What is the appropriate workup for an adult patient with no significant past medical history presenting with intention tremor?

Workup for Intention Tremor

In an adult with intention tremor and no significant past medical history, obtain MRI brain without and with contrast to identify cerebellar or brainstem pathology, as intention tremor is a hallmark of cerebellar dysfunction and requires structural imaging to exclude treatable causes such as demyelinating disease, stroke, or mass lesions. 1

Initial Clinical Assessment

Key Historical Features to Elicit

• Timing and progression: Determine when tremor began and whether it has worsened over time, as intention tremor in essential tremor typically develops years after postural tremor onset 2
• Associated neurological symptoms: Specifically assess for ataxia, gait instability, dysarthria, diplopia, or other focal deficits that suggest cerebellar or brainstem involvement 1, 3
• Medication history: Review all medications, as drug-induced tremor is common and certain agents can cause cerebellar toxicity 4
• Family history: Document any family history of tremor or neurodegenerative disease 2
• Alcohol responsiveness: Ask whether alcohol improves the tremor, which is characteristic of essential tremor 2

Focused Physical Examination

• Tremor characterization: Confirm that tremor occurs during goal-directed movement and worsens as the limb approaches the target (classic intention tremor) 5, 4
• Cerebellar testing: Perform finger-to-nose and heel-to-shin testing, assess for dysmetria, dysdiadochokinesia, and gait ataxia 1, 2
• Cranial nerve examination: Evaluate for nystagmus, dysarthria, and other brainstem signs 1, 3
• Postural and resting tremor: Assess whether tremor is also present with arms outstretched or at rest, as this helps differentiate essential tremor from pure cerebellar disease 4, 2
• Head and trunk involvement: Check for head tremor or truncal ataxia, which are more common in advanced essential tremor with intention component 2

Neuroimaging Strategy

Primary Imaging Modality

• MRI brain without and with contrast is the imaging study of choice for evaluating intention tremor, as it provides superior soft tissue contrast to identify cerebellar, brainstem, and white matter pathology 1
• MRI can detect demyelinating lesions (multiple sclerosis), stroke, cerebellar atrophy, mass lesions, and structural abnormalities affecting cerebellar pathways 1

When Imaging is Indicated

• Obtain MRI in all patients with intention tremor unless there is clear evidence of longstanding essential tremor with documented progression from postural to intention tremor 1, 2
• Imaging is particularly urgent if there are associated focal neurological deficits, rapid progression, or signs of increased intracranial pressure 1

CT Limitations

• CT head has limited utility for evaluating intention tremor due to poor soft tissue contrast and inability to adequately visualize the posterior fossa structures 1
• CT may be considered only if MRI is contraindicated or unavailable, but it is not the preferred modality 1

Laboratory Evaluation

Initial Laboratory Studies

• Complete blood count, comprehensive metabolic panel, thyroid function tests: Screen for metabolic causes and thyroid dysfunction, which can cause or exacerbate tremor 4
• Vitamin B12 level: Deficiency can cause cerebellar dysfunction 1
• Ceruloplasmin and 24-hour urine copper: Consider in patients under 40 years old to exclude Wilson disease 4

Additional Testing Based on Clinical Context

• Serological tests for infectious diseases (syphilis, Lyme disease) if neuroimaging shows inflammatory changes or if there is clinical suspicion 3
• Paraneoplastic antibody panel: Consider if there is rapid progression and concern for paraneoplastic cerebellar degeneration 1
• Genetic testing: May be appropriate if there is family history suggesting hereditary ataxia 4

Common Pitfalls to Avoid

Misdiagnosis Risks

• Do not assume all tremor in older adults is essential tremor or Parkinson disease without proper characterization, as intention tremor specifically indicates cerebellar pathology requiring different evaluation 5, 4
• Do not confuse kinetic tremor (present throughout movement) with intention tremor (worsens approaching target), as this distinction is critical for determining the underlying pathology 4, 2
• Do not overlook that 25-33% of essential tremor patients develop intention tremor as the disease progresses, but this still requires imaging to exclude other causes 2

Imaging Errors

• Do not rely on CT imaging for posterior fossa evaluation, as it has poor sensitivity for cerebellar and brainstem lesions 1
• Do not skip contrast administration on MRI, as enhancing lesions (tumors, demyelinating plaques, inflammatory lesions) may be missed 1

Treatment Considerations

• Do not initiate pharmacologic treatment for intention tremor before completing the diagnostic workup, as medications are generally ineffective for cerebellar intention tremor and the underlying cause must be identified first 5, 4
• Recognize that propranolol and other medications effective for essential tremor's postural component do not improve intention tremor 5

Differential Diagnosis Framework

Primary Considerations

• Cerebellar stroke or hemorrhage: Acute onset with associated ataxia and other cerebellar signs 1
• Multiple sclerosis: Demyelinating plaques affecting cerebellar pathways, often with relapsing-remitting course 1
• Essential tremor with intention component: Progressive disease with family history and alcohol responsiveness 2
• Cerebellar degeneration: Paraneoplastic, toxic (alcohol), or hereditary ataxias 1, 4
• Structural lesions: Tumors, arteriovenous malformations, or other mass lesions affecting cerebellum or brainstem 1

Secondary Considerations

• Drug-induced cerebellar toxicity: Anticonvulsants (phenytoin), lithium, chemotherapy agents 4
• Metabolic disorders: Wilson disease, vitamin deficiencies, thyroid dysfunction 4
• Infectious or inflammatory conditions: Cerebellitis, post-infectious syndromes 1