Tremor, stiffness and slowed movement have many possible causes. Distinguishing between them determines whether treatment works.
Essential tremor and Parkinson's disease are confused constantly, including by clinicians. The distinction is clinical and it is learnable: essential tremor is typically symmetric and appears with action, while the Parkinsonian tremor is asymmetric and most visible at rest. They respond to entirely different medications.
A further group of patients has drug-induced parkinsonism — most often from anti-nausea or antipsychotic medication — which can look identical to Parkinson's disease and which resolves when the offending drug is withdrawn. Screening for this is part of every movement disorder evaluation here.
For patients with established Parkinson's disease, the work is ongoing: timing levodopa around meals and daily routine, managing wearing-off and dyskinesia, and attending to the non-motor symptoms — constipation, orthostatic hypotension, REM sleep behaviour disorder, mood — that often affect quality of life more than the tremor does.
Movement symptoms that appear abruptly, that follow a new medication, or that come with fever, confusion or severe muscle rigidity should be evaluated urgently. Do not stop Parkinson's medication suddenly — abrupt withdrawal can be dangerous.
“Roughly one in five patients referred with “Parkinson’s” has something else. That is a diagnosis worth taking the time to get right.”