TY - CHAP M1 - Book, Section TI - Chapter 29. Parkinson Disease A1 - Tinklepaugh, Mark S. A2 - Atchabahian, Arthur A2 - Gupta, Ruchir PY - 2013 T2 - The Anesthesia Guide AB - Common neurodegenerative disease of the CNS characterized by loss of dopaminergic input in the basal gangliaCause:Generally considered idiopathic with some evidence of genetic and environmental componentsDecreased incidence with exposure to cigarette smoking and increased with exposure to pesticidesPrevalence and incidence:Affects 1 million people in the United States with approximately 50,000 new cases reported annuallyAverage age of onset is 60Main signs:Resting tremorRigidityBradykinesiaFestinating gaitPostural instabilityOther signs:Autonomic dysfunction (orthostatic hypotension, GERD, sialorrhea, cramps)Pharyngolaryngeal involvement with aspiration (most common cause of death)Respiratory involvement (chest rigidity, mixed obstructive–restrictive syndrome, decreased response to hypoxemia)DementiaDepressionOculogyric crisesTreatment:Goal of treatment: decrease cholinergic activity through anticholinergics or dopamine agonistsLevodopa:Levodopa absorbed in proximal small bowelConverted to dopamine by dopa decarboxylaseFive to 10% levodopa crosses blood–brain barrier; remainder converted to dopamine peripherallySide effects are N/V, vasoconstriction, hypovolemia, hypotension, decreased myocardial NE storesLevodopa supplementation leads to decreased endogenous production of dopaminePeripheral decarboxylase inhibitor (carbidopa) in combination with levodopa (Sinemet®) decreases peripheral levodopa metabolism which decreases dopamine side effectsEntacapone, a COMT inhibitor, used alone (Comtan®) or in combination with carbidopa and levodopa (Stalevo®) to decrease peripheral metabolism of levodopaAmantadine (Symadine®) releases Dopa in the striatumDopamine agonists:Bind to postsynaptic receptors in the brainPreferred in younger patients since they delay motor complicationsSide effects include somnolence, insomnia, nausea, hallucinations, and cardiac valvular fibrosis with pergolide (Permax®) and cabergoline (Dostinex®, Cabaser®)Other dopamine agonists include bromocriptine (Parlodel®), pramipexole (Mirapex®), and ropinirole (Requip®)Apomorphine (Apokyn®), another agonist, is the only injectable medication (SQ only, not IV)MAO-B inhibitors:Increase peripheral bioavailability of levodopa. Selegiline (Eldepryl®, Emsam®, Zelapar®) and rasagiline (Azilect®) commonly usedDeep brain stimulation (DBS):Used when drug therapy inadequatePacemaker implanted in brain to stimulate the subthalamic nucleus in the basal ganglia (see chapter 102, Awake craniotomy) SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=57260694 ER -