PDF - Basal Ganglia Flashcards
Composition of Basal Ganglia?
“The EPS”
- Striatum: caudate and putamen
- Globus Pallidus
- Substantia Nigra
- Subthalamic nucleus
What makes up the pyramidal system?
- Corticospinal tract
2. Corticobulbar tract
Pathology Parkinson’s?
- Loss of dopaminergic neurons in SN =
- Less direct pathway inhibition + more Indirect pathway stimulation of globus pallidus =
- Net inhibitory output from GPm to motor cortex =
- Decreased and slowed movement
What does decrease in GPM output cause?
GPm is INhibitory
Decrease: HYPERkinetic disorders
Increase: HYPOkinetic disorders
Pathology Hemiballismus?
- Destroyed subthalamic nucleus
2. Lessens GPM output
Pathology Huntington’s?
- Loss of GPl neurons
- Increases inhibition of STN
- Decreases GPm stimulation / output
- Increased movement
Sign OD on dopaminergic parkinson’s drugs?
Hyperkinesis
Presentation Parkinson’s?
- Resting tremor - prominent when sitting
- Asymmetric upper limbs - Rigidity
- Bradykinesia
- Decreased postural reflexes - fall easily when bumped
- This is least responsive to meds - Masked facies
- Micrographia
- Horse / soft speech
What to think if multiple small steps needed to turn around?
Parkinsons
Hallmark pathologic sign parkinson’s?
Loss of pigmented dopaminergic neurons in substantia nigra
- Lewy bodies seen
Most effective treatment parkinsons?
Leva dopa + Carbidopa
How does carbidopa work?
Inhibits peripheral metabolism of Levodopa before it enters the brain
Side effects L-dopa?
- Hallucinations
2. Psychosis
What is entacapone?
COMT inhibitor that smooths out plasma L dopa levels to help reduce side effects
Presentation Huntington’s?
- Choreoathetosis
- Dementia
- Depression / anxiety
