From the Guidelines
The workup for new onset tremors should begin with a thorough clinical history and physical examination to characterize the tremor and identify potential causes, as recommended by the American College of Radiology in their 2020 guidelines for movement disorders and neurodegenerative diseases 1. The clinical presentation of Parkinsonian syndromes, such as Parkinson's disease (PD), multiple system atrophy (MSA), corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP), can be complex and may include resting tremor, bradykinesia, and rigidity, making a thorough clinical evaluation essential for diagnosis 1. Key elements of the clinical history include:
- Timing of tremor onset
- Exacerbating factors
- Associated symptoms
- Medication history
- Family history Laboratory tests should include:
- Complete blood count
- Comprehensive metabolic panel
- Thyroid function tests
- Liver function tests
- Serum ceruloplasmin (to rule out Wilson's disease) Additional testing may include brain imaging (MRI preferred over CT) to rule out structural lesions, and in selected cases, electromyography to characterize the tremor pattern, as suggested by the American College of Radiology guidelines 1. Specific attention should be paid to medications that can cause tremors, including stimulants, antidepressants, lithium, valproic acid, and certain antipsychotics. If essential tremor is suspected, a therapeutic trial of propranolol or primidone may be both diagnostic and therapeutic. For parkinsonian tremor, a trial of levodopa/carbidopa may be considered. Referral to a neurologist is appropriate for tremors that are disabling, rapidly progressive, asymmetric, or accompanied by other neurological symptoms. The workup should be tailored to the patient's age, as younger patients may need evaluation for genetic or metabolic causes, while older patients are more likely to have neurodegenerative disorders or medication-induced tremors.
From the Research
Workup for New Onset Tremors
The workup for new onset tremors involves a thorough history and physical examination to categorize the tremor based on its activation condition, topographic distribution, and frequency 2. The following steps can be taken:
- Determine the type of tremor: resting, action, or a combination of both 3, 4
- Assess the anatomical pattern, tremor frequency, and amplitude 3
- Evaluate for underlying causes such as enhanced physiologic tremor, essential tremor, parkinsonian tremor, dystonic tremor, or psychogenic tremor 2, 3, 4
- Consider diagnostic tests such as single-photon emission computed tomography or transcranial ultrasonography if there is diagnostic uncertainty 2
Differential Diagnosis
The differential diagnosis for new onset tremors includes:
- Essential tremor: the most common pathologic tremor, affecting 0.4% to 6% of the population 2
- Parkinsonian tremor: typically unilateral, occurs at rest, and becomes less prominent with voluntary movement 2
- Enhanced physiologic tremor: can be caused by anxiety, medication use, caffeine intake, or fatigue 2
- Dystonic tremor: characterized by involuntary muscle contractions 3, 4
- Psychogenic tremor: features include abrupt onset, spontaneous remission, changing tremor characteristics, and extinction with distraction 2
Diagnostic Approach
The diagnostic approach for new onset tremors involves:
- A thorough history and physical examination to establish the type and characteristics of the tremor 2, 3, 4
- Evaluation of the patient's medical history, including medication use and underlying medical conditions 2, 3, 4
- Consideration of diagnostic tests such as imaging studies or laboratory tests to rule out underlying causes 2