6.07 Parkinson's Disease

Question 1

Dystonia

Answer 1

Relates to abnormalities of tone. There are many causes. Involves co-contraction of inappropriate muscles.

Syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements, and abnormal postures

NB Dystonia is a subcategory of dyskinesia

Question 2

How is dystonia currently classified?

Answer 2

In terms of age of onset (adult, infantile, juvenile), and distriution (focal, segmental, generalised)

Question 3

Primary dystonia

Answer 3

Develops spontaneously in the absence of any apparent cause and show no other neurologic symptoms

Question 4

Pathology of dystonias

Answer 4

Most of the mutations affect dopaminergic neurons and L-Dopa improves dystonias dramatically

Question 5

What types of movement disorders are there?

Answer 5

Akinesias, tremor, ataxia, hyperkinesia/dyskinesia (dystonia, athetosis, chorea, ballism, medicative dyskinesias, myoclonus)

Question 6

Athetosis

Answer 6

Slow irregular writhing of digits and face, related to cerebral palsy

Question 7

Chorea

Answer 7

Dance-like pattern of involuntary movement, constant movement and unpredictable, includes the face

Question 8

Types of chorea

Answer 8

Huntington’s chorea (autosomal dominant), Sydenham Chorea (children with rheumatic fever), various blood disorders

Question 9

Tardive dyskinesia

Answer 9

caused by neuroleptics, anti-emetics.

Bucco-lingual, grimacing, tongue protrusion, lip smacking, puckering

Question 10

Hemiballismus

Answer 10

Most violent form of dyskinesia, flinging, throwing, bizarre, dance-like.

Can be caused by subthalamic strokes and hyperglycaemic coma.

Question 11

Myoclonus

Answer 11

Brief, shock-like involuntary twitching of a muscle or group of muscles

May arise form abnormal oscillatory activity in SC, BS, or cortex

Question 12

Types of tremor

Answer 12

Physiological
Exaggerated physiological
Essential tremor
Hyperthyroid
Parkinsonian
Intention

Question 13

Physiological tremor

Answer 13

Seen normally - fine, low amplitude
Becomes exaggerated under anxiety caffeine, exercise, endocrine disorders

Can be alleviated by beta-blockers (under what circumstances?)

Question 14

essential tremor

Answer 14

Very common movement disorder
Often synchronised contraction of agonist and antagonist muscles 5-8Hz
Exacerbated by anxiety
Alleviated by alcohol, beta-blockers

Question 15

Hyperthyroid tremor

Answer 15

Looks like exaggerated physiological tremor or essential tremor if severe
Worsened by anxiety
Responds to beta-blockers and anti-thyroid medications e.g. carbimazole

Question 16

Parkinsonian tremor

Answer 16

Exhibited in PD and related disorders e.g. Dementia with Lewy Bodies, Multiple Systems Atrophy
4-5Hz, resting tremor, “pill-rolling”
Some improvement after beta-blockers
Responds to L-dopa

Question 17

Cerebellar intention tremor

Answer 17

Most evident when making precise or skilled movement

Can be quite low frequency 2-3Hz

Question 18

Tics

Answer 18

Twitchy, repetitive movements, not tremor-related

Question 19

Hypokinesia

Answer 19

Decreased activity level measured over time

Includes both bradykinesia and akinesia

Question 20

Main features of PD

Answer 20

Rigidity, bradykinesia, disordered postural reflexes, with/without resting tremor

Question 21

What are the three alpha-synucleinopathies?

Answer 21

PD, Dementia with Lewy Bodies, Multiple-Systems Atrophy

Question 22

What are the other types of Parkinsonism?

Answer 22

Tauopathies (PSP, Corticobasal degeneration, Frontotemporal dementia with Parkinsonism), TDP-43 proteinopathies

Question 23

What are the deep cerebellar nuclei?

Answer 23

Dentate, emboliform, globose and fastigial

Question 24

How do you diagnose PD?

Answer 24

Resting tremor, asymmetry of signs and symptoms, good response to L-dopa

no biological marker, though increased CSF alpha-synuclein can help diagnose it

Brain imaging to exclude other conditions

(Autopsy diagnosis is the gold standard.)

Question 25

Epidemiology of PD

Answer 25

Age of onset is usually 60-70

Only 4% have early onset ( usually genetic

Question 26

Where are neurons lost from PD?

Answer 26

Substantia nigra in midbrain: loss of dopaminergic neurons

Locus ceruleus (noradrenergic neurons)
Raphe neurons (serotonergic neurons)
Basal nucleus and mesencephalic locomotor area (cholinergic neurons)
Autonomic neurons

Question 27

How much dopaminergic cells need to be lost from SNc before symptoms?

Answer 27

60%

Question 28

What are Lewy bodies?

Answer 28

They are round pink, with a hyaline core and pale staining halo.
They are found in surviving neurons in the Snc, locus ceruleus, DMX of vagus. They are signs of a dying cell.