Confusable diagnoses · PANCE / PANRE

Parkinson Disease vs Essential Tremor

Written & clinically reviewed by Ryan Busch, PA-C · Updated August 2026 · Report an error

Parkinson Disease and Essential Tremor are easy to mix up on the boards. Here's a side-by-side comparison — presentation, workup, imaging, and first-line treatment — drawn from our full outlines.

Parkinson Disease vs Essential Tremor at a glance

  • Parkinson Disease: Progressive neurodegenerative movement disorder from nigrostriatal dopamine loss.
  • Essential Tremor: Bilateral, largely symmetric postural and kinetic tremor of the hands; the most common adult movement disorder.

Try two board-style questions on Parkinson Disease vs Essential Tremor

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Question 1NeurologyMedium
A 78-year-old male with Parkinson's disease on carbidopa-levodopa for 8 years now has 3-4 hours of good motor function after each dose, followed by return of rigidity and slowness in the 45 minutes before his next scheduled dose. Which of the following is the most appropriate medication adjustment to reduce 'off' time?
  • AAdd entacapone
  • BSwitch to bromocriptine
  • CAdd benztropine
  • DAdd pimavanserin
Reveal answer & full explanation
Correct answer: A — Add entacapone
  • AAdd entacapone✓
  • BSwitch to bromocriptine
  • CAdd benztropine
  • DAdd pimavanserin

Why Add entacapone is correct

  • Levodopa wearing-off (motor fluctuations) is common after 5–10 years of Parkinson's disease (PD) treatment.
  • Entacapone is a catechol-O-methyltransferase (COMT) inhibitor that blocks peripheral levodopa metabolism, thereby extending the effect of each levodopa dose.
  • Opicapone is another COMT inhibitor option.

Why the others are wrong

  • Switch to bromocriptine — Bromocriptine is an older dopamine agonist; switching away from carbidopa-levodopa is not the preferred strategy for wearing-off, and bromocriptine has a less favorable side-effect profile.
  • Add benztropine — An anticholinergic agent used for tremor; it does not address wearing-off and anticholinergics can worsen off-time and cognitive function.
  • Add pimavanserin — A selective serotonin 5-HT2A inverse agonist approved for the hallucinations and delusions of Parkinson disease psychosis; it has no dopaminergic action, so it neither extends each levodopa dose nor shortens off time.

Additional high-yield points

  • Monoamine oxidase B (MAO-B) inhibitors (rasagiline, safinamide) block central dopamine metabolism and are another strategy for wearing-off.
  • Additional strategies include more frequent smaller levodopa doses, dopamine agonists, and subcutaneous apomorphine for rescue.
  • Deep brain stimulation (DBS) is used for refractory motor fluctuations.
Question 2NeurologyMedium
A 58-year-old man reports a 5-year history of a bilateral hand tremor that is most noticeable when he writes, holds a coffee cup, or eats soup, and that disappears when his hands are at rest. His father had a similar tremor, and the patient notes it briefly improves after a glass of wine. He has no other medical problems and takes no medications. On exam, there is a symmetric postural and kinetic tremor of both hands with no resting tremor, bradykinesia, rigidity, ataxia, or dystonia. TSH is normal. The tremor now interferes with his work as an accountant. Which of the following is the most appropriate initial management?
  • APropranolol
  • BTrihexyphenidyl
  • CLevetiracetam
  • DTopiramate
Reveal answer & full explanation
Correct answer: A — Propranolol
  • APropranolol✓
  • BTrihexyphenidyl
  • CLevetiracetam
  • DTopiramate

Why Propranolol is correct

  • This vignette is classic essential tremor: bilateral, symmetric action (postural and kinetic) tremor present for years, absent at rest, with a positive family history and transient alcohol responsiveness, and no parkinsonian or cerebellar signs.
  • For functionally impairing essential tremor, the non-selective beta-blocker propranolol (60-320 mg/day) and primidone are the two guideline-supported first-line oral agents. Propranolol is a reasonable first choice in an otherwise healthy patient without asthma, severe bradycardia, or decompensated heart failure.

Why the others are wrong

  • Trihexyphenidyl — an anticholinergic used for some parkinsonian and dystonic tremors; it has no established role in essential tremor and risks confusion, urinary retention, and falls in older patients.
  • Levetiracetam — controlled trials found it ineffective for the limb tremor of essential tremor, so unlike topiramate it is not even a recognized second-line option and would only expose him to irritability and somnolence.
  • Topiramate — a real second-line agent for essential tremor, but it is reserved for patients who fail or cannot tolerate propranolol or primidone, not for initial therapy.
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Side-by-side comparison

FeatureParkinson DiseaseEssential Tremor
At a glanceProgressive neurodegenerative movement disorder from nigrostriatal dopamine loss.Bilateral, largely symmetric postural and kinetic tremor of the hands; the most common adult movement disorder.
Classic presentationAsymmetric rest tremor + bradykinesia + cogwheel rigidity with excellent response to levodopa is highly suggestive.; Motor: rest tremor (typically asymmetric, 4-6 Hz 'pill-rolling'), bradykinesia (slowness initiating and executing movement), rigidity (cogwheel or lead-pipe), postural instability (later); Gait: shuffling, short steps,…Bilateral symmetric hand tremor present with action and posture, absent at rest, often with positive family history and alcohol responsiveness.; Hand tremor with writing, drinking from a cup, eating soup, or holding a posture; Voice tremor produces a quavering quality, especially with sustained 'ahhh'; Head tremor (titubation),…
Workup / key labsMDS clinical diagnostic criteria: bradykinesia plus rest tremor and/or rigidity; supported by clear levodopa response, levodopa-induced dyskinesia, rest tremor, olfactory loss; red flags suggesting atypical parkinsonism must be absent.; Largely a clinical diagnosis; labs to exclude mimics: TSH, CBC, BMP, B12; Consider ceruloplasmin in…MDS 2018: isolated tremor syndrome of bilateral upper limb action tremor for ≥3 years, ± other locations, without other neurologic signs.; TSH to exclude hyperthyroidism; BMP and glucose if metabolic causes suspected; Ceruloplasmin if age <40 to rule out Wilson disease; Medication review for tremorogenic drugs
ImagingMRI brain — usually normal in PD; helps exclude vascular disease, NPH, atypical parkinsonism; DaTscan (123I-ioflupane SPECT) — shows reduced striatal dopamine transporter binding; differentiates PD/atypical parkinsonism from essential tremor or drug-induced parkinsonism, but does NOT distinguish PD from MSA/PSP/CBD; Levodopa challenge —…Brain imaging not routinely required — order MRI only if focal findings or atypical features; DaTscan SPECT can distinguish ET from PD when uncertain (normal in ET, abnormal in PD)
First-line treatmentLevodopa/carbidopa — most effective symptomatic therapy; carbidopa inhibits peripheral DOPA decarboxylase to reduce nausea and increase central availability; start low (25/100 TID) and titrate; Dopamine agonist — pramipexole, ropinirole, rotigotine (transdermal); levodopa remains the preferred initial dopaminergic therapy at any age…Propranolol 60-320 mg/day (non-selective beta-blocker) — first-line, may need long-acting formulation; contraindicated in asthma, severe bradycardia, decompensated HF; Primidone 25-250 mg/day, titrated slowly — comparably effective to propranolol; common acute first-dose toxicity (sedation, ataxia, nausea) often abates; Combination of…

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Full outlines

Parkinson Disease Essential Tremor All 514 diagnoses

Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.