Considering a Parkinson’s Diagnosis

Key Facts

Clinical Best Practices

  • Always ask for motor< and non-motor <symptoms.
  • Conduct a full medical examination<. Neurological examination is not sufficient.
  • Rule out other causes< of parkinsonism before making a PD diagnosis.
  • Once you make a diagnosis< of PD refer the patient to a neurologist/movement disorder specialist.

There are many causes of parkinsonism, but not all equate to a patient having Parkinson’s disease. You may be challenged with a patient that comes to your practice for the first time in whom you may suspect PD. By addressing the following issues you will have a better chance to establish the diagnosis of PD. 

Reason for the Visit

Most patients will come because they have noticed tremor< in one hand or stiffness or slowness in movements (ADLs, gait, etc). These are the most common symptoms of a PD patient. When a patient presents two or three of these symptoms (especially unilateral resting tremor<), the diagnosis is many times readily apparent. The challenge in diagnosing PD, however, is when the main cause of complaint is not tremor<, rigidity<, or bradykinesia<.

See “Symptoms<” for other symptoms associated with PD.

Personal Medical History

  • Occupation: Individuals who are health care workers, lawyers, accountants, teachers, or farm workers are more likely to develop PD.
  • Environment: Exposure to herbicides/pesticides has been linked to PD.
  • Other neurological conditions diagnosed in the past: Alzheimer’s or other dementias, essential tremor, progressive supranuclear palsy, hydrocephalus, psychosis, or bipolar disorder could help you in ruling in/out a PD diagnosis.
  • Other general conditions: Information on arthritis, depression, sleep disorders, orthostatic hypotension and constipation, among others, may help you in establishing your diagnosis.
  • Medication intake: Medications that block dopamine receptors (such as antipsychotic drugs) and drugs used for nausea, vomiting, and GERD (such as prochlorperazine, promethazine, and metoclopramide) can cause parkinsonism.

Family History

  • Having a first degree relative with PD increases your chances of getting PD perhaps 2- or 3-fold.

See “Genetic Testing<” for more information on the genetics aspects of PD.

Medical Examination

  • A full medical examinamtion must be conducted on all new patients. When considering a diagnosis of PD, a thorough neurological examination including gait< is essential.
  • Cognition, eye movements, asymmetry in motor function (rapidly alternating movements) or resting tremor, shuffling gait with reduced arm swing, and even handwriting demonstrating micrographia can help in the differential diagnosis. 

See “Physical Examination<” for details of a full medical examination.


  • Diagnostic tests< for PD do not exist.
  • The use of MRI and SPECT (DaTSCANi) may help you rule out other conditions.
  • Acute levodopa and apomorphine challenge should not be used to diagnose PD.

See “Diagnostic Tests<” for additional information on testing.

Diagnosis of Parkinsonism

Diagnosis of PD is clinical and based on medical history and physical examination.

  • To diagnose PD you should make sure that parkinsonism is present, that there are no other features suggesting a different condition, and that parkinsonism improves with dopaminergic medications.
  • To diagnose parkinsonism you need to have bradykinesia< present and at least one of the following:
  • Parkinson's diagnosis should be reviewed on a regular basis, especially if atypical features develop. 
  • Significant, sustained response to dopaminergic therapy with a gradually progressive course is a hallmark of PD, as compared with other causes of parkinsonism.

See “Diagnosis Criteria<” for other features that can help you support your diagnosis.

See “Symptoms<” for more detail on other symptoms.


  • Treatment should be tailored to each patient based on individual needs and preferences.
  • Although you may feel the need to prescribe a medication for your patient at this time, it is better not to do so.
  • If you consider that you need to start the treatment, remember that it is recommended that you start with a dopamine agonist< if your patient is younger than 50 years; you should consider starting with carbidopa/levodopa< if your patient is older than 70 years; either option is good if your patient is between 50 and 70 years old.
  • Pharmacological treatment is important, but paramedical therapies such as physical therapy (PT), occupational therapy (OT), and speech therapy are as important in the management of your patient.
  • Levodopa/carbidopa< is the main drug used for treatment of PD. This medication can cause dyskinesias<, but all patients will eventually need levodopa< in their therapeutic regimen as their PD progresses.
  • Other therapies for PD include dopamine agonists<, MAO-B inhibitors<, COMT inhibitors<, anti-cholinergics <and amantadine.
  • There are no products available to slow down the progression of PD, although selegiline and rasagiline may impact the course of the disease for the first five years of therapy (controversial at this point in time).

See “Treatments<” for more details on medications and alternative considerations in the treatment of your patient.


  • If you establish a diagnosis of PD, refer the patient to a Movement Disorders specialist (or neurologist) right away.
  • Early referrals to PT, OT and speech therapy are recommended when diagnosing PD.
  • Parkinson's patients have a higher risk of melanoma. Routine evaluation by a dermatologist is recommended. 

See “Referrals<” for other referral considerations.

Codes for PD

ICD-9 code: 332      Parkinson’s disease

ICD-9 code: 332.1  Secondary parkinsonism

ICD-9 code: 333     Other extrapyramidal disease and abnormal movement disorders

Billing Codes

99201-99205        New patient                                                     

99211-99215        Established patient                                       

99354-99359        Prolonged services       

See “Billing and Coding in PD<” for more details on billing and coding.