Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content ++ 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) ++ Neuro evaluation preoperatively can be useful to establish baseline cognitive ability and to assist in perioperative managementParkinson disease medications and glycopyrrolate (Robinul®) (to decrease sialorrhea and vagal tone) should be administered preoperativelyLevodopa half-life short (1–3 hours) and no IV formMay consider levodopa via OGT for lengthy non-GI surgeryAspiration and laryngospasm are a significant concern secondary to GERD, sialorrhea, and dysfunction of upper airway musculaturePhenothiazines, droperidol, and metoclopramide (Reglan®) are contraindicated as antidopaminergic effect exacerbates extrapyramidal symptoms ++ Regional versus general:Regional anesthesia may be preferredHypotension secondary to autonomic dysfunction and vasodilatory effect of dopamine agonists is a major concernRegional allows decreased perioperative opioids in patients with increased likelihood (8-fold) of postoperative hallucinations and confusionGeneral anesthesia:Intubation may be difficult due to skeletal muscle rigidityIn ... Your MyAccess profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth