What is the appropriate workup for a patient presenting with tremor (involuntary shaking)?

From the Guidelines

A tremor workup should begin with a thorough clinical assessment to determine the tremor type and potential causes, including Parkinsonian syndromes, as outlined in the 2020 American College of Radiology guidelines 1. The clinical assessment should include a detailed history focusing on onset, progression, exacerbating factors, family history, and medication use.

• Physical examination should evaluate the tremor's characteristics (rest, postural, action, or intention), distribution, frequency, and amplitude.
• Basic laboratory tests should include thyroid function tests (TSH, free T4), liver function tests, complete blood count, comprehensive metabolic panel, and serum ceruloplasmin (to rule out Wilson's disease).
• Consider testing blood glucose, calcium levels, and vitamin B12.
• If medication-induced tremor is suspected, review all medications including caffeine and alcohol use. Neuroimaging with MRI brain may be indicated if structural lesions are suspected, as suggested by the 2020 American College of Radiology guidelines 1. For persistent or severe tremors, referral to a neurologist is appropriate for specialized testing such as electromyography or accelerometry. Treatment depends on the underlying cause but may include propranolol (20-40mg twice daily) or primidone (starting at 25mg at bedtime and gradually increasing) for essential tremor, with propranolol being a well-established treatment option for over 40 years 1. This systematic approach helps identify treatable causes and guides appropriate management of the tremor, improving patient outcomes and quality of life.

From the Research

Tremor Workup

• The diagnosis of tremor is based on clinical information obtained from the history and physical examination 2, 3.
• The first step in evaluating a patient with tremor is to categorize the tremor based on its activation condition, topographic distribution, and frequency 2, 3.
• Tremors can be classified into two main types:
  • Action tremors, which occur with voluntary contraction of a muscle and can be further subdivided into postural, isometric, and kinetic tremors 2, 3, 4, 5.
  • Resting tremors, which occur in a body part that is relaxed and completely supported against gravity 2, 3, 4, 5.

Common Types of Tremor

• Essential tremor: the most common pathologic tremor, which affects 0.4% to 6% of the population and is often transmitted in an autosomal-dominant fashion 2, 3, 4, 5, 6.
• Parkinsonian tremor: typically unilateral, occurs at rest, and becomes less prominent with voluntary movement 2, 3.
• Psychogenic tremor: characterized by abrupt onset, spontaneous remission, changing tremor characteristics, and extinction with distraction 2, 3.
• Other types of tremor include cerebellar, dystonic, drug- or metabolic-induced, and orthostatic tremor 2, 3, 4, 5.

Diagnostic Approach

• A detailed history and focused neurologic examination are essential for establishing the diagnosis of tremor 4, 5, 6.
• The evaluation should attend to the many subtleties of tremor phenomenology, including the activation condition, topographic distribution, and frequency of the tremor 4, 5.
• Single-photon emission computed tomography and transcranial ultrasonography may be useful in diagnosing Parkinson disease 2, 3.