St Louis, Missouri 


    George T. Grossberg, MD, has the following relevant financial relationships: 
    Consultant or advisor for: Acadia; Avanir; Axsome; Biogen; BioXcel; Genentech; Karuna; Lundbeck; Otsuka; Roche; Takeda
    Research funding from: Janssen; Lilly
    Other: Safety Monitoring Committees: Anavex; EryDel; Intra-cellular Therapies; Merck; Newron


  • Mark F. Lew, MD

    Professor of Neurology
    Director Division of Movement Disorders
    VanDerMeulen Chair in Parkinson’s Research
    In Honor of Robert J Pasarow
    Co-Director Anenberg Center for Biomarkers in Parkinson’s Disease and Other Neurodegenerative Disorders
    University of Southern California Keck School of Medicine
    Los Angeles, California


    Mark F. Lew, MD, has the following relevant financial relationships:
    Consultant or advisor for: Acorda; Adamas; Kyowa; Neurocrine; Sunovion; Supernus
    Speaker or member of speakers bureau for: Acorda; Adamas; Kyowa; Neurocrine
    Research funding from: Jazz Pharma; Neuraly; Pharm2B; Sun Pharma


  • Frances McFarland, PhD, MA

    Medical Education Director, Medscape, LLC


    Frances McFarland, PhD, MA, has no relevant financial relationships.

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  • Susan L. Smith, MN, PhD

    Associate Director, Accreditation and Compliance, Medscape, LLC


    Susan L. Smith, MN, PhD, has no relevant financial relationships.

Peer Reviewer

This activity has been peer reviewed and the reviewer has no relevant financial relationships.

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Episode 2 – Making the Case for a Diagnosis of PDP

Authors: George T. Grossberg, MD; Mark F. Lew, MDFaculty and Disclosures

CME / ABIM MOC Released: 10/20/2022

Valid for credit through: 10/20/2023, 11:59 PM EST




Dr. Grossberg:

Hello, I'm Dr. George Grossberg. I'm the Professor and Director of the Division of Geriatric Psychiatry in the Department of Psychiatry and Behavioral Neuroscience at St. Louis University School of Medicine. [00:17] Welcome to episode 2 of this podcast series. In this episode, we'll be focusing on making the case for a diagnosis of Parkinson's disease psychosis. Now, I'm really very excited and very happy to have Dr. Mark Lew join me today. He's a well-known Professor of Neurology, Director of the Division of Movement Disorders at the Keck USC School of Medicine in Los Angeles, California. Welcome, Mark.

Dr. Lew:

Hello, thank you for having me today, George.

Dr. Grossberg:

So as I mentioned, in this episode, we're going to review basically two cases, focusing on and illustrating how we recognize and assess for Parkinson's disease psychosis in the clinical practice setting. But before we do that, let me remind our audience of the diagnostic criteria for Parkinson's disease psychosis. So first of all, the primary diagnosis of Parkinson's disease is generally based on the UK Parkinson's Disease Brain Bank Criteria. In addition, we need to have at least one of the following symptoms; hallucinations, [1:31] which I think, as you all know, are abnormal perceptions without a physical stimulus. Most commonly they're visual. delusions [1:41] which are firm, false beliefs, despite evidence to the contrary, So paranoid delusions are very common.

Dr. Grossberg:

Illusions, [1:51] which are misperceptions of real stimuli. I had a patient recently that looked at the bed post of their bed and thought it was a snake. And then false sense of presence, [2:02] which would basically mean where the individual feels that someone is around, whereas that individual is really not there. Also, very, very importantly, these symptoms occur after a Parkinson's disease diagnosis, and they need to be recurrent or continuous for at least one month. Let's talk about risk factors for Parkinson's disease psychosis. Very important to consider comorbid medical disorders. At the top of my list would be delirium. [2:36] Pretty much any and all causes of delirium can be accompanied by psychotic features. Infection would be way up on that list, for example. Comorbid depression, depression with psychotic features, dehydration, even severe sleep disturbance can be a risk factor for psychosis against a background of Parkinson's disease.

Dr. Grossberg:

And we're more likely to see psychotic symptomatology with progression of Parkinson's disease with more severe disease, especially in the older, older adult. We want to also keep in mind difficulties with sensory input, vision, hearing, smell and so on. [03:17] These could also be risk factors. And of course, psychotic symptoms tend to be worse as the day goes on, as we have more dim lighting, as maybe the patient gets more tired or more weary. And let's not forget the role of medications. There are a number of medications that these patients are often on, including narcotic analgesics, increased doses, particularly recently increased doses of dopaminergic or Parkinson's disease medications, as well as the notion of anticholinergic drugs, benzodiazepines, things that can cause delirium, which then also can be accompanied by psychotic features. Now, let's turn to Mark. Mark, why don't you tell us or share with us the details of your case?

