Parkinson's Disease

Question 1

What is the aetiology of PD?

Answer 1

Unknown

Question 2

Outline the pathophysiology of PD

Answer 2

Chronic, progressive movement disorder

Triad of bradykinesia, tremor and rigidity

Degeneration of substantia nigra = deficiency of dopamine

Question 3

What are the symptoms and signs of PD?

Answer 3

Tremor = resting

Bradykinesia - shuffling gait, falls

Hypertonia = rigidity (cog-wheel)

Abnormal gait = shuffling, flexed posture, reduced arm swing, turning en-bloc

Hypophonia

Reduced facial expression

Postural instability = falls

Micrographia (small cramped handwriting)

Non-motor =

• Dementia (can see lewy-body before PD), psychosis
• Depression
• Salivation
• Sweating
• Sphincter problems
• Sleep disorders
• Pain

Question 4

How should PD be investigated?

Answer 4

Hx - timeline, lifestyle, previous head injury, DH (antiepileptics, antipsychotics)

Neurological exam - tone, power, gait, handwriting

Bloods = Hb, TFT (hypo), U+Es, LFTs, B12/folate

MSU = rule out infection

Imaging = CT, MRI, PET

DAT scan = used to diff PD from central tremor

Carbidopa-levodopa test - do symptoms improve

Question 5

How is PD managed?

Answer 5

Lifestyle = aerobic exercise

Carbidopa-levodopa

• SE = nausea, orthostatic hypotension (don’t give B-blockers)
• quick half life = needs to be taken every few hours
• don’t suddenly stop taking = neuroleptic malignant syndrome (fever, marked rigidity, altered consciousness, leucocytosis, high CK)
• will end up stop working (converted in dopaminergic neurons, eventual loss of pre-synaptic - give dopamine agonist ropinirole (SE impulsivity))

Dopamine agonists (ropinirole)

• AD: less dyskinesia or motor fluctuation, longer duration of action, not neurotoxic
• DIS: less efficacy than L-DOPA, more psychiatric SEs, expensive
• SE = postural hypotension, nausea, psychosis, hallucinations, impulse control disorders (gambling, hypersexual, shopping)

MAO B inhibitors (selegiline) = help prevent breakdown of dopamine by inhibiting monoamine oxidase B, prolong action of L-DOPA

COMT inhibitors (entacapone, tolcapone) = reduce peripheral breakdown of L-DOPA, have to use with levodopa

DBS = electrodes in STN, generator in the chest (needs to be responding to levodopa but having severe SE)

Sleep problems = melatonin

Question 6

What are the possible complications of PD?

Answer 6

Dementia

Depression

Swallowing difficulties

Question 7

How is PD clinically diagnosed?

Answer 7

Clinical diagnosis

Bradykinesia + at least ONE of the following

• Muscular rigidity = typically lead pipe (can be cog wheel - when tremor present)
• 4 – 6 Hz rest tremor = pill rolling
• Postural instability not caused by primary visual, vestibular, cerebellar, or proprioceptive ◦ dysfunction

Question 8

What are the features of supportive criteria for a PD Dx?

Answer 8

Unilateral

Rest tremor present

Progressive

Persistent asymmetry

Excellent response (70 – 100%) to LD

Severe LD-induced chorea

LD response for ≥5 years

Clinical course of ≥10 years

Question 9

What are the non-motor symptoms of PD?

Answer 9

Neuropsychiatric dysfunction
◦ Mood Disorders
◦ Apathy + anhedonia
◦ Frontal executive dysfunction
◦ Dementia + Psychosis

Sleep Disorders
◦ Sleep fragmentation + insomnia 
◦ RBD 
◦ PLMS / RLS
◦ Excessive daytime somnolence

Autonomic dysfunction
◦ Orthostatic hypotension
◦ Urogenital dysfunction
◦ Constipation

Sensory symptoms + pain
◦ Olfactory dysfunction
◦ Abnormal sensations
◦ Pain

Question 10

What is a DAT scan?

Answer 10

Focus on the activity of the dopamine transporter

Loflupane I123 injection

Used with single-photon emission computed tomography (SPECT)

Detecting dopamine transporters (DaT) in suspected parkinsonian syndromes

Question 11

What is deep brain stimulation?

Answer 11

Deep brain stimulation involves the implantation of a wire, with 4 electrodes at its tip, into one of 3 target sites in the brain:

• the thalamus (this procedure is known as thalamic stimulation)
• the globus pallidus (this procedure is pallidal stimulation)
• the subthalamic nucleus (this procedure is subthalamic stimulation)

Question 12

Outline Hoehn and Yahr scale

Answer 12

• STAGE 1 = Unilateral disease
• STAGE 2 = Bilateral disease, without impairment of balance
• STAGE 3 = Mild to moderate bilateral disease; some postural instability; physically independent
• STAGE 4 = Severe disability; still able to walk or stand unassisted
• STAGE 5 = Wheelchair bound or bedridden unless aided

Question 13

Outline UPDRS

Answer 13

Unified Parkinsons Disease Rating Scale

42 question assessment
• 1 = mentation, behaviour, mood
• 2 = ADL
• 3 = motor sections
• 4 = modified Hoehn and Yahr scale
• 5 = Schwab and england ADL scale

Question 14

What is an essential tremor?

Answer 14

Progressive tremor of the upper extremities and head, present in posture and action, without other neurological signs or symptoms

Mainly symmetrical, rhythmic, involuntary oscillation movement disorder of the hands and forearms (69% of patients) that is usually absent at rest and present during posture and intentional movements