Movement Disorders Flashcards
1
Q
Movement Disorders
Overview
A
Neurologic diseases affecting voluntary control of movement or result in involuntary movements
Movement disorders divided into two categories:
-
Hypokinetic diseases
- Parkinson’s Syndrome
- Lewy Body Dementia
- Progressive Supranuclear Palsy
- Corticobasal degeneration
- Secondary Parkinsonism
- Drug-induced
- Vascular
- Post-traumatic
- Post-infectious
-
Hyperkinetic movements
- Essential tremor
- Huntington’s Disease
- Dystonia
- Tics
- Ataxia
- Tardive Dyskinesia
- Psychogenic Movement Disorders
2
Q
Hyperkinetic Movements
A
-
Tremor - Regular oscillations of a body part produced by alternating contractions of reciprocally innervated muscles
- Can be at rest, w/ holding a posture, or w/ action
- Myoclonus - Sudden “lightning-like” movements w/ irregular pauses between jerks
- Dystonia - Sustained muscle contractions resulting in abnormal fixed posture or repetitive involuntary movement
- Athetosis - Writhing movements due to continuous movement of adjacent muscle groups
- Chorea - An excess of rapid, arrhythmic, unpredictable movements, “dance-like”
- Ballism – Large amplitude, proximal, jerking or flinging movements
- Tics - Repeated, individually recognizable, intermittent movements or movement fragments that are briefly suppressible and are usually associated w/ awareness of an urge to perform the movement
- Akasthisia – sense of inner restlessness that often leads to voluntary movement
3
Q
Hypokinetic Movements
A
- Parkinsonism – a constellation of sx w/ multiple causes (one of which is Parkinson’s disease)
- Freezing of gait
- Psychomotor slowing
4
Q
Parkinsonism
A
A constellation of sx:
- Bradykinesia – slowness of movement
- Akinesia – difficulty initiating movement
- Rigidity
- Shuffling gait
- +/- tremor (mainly at REST)
- Masked facies – decreased facial expression
- Hypophonia – soft voice
Idiopathic Parkinson’s Disease is one cause of Parkinsonism
5
Q
Motor Control
A
Corticospinal tract and premotor areas ⇒ motor strength
Basal ganglia and cerebellum ⇒ other aspects of motor control
6
Q
Basal Ganglia
Components
A
-
Deep brain structures that facilitate or inhibit movement:
- Caudate
- Putamen
- Globus pallidus – interna and externa
- Substantia nigra – pars compacta and pars reticulata
- Subthalamic nucleus (STN)
- (Amygdala, nucleus accumbens, claustrum)
-
Other terminologies:
- Lentiform (lenticular) nucleus = globus pallidus + putamen
- Striatum = caudate + putamen
7
Q
Basal Ganglia
Function
A
Controls the contralateral side of the body
Largely facilitates or inhibits movement
8
Q
Basal Ganglia
Neurotransmitters
A
GABA (⊖) ⇒ striatum, globus pallidus
Glutamate (⊕) ⇒ subthalamic nucleus
Dopamine (⊕ or ⊖) ⇒ SN pars compacta
9
Q
Basal Ganglia
Circuitry
A
- Inputs to the basal ganglia: Cortex, substantia nigra pars compacta
- Outputs from the basal ganglia: globus pallidus internal segment and substantia nigra pars reticulata
- Mainly project to the thalamus → cortex ⇒ either stimulation or inhibition of movement
- Two pathways are involved: direct pathway and indirect pathway ⇒ opposite effects on movement
- Dopamine stimulates these pathways in different ways to facilitate movement
10
Q
Basal Ganglia
Direct Pathway
A
Facilitates Movement
- Inhibits output from basal ganglia
- Increases likelihood of movement
- Dopamine acting on D1 receptors is excitatory and stimulates this pathway
11
Q
Basal Ganglia
Indirect Pathway
A
Inhibits Movement
- Increases output from basal ganglia
- Decreases likelihood of movement
- Dopamine acting on D2 receptors is inhibitory on this pathway, thereby allowing movement
12
Q
Parkinson’s Disease
Overview
A
Neurodegenerative disorder characterized by loss of dopaminergic neurons in the substantia nigra.
