6. Movement Flashcards
What are the parts of the basal ganglia?
Caudate nucleus, putamen, globus pallidus, subthalamic nucleus, substantia nigra
- Striatum = caudate + putamen
- Lenticular nucleus = putamen + globus pallidus
- Movement disorders are often called extrapyramidal disorders
- They do NOT affect the corticospinal tract (pyramidal system)
- Basal ganglia has connections to cortex via thalamus
- Basal ganglia has 3 of 4 main dopamine pathways:
- Nigrostriatal
- Mesolimbic
- Mesocortical
What are the different types of abnormal movements?
Tremor
- Rhythmic movement due to alternating contractions between agonist and antagonist muscles
- Most common movement disorder
Chorea
- “Dance-like”
-
Irregular, asymmetric movements that are random and continuous
- Not repetitve or rhythmic, but flow from one muscle group to the next
Athetosis
- “Snake-like”
- Slow twisting and writhing movements that typically affects more distal muscles of fingers, arms, legs, neck
Ballism
- Violent, involuntary flailing of extremities
- Extreme form of chorea
Tic
- Random, repetitive, rapid, purposeless movements
- Motor, eye-blinking, or vocal
- Considered semi-voluntary (can be temporarily suppressed)
Myoclonus
- Rapid, brief, uncontrollable jerks
Dystonia
- Sustained, abnormal posture caused by simultaneous contraction of both agonist and antagonist muscles
Akathisia
- Subjective sense of inner restless in which patients feel compelled to move continuously
A 75 year-old man has trouble initiating his gait. However once he gets started, his steps become faster and faster until he has trouble stopping. This is called a festinating gait. When walking, he takes small steps and does not lift his feet off the ground. This is most consistent with…
Parkinson’s disease (PD)
Parkinson’s disease results from idiopathic destruction of dopamine producing neurons in the substantia nigra in the midbrain
- Symptoms don’t occur until 80% of dopamine producing neurons are destroyed
-
Lewy bodies
- Intracytoplasmic inclusions composed of alpha-synuclein
- Pathological hallmark of PD
- Lewy-body dementia and PD are likely the same illness with different clinical manifestations
An 80 year old man presents to your office complaining of difficulty walking. Over the last year he has noticed he has a hard time “getting started” and it takes him much longer to get up from a chair. He says he has problems turning around at the end of the hallway. On exam, you note he takes small, shuffling steps with little ground clearance and has little to no arm swing. What are the criteria for diagnosing Parkinson’s disease?
“TRAP” mnemonic:
- Tremor - unilaeral, worse at rest, disseapears with movements
- Rigidity - “cogwheel”
- Akinesia/bradykinesia - slowness of movement
-
Postural instability - loss of postural reflexes, shuffling gait, reduced arm swing
- Festinating gait = involuntary quickening of gait
- “Freezing” episode = stuck while walking
Other symptoms:
- “Masked” facies
- Anosmia = loss of smell
- Dysphagia/dysarthria
- Urinary dysfunction/constipation
- Autonomic dysfunction
- Sleep disruptions (particularly REM)
- Micrographia = small hand-writing
- “On-off phenomenon” = later-stage patients who develop acute episodes of bradykinesia and rigidty that remit
Parkinson’s disease is primarily a clinical diagnosis. What additional test was approved by the FDA in 2011 to aid with diagnosis?
DaTscan
- A contrast agent is used with single-photon emission computed tomography (SPECT) for detecting dopamine transporters (DaT) in suspected parkinsonian syndromes
A 65 year-old man is referred for possible Parkinson’s disease. He is rigid on exam, though his symptoms are very symmetrical, making you very wary of this diagnosis. He also has a wide-eyed stare and trouble looking down. His wife reports he has had several significant falls when going upstairs. The patient himself seems unconcerned about his condition, something his wife says is quite unusual for him. You decide to give a trial of Sinemet, but are not optimistic as you strongly suspect he has…
Progressive supranuclear palsy (PSP)
- Symptoms
- Vertical gaze palsy (“Reptilian stare”) - primarily downward gaze, imbalance → falls, changes in mood and behavior (depression, apathy, dementia), rigidity, slowing of movements, bladder/bowel incontinence
- Cause = “tauopathy”
- Midbrain atrophy
- “Hummingbird sign” or “penguin sign”
- “Mickey Mouse sign”
- Midbrain atrophy
- No treatment
- Does NOT respond to Parkinson’s disease treatment
A 55 year-old man is started on dopamine-agonist therapy for Parkinson’s disease. The two main options are Ropinirole (Requip) or Pamiprexole (Mirapex). A possible behavioral side effect of these medication is…
Impulse control disorders such as pathological gambling or hypersexuality
A 65 year-old man with Parkinson’s disease develops paranoia and hallucinations. Your first step should be to…
Reduce his carbadopa-levadopa (Sinimet)
Carbidopa
- Prevents conversion of levadopa to dopamine, which prevents vomiting
- Does not cross the BBB, so the levadopa can be converted to dopamine in the CNS
Levadopa is used instead of dopamine since dopamine can’t cross BBB
The most appropriate antipsychotic to use is quetiapine (Seroquel)
- Can cause orthostatic hypotension
- Treat with fludrocortisone
What structure is a common target for deep brain stimulation in Parkinson’s disease?
