43 Movement Disorders

Hyperkinetic Disorders

Huntingtons

• know lateral ventricle large

• Loss of caudate, loss of GABA, no inhibition = breakthrough of movement. Indirect pathway

• each generation passes on more repeats to later generation = worse symptoms

• anticipation: earlier symptoms with each gen

• excitotoxicity mechanism

• NMDA binding to glutamate toxicity

• usually adopted because most people know about it before have kids

• chorea: dance like abnormal movements

Treatment

Hemiballism

• No subthalamic nucleus. No inhibitory of thalamus = movement breakthrough

• once stroke affects IC = hemiplegia

• only half of body

Wilson's

• deposit in liver (cirrhosis)

• elbows beat like wings of bird

• Mood disorders at very young age

• dysarthria: difficult to get words out, slow irregular speech

Tardive dyskinesia

• face secondary to medications

• antipsychotic/antiemetic blocks D2, increase D2 sensitivity, hyperkinesia via D2 endogenous

• hypersensitivity of D2 receptors

L- DOPA Dyskinesia

• D2 preferentially bound = blocked inhibitory pathway = dyskinesia

Hypokinetic Disorders

Parkinson

• Dopamine naturally broken down by MAO

• MAO sits on outer membrane of mitochondria

• result: Parkinson

• pt cannot initiate movement

• Loss of D1, no disinhibition, less movement

• no movement in stopping/ending

• initiation is difficult; once initiated, cannot be stopped = festination

• Loss of D1, no disinhibition, less movement

• parts of brain becomes pale because lose melanin containing dopaminergic neuron

• now used to induce parkinson's in lab rats

• shuffling: shuffles feet

• cogwheel: moving arms stutters as if stopping on stops of cogwheel

Tremor

Rigidity

• simultaneous activation of flexors/extensors

Treatment

• propanolol for central tremor

• initially usually tremor symptoms

• once develops bradykinesia/rigidity, add more drugs

• L dopa last

L- Dopa

• vit B6 promotes conversion of L-dopa to dopamine in periphery

• off so severe akinesia: no movement, frozen

• dyskinesia: involuntary

Entacapone

Seleginine

• SSRI raises serotonin; selegiline blocks breakdown = very high serotonin

Other Movement Disorders

• myoclonus: sudden contraction once

• dystonia: sustained contraction

• writer's cramp: after writing for so long, arms spasm

• blepharospasm: twitching of eye muscles (blinking)