When performing a differential diagnosis for Parkinson’s disease (PD), it is important to rule out other conditions that can present with similar symptoms, such as tremors, bradykinesia, rigidity, and postural instability. These include other neurodegenerative diseases, secondary parkinsonism, and mimicking disorders. Below are the key conditions to consider:
1. Parkinsonism-Plus Syndromes (Atypical Parkinsonism)
These conditions are neurodegenerative disorders that share features with Parkinson’s disease but have additional signs and often a poorer response to levodopa.
- Progressive Supranuclear Palsy (PSP):
Early gait instability and frequent falls
Vertical gaze palsy (difficulty looking up or down)
Poor response to levodopa
- Multiple System Atrophy (MSA):
Autonomic dysfunction (e.g., orthostatic hypotension, urinary incontinence)
Cerebellar signs (ataxia, dysarthria)
Poor response to levodopa
- Corticobasal Degeneration (CBD):
Asymmetrical symptoms
“Alien limb” phenomenon (limb moves involuntarily)
Apraxia (difficulty with motor planning)
- Dementia with Lewy Bodies (DLB):
Early onset cognitive decline
Visual hallucinations
Fluctuating cognition
2. Secondary Parkinsonism
These are conditions that cause parkinsonism but are due to identifiable causes such as medications, toxins, or brain damage.
- Drug-Induced Parkinsonism:
Caused by antipsychotics, antiemetics, or other dopamine-blocking agents
Symmetrical onset of symptoms
Reversible if the offending drug is discontinued
- Vascular Parkinsonism:
Often presents with lower body parkinsonism (gait problems, less tremor)
History of stroke or cerebrovascular disease
MRI may show multiple small vessel ischemic changes
- Normal Pressure Hydrocephalus (NPH):
Triad of symptoms: gait disturbance, urinary incontinence, and cognitive decline
Enlarged ventricles seen on brain imaging (MRI or CT)
May improve with cerebrospinal fluid (CSF) shunting
- Toxin-Induced Parkinsonism:
Exposure to substances such as carbon monoxide, manganese, or pesticides
May have a more rapid onset than PD
3. Other Mimicking Disorders
Some conditions present with features of Parkinsonism but are distinct due to underlying causes or different treatments.
- Essential Tremor (ET):
Tremor predominantly during voluntary movement (postural/action tremor)
No bradykinesia or rigidity
Family history common
- Wilson’s Disease:
Occurs in younger patients (adolescents or young adults)
Associated with liver dysfunction, psychiatric symptoms, and copper deposition in tissues
Kayser-Fleischer rings visible in the eyes
- Dystonia:
Sustained or intermittent muscle contractions causing abnormal postures or repetitive movements
Often seen in younger patients and can involve specific body parts
- Normal Aging:
Can present with mild bradykinesia, rigidity, and gait instability, but lacks the typical tremor and progressive nature of PD.
4. Psychogenic Parkinsonism (Functional Movement Disorder)
Symptoms may include tremor, bradykinesia, or gait problems, but are inconsistent or variable over time.
Symptoms may improve with distraction or worsen with attention.
There is no clear neurodegenerative pathology.
Key Diagnostic Tools:
- Levodopa Challenge Test: Parkinson’s disease typically responds to levodopa, whereas many other forms of parkinsonism do not.
- MRI/CT Scan: To rule out vascular causes, normal pressure hydrocephalus, or brain tumors.
- DaTscan (Dopamine Transporter Imaging): To differentiate PD from essential tremor or drug-induced parkinsonism.
- Copper Levels and Liver Function Tests: To assess for Wilson’s disease.
Considering these conditions helps refine the diagnosis and guide appropriate treatment.
Одобрено от Dr. Petya Stefanova
