Tremors are generally felt in extremities and more notably in the hands. Patients typically present after they have experienced tremors for at least some time period. Differential diagnoses can be divided based upon whether these are experienced at rest or during action. Although patients may not think about tremors this way, nor use this description as a part of their chief complaint, a clinician can think about action tremors versus tremors at rest because this method helps narrow differential diagnoses quite efficiently. Early on in the process of taking history, a clinician can ask a patient to stretch their hands out to make this determination or ask the patient to describe in their own words if the tremors occur at rest or with action.
The main categories for tremors are 1) resting 2) postural or action, and 3) kinetic and intentional (a subtype of Kinetic). Although differentials are listed in the clinical mind map under these separate categories, several of these types may overlap. A complete history, physical exam, review of risk factors and additional clinical features can help arrive at the correct diagnosis. A helpful mnemonic to remember differentials for postural/action tremors is Every Drug High and Dry Passes CW.
A few differentials which are not listed in this clinical mind map are: 1) SWEDD (Scans With-out Evidence of Dopaminergic Deficit), which are isolated rest and action tremors of the arms, resembling those of early Parkinson’s Disease, that have failed to evolve over time into more generalized Parkinson’s Disease. 2) Writer’s tremors which occur specifically during supination and pronation, which are also called “writer’s cramps” or “writer’s dystonia” and 3) Orthostatic tremors, which are limited to the legs and trunk.
Using the Epi-logical approach, age appropriate diagnoses must be considered at least initially. For example, Parkinson's disease should be considered in a middle-old age patient with resting tremors, essential and drug induced tremors may be considered in all age groups, and cerebellar or intention tremors may be considered in patients at risk for cerebellar lesions such as stroke or a mass. Wilson's disease and hyperthyroidism may be considered in a younger population.
With the exception of an acutely evolving cerebellar stroke or thyroid storm, almost no urgent/emergent situations exist for tremors. Therefore, signs for an evolving stroke (remember FAST) must be considered when evaluating a patient with new onset tremors.
In order to weigh and remove anchor bias, a clinician must ask questions about a complete description of tremors, timing, triggers, past medical history, use of medications and risk factors associated with individual diagnoses. Lab/tests as described in the clinical mind map may further help arrive at the correct diagnosis.