Parkinson's syndrome ≠ Parkinson's disease-a clarification of the differential diagnosis of Parkinson's syndrome

Parkinson's syndrome is not the same as Parkinson's disease (PD)
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Parkinson’s syndrome is a group of syndromes whose main manifestations are bradykinesia, rigidity and/or tremor.
It has a wide range of differential diagnosis, which also reflects the involvement of different parts of the basal ganglia.
Atypical Parkinson’s syndrome Including a group of neurodegenerative diseases, which are collectively manifested as akinesia-rigidity syndrome
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Its clinical course, prognosis, and treatment are different from those of PD
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This article briefly summarizes the relevant points in the differential diagnosis of Parkinson's syndrome
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Yimaitong compiles and organizes, please do not reprint without authorization
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Clinical examination-the basis for the differential diagnosis of Parkinson's syndrome Careful and comprehensive clinical examination is still the basis for the differential diagnosis of Parkinson's syndrome.
It should at least include the following aspects
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 Extrapyramidal motor system ➤ Bradykinesia is the core feature of Parkinson's syndrome
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In the British Brain Bank Standards, bradykinesia is defined as the slow initiation of spontaneous movements, while the speed and amplitude of repetitive movements gradually decrease
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In the new clinical diagnostic criteria for Parkinson’s disease by the Society for Movement Disorders (MDS), the reduction in amplitude or speed in repetitive motion is emphasized, and this reduction is usually not seen in progressive supranuclear palsy (PSP) or other atypical Parkinson’s syndrome Levy
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➤ Rigidity, that is, resistance to passive actions that is not related to speed, usually manifests as unilateral onset and persistent asymmetry in PD
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This is also true for most patients with MSA-P and typical cortical basal ganglia degeneration (CBS) (there are also cases of CBS with symmetry)
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➤ Tremor is usually seen in Parkinson's syndrome and is a supportive indicator but not necessary for diagnosis
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➤ Myoclonus is not found in PD, DLB, and PSP, but it is common in CBS and MSA
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➤ PD often has dystonia during the movement fluctuation phase, usually as asymmetrical dystonia of the foot during the off phase
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The dystonia in MSA is usually not limited to the off period; the dystonia in PSP is usually non-fluctuating; in CBS, dystonia in the affected limb is a feature and common symptom related to the diagnosis
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➤ Posture abnormalities are also common in Parkinson's syndrome, including bent posture, hunchback, and Pizza syndrome
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➤ Freezing, that is, a sudden stop or hesitation in motion, usually seen in the motion fluctuation phase of PD
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The effect of dopamine treatment Dopamine treatment is very helpful in differential diagnosis
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A clear and obvious effect on dopamine can indicate PD, and the observable response to the lack of high-dose levodopa is the absolute exclusion criterion for PD
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The side effects of dopaminergic therapy also have diagnostic value
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Levodopa-induced choreographic dyskinesia, especially in the limbs, supports the diagnosis of PD, which is very unlikely in atypical Parkinson’s syndrome
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However, levodopa-induced facial and neck dystonia (a bitter smile) may also be seen in atypical Parkinson's syndrome, but it rarely occurs in MSA
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Dyskinesia induced by levodopa is usually not seen in PSP
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 Eye movement disorders Clinical examination of eye movement is essential for the differential diagnosis of neurodegenerative Parkinson's syndrome
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Due to the overlap of the eye movement changes of various Parkinson's syndromes, routine examinations usually cannot detect slight changes and require technical means, such as video nystagmus (VOG)
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 Sensory disturbances Hypoosmia is clearly related to PD, and it often occurs in the early stages of motor symptoms
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It is best to pass an UpSIT test or a sniffer stick check
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Hypoosmia strongly suggests PD, while normal sense of smell suggests atypical Parkinson's syndrome
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 Sleep disorders Sleep disorders can be found in all Parkinson’s syndromes.
Possible causes include nocturnal inability to exercise, nocturnal psychosis, restless legs syndrome, disturbances in starting or maintaining sleep, daytime sleepiness, sleep episodes, and accompanying medical problems in the elderly ( Such as nocturia, depression, sleep apnea)
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Autonomic dysfunction Autonomic dysfunction is the core feature of MSA (MSA-P>MSA-C), but it also often appears in PD and DLB (synucleinopathy)
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For other Parkinson's syndromes (tau disease), autonomic symptoms may be comorbidities
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 Cortical dysfunction Frontal lobe symptoms often occur in PSP and CBD, but not in PD, MSA, and DLB
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We recommend testing for pathological applause, grasping reflex, and palmoplantar reflex for all Parkinson's patients
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Cognitive test-the key to the differential diagnosis of Parkinson's syndrome Cognitive test is considered to be the key to the differential diagnosis of all Parkinson's syndrome patients to assess the presence of mild cognitive impairment and the affected cognitive area
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Cognitive function is usually impaired in the early stages of DLB, CBD and PSP, but is preserved in the early stages of PD and MSA
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Among them, the Montreal Cognitive Assessment (MoCA) is more sensitive in CBS, PSP and DLB, so it is recommended to use it as a screening tool for general cognitive impairment
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Imaging examination-a common tool in the differential diagnosis of Parkinson's syndrome.
Magnetic resonance imaging (MRI) has been widely used in the diagnosis and differential diagnosis of Parkinson's syndrome.
