43 Movement 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

LDOPA 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

LDopa

  • 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)