14.2 Movement Disorders Flashcards
What is normal movement thanks to?
- An intact cortex and normal CNS
- Is fine tuned by the cerebellum & basal ganglia for fluid movement
What can movement disorders be often due to?
- Usually due to problems with fluid movement
- E.g. cerebellum, basal ganglia, metabolic
- Leading to:
- HypOkinesia = too little movement
- HypERkinesia = too much movement
Label the diagram (basal ganglia)
Explain normal basal ganglia function (how)? (ALL)
Green = stimulates
Red = inhibits
Explain what happens in the direct pathway (normal basal ganglia function)
Direct pathway = MORE go
Explain what happens in the indirect pathway (normal basal ganglia function)
Indirect pathway = MORE stop & LESS go
What is the purpose of the substantia nigra in normal basal ganglia function?
To lubricate the indirect & direct pathways (like oil in a car)
How does the substantia nigra balance the direct & indirect pathway?
- D1 receptors = STIMULATE (GO pathway - direct pathway)
- D2 receptors = INHIBIT (STOP pathway - indirect pathway)
If balance is disrupted then = disrupted movement
Briefly describe Parkinsonism & causes
- It is a HYP**O**KINESIA disorder
- Slow movement
- Rigidity in the WHOLE range of movement
- Have an ABNORMAL movement (e.g. freezing movements)
- Is due to damage to substantia nigra
- TOO much STOP and not enough GO
- Is a neurodegenerative disorder
- Causes:
- Examples include vascular dementia - which is where stroke disease is affecting that area of the brain (substantia nigra)
- Idiopathic Parkinson’s disease
- Medications that block dopamine
- Dementia with Lewy bodies (rare)
- Have to have 1 of the following:
- Rigidity
- Rest tremor
- Postural instability
What do you look for if someone has hyp**ER**kinesia? (& where might the lesion be?)
- TOO much movement
- Tremor
- Chorea
- Dystonia
-
Myoclonus
- Jerky (shock-like movements)
- Lots of causes
- Normal –> Medications –> Epilepsy –> Dementia
- Can be picked up on EMG
-
Tics
- Usually brief (often stereotyped)
- Can be movement OR sound
- Can be simple or complex
- Can be suppressed for short peroids of timie
- E.g. Tourette’s syndrome - MOST common
Lesion may be:
- CEREBELLAR
- STRIATAL
- SYSTEMIC
What do you look for if someone has hypOkinesia? (& what due to)
- Akinetic-rigid syndromes
- Parkinsonism
Due to:
- Lesion in substantia nigra OR systemic lesion
What do you look for when someone has a tremor?
- Rhythmical, sinusoidal, alternating movement
- Shaking
- Type of tremor can lead to diagnosis
-
Postural
-
Essential tremor
- Observes straight away when HOLDING a position
- Can be fine OR remarked
- Thyrotoxicosis/salbutamol
-
Essential tremor
-
Action/kinetic
- Cerebellar dysfunction (stroke, tremour, genetic, alcohol)
-
Rest
- Parkinsonism
-
Postural
ALL types can link/OVERLAP together (OFTEN)
What is chorea?
Chorea = random
- “dance-like” unpredictable, flowing movements moving from one area to another
- Affects the INDIRECT pathway
- Loss of inhibition of indirect pathway (striatum affected)
- Leads to TOO much GO
- Loss of inhibition of indirect pathway (striatum affected)
- E.g. hemi-chorea (affecting half the body)
What is ballism?
- Is chorea that affects proximal joints so movements are LARGE & FLINGING
- E.g. hemi-ballismus (affecting half the body)
What are the causes of chorea?
-
Any stroke lesion of the striatum
- E.g. stroke, tremour etc
-
Neurodegenerative/genetic
- E.g. Huntington’s Chorea, Wilson’s disease
- Immune mediated
- Drug induced
Explain Wilson’s Disease
- When excess COPPER in blood stream (& liver & brain)
- Can be presented in Parkinsonism, chorea, dystonia, psychiatric issues, liver disease (MIX of movement disorders)
- DO NOT miss as easily treatable and reversible (especially to brain & liver)
