Differential Diagnosis

Key Facts

  • Parkinsonism is different from Parkinson’s disease.
  • Parkinsonism can be induced by multiple medications.
  • DaTSCAN can be used to differentiate between essential tremor and parkinsonian syndromes.

Clinical Best Practices

  • Diagnose PD using the UK PDS Brain Bank Diagnostic Criteria.
  • Diagnosis may take time and may not be definitive after first visit.
  • Refer to a movement disorder specialist in complex cases.

Parkinson's disease must be differentiated from other conditions, especially those presenting with tremor. Remember that parkinsonism refers to any condition that causes a combination of the movement abnormalities seen in PD—such as tremors, slow movement, impaired speech, or muscle stiffness—resulting from the loss of dopamine-containing neurons. Not everyone who has parkinsonism has Parkinson's disease.

Table of Contents 

Other Diagnoses 

Other diagnoses that you should consider:

  • Essential tremor - may have overflow to rest in severe cases, have patient lie down to assess tremor (pearl)
  • Progressive supranuclear palsy (PSP) - loss of vertical eye movements
  • Multiple system atrophy (MSA) - marked autonomic symptoms early at time of diagnosis
  • Corticobasal degeneration (CBD) -  alien limb, spasticity, cortical sensory loss
  • Diffuse Lewy bodyi dementia (LBD) - early dementia presenting within 2 years of motor symptoms
  • Alzheimer's disease
  • Drug-induced parkinsonism
  • Vascular parkinsonism

Click here for a differential diagnosis table with information on these eight conditions.