Parkinson's disease differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Fahimeh Shojaei, M.D.

Overview

Parkinson disease must be differentiated from other diseases that can mimic this disease clinically or radiologically such as: essential tremor, scans without evidence of dopaminergic deficit (SWEDD), dementia with Lewy bodies, multiple system atrophy, corticobasal degeneration, progressive supranuclear palsy, idiopathic and familial basal ganglia calcification, and secondary parkinsonism.

Differential Diagnosis

• Parkinson disease must be differentiated from other diseases that can mimic this disease clinically or radiologically such as:

Essential tremor

• Essential tremor is demonstrated by bilateral resting tremor of arms, head, chin and trunk. Tremor of PD is action tremor and it seems to be easy to differentiate it from resting tremor of ET but sometimes we can see resting tremor in PD patient and conversely action tremor in ET patients.

Scans without evidence of dopaminergic deficit (SWEDD)

• Patients with scans without evidence of dopaminergic deficit have upper extremity resting tremor but their disease does not progress to the complete PD and there are no evidence of dopamine depletion in their NS.

Dementia with Lewy bodies

• Dementia will finally occurs in the most cases of Parkinson disease but the timing of dementia in PD is after full developing of PD and mostly after at least one year of disease start date. When dementia occurs with or before the signs and symptoms of Parkinson disease we will categorize it as dementia with lewy body.

Multiple system atrophy

• MSA is an idiopathic disease characterized by autonomic problems such as urogenital dysfunction, ataxia and parkinsonism symptoms. MSA patients have resting tremor in arms, rigidity and bradykinesia. The underlying pathophysiology of MSA is myelin dysfunction and inclusions in glial cell throughout CNS.

Corticobasal degeneration

• Clinical features of CBD is asymmetric movement disorders including rigidity, akinesia and dystonia. cognitive disorder is very common in this disease and can be the presenting sign of it. there are evidences of asymmetric frontoparietal cortical atrophy in autopsy in CBD patients. In microscopic evaluation there are neuronal loss, ballooned achromatic and gliosis.

Progressive supranuclear palsy

• Abnormal gait is the most common presentation of PSP disease. As opposed to idiopathic Parkinson disease, their trunk is extended and arms are abducted. They commonly fall from behind leading to bruises and lacerations. They can also have supranuclear ophthalmoparesis or ophtalmoplegia.

Idiopathic and familial basal ganglia calcification

• Accumulation of calcium in some brain regions and the basal ganglia is known as idiopathic basal ganglia calcification or bilateral striatopallidodentate calcinosis. Some of these patients can have parkinsonism symptoms such as dystonia, ataxia and chorea mostly between ages 20_60. The autosomal dominant form of the disease which is known as familial form can be the result of several mutations such as: The SLC20A2 gene on chromosome 8p11.2, the PDGFRB gene on chromosome 5q32, the PDGFB gene on chromosome 22q13.1 and the XPR1 gene on chromosome 1q25.3.

Secondary parkinsonism

• Vascular parkinsonism
  • Some studies suggest that in old ages, microscopic and lacunar infarction or atherosclerosis in basal ganglia can cause Parkinsonism symptoms.

• Drug-induced parkinsonism
  • The most common type of secondary parkinsonism is drug induced PD. Antiemetic and antipsychotic drugs are mostly the cause. They can cause akathisia and orofacial dyskinesia which in these cases we can differentiate them from idiopathic PD but sometimes they are similar to PD and have symmetrical resting tremor.