10.9 Movement Disorders Flashcards
Risk factors for Parkinson’s disease
- age (older)
- male
Pathology of Parkinson’s disease
- Substantia Nigra, where dopaminergic neurons have their cell bodies
- cells which make dopamine are killed off
- Lewy body, in a cell in the substantia nigra, containing toxic protein, synuclein.
Physiology of Parkinson’s disease
- basal ganglia run and activates motor activity
- also need dopamine (made in substantia nigra)
- dopamine allows movement to occur
Function of basal ganglia
- Basal ganglia: cognitive, affective, motor functions
Motor Function:
• Maintain amplitude of movements
• Concerned with the correct sequence of movements
Cognitive Function:
• Selecting tasks.
• Selecting specific motor tasks.
• Selecting one behaviour over another
• Interacting with frontal lobe// Part of the inhibitory network of the frontal lobe
Pathophysiology / cause of Parkinson’s disease
RARE:
- genetic
- environmental
- Rare genetic mutations have indicated involvement of the protein, synuclein(toxic if in excess)
• A normal protein, involved in cellular membrane turnover
• Toxic in excess
- Progression of neurodegenerative process: (from bottom to top)
Brainstem →→→→ cortex
Clinical manifestations of Parkinson’s disease
Early
Early: Pre-motor features
- REM sleep behaviour disorder (RBD)
- loss of sense of smell (olfactory bulb affected early)
- constipation
- change in mood
Clinical manifestations of Parkinson’s disease
At time of clinical diagnosis
At time of diagnosis - Motor manifestations
Tremor:
- Unilateral, a REST tremor
- Brought out by doing calculations, and often seen when walking.
Rigidity
Bradykinesia
- slow movement
- Major cause of disability in PD.
- Bradykinesia affects all voluntary action (swallowing, speech, walking etc)
- Loss of automatic movements and a scaling down (=reduction in amplitude) of movements.
- The sequence effect (SE) is characterized by progressive slowness in speed or a decrease in amplitude (it gets smaller) of sequential movements.
- loss of automatic movement
Postural Instability
- CLINICAL PICTURE Asymmetrical
Clinical manifestations of Parkinson’s disease
Progression of disease
Non motor symptoms of PD (not related to dopamine hormone)
• Depression
• Autonomic failure (frequency, constipation, postural hypotension)
• Falling
• Sleep disorders
• Dementia
Describe the functions of the 3 parts of the brain of the motor system
Cerebellum - movement
Basal Ganglia - running motor program systems
Cortex - how we interact with our outside world using our limbs and voice
Myoclonus
Description
Causes
- Description: Rapid jerks
- Top-tip: “a fragment of epilepsy”
- can be focal or generalised
Causes
- Normal: Sleep starts
- Pathological:
• Organ failure (kidney/liver)
➡️liver flap/asterixis
➡️ brain -> delirium
• Epilepsies (JME) ➡️ juvenile
Tremor
Description
Causes
Important notes
Underlying systems involved
- Description: sinusoidal movement of a body part
- Top-tip: Action induced; not usually cerebellar
Causes
- Normal: Physiological
- Pathological:
• Medication
• Essential Tremor
• Parkinson’s disease (rest)
• Cerebellar disease
Important notes
- Most tremor does NOT indicate a cerebellar problem
- Most tremor is tremor…..usually physiological/medicines
- Other than PD, tremor is ACTION tremor, not REST (Parkinson’s is the only exception)
Underlying systems involved
- Motor cortex
- Premotor cortex
- Inferior olive
Hemiballismus
Description
Top-tip
Causes
Description: throwing movements of ONE side of the body
Top-tip: Lacunar stroke; may be due to raised glucose in DM
Causes (focal cause)
- Lacunar stroke of subthalamic nucleus
- Non-ketotic hyperglycaemia causes similar movement
- Infarction in the sub-thalamic nucleus (a lacunar stroke)
Dystonia
Description
Top-tip
Causes
Description: Sustained muscle contractions that cause abnormal repetitive movements or postures
Top-tip: “Anything goes”: Children-Adults/Focal-Generalized/Brain injured-Normal brain (wide range of manifestations)
Causes
- Brain injury (stroke, trauma)
- Drug induced (dopamine blockers)
- Genetic (children): legs→→→ generalized {very uncommon} [misdiagnosed with cerebral palsy]
- Focal (idiopathic): head and neck
- Occupational/Task specific (musicians, sportspeople)
Chorea
Description
Causes
Description: Fragments of normal movements (“fidgety”)
Causes
- Genetic: Huntington disease
➡️Autosomal Dominant
➡️Cognitive impairment and depression common
- Autoimmune: Sydenham’s chorea (consequence of rheumatic fever)
Tics
Description
Top-tips
Causes
Description: Stereotyped movements, often with vocal component
movement carried out tends to be same movement everytime
Top-tip: suppressible and suggestible (ask pt to stop for 20sec)
Causes
- ? Normal development/Physiological: young boys
- ? Genetic: Tourette’s syndrome
➡️Motor tics (simple →→ complex)
➡️Vocal tics
➡️Premonitory urge
➡️Significant psychiatric comorbidity, largely OCD.
- likely an underlying sense of anxiety (pt feel this movement is the only way to get rid of anxiety)
