PD Flashcards
What is Parkinson’s disease?
Chronic, progressive, neurodegenerative disorder
- Characterized by motor and non-motor symptoms - Caused by depletion of dopamine producing neurons in the substantia nigra of the basal ganglia - Presence of Lewy bodies (alpha-synuclein aggregates) in residual dopaminergic cells
Etiology
Cause is largely unknown for most people diagnosed with PD
PD is not considered a hereditary condition
Likely combination of genetic risk factors and environmental factors
Several genes related to PD have been identified:
- Mutations in the LRRK2 gene have been found to be the greatest genetic contributor to PD 1
- (PARK 1) – first gene identified
- Parkin gene (PARK 2), LRRK2, PARK7, PINK1, SNCA gene
Environmental factors:
Occupation
Rural living
Oxidative stress
Pesticides, methamphetamine/amphetamine use
Rare cases of PD caused by single genetic mutation passed from generation to generation resulting in great number of PD within an extended family
What are other etiologies of parkonsonism?
Parkinsonism
Drug-induced
Vascular
Cerebrovascular disease
-Parkinson-plus syndromes
Progressive supranuclear palsy (PSP)
Multi system atrophy (MSA)
Corticobasal ganglionic degeneration (CBD)What drugs can induce parkonsonism?
Phenothiazines – typical antipsychotics (Thorazine, Prolixin); Compazine
Butyrophenones - Haldol
Benzamides – atypical antipsychotics
What is the etiology of PD?
Estimated to be 1 million people in US with PD and 5 million worldwide
Affects 1% of the population over age of 65
Approximately 60,000 new PD cases each year
Family history in 5-10% of patients
Men may have a slightly higher risk of developing PD
Name some assessment tools used to evaluate people with PD
United Parkinson’s Disease Rating Scale (UPDRS)
-Subjective reports and objective exam of motor and non-motor symptoms
Hoehn and Yahr Scale: Stages 1-5
Schwab and England ADL scale: 10- 100%
Patient diaries: Records length of daily ON/OFF/Dyskinetic periods
Olfaction: BSIT
Caregiver reports
Depression screen: GDS, PHQ-9
Cognitive screen: Montreal Cognitive Assessment (MoCA)
Describe the stages of Hoehn & Yahr Scale
Stage 1 – unilateral, minimal to no functional impairment
Stage 2 – bilateral without balance impairment
Stage 3 – Still independent, balance problems
Stage 4 – More disabled, unable to live alone, can stand and walk unassisted
Stage 5 – wheelchair or bedbound unless assisted
How do you formulate a diagnosis for PD?
PD is a clinical diagnosis
Careful history with chronology of symptoms
Thorough physical exam
Positive levodopa response reinforces a PD diagnosis
Challenges in dx: gradual onset, variable, nonspecific, subtle changes could be attributed to aging
No tests or studies that can confirm diagnosis – only autopsy
Abnormal olfactory test is supportive of PD diagnosis
What is DAT-SPECT
DAT-SPECT is a diagnostic tool that can identify patients with parkinsonism:
- Uses an IV administered radioactive tracer that allows for visualization of the dopamine transporters in the brain
- Cannot differentiate between PD and other forms of parkinsonismsuch MSA, PSP, CBD, or LBD
What are general physical assessment findings?
Skin changes (seborrheic dermatitis) Orthostatic hypotension Musculoskeletal changes due to aging or injury
What are neuro exam findings?
- Mental status: Depression, anxiety, cognitive changes
- Cranial nerves: Olfaction, limited upgaze, masked facies, hypophonia
- Motor: cogwheel rigidity
- Reflexes: + Myerson’s sign
- Sensory: objectively normal; often subjective symptomatology
- Coordination: decreased RAM speed
- Gait: decreased arm swing, stooped posture, short or shuffling steps
- MS: tremor
What is the Myerson’s sign?
Myerson’s sign or glabellar tap sign is a clinical physical examination finding in which a patient is unable to resist blinking when tapped repetitively on the glabella, the area above the nose and between the eyebrows. It is often referred to as the glabellar reflex.
DDX PD
Parkinson-plus syndromes including - Progressive supranuclear palsy - Multiple system atrophy - Lewy body disease Vascular parkinsonism Drug-induced parkinsonism Multifactorial gait disturbance Essential tremor
When might you think that PD is an incorrect diagnosis?
Other diagnoses should be considered if:
- No benefit from levodopa - Initial bilateral symptoms - Gait-predominant symptoms only - History of CVA, diabetes, psychiatric comorbidities, use of illegal drugs or antipsychotics - Abnormal eye movements upon exam - Early autonomic symptoms - Dementia or psychosis within one year of diagnosis
What are the cardinal motor symptoms of PD?
TREMOR
BRADYKINESIA
RIGIDITY
(POSTURAL INSTABILITY)
Discuss the tremor seen in PD
Not all PD patients present with or develop a tremor!
In 70% of cases, tremor is the first symptom
“Pill rolling tremor” is most prominent in fingers and hand
Involuntary movement that commonly affects the limbs and/or jaw
Present during rest and resolves with action
Starts unilaterally
Increases with stress, anxiety, excitement
Ceases with sleep
50% of patients presenting with tremor do not have PD.
Discuss bradykinesia seen in PD
Slowness of movement
Decrease in: Walking speed Eye blinking Facial expression Eating and chewing
Discuss rigidity seen in PD
Muscular stiffness and increased muscle tone
Patients are usually unaware of rigidity, more troubled by slowness
Detected on exam, described as “cogwheeling”
Can be brought out by distracting maneuvers in the contralateral limb
Describe postural instability seen in PD
Loss of postural reflexes, resulting in falls
Some patients will fall several times a day
Falls in PD results in tremendous morbidity and mortality
Gait impairment caused by:
- Shuffling - Festination - Freezing of gait
Describe additional motor symptoms seen in PD
Reduced arm swing
Stooped posture
Dystonia (involuntary muscle contraction/abnormal posture holding of limb)
Micrographia (small handwriting)
Hypomimia (reduced facial expression)
Fine motor impairment