Dr. Lew:

[4:04] Sure. Well, this is a fairly involved case as most of my patients are. This is a 69-year-old gentleman with Parkinson's disease for 12 to 13 years, so a good bit over a decade. And he presents with his wife, who is reporting that he's been having more difficulty with his cognition over the last 12 months or so. And he had formal neuropsychiatric testing, psychometric testing, about 18 months prior, which revealed MCI. Additionally, he suffers from classic urinary urgency and frequency that most of these patients have. But in addition, he has a history of kidney stones, and this became evident when he had a presentation with confusion, disorientation and hallucinations, and was found to be uroseptic based on presentation of kidney stones. So at that time, his infection was treated, the kidney stones were treated, and he's not had any problems with hallucinations for just about two years now.

Dr. Lew:

So currently, at the visit with his wife, he denies hallucinations or paranoia, but upon very detailed questioning, he noted that he thought that there were some animals in the yard when he looked out the window at night, but when his wife went and turned on the security lights, he just saw some landscaping stones and bushes in the distance. His wife, again, emphasized the issue that she felt his cognition had changed over the last year or so and wanted to have him repeat the neuropsych testing. They also didn't really want to change his medications at this visit. They didn't feel that the issue with nighttime illusions in the backyard was a significant issue. So he went on and had repeat formal neuropsych testing, which showed major neurocognitive disorder or dementia. He was prescribed a rivastigmine patch.

Dr. Lew:

Two months later, his wife called up complaining that the patient was having delusions, he was paranoid, he was having hallucinations that somebody was trying to break into the house for three days. He also thought that there were people outside of his house at night on a regular basis over those three days. Careful questioning revealed that the patient had friends and family in from out of town, and he admitted to taking several extra doses a day of his carbidopa levodopa. So with that, we talked about having his wife manage his medications moving forward, with the expectation that hopefully this episode of psychosis would clear. So he was seen in the office two months later, his psychosis had abated.

Dr. Lew:

But his wife reported that they saw the urologist, which was a routine occurrence given his previous history. And he was started on tolterodine to treat his nocturia [8:17] and to hopefully allow him to sleep better. For several nights prior to his presentation at the visit, he was hallucinating. So I asked them to discontinue the tolterodine, which has anticholinergic properties, and I thought may have very well been contributing or main cause of his psychosis at the time. And I asked them to follow up with the urologist. So they did this and the tolterodine was discontinued, but his wife called in two weeks later that he was hallucinating nightly, again, typically late at night, about people trying to break into the house. And the patient had called 911 on two separate occasions. So because of the urgency of the situation, he was started on quetiapine at night while we awaited authorization for pimavanserin.

Dr. Grossberg:

So thank you, Mark. That's really a great case. And as I was listening to your description I was able to recognize a number of the risk factors that we talked about earlier. So this gentleman, for example, had a significant UTI, at least early on. Again, maybe causing a delirium with psychotic features. You also pointed out, I think very nicely, that maybe in the earlier stages of the psychotic process in Parkinson's disease, the patient themselves might be aware, but as the disease progresses, they're less aware of the psychotic symptomatology. So you really have to bring the family in to give you the details to be able to make the diagnosis. And you pointed out as well that the psychotic symptoms became more pronounced, also commensurate with increased cognitive decline.

Dr. Grossberg:

Another great feature of your case, when the patient was taking their own medication, and they were taking too much of their dopaminergic medication, triggering the psychotic symptomatology. So again, you very appropriately said, "Hey, we need to get your wife to oversee medication management." I think another great example in this case is the use of anticholinergic drugs, many of which avidly cross the blood-brain barrier, and can cause delirium with psychotic features [10:52] as evidenced in this case by the prescription of tolterodine. And then as you pointed out, starting him on quetiapine and awaiting authorization for pimavanserin would be, in my case, the way to go.

Dr. Lew:

Yeah. I think that the most common risk factor we look for is typically infection in our patients with Parkinson's disease. And in these patients who routinely have urgency and frequency, they may not even be aware that they have an infection. And then I think the other most common risk factor is medications. And you really have to review with the patient any new medications [11:38] and any medications that they may be on that you did not prescribe because of the potential for these kinds of side effects.

Dr. Lew:

And then I think finally, the issue with him taking extra doses, I always tell my patients, and say, "Look, life gets in the way, we get that, but you just have to be judicious and careful." And I think in this case, my patient just was a little overzealous and took several extra doses a day, and it really tipped him over. And he had a very fine line, with his diagnosis of major neurocognitive disorder.

