Movement disorders Flashcards
Cause of movement disorders?
- extrapyramidal (basal ganglia) or cerebellar dysfxn
Fxn of basal ganglia?
- modulate motor cortical activity but also the activity of the association cortex in the frontal lobes
Characteristics of Huntington’s?
- progressive autosomal dom
- affects motor fxn, cognition, and behavior - pathophys causes brain cells to waste away
- mean onset is age 40, mean duration is 20 years
- characterized by: chronic progressive chorea, psych changes, dementia
GABA involvement in Huntington’s?
- decrease in GABA and GABA receptors in basal ganglia
- GABA is inhibitory NT: this leads to jerky movements because of decreased GABA
- Also reducing acetylcholine
- Dopamine not affected - lead toimbalance of dopamine and acetylcholine
signs of adult onset of huntington’s?
- chorea affects limb and trunk
- dystonia
- rigidity
- postural instability
- myoclonus
- nystagmus
Signs of juvenile onset of Huntington’s disease?
- very rare
- bradykinesia
- rigidity
- quicker progression
Early psych manifestations of Huntington’s?
- depression
- personality changes: memory loss, impulsive behavior, moodiness, antisocial behavior (sociopath)
- emotional outbursts
- depression: lack of initiative, loss of spontaneity, inability to concentrate
Early and late physical signs of Huntington’s?
early:
fidgeting, and restlessness
later: chorea*** dystonic posturing akinesia dementia
Dx studies for Huntingtons?
- MRI: caudate atrophy
- PET: abnorm metabolic changes in caudate
- genetic testing: sensitive and specific, easy confirmation of clinical dx, dx of atypical pts, and presymptomatic testing in at risk individuals (raises ethical questions)
Tx of Huntington’s?
- tx sxs only, no med will change course of Huntingtons:
downreg of dopaminergic neurotransmission
suppress chorea: *Tetrabenazine (VAMT inhibitor)
*Neuroleptics (antpsychotics) - deplete dopamine - underlying postural instability and rigidity will worsen
- tx of depression and psychosis
other meds:
anticonvulsants, antipsychotics, antidepressants
Anticonvulsants used in Huntingtons?
- Clonazepam (klonopin)
- Valproic acid (depakote)
Antipsychotic meds used in huntington’s?
- Resperidone (resperdal)
- olanzapine (zyprexa)
Antidepressants used in Huntingon’s?
- Fluoxetine (Prozac)
- sertraline (zoloft)
- nortriptyline (Aventyl, pamelor) - TCAs dangerous in overdose -QT prolong and torsades
SEs of Huntington’s meds?
- Hyper-excitability, fatigue and restlessness
- antipsychotic drugs may cause SEs that mimic signs of Parkinson’s disease, including involuntary twitching in face and body (tardive dyskinesia)
Characteristics of an essential tremor?
- most common cause of tremors
- ranges from cosmetic to disabling
- affect both sides of body symmetrically
- more prom with ACTION than rest
- frequency of tremor is constant
- amplitude can vary - stress or caffeine (stimulants), sleep deprivation - amplify it, alcohol will depress it in small amounts
(tremor is most common sx of parkinsons - Ddx)
- tremor usually starts earlier than Parkinsons (have tremor - 4x more likely to develop parkinsons)
What muscles do essential tremors affect?
- neck and head muscles
- muscles of the voice
- muscles of the arms and hands
Tx of essential tremor?
- propanolol (inderol): BBlocker
- atenolol (tenormin) - BB of choice for those with asthma or bronchospasm
- mysoline (primidone): anticonvulsant
- gabapentin (neurontin): anticonvulsant
- botulinum toxin injections