What is the initial workup for Parkinson's disease?

From the Guidelines

The initial workup for Parkinson's disease should primarily focus on a thorough clinical evaluation, including a detailed history and neurological examination, to identify cardinal motor symptoms and rule out other conditions, as stated in the ACR Appropriateness Criteria for movement disorders and neurodegenerative diseases 1. The clinical presentation of Parkinson's disease is characterized by resting tremor, bradykinesia, and rigidity, and the estimated interval between initial loss of dopaminergic neurons and the appearance of symptoms is approximately 5 years 1. Key aspects of the initial workup include:

• A detailed history of symptom onset, progression, and any asymmetry
• A thorough neurological examination to identify cardinal motor symptoms, including resting tremor, bradykinesia, rigidity, and postural instability
• Basic laboratory tests to rule out other conditions, such as complete blood count, metabolic panel, thyroid function tests, vitamin B12 levels, and syphilis serology
• Neuroimaging, such as MRI of the brain, to exclude other pathologies like stroke, tumors, or hydrocephalus that might mimic parkinsonian symptoms 1 It is essential to note that correctly diagnosing a Parkinsonian syndrome on clinical features alone can be challenging, and imaging remains an essential diagnostic tool in the evaluation of a patient presenting with Parkinsonian symptoms 1. A trial of levodopa with a clear clinical response can support the diagnosis, though this is not always performed initially, and DaTscan (dopamine transporter scan) may be used in uncertain cases to detect dopaminergic deficiency 1.

From the Research

Initial Workup for Parkinson's Disease

The initial workup for Parkinson's disease involves a combination of history taking, physical examination, and diagnostic tests to confirm the diagnosis and rule out other conditions.

• History taking: includes prodromal features (eg, rapid eye movement sleep behavior disorder, hyposmia, constipation), characteristic movement difficulty (eg, tremor, stiffness, slowness), and psychological or cognitive problems (eg, cognitive decline, depression, anxiety) 2
• Physical examination: typically demonstrates bradykinesia with tremor, rigidity, or both 2
• Diagnostic tests:
  • Dopamine transporter single-photon emission computed tomography can improve the accuracy of diagnosis when the presence of parkinsonism is uncertain 2
  • Other tests such as Unified Parkinson Disease Rating Scale (UPDRS) can assess the clinical severity of PD 3, 4

Differential Diagnosis

It is essential to differentiate Parkinson's disease from other parkinsonian syndromes, such as:

• Progressive supranuclear palsy (PSP)
• Multiple systems atrophy (MSA)
• Corticobasal degeneration (CBD)
• Vascular parkinsonism (VP)
• Parkinsonism with dementia (Lewy body dementia, LBD) 5

Treatment Initiation

The initiation of pharmacologic therapy for Parkinson's disease must take into consideration the degree of dysfunction the patient is experiencing, the question of neuroprotection, the degree of motor response required, and the potential complications of long-term treatment 5.

• Dopamine agonists or levodopa may be initiated as initial treatment for Parkinson's disease 5, 4
• Pramipexole and levodopa both ameliorate the motor symptoms of early Parkinson disease, but pramipexole may have a lower risk of developing dopaminergic motor complications 3, 4