Dr. Grossberg:

Yeah, I think it was also a really good pickup on your part to find out that he was self-administering medications. A lot of people would've assumed already that because of his cognitive impairment, somebody else was administering and monitoring the meds, but that was not the case. And I think for clinicians, it's important in general to make sure that someone who's taking their own medicines is indeed able to responsibly do so. And if there's any question at all, I usually bring in the family member, I talk about checks and balances, "You're in charge of your medicine, but I want your wife to just look over your shoulder." Now, my case is a lot less detailed.

Dr. Grossberg:

So this is a gentleman that we actually saw recently in our outpatient clinic, a 76-year-old man with moderate stages of Parkinson's disease. He's had the disease for maybe five or six years, begins to see rodents, mice, during the day, on occasion, it was not persistent. Initially, not that distressing, but they became much more distressing and persistent at night, especially when these rodents began to invade the bed [13:40] at night. And not only was he up and not able to sleep because of these visual hallucinations, but of course his wife was also not able to sleep. [13:50] So this illustrates the notion that visual hallucinations among hallucinations are the most common in Parkinson's disease psychosis. It's not uncommon for patients to see animals of various sorts.

Dr. Grossberg (17:24):

As we mentioned earlier, it's not uncommon as well for these hallucinatory phenomena to be more prominent in dim light, late afternoon, early evening or at nighttime. Now, we talked about the notion of persistence of psychotic symptoms. What's also important is impact. So when they became more impactful and started to disturb his sleep and his wife's sleep, then we needed to intervene. So we reviewed his meds, to make sure that his Parkinson's meds were stable, were not recently increased. As you mentioned, Mark, looking for infections, all the different things that we talked about, to make sure that we are indeed treating Parkinson's disease psychosis, is very, very important.

Dr. Grossberg:

When it comes to assessing for Parkinson's disease psychosis, what do you do, Mark, routinely in your practice? But even more importantly, what do you recommend that clinicians, whether they're primary care or other clinicians who see these patients, do so that they won't miss a diagnosis of Parkinson's disease psychosis, so they can recognize the symptoms and treat early? So what do you do?

Dr. Lew:

So most patients are in an office where their clinician is under a significant timeframe pressure. So we don't typically have enough time to go through formal scales with patients as we might have in a research visit, for instance. So I typically make questions about psychosis part of their routine. Most patients won't volunteer this information, so you really have to ask them about it because they can be embarrassed. So you want to make this seem very regular and routine. So just like I ask them about their balance, their swallowing, do they have any constipation? Are they exercising? How are they sleeping? I ask them are they seeing or hearing things that don't exist that other people are unable to see or hear? Are they having any paranoid delusions, typically about things like infidelity or money?

Dr. Lew:

So in this way, I try to bring them into the conversation [16:27] and I think it's extremely necessary, as I said, because most patients won't volunteer the information.

Dr. Grossberg:

That's very important. We've talked about the various symptoms, the various associated features and the various triggers already. I think one that we want to keep in mind as well, maybe other known psychiatric illnesses which can be accompanied by psychotic features. So definitely keep in mind something like schizophrenia, even bipolar affective disorder with psychosis.

Dr. Lew:

Right. And I think depression with psychosis as well.

Dr. Lew (21:30):

But you're absolutely correct. And you reviewed this earlier, in order to formally make a diagnosis of Parkinson's disease psychosis, we have to have a previous diagnosis of Parkinson's disease. So if the patient has a primary dementing disorder, Alzheimer's disease with psychosis, again, need to fall back on our history and examination to differentiate.

Dr. Grossberg:

Yeah. And we know that the psychotic symptoms, that Parkinson's disease psychosis can occur with or without dementia. So in your practice, just briefly, how does comorbid dementia affect the assessment for Parkinson's disease psychosis?

Dr. Lew:

Yeah, so clearly, in a patient who has dementia, we know they have a brain with little reserve, and we see psychosis in the population of PD with dementia much more frequently. When a patient is being evaluated that we know has dementia, it can be very complicated to treat them. My personal experience has been in patients with significant or profound dementia. So the psychosis can be much more complex to treat, that the routine medications may not be as effective in this population.

Dr. Grossberg:

Yeah, those are great clinical vignettes and comments. So Mark, thank you for this excellent discussion. I think we all benefited from that, and I do want to thank our listening audience for participating in this activity. So please continue to answer the questions that follow and complete the evaluation. Again, thank you all very much.

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