From Stoelting’s Anesthesia and Co-existing disease
Neurodegenerative disorder –> loss of dopaminergic fibers in basal ganglia, regional dopamine depletion –> decreased inhibition of neurons in extrapyramidal system –> unopposed stimulation by Ach
Sx and Symptoms: Triad of tremor, rigidity, akinesia; dementia and depression.
Medical Tx: goal to increase dopamine in basal ganglia or decrease neuronal effects of Ach
- Levodopa + decarboxylase inhibitor (side effects: dyskinesia, psych disturbances)
- Amantadine – antiviral helps symptoms
- Selegiline – type B MOA inhibitor, inhibits catabolism of dopamine in CNS. Not associated with tyramine-associated hypertensive crisis.
Surgical Tx: Deep Brain stimulator may help tremor; Pallidotomy improves levodopa induced dyskinesias
Anesthesia Management: Levodopa should be continued on day of surgery and peri-op, and repeated intra-op via NG/OG if needed as muscle rigidity can interfere with respiration. Butyrophenonenes (droperidol, haloperidol) antagonize dopamine in basal ganglia. Alfentanil can cause acute dystonic rx 2/2 opioid-induced decreases in central dopaminergic transmission. Ketamine can exageratte sympathetic responses.
Anesthesia for Deep Brain Stimulator Placement: Some patients may hold levodopa, usually done under sedation, make sure to avoid propofol and benzodiazepines as they can alter microelectrode monitoring, opioids and precedex are good alternatives. Sitting position is usual, so air embolism is risk.