Subthalamic nucleus
- Thalamus & globus pallidus are also targets
Deep brain stimulation indications:
- Advanced disease with severe “on-off” responses to medications
- Dyskinesia, tremors
What is the treatment for Parkinson’s disease?
- Dopamine agonists = initial treatment
-
Requip/Ropinirole & Mirapex/Pramipexole
- Contraindicated in old people due to psychiatric symptoms
-
Requip/Ropinirole & Mirapex/Pramipexole
-
Carbadopa-levadopa (Sinemet)
- Most effective treatment for PD
- Can be combined with catechol O-methyltransferase (COMT) inhibitors
- Entacapone & tolcapone
- Prolong effect of carbadopa-levadopa by blocking an enzyme that breaks down levodopa
- Prevent “wearing off”
- SE: dyskinesia
- Other medications
- Amantadine, selegiline (MAO-i), trihexyphenidyl (anticholinergic)
A 60 year old man presents to the ER with complains of unsteadiness and lightheadedness on standing. He also has constipation. He has mild resting tremor and cogwheeling which is equal in the upper limbs. His BP falls from 150/95 to 100/65 when he stands. What is the diagnosis?
Multiple system atrophy (MSA)
Two types:
- MSA-parkinsonian type
- MSA-cerebellar type
Imaging: “hot cross buns” sign
Several members of a large family are affected by the onset of dementia, psychosis, movements that are irregular, rapid, uncontrolled, and involuntary. These movements seems to flow randomly from one part of the body to another. In each generation, family members are affected at a younger age.
- What is the most likely diagnosis for this family?
- What intracranial structure is most likely to appear abnormal on neuroimaging?
- What is the mechanism of inheritance?
- What does anticipation mean?
- Which medication might prove useful in treating the patient’s chorea?
- Huntington’s Disease
- Caudate nucleus
-
Autosomal dominant, trinucleotide (CAG) repeat
- > 38 repeats
- Each generation is affected earlier than the previous
- Haloperidol
Huntington’s dementia
- A familial dementia marked by psychosis and chorea
- Death after 10-15 years
A 27 year-old woman presents with chorea. Which lab test is an essential part of her evaluation?
Pregnancy test
- The patient likely has chorea gravidarum
-
Sydenham’s chorea
- Results from childhood infection with GAS and patients with rheumatic fever
A 34 year-old man presents with a 3-month history of irritability and personality change. On examination, the patient has an enlarged liver and a coarse tremor of his arms. His movements are slow and he is dysarthric.
- What is the most likely diagnosis?
- Metabolism of which metal is abnormal in these patients?
- Wilson’s disease (hepatolenticular degeneration)
- Copper
Autosomal recessive disorder of copper accumulation → damage in liver, brain, eyes
Symptoms
- Acute hepatitis in early adolescence
- Movement disorder or ataxia = “wing-flapping tremor”
- Mood or psychotic symptoms
Signs:
- Midbrain has “panda sign” appearance
- Kayser-Fleischer ring around periphery of cornea caused by deposition of copper
Labs
- Serum ceruloplasmin < 200mg/L
- 24-h urinary copper > 50 mcg/day
- Elevated LFTs (AST, ALT, bili, PT, PTT)
- Low albumin
Treatment
- Low-copper diet (avoid chocolate, nuts, shellfish)
- Zinc salts block copper absorption
- Penicillamine & trientine increases copper excretion
- Liver transplant in severe liver disease
A 26 year-old man goes camping with a friend. They use an old space- heater to keep warm and are found comatose the next morning. The ER physician suspects carbon monoxide poisoning. The patient makes a gradual recovery, but is left with what residual movement disorder?
Parkinsonism
CO poisoning:
- Bilateral hyperintensity in globus pallidus
A 45 year-old alcoholic homeless man comes into the hospital with altered mental status. Physical exam reveals spider angiomas, icteric sclera, increased muscle tone, hyperreflexia, and positive Babinski sign. When asked to hold out his arms with wrists flexed, you observe a flapping motion/tremor. What is the treatment for his condition?
Lactulose
The patient has hepatic encephalopathy
- Bilateral, symmetric hyperintense lesions in the basal ganglia (globus pallidus)
- Due to impaired metabolism of metals (manganese and copper)
