Pharmacology of the basal ganglia disorders Flashcards
What are the 2 classes of movement disorders?
Hyperkinetic
Hypokinetic
What disorders are classed as hyperkinetic?
Hemiballismus Huntingdon's Disease Dystonias Wilson's disease (dystonic) Essential tremor Chorea Athetosis
What disorders are classed as hypokinetic?
Parkinson's Multiple systems atrophy Progressive supranuclear palsy Wilson's Disease (psuedoparkinsonism) Essential tremor
How are movement disorders classified?
By activities, assessing rhythm, speed and control
What is dystonia?
Twisting and repetitive movements or abnormal postures
What is athetosis?
Writhing movements
What is chorea?
Twitching or jerking of a group of muscles
What is ballismus?
Large, flinging limb movements
What key region is associated with Parkinson’s Disease?
Substantia Nigra (degeneration of dopaminergic neurons)
What key region is associated with Huntingdon’s Disease?
Striatum (degeneration of GABAergic cells)
What key region is associated with Hemiballismus?
Subthalamic Nuclei
What area of the brain is thought to be responsible for generation of tremors?
Globus Pallidus
What are the 3 main groups of Parkinsonism?
Pure Parkinsonism
Parkinsonism with extras
Pseudoparkinsonism
What is Pure Parkinsonism?
Damage to substantia nigra with classic Parkinson’s Disease, including:
Idiopathic (Parkinson’s Disease)
Iatrogenic (induced Parkinson’s e.g. through drug use)
Post-encephalitic
What is Parkinsonism with extras?
Classic Parkinson’s Disease plus additional symptoms due to damage to additional sites:
Multiple Systems Atrophy (e.g. classic + ANS symptoms)
Progressive supranuclear palsy (classic + damage to midbrain)
What is Pseudoparkinsonism?
Parkinson-like symptoms without degeneration to substantia nigra due to:
Wilson’s Disease
Benign Essential Tremor
Trauma and vascular-related
What are the 4 cardinal symptoms of Parkinson’s Disease?
Tremor (resting)
Rigidity (smooth movements that are difficult to do)
Akinesia (bradykinesia)
Postural instability
What additional symptoms can be present in Parkinson’s Disease?
Micrographia (small, cramped writing)
Mask-like face (lack of expression)
Sleep disturbances
Aprosodia (change in rhythm, speed etc. of speech)
What dopamine pathway is involved in Parkinson’s Disease?
Nigrostriatal (Substantia nigra to Striatum)
What are the treatment principles for Parkinson’s?
Don’t start treatment until quality of life is significantly disrupted
Multi-disciplinary (input from SLT, OT, Physio etc.)
Gradual treatment (to avoid reaching maximum doses)
Why can dopamine not be used as a treatment for Parkinson’s and how can this be overcome?
Can not cross blood brain barrier
Use of dopamine precursor which can cross BBB (L-Dopa)
What is the problem with using L-Dopa to treat Parkinson’s and how can this be overcome?
Levodopa is metabolised quickly (before it gets into the CNS).
Use of dopa-decarboxylase inhibitors (Carbidopa or Benserazide) in combination with L-Dopa