Motor Disorders - Random Order!!! Flashcards
What is the presentation of “hemiparetic gait after stroke”?
Classically, see probelms with extensors of upper limb - so Flexed upper limbs and then problems with Flexion in lower extremities so see Extended Legs and circumduction of lower extremity
What is a non-rhythmical, non-stereotypes, Hyperkinetic disorder?
Either Chorea or Myoclonus depending on speed
Myoclonus - SUPER fast
Chorea-medium fast
But both are neither rhythmical or stereotyped
Treatments used in Essential Tremor?
First line agents - Propanolol (non-selective beta blocker) and Primidone (anticonvulsant)
Others include Anticonvulsants, botulinum or surgery/DBS of thalamus
What are the other Parkinsonian Syndromes?
Tend to be related degenerative disorders that are more widespread:
1) Progressive Supranuclear Palsy = Early valls, Vertical Opthalmoglegia
2) Multiple System Atrophy = Parkinsonism + Ataxia + Dysautonomia (Shy-Drager)
3) Corticobasal Syndrome = Parkinsonism + Alien Limb phenomenon and Asymmetric motor signs
What is the MAIn difference that you can see in tremor between Parkinson’s and Essential Tremor?
Parkinsons - Tremor maximal activation at REST!!!
ET: maximal activation with maintenance of posture or movement
What is Dystonia?
Syndrome of sustained stereotyped movements and contractions that can lead to abnormal postures etc
Describe the scale of movement characteristics from chorea to athetosis to ballismus
Chorea - brief movements, non-stereotyped, non-rhythmical, random distribution
More Distal > Proximal
Discontinuous
Athetosis - Chorea + Flowing continueous snake-like movements
Ballismus - wild flining and random movements
Proximal> Distal
What is the mechanism for spasticity?
Disinhibition of Anterior Horn Cells becuase have interruption of Pyramidal Tract leading to increased excitation
Distinguish PD from ET based on history alone?
PD - age of onset 55-65 and symptoms last for a few months prior to presentation, no family history and no response to alcohol
ET - variable age of onset, symptoms can last for years before presentation, Autosomal Dominant so runs in families, CALMS down with EtOH
Upper Motor Syndrome - what you you typically see?
Contralateral Hemiparases if above the decussation and Ipsilateral if below
Weakness, Hyperreflexia, Babinksi, Clonus
Clinical Features of HD?
Chorea, Dementia, Gait disorders
Affective disorders, behavioral disturbances, Psychosis, Dysarthria, Dysphagia
[Main cause of death is dysphagia]
Pathophysiology of Parkinson’s Disease?
Degeneration of Nigral neurons leads to increase in excitability of Sub-Thalamic Nucleus and Globus Pallidus internal (main output from BG which increases inhibition on motor cortex)
Decreased Excitation of motor cortex from increased inhibition on Motor thalamus
What does the term Spastic Quadraparesis and Parapesis refer to?
Spastic quadraparesis - UMN syndrome involving all 4 limbs but sparing face - refers to lesion involving cervical cord above C5
Spastic PArapesis - UMN syndrome involving both lower extremities and implies lesion of SC below cervical region enlargement
What is the role of the cerebellum in movement?
Monitors ongoing movement and initiates new movement
ensures appropriate speed and accuracy of movements
What are some drugs that can cause a presentation similar to parkinsons?
Anti-psychotics (especially those that block Da)
Anti-emetics - Metoclorpramide!!
Toxins like MTMP, Manganese and CO
What are the Da agonists? What are they used for? Which one is a “rescue therapy”?
Work on Da receptor and used in Parkinson’s Disease
Pramipexoe, Ropinirole, Rotigotine
**Apomorphine - Acute Rescue therapy that starts right away but only lasts a short term
What is the mainstay of treatment for PArkinson’s Disease and what is it given with and why?
L-Dopa, which is Da Precursor, given bc DA can’t cross BBB
Must be given with Peripheral Da-Decarboxylase Inhibitor Carbidopa so it’s kept in the L-Da form before crossing BBB
[if converted in periphery, circulating Da causes Nausea bc activates Area Postrema in medulla that doesn’t have BBB]
What is a Rhytmical Hyperkinetic disorder?
Tremor = rhythmical ossilation of a body part
Treatment for Dystonias?
Botulinum toxin into overactive muscles at sub-therapeutic doses to lightly block Ach release at the presynaptic junction and cause weakness
Main cause of Acute Hemiballismus?
Stroke of Sub-Thalamic Nucleus
What are the 3 main body parts that present with ET?
Upper Limbs, Head, voice
What are the 4 drug treatments for Spasticity and their mechanisms of actoin?
Baclofen - enhances GABA-mediated inhibition at SC level
Benzos - enhance GABA inhibition at SC level
Tizanidine - A2 adrenergic receptor Agonist to inhibit excitatory sensory afferents TO the motor neurons
Botulinum Toxin - blocks release of Ach at Pre-synaptic Nerve Terminal in NMJ causing weaker responses at muscles
{3 act on the Anterior Horn and 1 acts on the muscles]
Where does deep brain stimulation for Parkinson’s disease act in the brain?
GPi = Globus Pallidus interna
Sub-Thalamic Nucleus
What are “Cerebellar Signs”?
Incoordination
Dysmetria - finger to nose test - can’t gauge accuracy of target
Dysdiadokinesia - rapid repetitive movements are slow and incoordinated
Ataxia - gait, heal to shin test; See BROAD BASE stepping
Dysarthria - scanning
Nystagmus and - **ocular overshoot dysmetria **
What is a Non-rhytmical, Stereotyped Hyperkinetic disorder?
Either Dystonia (slow) or Tics (rapid)
Distinguish PD from ET based on Physical Exam
PD - Max activation of tremor at rest, slower, “pill-rolling’ and UNILATERAL
- Hand, foot, chin, lips
Small hanwritting with no trumor
noticeably progressive with associated signs
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ET: Max activation with posture and movement, faster, Flexion/extention morphology, BILATERAL
- hands, head and voice
Normal hanwritting but is tremulous
Not noticably progressive and no associated signs
What are the different sustained stereotyped spasms seen in Focal Dystonias?
Blepharospasm - involuntary eye closure
Oromandibular
Cervical Dystonia - Torticollis - involuntary head turning
Laryngeal - involuntary vocal cord spasm (abduction - whispery; adduction - strangulation) = shouting/whisper better than speaking
Dystonic Writer’s cramp - Task specific musicians and writers
What do you see in Lower Motor neuron syndromes?
weakness, reduced tone/bulk, less reflexes
Fasciculations
Ipsilateral problems
Characteristic features of Parkinson’s Disease?
**Bradykinesia **
Involuntary tremors/RESTING tremor = Pill-rolling
**Cogwheel Rigidity **
bending forward, festinations
Small handwritting, decreased blink rate and facial expression
Freezing and robotic turning
Impaired postural righting reflexes - Fall risk!!
Shuffling gait; Can’t get out of chair or turn in bed
Long-term - see dementia
***STARTS UNILATERAL! **
Genetics of Huntington’s Disease
Pathology?
**Autosomal Dominant and 100% Penetrant **
onset 20-40 but variable - randomly have childhood senescence and then see younger and younger in families
**CHROMOSOME 4 >40 Unstable Triple Repeat of CAG = Huntingtin gene **
-length of repeat inverseley related to age of onset
See Neuronal Loss and Gliosis in STRIATUM
