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Neurology Parkinson Disease Diagnosis Parkinsonism refers to any cause ofparkinsonian symptoms and signs. Parkinson disease, caused by the degeneration ofdopa- minergic neurons in the substantia nigra of the midbrain, is characterized by bradykinesia (slowed movement and decreased amplitude of repetitive movement) and at least one of the following: . rigidity (cogwheel type) . resting tremor (or with movement) o postural reflex abnormality (falling) Neurologic signs and symptoms are asymmetric at onset. Diminished sense of smell, constipation, and acting out dreams may precede the onset of motor symptoms by years. Early dementia within the first year of the appearance of parkinsonism is a hallmark of dementia with Lewy bodies. Parkinson disease is a clinical diagnosis. Brain imaging may be obtained to exclude other disease processes such as hydrocepha- lus, vascular disease, and other degenerative diseases that may mimic Parkinson disease. DOT{'T BE TRICKED . Early symmetric symptoms or signs, early falls, rapid progression, poor or waning response to levodopa, early autonomic failure or dementia, and ataxia suggest a diagnosis other than Parkinson disease. STUDY TABIE: Differential Diagnosis of Parkinson Disease Disease Considerations Multiple system atrophy Severe orthostatic hypotension and ataxia MRI showing "necrosis" of the putamen and cerebellar atrophy Progressive supra nuclear Unexplained falls (typically backward), inabilityto move eyes vertically, and parkinsonian features pa lsy Dementia with Lewy Early dementia, parkinsonism, and visual hallucinations bodies Med ication-ind uced Antiemetics (prochlorperazine, metoclopramide), antipsychotics (haloperidol), reserpine, lithium, and parkinsonism methyldopa DO]{'T BE TRICKED o DruB induced parkinsonism is distinguished from Parkinson disease by the symmetry of symptoms and the absence of typical nonmotor features (e.g., slow mental processing speed; depression, anxiety, apathy; REM sleep disorder; postural hypotension; impaired sense of smell; truncal and cervical stooped posture).

DO]{'T BE TRICKED o DruB induced parkinsonism is distinguished from Parkinson disease by the symmetry of symptoms and the absence of typical nonmotor features (e.g., slow mental processing speed; depression, anxiety, apathy; REM sleep disorder; postural hypotension; impaired sense of smell; truncal and cervical stooped posture). Treatment Levodopa is the most effective medication used in the treatment of Parkinson disease but is associated with motor fluctuations, including dyskinesias, and a "wearing-off" eff.ect (enhanced parkinsonian symptoms as dopamine levels decline). Initiating therapy with a dopamine agonist (pramipexole, ropinirole) in patients younger than 65 years avoids the early appearance of these side effects. Levodopa is the drug of choice in older patients. Levodopa is administered in combination with carbidopa, which prevents the peripheral conversion of levodopa to dopamine. DON'T BE TRICKED . In patients who experience severe peripheral adverse eflects oflevodopa (nausea or orthostatic hypotension), prescribe higher doses of carbidopa. 301