What investigations are needed for a 69-year-old male with Hypertension (HTN), Dyslipidemia, Obesity (Body Mass Index (BMI) 34.1), Nephrolithiasis, Prostate Cancer (Gleason 7), Androgen Deprivation Therapy (ADT), experiencing intermittent unsteadiness and a sensation of falling?

Diagnostic Approach for Intermittent Unsteadiness in a 69-Year-Old Male with Prostate Cancer

Brain and cervical spine MRI with contrast are essential first-line investigations for this patient with intermittent unsteadiness and abnormal tandem gait, as these symptoms strongly suggest a central neurological etiology requiring immediate evaluation. 1

Clinical Assessment Findings

The patient presents with:

• Intermittent, short episodes (10 minutes) of unsteadiness
• Sensation of falling toward one side (predominantly left)
• Abnormal tandem gait
• Normal neurological examination otherwise
• Significant medical history including:
  • Hypertension
  • Dyslipidemia
  • Obesity (BMI 34.1)
  • Prostate cancer (Gleason 7)
  • On androgen deprivation therapy (ADT) since 2022

Recommended Investigations

Neuroimaging (Priority)

• MRI of brain with and without contrast
• MRI of cervical spine with and without contrast

These imaging studies are crucial as the American College of Radiology recommends MRI with contrast of both the cervical spine and brain to rule out central causes in patients with bilateral unsteadiness and normal initial examination 1. Standard imaging may miss subtle foraminal stenosis or dynamic compression.

Cardiovascular Assessment

• 12-lead ECG to assess for arrhythmias or conduction abnormalities
• Carotid ultrasound to evaluate for carotid stenosis
• Blood pressure measurements (including orthostatic measurements)

Hypertension is a significant risk factor that can cause cerebrovascular disease leading to unsteadiness, and this patient has multiple cardiovascular risk factors 2.

Laboratory Tests

1. Complete blood count
2. Comprehensive metabolic panel
3. HbA1c (patients on ADT are at higher risk for insulin resistance and diabetes) 3
4. Lipid profile
5. Thyroid function tests
6. Vitamin B12, folate levels
7. Inflammatory markers (ESR, CRP)

These tests are important as metabolic causes such as diabetes mellitus, vitamin B12 deficiency, and thyroid dysfunction should be considered in the differential diagnosis of unsteadiness 1.

Rationale for Investigations

1. Central Nervous System Pathology: The patient's presentation with intermittent unsteadiness and abnormal tandem gait suggests a possible central neurological cause. The absence of vertigo makes peripheral vestibular disorders less likely.

2. Cardiovascular Risk: The patient has multiple cardiovascular risk factors (hypertension, dyslipidemia, obesity) that increase the risk of cerebrovascular disease, which can manifest as unsteadiness 2.

3. ADT Complications: Patients on ADT for prostate cancer have increased risk of metabolic syndrome, insulin resistance, and cardiovascular disease 4, 5, 6, 3. These metabolic changes can contribute to cerebrovascular disease and neurological symptoms.

Important Considerations

• ADT and Cardiovascular Risk: ADT is associated with increased cardiovascular mortality and metabolic complications including insulin resistance, diabetes, and dyslipidemia 5, 6. These metabolic alterations may contribute to cerebrovascular disease and the patient's symptoms.

• Timing of Symptoms: The short duration (10 minutes) of symptoms suggests transient ischemic attacks (TIAs) as a possible etiology, especially given the patient's vascular risk factors.

• Normal Neurological Examination: Despite the normal finger-nose test, rapid alternating movements, cranial nerves, motor strength, and DTRs, the abnormal tandem gait is significant and warrants thorough investigation.

Pitfalls to Avoid

1. Attributing symptoms solely to aging: Unsteadiness is not a normal part of aging and requires thorough investigation.

2. Overlooking metabolic causes: ADT can cause metabolic derangements that contribute to neurological symptoms 3.

3. Inadequate imaging: Standard imaging may miss subtle abnormalities; dedicated neuroimaging with contrast is essential 1.

4. Delayed diagnosis: Prompt evaluation is crucial as early intervention for conditions like TIAs can prevent stroke.

5. Focusing only on prostate cancer: While the patient has prostate cancer, his symptoms are more likely related to cerebrovascular disease or other neurological conditions rather than direct cancer effects.

By following this comprehensive diagnostic approach, the underlying cause of the patient's unsteadiness can be identified and appropriate treatment initiated to prevent further neurological complications and improve quality of life.