How to distinguish between Parkinson's disease dementia and Lewy body dementia?

*It is only for medical professionals to read the reference symptom level and time of appearance is the key
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 In clinical practice, we often encounter patients with Parkinson's syndrome and dementia at the same time.
So is it caused by Parkinson's disease or Lewy body dementia? How should we diagnose and differentially diagnose it in clinical practice? At the 2021 Alzheimer’s Disease Prevention and Treatment Hotspot Issues Seminar, Professor Chen Biao from the Parkinson’s Disease Clinical Diagnosis and Research Center of Capital Medical University gave a wonderful topic on "Differential Diagnosis and Treatment of Parkinson’s and Lewy Body Dementia" Report
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1 Understanding the concept ▌ Parkinson’s disease and Parkinson’s disease dementia Parkinson’s disease (Parkinson’s disease, PD) is a common degenerative disease of the nervous system in middle-aged and elderly people.
Movement symptoms
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Common non-motor symptoms are cognitive impairment, anxiety, depression and so on
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Parkinson’s disease dementia (PD Dementia, PDD) is a clinical manifestation of the middle and late stages of PD.
In PD patients, the incidence of PDD is about 24%-31%.
The four core cognitive domains (executive power, attention, visual space) , Memory) can be diagnosed as PDD if any two cognitive domains are impaired
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▌ Dementia with Lewy body (DLB) is one of the most common neurodegenerative diseases.
Its main clinical features are fluctuating cognitive dysfunction, visual hallucinations and motor symptoms similar to Parkinson’s disease.
Cognitive impairment of the disease often appears before motor symptoms, and the main pathological feature is that Lewy body (LB) is widely distributed in the cerebral cortex and brainstem
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2 Clinical features of both ▌ Clinical features of PD In clinical practice, PD usually develops after 60 years of age, with insidious onset and slow progress.
The main clinical manifestations are "slow, shaking, stiff, and falling", and the symptoms mostly start on one upper limb.
Gradually spread to the ipsilateral lower extremities, and then manifest as the contralateral upper and lower extremities (65%~70%) involved
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Figure 1: Clinical features of PD (from the lecturer's courseware) ▌ Compared with PD, DLB has its own clinical features, which are mainly divided into four categories: cognitive impairment, visual hallucinations, Parkinson's disease syndrome and rapid eye movement sleep Behavioral Disorders (RBD)
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DLB patients are mainly dementia, and the symptoms of dementia have obvious fluctuations, while the symptoms of Parkinson's are often mild
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3 Differentiation of diagnostic criteria Professor Chen Biao introduced that the guidelines for the diagnosis of PDD and DLB have been updated in recent years at home and abroad
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Among them, the diagnostic criteria of PDD mainly refer to the "Diagnostic Criteria and Treatment Guidelines for Parkinson's Disease Dementia" updated in 2021, which was published in the Chinese Journal of Neurology in August 2021.
The specific diagnostic criteria for PDD are shown in Table 1.
The diagnostic process of PDD See Figure 2
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Table 1 Diagnostic criteria of PDD Figure 2: Diagnostic process of PDD For the diagnostic criteria of DLB, Professor Chen Biao said that the foreign guidelines were updated in 2017, and the new guidelines clearly delineated the boundaries of clinical symptoms and markers
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The original supporting features or prompting features are further subdivided into supporting markers, prompting markers and supporting clinical features.
The specific DLB diagnostic criteria are shown in Table 2
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Table 2 Diagnostic criteria for DLB to distinguish PDD from DLB.
At present, it is still recommended in clinical practice to use the "one-year principle" as the time boundary for distinguishing DLB from PDD, that is, extrapyramidal symptoms.
If dementia occurs within 1 year after the appearance, the diagnosis tends to be DLB, and if dementia occurs after 1 year of extravertebral symptoms, the diagnosis is more inclined to PDD
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However, in clinical pathology or clinical trials, there is no distinction, and DLB and PDD are collectively referred to as Lewy body disease or α-synuclein disease
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4 Differences in treatment Professor Chen Biao introduced that extrapyramidal symptoms, cognitive dysfunction, and mental symptoms coexist in PDD patients.
Treatment is often difficult.
It is necessary to evaluate the patient's clinical symptoms and severity in detail, and carefully adjust the treatment drugs
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Moreover, because PDD patients have different cognitive domain impairments and different pathophysiological mechanisms, multi-method treatment and continuous clinical research to explore effective drugs have become very important
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Professor Chen Biao emphasized that in the clinical face of PDD patients, we must first find out whether the patient's dementia is induced by anti-PD drugs or caused by the disease
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Induced by anti-PD drugs: The following anti-PD drugs should be gradually reduced or stopped according to the most easily induced probability: anticholinergics-amantadine-MAO-B-dopamine receptor agonists, if still It is necessary to reduce the dose of compound levodopa, but beware of the consequences that may aggravate the motor symptoms of PD
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Caused by disease: If the effect of drug adjustment is not ideal, it may be the latter factor, and symptomatic medication should be considered
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Figure 3: Parkinson's disease treatment methods and principles (from the lecturer's courseware) For the treatment of DLB, like PDD, there is currently no effective cure
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The whole process of management, early comprehensive treatment is very important, the whole process of management includes effective drug treatment and non-drug treatment
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Drug therapy includes anti-Parkinson's disease exercise therapy, antipsychotic drug therapy, anti-dementia therapy, and some mood-related therapies; non-drug therapy includes transcranial magnetic stimulation, aerobic functional exercise, scientific diet and nutrition management, patient and care The education and care of the readers
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 References: [1] Professional Committee of Neurodegenerative Diseases of Chinese Microcirculation Society.
Chinese Expert Consensus on Diagnosis and Treatment of Dementia with Lewy Body[J].
Chinese Journal of Geriatrics,2015,34(4):339-344.
[2]Walker Z,Possin KL,Boeve BF,et al.
Lewy body dementias[J].
Lancet,2015,386(10004):1683-1697[3]McKeith IG,Boeve BF,Dickson DW,et al.
,Diagnosis and management of dementia with Lewy bodies:Fourth consensus report of the DLB Consortium.
Neurology.
2017 Jul 4;89(1):88-100.
[4] Parkinson's Disease and Movement Disorders Group of Neurology Branch of Chinese Medical Association
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Diagnostic criteria and treatment guidelines for Parkinson’s disease dementia (Second Edition)[J].
Chinese Journal of Neurology 2021,8(54):762-771