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Source: Chen JJ, Dashtipour K. Parkinson disease. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861§ionid=134127873.
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Loss of neurons and presence of Lewy bodies in substantia nigra pars compacta.
Degree of nigrostriatal dopamine loss correlates directly with severity of motor symptoms.
Reduced activation of dopamine-1 and dopamine-2 receptors results in greater inhibition of thalamus.
Loss of presynaptic nigrostriatal dopamine neurons inhibits thalamic activity and reduces activation of motor cortex.
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Affects up to 1 million individuals in United States.
Annual incidence ranges from 10 to 120 per 100,000 persons depending on age.
Affects 0.5% of people in their sixties and 2.5% of those older than age 80.
Usual age at diagnosis is 55–65 years.
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Increasing age.
Male sex.
Heredity (close relative with disease)
Toxin exposure (eg, herbicides, pesticides)
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CLINICAL PRESENTATION
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MEANS OF CONFIRMATION AND DIAGNOSIS
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Bradykinesia and at least one of the following:
Restring tremor.
Rigidity.
Postural instability.
Exclude other types of parkinsonism or tremor disorders (see Differential Diagnosis)
Presence of at least three supportive positive criteria:
Asymmetry of motor signs/symptoms.
Unilateral onset.
Progressive disorder.
Resting tremor.
Excellent response to carbidopa/L-dopa.
L-dopa response for 5 years or longer.
Presence of L-dopa dyskinesias.
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DIFFERENTIAL DIAGNOSIS
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Essential tremor.
Pharmaco toxicity (drug-induced)
Antiemetics (metoclopramide, prochlorperazine)
Antipsychotics (chlorpromazine, fluphenazine, haloperidol, olanzapine, risperidone, thioridazine)
Other drugs (α-methyldopa, cinnarizine, flunarizine, tetrabenazine)
Environmental toxicity (manganese, organophosphates)
Infections (HIV, subacute sclerosing panencephalitis)
Metabolic disorder (hypothyroidism, parathyroid abnormalities)
Neoplasms, strokes, traumatic lesions involving the nigrostriatal pathways.
Normal-pressure hydrocephalus.
Parkinsonism with other neuronal system ...