movement disorders

• normal movement has intact signalling from the cortex to the neuromuscular junction,

  movements are fine-tuned by the cerebellum to the basal ganglia

  
  

  disruption/lesions anyway along this cause movement disorders (basal ganglia and cerebellum in particular with fluidity of movement)

  
• what are the main features of the basal ganglia?


  • striatum (putamen and the caudate)
  • subthalamic nucleus
  • substancia nigra
  • globus pallidus
• what are the main features of the basal ganglia?


  • striatum (putamen and the caudate)
  • subthalamic nucleus
  • substancia nigra
  • globus pallidus

  
• what are other terms for hypokinesia?

  akinetic-rigid syndrome

  Pakrinsonism
• what are the 3 requirements for a Parkinsonism diagnosis?


  • bradykinesia plus one or more of the following (postural instability, tremor of 4-6Hz and rigidity)

  
• how does decreased input from the substantia nigra pars compacta affect movement?


  damage to the substantia nigra -> doesn't activate the stop pathway or inhibit the indirect pathway

  • increased rigidity / tone
  • smaller amplitude and slower movement -> bradykinesia
  • balance affected
  • shuffling gait
  • imbalance in basal ganglia leads to a tremor at rest
• what are the different causes of Parkinsonism

  • idiopathic Parkinsonism
  • vascular Parkinsonism
  • form medications that block dopamine
  • rarer causes -> dementia with Lewy bodies, Parkinson's plus syndrome (PSP - progressive supranuclear palsy, MSA - multiple system atrophy)
• what is idiopathic Parkinson's disease based on?


  • the loss of neurones in the brain especially in the substantia nigra
  • associated with alpha synuclein misfolding and aggregating as lewy bodies
• what is vascular parkinsonism normally caused by?


  • caused by a stroke and normally progresses in a step-wise manner
• examples of medications that can block dopamine 


  • anti-emetics
  • antipsychotics

  NOTE - this is reversible
• examples of hyperkinesia


  • tremor
  • myoclonus (sudden brief twitching of a muscle or group of muscles)
  • dystonia ( uncontrolled and sometimes painful muscle movements /spasms)
  • chorea
  • tics
• what are tremors?


  • Rhythmical, sinusoidal, alternating movement

  • Shaking

  • Type of tremor -> diagnosis
• your patient comes in with evidence of a postural tremor (occurs when holding a position against gravity, such as holding the arms outstretched) what are likely causes of the tremor?

  • essential tremor
  • thyrotoxicosis
  • salbutamol
• your patient comes in with evidence of an action tremor/ akinetic tremor (when the body is moved, finger-to-nose test), what are likely causes of this?


  • strokes
  • tumors
  • genetic
  • alcohol
• your patient comes in with a rest tremor, what is the likely cause of the tremor?

  Parkinsonism
• what is chorea?


  •“dance-like” unpredictable, flowing movements moving from one area to another

  •Ballism - chorea that affects proximal joints so movements are large and flinging. characterized by the abrupt onset of vigorous, rapidly executed, poorly patterned involuntary movement of the limbs.

  •Hemi-chorea/hemi-ballismus - Affecting half the body (normally structural like stroke - hemiballism)
• what are the different types of causes of chorea?


  • immune mediated -> Sydenham's chorea
  • structural lesions to the striatum -> strokes, tumors
  • neurodegenerative / genetic -> Huntington's Chorea, Wilson's disease
  • drug induced -> levodopa induced dyskinesia in Parkinson's disease (too much dopamine, not enough indirect pathway inhibition so cannot stop moving)
• what is meant by dystonia?


  • Sustained or intermittent muscle contraction resulting in abnormal postural movement
  • Can be repetitive, can be task specific (writers cramp)
  • can be painful
  • the patient may have a geste antagoniste
• what is a geste antagoniste?


  Using the sensory trick called "geste antagoniste" in which you lightly touch a different part of your body than the one that is cramping or curling can sometimes quiet the dystonia. For example, touching your chin may prevent your neck from twisting.

  
  

  for example touching the hand may stop it from cramping
• what are common causes of dystonia?


  • idiopathic - like overuse of muscles in musicians
  • genetic
  • part of other conditions like Parkinson's
  • structural lesions -> in the brain, spinal cord or peripheral nerve
  • immune mediated / post virus
  • drug induced (antipsychotics and antiemetics)
• what is meant by myoclonus?

  • Jerky, shock-like movements

  • Lots of causes

  • normal -> medications -> epilepsy -> dementia

  • Can be picked up by EMG
• what are tics and how are they caused?

  •Usually brief, often stereotyped

  •Can be movement or sound

  •Can be simple or complex

  •Can be suppressed for short periods of time

  •Tourette’s Syndrome most common cause, also seen in Huntington's chorea, Wilson's disease or with some medications

  note that ticks can be suppressed for a short time but myoclonus cannot
• what is wilson's disease and how is it relevant to Parkinson's


  • Caused by genetic mutation causing caeruloplasmin deficiency resulting in too much unbound copper int the system, causing neurological and liver damage by copper deposits
  • can present with Parkinsonism, chorea, dystonia, psychiatric issues, liver disease
  • important not to miss as it can lead to the brain and liver damage

  
• what is a functional movement disorder?


  •Abnormal movement due to the nervous system not working properly without an underlying neurological disease

  Can cause;

  •gait abnormalities

  •tremor,

  •jerking movements

  •mimic dystonia
• what are positive signs for functional movement disorders?


  • entrainment
  • distractibility
  • incongruence
  • tremor variability
• outline signs and symptoms you may see in Parkinson's disease:

  here

  
• what is the mechanism behind chorea?

  death of dopaminergic neurones and the loss of dopamine -> decreased action on the striatum -> decreased inhibition of the indirect pathway is greater than decreased action on the direct pathway -> loss of inhibition of movement -> chorea / dance-like movements

  
• dementia with lewy bodies is the same pathology as Parkinson's but it does not follow the BRAAK hypothesis with it beginning in the gut and progressing to the brain