Treatment of Basal Ganglia Disorders Flashcards
4 cardinal symptoms of Parkinson’s.
1) Bradykinesia - can best be demonstrated by rapid alternating movements on exam
2) Resting tremor - pill rolling when mild
3) Rigidity
4) Festinating gait - first p/w loss of arm swing, then later stooped posture and increased difficulty with turning/doorways/etc.
Roles of dopamine in direct and indirect pathways in basal ganglia.
Dopamine synthesized from substantia nigra pars compacta.
Has excitatory effects on direct pathway (D1) and inhibitory effects on indirect pathway (D2) but ultimately both facilitate movement via activation of motor thalamus.
Loss of dopaminergic neurons can be detected in:
Putamen of the striatum, where axon terminals are, so that loss of dopamine in LEFT putamen results in RIGHT body symptoms.
Primary pharmacotherapy treatment for PD?
Potential side effects?
Sinemet - combination of L-DOPA and carbidopa
Side effects include: dyskinesia, “on-off” phenomena, psychosis, orthostatic hypotension
Surgical treatments of PD include:
Pallidotomy (irreversible) and DBS (adjustable and reversbile)
How do effects of DBS compare to medical therapy?
DBS provides almost double the “on” time without dyskinesia! However, like medical therapy it does not alter progression of the disease.
Moreover, DBS does not demonstrate improvements in speech.
What are the two areas that are inhibited by DBS?
GPi and subthalamic nucleus.
Steps for DBS surgery
MRI shows us where we want to target.
Stereotaxy acts as “GPS” that guides us to that target.
Intraoperative testing performed to confirm best possible location. Two techniques: microelectrode recording (MER) and stimulation
Other movement disorders being treated by DBS?
Essential (kinetic/action) tremor and dystonia
What are the features of dystonia?
A movement disorder, often hereditary, characterized by co-contraction of antagonistic muscles, leading to twisting movements and abnormal posture.
