Parkinsons

Question 1

What are the basal ganglia for?

Answer 1

• Essential for correct processing of readiness potential – in terms of initiation
• Striatum – Cuadate Nucleus – Putamen
• Globus Pallidus
• Important connections with substantia nigra and subthalamic nucleus

Question 2

What is Parkinsons disease?

Answer 2

• Neurodegenerative disease

* Destruction of Dopaminergic neurones of the substrantia nigra (that connect to the striatum)

Question 3

What are the symptoms?

Answer 3

• Bradykinesia • Rigidity • Tremor
Insidious onset
Resting tremor 
Stiffness / Slowness of movement 
Difficulty getting out of a chair 
Difficulty rolling over in bed 
Clumsiness 
Frequent Falls 
Smaller hand writing 
Mental Slowness 
Insomnia
• Cranial Nerves: impairment of upward gaze, Repeated taps on forehead causes reflex blinking without fatigue, tremulous eyelids
• Psychiatric – Depression
– Dementia
– Cognitiveproblems 
• Mask like face 
• Decreased blinking 
• Drool 
• Greasy skin / seborrhoeic dermatitis is common

Question 4

What are the causes?

Answer 4

– Pesticides, wood pulp
– Genetic susceptibility • Alpha-synuclein (Ch4)
• Neuropleptic therapy
• MPTP toxin (illicit drug contamination)
• Post encephalitis
• Repeated Head Injury
• Juvenile Autosmomal Recessive Parkinsons (Parkin Gene Ch6)
• Sporadic
• Unknown
• ?Environmental

Question 5

Who develops it?

Answer 5

• 1-2% of 60 year olds

* 20 in 100,000 • Mean age of onset is 57 years old.

Question 6

What are the cardinal signs of Parkinsons?

Answer 6

• Tremor
• Rigidity
– Lead pipe rigidity • Extensors & flexors
– Cog-wheel rigidity • Sinkinesis
– Normal power and reflexes
• Gait – Simian, Shuffling, small stepped – Reducded arm swing – Falls easily

Question 7

What happens?

Answer 7

• The flailing limbs is due to medication.
• Difficulty in initiating voluntary movements.
• Requireintenseconcentrationtoinitiate
movement.
• Loose associated movements (arm swing / emotion).
There’s 80% ganglia degeneration before symptoms start.

Question 8

What’s the pathology?

Answer 8

Pathology – Reduced melanin pigmentation in the SN.
• Macro – (dopamine is a precursor to melanin)
• Micro
– Degeneration of dopaminergic neurones from the SN to the CN & Putamen (Striatum)

Question 9

What happens normally in the brain and what happens in Parkinson’s?

Answer 9

• The pallidum is spontaneously active
• Various nuclei inhibit the pallidum to allow controlled movement
• Dopamine facilitates the release (of pallidum) from inhibition
• No Dopamine = no inhibition of the striatum = poverty of motion – Greater exertion in effort for a given movement
• Treatment brings excess / uncontrolled dopamine – Dyskinesia
• Pharmacology is gross and cannot reproduce the subtle sophistication of physiology.

Question 10

What are the treatments?

Answer 10

• Levadopa
Treatments
• Dopa Decarboxylase Inhibitor – Prevents peripheral use of Levadopa – Can’t cross Blood Brain Barrier
• Ecstasy • Deep Brain Stimulation

Question 11

What are the treatment complications?

Answer 11

• Psychoticsymptoms
– Pyschotics treated with dopamine depletion develop PD.
– Long term PD treatment = psychotic behaviour – Nausea & Vomiting – Confusion – Visual Hallucinations
– Drug Infectivity – End of Dose Dyskinesia / Dopa induced dyskinesia – On and Off Syndrome

Question 12

How can treatment complications be managed?

Answer 12

• Small doses, more frequently
• Selegiline
• Dopamergic agonists – Potentiate the effects
• Apomorphine Infusion • Drug Holidays

Question 13

How does Parkinson’s relate to dentistry?

Answer 13

• Dry Mouth
– Regular review, saliva replacement, fluoride
• Cant brush their teeth
• Bruxism / Tooth wear
• Drooling • Lack of control of musculature
• Dentures wont fit – Inhalation risk
• Adrenaline