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
16
Q
Lewy Body Dementia
A
- 2nd most common form of neurodegenerative dementia
- An α-synucleinopathy
-
Clinical features:
- Parkinsonism starts w/ or follows dementia onset
- Fluctuating cognition
- Recurrent visual hallucinations – typically complex
- Treatment: balance between levodopa for parkinsonism, and treating psychosis
17
Q
Multiple System Atrophy
A
- An α-synucleinopathy
-
Clinical features:
- Parkinsonism – Poorly responsive to levodopa, more symmetric, faster progression
- Autonomic failure – Orthostatic hypotension, erectile dysfunction, urinary difficulty
- Cerebellar dysfunction
- Relative preservation of cognition
- Anterocollis – patterned, repetitive muscle contractions that result in neck flexion
-
Subtypes:
- MSA-P (Striatonigral degeneration) – mostly parkinsonism
- MSA-C (Olivopontocerebellar atrophy) – mostly ataxia
- MSA-A (Shy-Drager, no longer considered a distinct subtype) – mostly autonomic failure
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
19
Q
Corticobasal Degeneration
A
Tauopathy
- Parkinsonism w/ poor response to levodopa (sometimes markedly asymmetric)
- Alien limb phenomenon – arm or leg assumes postures without the patient’s voluntary control
- Cortical sensory deficits
- Graphesthesia – unable to identify numbers drawn on the hand
- Loss of stereognosis – unable to identify objects by feel
- Significant dystonia, spasticity, rigidity (often unilateral)
- Cortical myoclonus, apraxia
- Dementia later in the course of disease
20
Q
Secondary Parkinsonism
A
-
Drug-induced parkinsonism
- Most common extra-pyramidal syndrome
- Often caused by dopamine-blocking drugs
- Including some antipsychotics and antiemetics
- Can take months to a year to resolve after stopping the offending medication
-
Other secondary causes include:
- Vascular parkinsonism
- Post-encephalitic parkinsonism
- Post-traumatic parkinsonism
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
22
Q
Hypokinetic Conditions
Comparison
A
- Parkinson’s Syndrome: tremor, asymmetry, slower progression
- Lewy Body Dementia: early dementia, visual hallucinations
- Multiple System Atrophy: associated autonomic sx; parkinsonism type, cerebellar type
- Progressive Supranuclear Palsy: early falls, opthalmoplegia
- Corticobasal degeneration: unilateral dystonia, alien hand, apraxia
-
Secondary Parkinsonism
- Drug-induced (Dopamine blockade)
- Vascular
- Post-traumatic
- Post-infectious
23
Q
Essential Tremor
Overview
A
Very common cause of tremor
Clinical features:
- Tremor that slowly worsens over years
- Tremor is worst w/ posture and action (unlike rest tremor of Parkinson’s disease)
- Affects arms/hands first, but can also affect head, jaw, voice, legs trunk
- Bilateral, usually roughly symmetric
- Can become disabling in severe cases
- Fhx in ~60%
- Often improves acutely w/ alcohol
24
Q
Essential Tremor
Treatment
A
- Propranolol (β-blocker) ⇒ first-line therapy
- Primidone (older anti-epileptic med) is another option
- There are other second line treatments which are less likely to be effective
- Deep brain stimulation can be considered if medication fails ⇒ target is typically the VM nucleus of the thalamus
25
Huntington’s Disease
Overview
* _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
26
Huntington’s Disease
Treatment
* Treatment is symptomatic
* **Tetrabenazine** is FDA approved ⇒ **⊗** **reuptake and depletes storage of dopamine** and other monoamines
* Other dopamine-blocking medications such as **haloperidol, risperidone** have been used
27
Dystonia
**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
28
Tics
**Semi-voluntary (e.g. suppressible), repetitive, rapid, non-rhythmic movements or sounds.**
* Sensory component – urge to perform the movement
* Associated compulsions
* May be associated w/ **OCD, ADHD**
* Occasionally tics are disabling
29
Tourette Syndrome
A syndrome consisting of **both motor and vocal tics**, beginning in childhood and lasting over a year.
30
Tics
Treatment
* **Alpha-agonists** such as clonidine
* **Anti-psychotics** such as haloperidol
* **DBS** in severe cases – also option for treatment of refractory OCD
31
Ataxia
Overview
* **Physical finding**, not a disease
* Results from **damage to cerebellum or cerebellar pathways**
* Features:
* **Dysmetria** – poor targeting of planned movements
* **Dysdiadokinesia** – poor sequencing of planned movements
* **Intention tremor** – typically coarse, worse closer to the intended target
* **Gait abnormalities** – wide based gait w/ poor balance “Drunken sailor’s walk”
* **Eye movement abnormalities**
32
Ataxia
Etiologies
* **Lesion in the following areas of the brain** (caused by strokes, demyelination, brain tumors, etc.):
* Cerebellum
* Pons
* Midbrain (Red Nucleus)
* Olivary Nucleus
* Thalamus (Cerebellar Inflow Nucleus)
* **Acute intoxication**
* Alcohol, phenytoin, others
* **Chronic substance abuse**
* Including alcohol which causes cerebellar degeneration
* **Genetic Ataxias**
* Autosomal Dominant Ataxias (Spinocerebellar ataxias)
* Autosomal Recessive Ataxias (e.g. Friedreich’s ataxia)
* **Metabolic**
* Vitamin E deficiency, Thiamine deficiency, hypothyroidism
* **Autoimmune/paraneoplastic**
* Gluten ataxia
* Anti-YO, HU, TR
* **Multiple System Atrophy**, Cerebellar Type (MSA-C)
33
Psychogenic Movement Disorders
* _Key features:_
* **Sudden onset**
* **Variability** – changing phenomenology (frequency, amplitude, direction)
* **Distractibility**
* **Entrainment** – will change in rhythm to match other movements
* **Coherence** – all body parts moving to the same rhythm
* **Suggestibility**
* Not uncommon – up to 10% of new pt visits in movement disorders clinic
* _Risk factors:_
* Having other neurologic conditions
* Recent significant stress/trauma (emotional or physical)
* Psychiatric disorders
* H/O childhood abuse/neglect
* Treatment consists of **engaging the pt in the diagnosis, physical therapy, psychiatric care, and psychotherapy**
34
Movement Disorders
Take Home Points
* **Dopamine acts on the basal ganglia on both the indirect and direct pathways to facilitate movements**
* Parkinson’s disease and other movement d/o are **clinical diagnoses**
* Based on carful hx and PE
* **Parkinson’s disease has many available treatments**
* With appropriate management, pts can sustain a good QOL
