What is the initial workup for a 19-year-old patient presenting with tremors?

Initial Workup for a 19-Year-Old Patient with Tremor

Begin by characterizing the tremor's activation pattern—whether it occurs at rest, with posture, or during action—as this single feature will guide your entire diagnostic algorithm and determine which life-threatening conditions must be ruled out first.

Step 1: Characterize the Tremor Phenomenology

The first critical step is determining when the tremor occurs, as this narrows your differential dramatically:

• Resting tremor (4-6 Hz) that improves with movement suggests Parkinsonian tremor 1
• Postural/action tremor that worsens with goal-directed activity suggests essential tremor 1
• Intention tremor that becomes more pronounced during goal-directed movements with associated dysarthria and ataxic gait suggests cerebellar pathology 1
• Highly variable tremor that stops completely with distraction is the hallmark of functional tremor 1

Document the tremor's topographic distribution (unilateral vs. bilateral, which body parts), frequency, and factors that worsen or improve it 2.

Step 2: Rule Out Life-Threatening Secondary Causes First

In a 19-year-old, Wilson's disease is the most critical diagnosis not to miss as it is treatable and can present with tremor, dystonia, and parkinsonian features at this age 3, 2:

• Check serum ceruloplasmin and 24-hour urinary copper 2, 1
• Perform slit-lamp examination looking for Kayser-Fleischer rings 2
• Drooling and oropharyngeal dystonia are characteristic manifestations of Wilson's disease 3

Additional metabolic and drug-induced causes to evaluate:

• Thyroid function tests to rule out hyperthyroidism causing enhanced physiologic tremor 2
• Comprehensive medication review including caffeine intake, as these commonly cause or enhance tremor 4, 5
• Toxicology screening if substance abuse is suspected 3
• Serum glucose to exclude hypoglycemia 3
• Electrolytes including calcium and magnesium 3

Step 3: Focused Neurological Examination

Look for specific features that distinguish primary tremor disorders:

For Parkinsonian features:

• Assess for bradykinesia, rigidity, and postural instability 2, 1
• Evaluate gait pattern: shuffling, festination, or freezing 2
• Red flags for atypical parkinsonism (critical in young patients): early prominent falls, rapid progression, poor levodopa response, early autonomic dysfunction, vertical gaze palsy 2, 1

For essential tremor:

• Bilateral upper limb action tremor is the classic presentation 6
• Family history is positive in 50% of cases (autosomal dominant) 4, 5

For cerebellar tremor:

• Look for dysarthria and ataxic gait 1
• Tremor becomes more pronounced during goal-directed movements 1

For functional tremor:

• Abrupt onset and spontaneous remission 4, 5
• Changing tremor characteristics 4, 5
• Extinction with distraction is the hallmark diagnostic feature 1, 5

Step 4: Neuroimaging

MRI brain without contrast is the optimal imaging modality to evaluate for structural causes and parkinsonian syndromes 2:

• Essential for ruling out cerebellar pathology, stroke, or mass lesions
• Can identify characteristic findings in atypical parkinsonism
• Should be obtained in any young patient with tremor to exclude secondary causes

Step 5: Additional Testing Based on Clinical Suspicion

If Parkinsonian features are present:

• Consider single-photon emission computed tomography (SPECT) to visualize dopaminergic pathway integrity if diagnostic uncertainty exists 4, 5
• Therapeutic trial of levodopa/carbidopa: robust response supports Parkinson's disease, poor response suggests atypical parkinsonism 2

If functional tremor is suspected:

• Demonstration of specific clinical signs (distractibility, variability, extinction with distraction) establishes the diagnosis 1
• Do not treat as a diagnosis of exclusion 1

Critical Pitfalls to Avoid

• Do not assume all tremors in young patients are benign essential tremor—Wilson's disease must be excluded as it is treatable and fatal if missed 3, 2
• Do not overlook medication and substance-induced tremor, including caffeine, which is extremely common in this age group 1, 4
• Do not confuse akathisia (severe restlessness from antipsychotics manifesting as pacing) with tremor 1
• Do not provide adaptive equipment in the acute phase if functional tremor is suspected, as this may prevent improvement 1

Summary Algorithm

1. Characterize tremor activation: rest vs. postural vs. action vs. intention 1, 4
2. Immediate labs: ceruloplasmin, 24-hour urinary copper, thyroid function, glucose, electrolytes 3, 2, 1
3. Slit-lamp exam for Kayser-Fleischer rings 2
4. Comprehensive medication/substance history 1, 4
5. Focused neurological exam for parkinsonian features, cerebellar signs, dystonia 2, 1
6. MRI brain without contrast 2
7. Additional testing based on clinical findings (SPECT if parkinsonian, levodopa trial, etc.) 2, 4