Module 12.2 - Parkinson’s Disease

Question 1

What is Parkinson’s disease?

Answer 1

Chronic, progressive neurodegenerative disorder characterized by depletion of dopamine-producing cells in the midbrain (substantia nigra)

Question 2

How do you diagnose a patient with Parkinson’s?

Answer 2

4 Cardinal Signs for Diagnosis:

1. Bradykinesia – extreme slowness of movements and reflexes

2. Rest tremors – 4-6 Hz tremor observed in fully resting limb and is suppressed when initiating movement.

3. Rigidity – velocity independent resistance to passive movement of major joints while individual is in relaxed position.

4. Postural instability (occurs later in disease process); slumped posture and loss of posture reflexes

For diagnosis refer to the Movement Disorder Society clinical diagnostic criteria for PD with absolute exclusion criteria and red flags; requires motor parkinsonism’s (bradykinesia plus tremor or rigidity) as the central feature of the disease with no absolute exclusion criteria noted and no red flags.

Question 3

Describe the etiology associated with Parkinson’s disease

Answer 3

• Average onset- 60 years of age
• Incidence higher in men than women
• Caucasians with a higher prevalence
• No single cause identified
• Environmental/genetic causes theorized: multiple gene mutations identified (Park1 gene); occupation exposure to heavy metals associated with increased risk

Question 4

What are the clinical manifestations associated with Parkinson’s Disease

Answer 4

A. Classic Triad:

• Resting tremor- occurs in arm/legs most frequently
• Rigidity: occurs in arms/legs, neck with decreased/restricted ROM
• Bradykinesia (see above)

B. Additional Motor Symptoms:

• Postural instability (see above)
• Pull test: individual steps backwards to recover from a slight tug from behind
• Falls: increased incidence late in disease; result of gait problems, decreased DTRs

C. Gate attributes

• Diminished arm swing
• Shuffling steps
• Bent forward posture
• Frozen gait- individual gets stuck or frozen while walking

D. Neuropsychiatric findings

• Depression
• Dementia
• Anxiety
• Psychosis
• Apathy
• Sleep disturbance
• Disinhibition

E. Autonomic dysfunction

• Urinary incontinence
• Sexual dysfunction
• Constipation
• Orthostatic hypotension
• Impaired thermoregulation
• Sensory disorders- pain and paresthesias

F. Craniofacial abnormalities

• Masked face – fixed, immobile, staring eyes (expressionless)
• Dysphagia
• Involuntary closure of eye lid
• Excessive drooling
• Dysarthria – unclear articulation of speech

Question 5

What lab/diagnostic tests are used to diagnose Parkinson’s disease?

Answer 5

• History and PE is basis for diagnosis
• Conventional Neuro diagnostic testing (MRI brain or CT) are not usually helpful in diagnosis PD- most often normal
• Clinical rating scales such as from the International Parkinson and Movement Disorder Society as useful in establishing a standard evaluation and disease progression over time for individuals with PD

Question 6

How do you manage a patient with Parkinson’s disease?

Answer 6

• Neurologist consult
• Pharmacological intervention- to provide symptom relief and improve baseline functioning
  
  • Carbidopa-levodopa combo (sinemet) is standard treatment- withheld until symptoms worsen due to decreasing effectiveness over time
  • Dopamine agonists (ropinirole and pramipexole) useful in decreasing motor complications
  • Anticholinergics (trihexyphenidyl and benztropine mesylate) for tremors; but should be avoided if possible- may worsen confusion
  • Amantadine (Symmetrel) for early in disease for dyskinesias
  • MAO-B inhibitors (rasagiline and selegiline) used to treat motor symptoms
• Deep brain stimulation surgery- mechanisms unknown- useful for some individuals to help regain motor function; not for all patients; consult neurosurgery
• Nutrition support
• Exercise- PT and OT consults
• Management of neuro-psychiatric comorbities- depression