What are the causes of rotatory dizziness (vertigo) in a patient with breast cancer?

Causes of Rotatory Dizziness in Patients with Breast Cancer

In breast cancer patients presenting with rotatory dizziness (vertigo), you must immediately consider brain metastases, leptomeningeal disease, and posterior fossa metastases, particularly when accompanied by headache, ataxia, or other neurological symptoms—these are red flags requiring urgent brain MRI. 1

Primary Etiologies to Consider

Cancer-Related Central Causes (Most Critical)

Brain metastases are a major concern in breast cancer patients with vertigo, particularly in HER2-positive disease where brain metastases occur with high prevalence. 1 The ASCO guidelines emphasize maintaining a low threshold for brain MRI when any neurological symptoms appear, including vertigo, new headaches, nausea/vomiting, or gait disturbance. 1

Leptomeningeal disease (LMD) occurs in approximately 5% of advanced breast cancer patients and carries a poor prognosis (median survival ~4 weeks without treatment, extending to months with aggressive therapy). 2 LMD diagnosis requires:

• Clinical evaluation
• Cerebrospinal fluid MRI
• CSF analysis

Posterior fossa metastases occur in approximately 8% of breast cancer survivors presenting with vertigo. 3 These include:

• Cerebellopontine angle lesions
• Cerebellar metastases
• Skull base metastases extending to temporal bone with inner ear destruction 4

Red Flag Symptom Combinations

Research demonstrates significantly elevated risk of brain metastases when vertigo occurs with: 5

• Headache (OR 18.6) - highest risk
• Ataxia (OR 12.1) - second highest risk
• Seizures (OR 10.9)
• Visual symptoms (OR 10.4)
• Altered mental status (OR 7.4)
• Focal weakness (OR 7.4)
• Focal sensory complaints (OR 6.9)
• Speech impairment (OR 6.3)

Critical caveat: Vertigo with headache or ataxia remained statistically significant after multivariate analysis, making these the most important red flags. 5

Vascular and Metabolic Causes

In breast cancer survivors without metastases, the most common causes are: 3

• Vascular insufficiency (31% of cases) - particularly posterior circulation
• Hyperlipidemia (22% of cases)
• Peripheral labyrinthine disorders (39% of cases)

Paraneoplastic Syndromes

Paraneoplastic cerebellar degeneration (PCD) is rare but important, caused by anti-Yo (anti-Purkinje cell) antibodies in breast cancer patients. 6, 7 Key features include:

• Continuous down-beating nystagmus
• Abnormal video head impulse testing (vHIT) of posterior canals only
• Progressive cerebellar dysfunction
• Can initially mimic acute vestibular syndrome

Anti-Ma2-associated encephalitis can present with acute vestibular syndrome, bilateral ptosis, circumlimbal injections, and vertical saccadic slowing. 7

Diagnostic Algorithm

Immediate Assessment Required:

1. Detailed neurological examination looking specifically for:

   • Nystagmus pattern (down-beating suggests central cause)
   • Focal motor/sensory deficits
   • Cerebellar signs (ataxia, dysmetria)
   • Cranial nerve abnormalities

2. HINTS examination (if trained practitioner available):

   • Head Impulse test
   • Nystagmus evaluation
   • Test of Skew
   • Abnormal HINTS = central cause requiring immediate imaging

3. Brain MRI without IV contrast is the primary imaging modality when: 1

   • Any red flag symptoms present
   • High vascular risk factors
   • Known extracranial metastases
   • Symptoms persist or progress

Common Pitfall to Avoid:

Do not assume peripheral vestibular neuritis in breast cancer patients without imaging, especially if:

• Patient has known extracranial metastases
• Symptoms accompanied by headache or ataxia
• Nystagmus pattern is atypical (down-beating, direction-changing without head position change)
• No response to conservative vestibular maneuvers (Epley, etc.)

The study by Chen et al. 3 found that 61% of breast cancer survivors with vertigo had central causes, not peripheral labyrinthine disease, emphasizing the importance of thorough evaluation.

Treatment-Related Causes

Chemotherapy-induced cognitive and vestibular effects can contribute to dizziness, though typically manifest as disequilibrium rather than true rotatory vertigo. 8 This is more relevant for chronic symptoms rather than acute presentations.

Clinical Decision Point

If isolated vertigo without red flags: Consider peripheral causes but maintain high suspicion, particularly in patients with:

• History of breast cancer (even decades prior—metastases can occur 33 years post-treatment) 4
• HER2-positive disease
• Known systemic metastases

If vertigo plus ANY red flag symptom: Obtain brain MRI immediately; do not delay for conservative management trials. 1, 5