What is the differential diagnosis and management for an elderly female patient with a 3-week history of nausea and dizziness following a fall, now presenting with vomiting, worsened by walking, and unremarkable vitals and physical assessment?

Differential Diagnosis for Post-Fall Nausea, Dizziness, and Vomiting in an Elderly Patient

This patient most likely has benign paroxysmal positional vertigo (BPPV) triggered by the fall 3 weeks ago, given the classic presentation of positional nausea worsened by walking, delayed onset after trauma, and absence of neurological deficits. 1, 2

Primary Differential Diagnoses

Most Likely: Benign Paroxysmal Positional Vertigo (BPPV)

• BPPV is the most common cause of vertigo (42% of cases in primary care) and frequently occurs after head trauma in elderly patients 2, 3
• The 3-week delay between fall and symptom onset is typical, as BPPV can develop days to weeks after trauma 1
• Nausea worsening with walking and position changes is pathognomonic for BPPV 1, 2
• Elderly patients may present with isolated instability brought on by position changes rather than classic spinning vertigo 1
• The absence of headache, visual disturbances, aphasia, and gait ataxia argues against central causes 1, 2

Critical to Exclude: Delayed Subdural Hematoma

• Despite negative FAST, elderly patients remain at risk for delayed subdural hematoma up to several weeks post-fall 1
• The gradual onset of nausea and vomiting over 3 weeks could represent slowly expanding intracranial pathology 1
• FAST ultrasound has limited sensitivity for subdural collections and cannot exclude this diagnosis 1
• Any elderly patient with persistent symptoms 3 weeks post-fall requires CT head imaging to exclude delayed intracranial hemorrhage 1

Other Peripheral Vestibular Causes

• Vestibular neuritis or labyrinthitis could present with persistent nausea and dizziness, though typically these cause acute vestibular syndrome with continuous symptoms rather than positional triggers 3
• Post-traumatic vestibular dysfunction can occur after head trauma without obvious neurological findings 1

Central Causes (Lower Probability Given Presentation)

• Posterior circulation stroke remains possible even without focal neurological deficits, as 75-80% of stroke patients with acute vestibular syndrome may lack obvious focal signs 1, 2
• However, the 3-week gradual onset and positional nature make acute stroke unlikely 1
• Vertebrobasilar insufficiency could cause episodic symptoms but typically includes other brainstem signs 1

Metabolic and Medication-Related Causes

• Dehydration from prolonged nausea could perpetuate symptoms 4, 5
• Medication adverse effects should be reviewed, particularly any new medications started after the fall 4, 5
• Electrolyte disturbances (hyponatremia, hypercalcemia) can cause nausea and dizziness 4

Immediate Diagnostic Approach

Bedside Testing (Perform Immediately)

• Perform Dix-Hallpike maneuver to diagnose BPPV - this is the single most important diagnostic test 1, 2, 3
• Observe for characteristic nystagmus during the maneuver, which confirms BPPV 1, 3
• Perform supine roll test if Dix-Hallpike is negative but suspicion remains high 1, 3
• Complete HINTS examination (Head Impulse, Nystagmus, Test of Skew) to distinguish peripheral from central causes 1, 2

Urgent Imaging Required

• CT head without contrast is mandatory given the 3-week interval since fall and persistent symptoms 1
• The negative FAST does not exclude delayed subdural hematoma or other intracranial pathology 1
• CT is preferred over MRI initially due to speed and ability to detect acute hemorrhage 1
• If CT is negative and symptoms persist, consider MRI brain to evaluate for posterior circulation infarct, which can be missed on CT in 11% of cases 1

Laboratory Testing

• Basic metabolic panel to assess for electrolyte disturbances and renal function 4, 5
• Complete blood count if infection or anemia suspected 4
• Consider thyroid function tests if other causes excluded 3

Management Strategy

If BPPV Confirmed (Positive Dix-Hallpike)

• Perform canalith repositioning procedure (Epley maneuver) immediately - this is first-line treatment with 80% success rate after 1-3 treatments 1, 2
• Administer prochlorperazine 5-10 mg orally or IV prophylactically before the maneuver if patient has severe nausea 1, 2
• Avoid routine vestibular suppressants as they delay central compensation and increase fall risk in elderly patients 1, 2
• Reassess within 1 month to document symptom resolution 1, 2

Antiemetic Management

• For acute severe nausea/vomiting: prochlorperazine 5-10 mg orally or IV, maximum 3 doses per 24 hours 2
• Ondansetron 8 mg orally can be used as alternative, particularly if extrapyramidal side effects are a concern 6
• Limit antiemetic use to shortest duration necessary (typically 24-48 hours) to avoid masking underlying pathology 1, 2
• Avoid metoclopramide in elderly patients due to high risk of tardive dyskinesia and extrapyramidal symptoms 7

If Imaging Shows Subdural Hematoma

• Immediate neurosurgical consultation required 1
• Antiemetics may be used for symptom control but do not delay definitive treatment 4

If All Testing Negative

• Consider gastroparesis or gastric neuromuscular dysfunction, particularly if patient has diabetes 1, 8
• Gastric emptying scintigraphy (4-hour study) is gold standard for diagnosing gastroparesis 1
• Trial of dietary modifications: small frequent meals, avoid trigger foods 1, 4

Critical Pitfalls to Avoid

Imaging Pitfalls

• Never rely on negative FAST alone in elderly patients with persistent symptoms after fall 1
• FAST has poor sensitivity for subdural hematomas and intracranial pathology 1
• Do not assume absence of headache excludes intracranial pathology - elderly patients may not report headache with subdural hematoma 1

Medication Pitfalls

• Avoid prolonged vestibular suppressants (benzodiazepines, antihistamines) as they significantly increase fall risk in elderly patients 1, 2
• These medications cause cognitive impairment and delay vestibular compensation 1, 2
• Never use metoclopramide routinely in elderly patients - risk of irreversible tardive dyskinesia increases with age 7

Diagnostic Pitfalls

• Do not skip Dix-Hallpike testing based on patient's symptom description alone 1, 3
• Elderly patients often describe BPPV atypically as "instability" rather than spinning 1
• Absence of focal neurological signs does not exclude posterior circulation stroke 1, 2
• Up to 75% of stroke patients with vertigo may have no obvious focal deficits 1, 2

Management Pitfalls

• Do not treat empirically with antiemetics without establishing diagnosis 2, 4
• This delays appropriate treatment and may mask serious pathology 2
• Do not discharge elderly patient with unresolved positional vertigo without fall precautions and safety assessment 1, 2
• BPPV significantly increases fall risk, which can be catastrophic in elderly patients 1

Follow-Up Requirements

• Mandatory reassessment within 1 month to document resolution or identify persistent symptoms requiring further evaluation 1, 2
• If symptoms persist after initial BPPV treatment, repeat Dix-Hallpike and consider alternative diagnoses 1, 2
• Persistent symptoms warrant MRI brain if not already performed to exclude central pathology 1, 2
• Monitor for recurrence, as BPPV can recur in up to 50% of patients 1