- 2nd most common neurodegenerative disorder behind Alzheimer’s Disease
- Up to 10% of cases have a specific gene mutation
- Onset at age 50 or older but younger cases are seen
13
Q
Parkinson’s Disease
Clinical Manifestations
A
-
Cardinal Features of PD: TRAP mnemonic
- T: tremor – typically a resting tremor
- R: rigidity
- A: akinesia or bradykinesia
- P: postural instability
- Masked facies, hypophonia, micrographia
- Symptoms are typically asymmetric
-
Non-motor features of PD
- Depression/Apathy
- Constipation
- Sexual dysfunction
- Urinary dysfunction
- Orthostatic hypotension
- Cognitive decline – typically late in the course
14
Q
Parkinson’s Disease
Treatment
A
- Mainstay of pharmacologic treatment is levodopa
- Exercise – Studies show a possible disease modifying effect
- Physical, occupational, and speech therapy – Programs specifically designed for Parkinsonism
-
Deep Brain Stimulation
- Adjustable stimulation that modulates basal ganglia circuitry
- Improves levodopa-responsive symptoms, tremor, bradykinesia, dystonia, increases ON time, reduces dyskinesia
- Contraindications include atypical parkinsonism, dementia, uncontrolled psychiatric disease, high surgical risk due to other medical conditions
15
Q
Atypical Parkinsonian Syndromes
A
Neurodegenerative diseases with parkinsonism as a clinical feature.
Both synucleinopathies and tauopathies can have features of Parkinsonism.
- α-synucleinopathies often have REM sleep behavior disorder as a prodrome
- All forms of atypical parkinsonism warrant a levodopa trial, up to high doses if tolerated
- Otherwise, symptomatic treatment is utilized
- PT/OT, botulinum toxin for dystonia, anti-depressants, tx for orthostatic hypotension
- DBS is not efficacious
18
Q
Progressive Supranuclear Palsy
A
Tauopathy
Clinical features:
- Early falls – often due to retropulsion and postural instability
- Parkinsonism that is poorly responsive to levodopa, more rapid progression
- Ophthalmoplegia, or impaired vertical eye movements
- Square wave jerks
- Loss of downgaze is fairly specific
- Can involve horizontal eye movements over time
- “Stare” – wide stare, procerus activation
- Dementia
21
Q
DATscan
A
- Uses ioflupane iodine-123 injection w/ SPECT to image presynaptic dopamine transporters in the striatum
- Does not differentiate between PD, MSA, PSP
- Useful in differentiating essential tremor from PD/MSA/PSP
- Also helpful in differentiating drug-induced parkinsonism from PD
- Is not needed to confirm diagnosis, but can provide info if dx is not clear
25
Q
Huntington’s Disease
Overview
A
- Autosomal dominant CAG repeat disease on chromosome 4 affecting the Huntingtin gene
- Onset typically in adulthood
- Duration 5-20 years
-
Triad of clinical signs: chorea, cognitive deficits, psychiatric disease
- In later stages, can develop into bradykinesia/rigidity
- Higher rates of suicide in this population
27
Q
Dystonia
A
Sustained or intermittent muscle contractions causing abnormal (often repetitive) movements, postures, or both.
-
Causes:
- Idiopathic (most cases)
- Medication-induced (dopamine blockade)
- Genetic causes
- Structural – Trauma, stroke
-
Can affect one part of the body, multiple parts of the body, or can be generalized to affect the whole body
- Focal – Cervical dystonia (affects neck, most common form), blepharospasm, spasmodic dysphonia
- Task-specific – embouchure dystonia in musician’s, writer’s cramp, “yips” in golfers
- Segmental – Meige syndrome
- Generalized – many of the genetic dystonias such as DYT-1, dopa-responsive dystonia, or secondary dystonias in conditions like Lesch-Nyhan syndrome
- Can be associated w/ geste antagoniste (sensory trick which temporarily relieves the dystonia)
- Treatment includes botulinum toxin for more focal dystonias
