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 Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process 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 Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.