Parkinson's disease and parkinsonism

Parkinson’s disease and Parkinsonism

I. What every physician needs to know.

Idiopathic Parkinson’s disease is a progressive neurologic disorder characterized by motor dysfunction including rest tremor, bradykinesia, postural instability and rigidity of movement. Symptoms can progress to include speech and swallowing problems, and in some cases, dementia or psychosis.

While the exact mechanism remains unknown, there is clear nerve cell loss in the dopamine-producing substantia nigra, leading to diminished dopamine in the basal ganglia. Pathology shows intracytoplasmic inclusions in the neurons, known as Lewy bodies, which are a hallmark finding of Parkinson’s disease. Idiopathic Parkinson’s disease is a clinical diagnosis of exclusion.

Parkinsonism is the cluster of traits seen in Parkinson’s disease, but with an alternate etiology (medication or toxin induced, post-infectious or neurologic). Identifying the drug induced variant is important, as symptoms can improve once the offending agent is discontinued. Other forms of parkinsonism often have a more rapid, aggressive course, and are less responsive to dopamine replacement medications.

II. Diagnostic Confirmation: Are you sure your patient has Parkinson's disease/Parkinsonism?

Parkinsonism is diagnosed based on clinical features. A diagnosis of idiopathic Parkinson’s disease requires ruling out secondary causes. Medications must be reviewed for possible causative agents, such as antipsychotics, or antiemetics. Parkinson’s should not be considered as a potential diagnosis when bradykinesia with either tremor or rigidity of movement are absent.

A. History Part I: Pattern Recognition:

The typical Parkinson’s patient is in their 60s or older. They may initially present with unilateral tremor, or decreased arm swing. Although symptoms usually become bilateral, one side may remain more pronounced. Facial expression is blunted, described as a “masked facies”. The patient typically has difficulty with the initiation of movement. Passive extension and flexion at the elbow can feel like ratcheting, described as cog-wheel rigidity.

B. History Part 2: Prevalence:

Mean age of diagnosis for idiopathic Parkinson’s disease is late 50s. There is no racial or ethnic predisposition, but men are affected more frequently than women. Multiple meta-analyses have shown that age and a family history of Parkinson’s disease are associated with an increased risk for development of Parkinson’s. Interestingly, cigarette smoking has been associated with decreased risk.

C. History Part 3: Competing diagnoses that can mimic Parkinson's disease/Parkinsonism.

Essential tremor is a type of action tremor, usually symmetrically involving hands and/or head. It is of unclear etiology, and is oftentimes linked with autosomal dominant inheritance. Patients do not have other parkinsonian symptoms. Most common pharmacologic agent for treatment is beta-blockers.

Lewy Body Dementia is typically characterized by parkinsonism, visual hallucinations and mental decline. It is the second most common neurodegenerative disorder in the United States following Alzheimer’s Disease.

Drug-induced parkinsonism is commonly caused by antipsychotics, antiemetics, antiepileptics and calcium channel blockers. It is usually reversible and typically resolves within weeks to months with cessation of the offending agent.

Parkinson Syndromes: These include corticobasal degeneration (can be associated with akinesia, dystonia or myoclonus), multi system atrophy (can be associated with dysautonomia, pyramidal symptoms) and progressive supranuclear palsy (classically associated with ophthalmoplegia).

D. Physical Examination Findings.

• Resting tremor of extremity

• Bradykinesia

• Cogwheel rigidity of limbs

• Masked facies (lack of expression or facial animation)

• Postural instability

• Micrographia

• Short stepped gait

E. What diagnostic tests should be performed?

Diagnosis is predominantly based on physical exam and excluding potential secondary causes of parkinsonism. The Movement Disorder Society has issued a diagnostic set of criteria for the diagnosis.

1. What laboratory studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?

No lab tests can currently diagnose Parkinson’s disease or parkinsonism.

2. What imaging studies (if any) should be ordered to help establish the diagnosis? How should the results be interpreted?

No radiographic studies are routinely used to diagnose Parkinson’s disease. Brain imaging can identify strokes, tumors or other brain injury that could possibly lead to parkinsonism. When the clinical diagnosis is uncertain, some facilities offer dopamine transporter imaging studies (MRI or SPECT), which can identify the presynaptic neuron degeneration seen in Parkinson’s disease.

F. Over-utilized or “wasted” diagnostic tests associated with this diagnosis.

N/A

III. Default Management.

There are no pharmacologic treatments that can slow or reverse the natural course of Parkinson’s disease. Initiating pharmacologic therapies is dependent upon degree of functional disability. Levodopa remains the first drug of choice when symptoms have impaired the patient.

A. Immediate management.

If the patient is taking medications which can induce parkinsonism, they need to be discontinued if clinically able, or transitioned to other medications that have a lower risk of causing symptoms. Computed tomography (CT) and/or magnetic resonance imaging (MRI) brain can be obtained if there is concern for an acute intracranial event causing symptoms. Neurology consult is often advisable.

B. Physical Examination Tips to Guide Management.

Monitor movement for stiffness or freezing episodes, and whether symptom-free time is increased with treatment.

C. Laboratory Tests to Monitor Response To, and Adjustments in, Management.

D. Long-term management.

Levodopa remains the first drug of choice when symptoms become disabling for the patient. Dopamine agonists can be initiated as monotherapy or in combination with other pharmacologic agents. Other classes of agents include MAO-B inhibitors, anticholinergic agents, and amantadine.

Nonpharmacologic management includes physical therapy, speech therapy, and nutritional support. Caregiver support and education is vital.

Physical therapy and gait training.

E. Common Pitfalls and Side-Effects of Management.

It is imperative to assess for drug-drug interactions when starting a new pharmacologic agent.

IV. Management with Co-Morbidities.

Side effects of pharmacologic therapies for Parkinson’s disease pose many management challenges and it is imperative to check for adverse side effects to the patient’s comorbidities as well as potential drug-drug interactions.

A. Renal Insufficiency.

Medications, namely pramipexole, ropinirole, selegiline and amantadine may need to be renally dosed and some are contraindicated in the setting of ESRD.

B. Liver Insufficiency.

No change in standard management.

C. Systolic and Diastolic Heart Failure.

Potentially increased risk of development of new heart failure has been associated with use of pramipexole.

D. Coronary Artery Disease or Peripheral Vascular Disease.

Per labeling, use of levodopa/carbidopa and bromocriptine, must be used with caution in patients with history of cardiac disease.

E. Diabetes or other Endocrine issues.

No change in standard management.

F. Malignancy.

Patients with Parkinson’s disease are at increased risk of development of melanoma.

G. Immunosuppression (HIV, chronic steroids, etc).

No change in standard management.

H. Primary Lung Disease (COPD, Asthma, ILD).

Patients with severe Parkinson’s may have swallowing difficulty and therefore increased risk of aspiration pneumonias.

I. Gastrointestinal or Nutrition Issues.

Patients may develop malnutrition in the setting of impaired swallowing function. Discussions of parenteral nutrition may be warranted depending on the patient’s nutritional status and goals of care.

J. Hematologic or Coagulation Issues.

No change in standard management.

K. Dementia or Psychiatric Illness/Treatment.

Anticholinergic medications, such as Trihexyphenidyl, should not be used in patients with dementia or cognitive impairment.

V. Transitions of Care.

A. Sign-out considerations While Hospitalized.

Patients are not usually hospitalized for the initial diagnosis of Parkinson’s disease itself. If the patient has known Parkinson’s disease, hospitalizations may occur in the setting of aspiration pneumonia, worsening movement symptoms, debilitation, failure to thrive, or overwhelming caregiver burden with the need for placement.

B. Anticipated Length of Stay.

Dependent upon coexisting medical issues at time of admission, and need for rehab disposition.

C. When is the Patient Ready for Discharge.

When coexisting medical issues are stabilized.

D. Arranging for Clinic Follow-up.

Patients newly diagnosed with Parkinson’s disease should be referred to a Neurologist.

1. When should clinic follow up be arranged and with whom.

Primary care within 2 weeks (max) and neurology within the month. Acute medical issues (cardiac, infection, etc.) should be resolved prior to the neurologist assessing for changes in therapy.

2. What tests should be conducted prior to discharge to enable best clinic first visit.

Physical and occupational therapy, and home safety assessments if applicable.

3. What tests should be ordered as an outpatient prior to, or on the day of, the clinic visit.

NA

E. Placement Considerations.

Once acute reasons for hospitalization are improved, the patient’s functional abilities and caregiver’s ability to manage in the home environment are assessed. This will likely involve PT, OT, speech therapy, case management, social work and all involved home caregivers. Setting up visiting nurses and additional home caregivers may be warranted.

Patients with Parkinson’s disease can easily become deconditioned. Short term rehab can be of benefit, and there are some programs that specialize in Parkinson’s care. Depending on the patient’s functionality, swallowing abilities and nutritional status, discussions of parenteral feeding may need to be addressed.

F. Prognosis and Patient Counseling.

Parkinson’s is a progressive disease, although the rate and degree of progression is variable. Treatments such as levodopa that initially provide great improvement in motor skills, tend to lose their effect or longevity with time.

There are many Parkinson’s support groups that patients and their families can benefit from. There is currently no genetic testing recommended for family members.

VI. Patient Safety and Quality Measures.

A. Core Indicator Standards and Documentation.

None.

The American Academy of Neurology (www.aan.com) has guidelines on the management of Parkinson’s disease. The Movement Disorder Society also has a clinical criteria set for diagnosis.

B. Appropriate Prophylaxis and Other Measures to Prevent Readmission.

Ensure adequate nutrition and safe swallowing.

Fall prevention and physical therapy to strengthen the patient.

If the patient is to return home on discharge, make sure the primary caregiver has adequate support systems and community resources available to assist in care.

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