It is recommended to perform FLAIR, T1 and T2* sequences
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In the differential diagnosis of Parkinson's disease, CT is not recommended, and brain parenchymal ultrasound examination can be reserved for examiners with special experience
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 Differential diagnosis of major diseases Parkinson’s syndrome is a collective term for a group of syndromes with bradykinesia, rigidity and/or tremor as the main manifestations.
Its differential diagnosis has a wide range, as shown in Table 1
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Table 1 Differential Diagnosis of Parkinson’s Syndrome PD The most common cause of Parkinson’s syndrome is Parkinson’s disease (approximately 75%).
The previous diagnosis of PD was mainly based on the appearance of the “three main signs of Parkinson’s syndrome”.
"(Tremor, rigidity, and motor retardation) two of them, but the autopsy results found that the diagnostic error rate under this standard reached 24%.
Later clinical pathological studies found that there is asymmetric static tremor and responds well to Dopa.
Kimson syndrome can better predict the final correct pathological diagnosis.
According to the revised standard (that is, the British Brain Bank Standard), 99% of clinically diagnosed PD have been pathologically confirmed.
PD brain dopamine system PET or SPECT images suggest striatal dopamine The uptake of energy markers is reduced, especially in the posterior part of the putamen.
Imaging examination is helpful for the diagnosis of difficult cases and scientific research, but it is not necessary in actual clinical practice, because it is generally only necessary to pass the clinical diagnostic criteria.
Make a diagnosis of PD.
Atypical Parkinson’s Syndrome Atypical Parkinson’s syndrome is a group of neurodegenerative diseases, usually more extensive than PD, including substantia nigra, striatum and/or globus pallidus In general, although it can be manifested as Parkinson's syndrome (stiffness and retardation), the clinical manifestations are slightly different from PD, which also reflects the different underlying pathological basis.
(1) Multiple system atrophy (MSA) Multiple system atrophy (MSA) can have a comprehensive manifestation of Parkinson’s syndrome, cerebellum and autonomic nervous system involvement, which can be divided into Parkinson’s syndrome predominant type (MSA-p) and cerebellar predominant type (MSA- c).
Clinically, MSA should be suspected when the patient has symptoms of atypical Parkinson's syndrome and signs of the cerebellum and/or early typical autonomic dysfunction (commonly orthostatic hypotension).
MSA The pathological features of the substantia nigra, the striatum, the degeneration of neurons in the cerebellar olive nucleus and the formation of intracellular inclusion bodies, the main component of the latter is α-synuclein.
T2 of MRIThe sequence can show the pathological iron deposition of MSA-p type, that is, the appearance of high signal on the outer surface of the putamen (the edge of the putamen), or the atrophy of the cerebellum and brainstem of the MSA-c type.
(2) Progressive nuclei Supranuclear palsy (PSP) Progressive supranuclear palsy (PSP) is another form of atypical Parkinson’s syndrome.
Its main characteristics are slow saccades, apraxia of the eyelids, and restricted eye movement, which can manifest as downward Gaze.
Patients often feel stiffness in the neck, abnormal gait and falls in the early stages.
In the later stages, there will be obvious speech and swallowing difficulties and dementia.
MRI examinations suggest characteristic manifestations, that is, the midbrain atrophy is obvious while the pons are relatively reserved (arrow "Hummingbird sign" can be seen in the shape).
Pathologically speaking, PSP is characterized by degeneration of substantia nigra and globus pallidus neurons with intracellular neurofibrillary tangles and formation of inclusion bodies.
The main component of the latter is tau protein.
(3) Cortical basal ganglia degeneration is not common.
It often manifests as asymmetric dystonia, clumsiness with one hand, and abnormal cortical sensory dysfunction, including apraxia, agnosia, focal myoclonus or alien limb phenomena ( It is difficult for the patient to perceive the position of the limbs in space).
Dementia may appear at any stage of the disease process.
MRI can usually show asymmetrical atrophy of the cortex.
Pathological findings include degeneration of colorless neurons and aggregation of tau protein, which is similar to the performance of PSP Similar.
Secondary Parkinson’s syndrome may be related to drugs, stroke, tumor, infection, or exposure to poisons such as carbon monoxide and manganese.
The use of dopamine antagonists such as neuroleptics is the most common cause of secondary Parkinsonism.
Although These drugs are widely used in psychiatric departments, but doctors should be aware that these drugs are also neuroleptics and can cause secondary Parkinson’s syndrome and tardive dyskinesias, such as methoxychlor, which is mainly used to treat gastrointestinal discomfort.
Primamide, chlorpromazine.
Other drugs that can cause secondary Parkinson’s syndrome include tetrabenazine, amiodarone, lithium preparations, etc.
Other neurodegenerative diseases Finally, Parkinson’s syndrome also has many other degenerative diseases Features such as hepatolenticular degeneration, Huntington's disease (especially juvenile type, which is Westphal variant), dopa-responsive dystonia, and degeneration of iron in the brain, such as pantothenic acid kinase (PANK) related Neurodegenerative disease (previously known as Hallerwarden-Spatz disease).
For related causes of non-PD Parkinson's syndrome, see Table 2.
Table 2 Features that do not support the diagnosis of PD References: [1] Parkinson's Disease.
Harrison Neurology[M].
2018.
[2] GU HÖglinger et al.
Differentiation of atypical Parkinson syndromes.
J Neural Transm (Vienna) 2017 Aug;124(8):997-1004.