What is the cause of persistent dizziness in a 47-year-old patient who fell and has been clinically unstable for a week without vomiting or visual disturbances?

Post-Traumatic Persistent Dizziness: Differential Diagnosis

The most likely cause of persistent dizziness one week after a fall in this 47-year-old patient is post-traumatic BPPV (benign paroxysmal positional vertigo), though post-traumatic vertigo with mixed peripheral and central vestibular damage must also be considered given the chronic presentation. 1

Categorizing the Clinical Presentation

This patient fits the chronic vestibular syndrome pattern—dizziness lasting one week or longer without spontaneous resolution. 1 The American Academy of Otolaryngology-Head and Neck Surgery emphasizes that timing and triggers are more diagnostically valuable than the specific descriptor patients use for their dizziness. 1

Key Differential Diagnoses After Trauma

Post-traumatic BPPV is the primary consideration:

• BPPV after trauma demonstrates higher recurrence rates and more refractory symptoms compared to spontaneous BPPV. 1
• The condition presents as brief episodes of positional vertigo triggered by head position changes, typically lasting less than 1 minute. 1
• Diagnosis requires performing the Dix-Hallpike maneuver, which reliably identifies BPPV and makes expensive imaging unnecessary in typical presentations. 1

Post-traumatic vertigo (broader category) must be considered:

• This can present with vertigo, disequilibrium, tinnitus, and headache due to damage of peripheral or central structures. 1
• The clinical manifestations are often complicated and may involve multiple vestibular pathways. 1

Critical Red Flags Requiring Immediate CNS Evaluation

The American Academy of Otolaryngology-Head and Neck Surgery identifies specific warning signs that mandate neurological assessment: 2

• Nystagmus patterns suggesting central pathology:

  • Direction-changing nystagmus without head position changes 2
  • Downward-beating nystagmus in Dix-Hallpike maneuver 2
  • Spontaneous nystagmus present without provocative maneuvers 2

• Associated neurological symptoms including focal deficits, severe headache, or gait disturbance beyond what BPPV would explain 2

• Lack of response after 2-3 repositioning maneuvers if BPPV treatment is attempted 2

Approximately 3% of BPPV treatment failures harbor underlying CNS disorders, and 10% of cerebellar strokes initially mimic peripheral vestibular processes. 2

Recommended Diagnostic Approach

Immediate Physical Examination

Perform the Dix-Hallpike maneuver as the first-line diagnostic test:

• This simple bedside test reliably identifies BPPV and avoids unnecessary medications and imaging. 1
• The test should be repeated even if previously performed, as 8-50% of patients have persistent BPPV after initial treatment attempts. 2

Assess for lateral canal involvement:

• Perform the supine roll test, as lateral canal BPPV (particularly the apogeotropic variant) may be more refractory to treatment. 2

Complete neurological examination:

• Focused posterior circulation assessment including cranial nerves, cerebellar testing, and gait evaluation 3
• Note that up to 80% of stroke patients with acute vestibular syndrome may have no focal neurologic signs, so absence of deficits does not rule out central pathology. 3

When to Obtain Brain Imaging

The American Academy of Otolaryngology-Head and Neck Surgery recommends MRI of the brain and posterior fossa (not CT, which frequently misses posterior circulation strokes) in these scenarios: 2, 3

• Atypical or refractory symptoms after 2-3 repositioning attempts 2
• Central nystagmus patterns 2
• Associated neurological symptoms 2
• Any focal neurological deficits on examination 3

Treatment Algorithm

If BPPV is Confirmed

Canalith repositioning procedures (CRP) are first-line treatment:

• Repeated CRP maneuvers achieve 90-98% success rates. 2
• Multiple treatment sessions may be necessary, particularly in post-traumatic cases. 2

Vestibular suppressant medications have limited role:

• Meclizine (25-100 mg daily in divided doses) is FDA-approved for vertigo associated with vestibular system diseases. 4
• However, long-term use should be avoided as these medications interfere with natural balance recovery and central compensation. 5
• Use only for acute symptom management during severe episodes. 5

If BPPV is Not Present or Treatment Fails

Consider vestibular rehabilitation:

• Promotes central compensation mechanisms and improves balance. 5
• Particularly beneficial for post-traumatic vertigo with mixed peripheral and central components. 5

Reassess at one month:

• The American Academy of Otolaryngology-Head and Neck Surgery emphasizes not missing the 1-month reassessment window, balancing spontaneous resolution rates (20-80%) against unnecessary suffering. 2

Fall Risk Counseling

This patient requires immediate fall prevention counseling:

• BPPV and post-traumatic vertigo significantly increase fall risk, particularly concerning in patients with preexisting balance issues. 1
• Provide home safety assessment recommendations and consider activity restrictions until symptoms resolve. 1, 5
• Patients should sit or lie down immediately when feeling dizzy and avoid driving during acute episodes. 5

Common Pitfalls to Avoid

• Never assume the initial diagnosis was correct—approximately 3% of patients have missed CNS disorders. 2
• Never rely solely on CT imaging for suspected stroke in the posterior circulation. 3
• Never assume absence of focal neurologic deficits rules out stroke—up to 80% of posterior circulation strokes present without focal signs. 3
• Never prescribe long-term vestibular suppressants—they impair natural compensation mechanisms. 5