Dizziness and Vertigo: MCCQE1 Preparation Guide

Introduction

Dizziness is one of the most common presenting complaints in Canadian emergency departments and family practice clinics. For the MCCQE1, the challenge lies not just in recalling the causes, but in the clinical reasoning required to differentiate benign peripheral vestibular disorders from life-threatening central causes (e.g., posterior circulation stroke).

This guide is structured to help you master the MCCQE1 objectives related to dizziness, utilizing the CanMEDS framework to ensure a holistic approach to patient care.

Classification of Dizziness

The first step in the clinical approach is to clarify what the patient means by “dizzy.” Although recent evidence suggests focusing on timing and triggers is more diagnostic than symptom quality, the traditional classification remains relevant for the MCCQE1.

Vertigo: Peripheral vs. Central

Differentiating between peripheral and central vertigo is the highest-yield concept for the MCCQE1.

Comparative Table: Peripheral vs. Central Vertigo

Clinical Assessment

1. History Taking

Focus on the TiTrATE approach (Timing, Triggers, And Targeted Exam) which is gaining traction in Canadian emergency medicine.

• Timing: Episodic vs. Continuous.
• Triggers: Spontaneous vs. Triggered (e.g., by head movement, Valsalva).
• Medications: Review for ototoxic drugs (aminoglycosides) or antihypertensives.

2. Physical Examination

The HINTS Exam

For patients with Acute Vestibular Syndrome (continuous vertigo, nystagmus, nausea/vomiting), the HINTS exam is more sensitive than early MRI for detecting stroke.

HINTS Acronym:
H - Head Impulse test
N - Nystagmus
T - Test of Skew

Interpretation suggesting CENTRAL cause (Stroke):

• Head Impulse: Normal (no catch-up saccade).
• Nystagmus: Direction-changing or Vertical.
• Test of Skew: Vertical skew deviation present (cover-uncover test).

The Dix-Hallpike Maneuver

Used to diagnose Benign Paroxysmal Positional Vertigo (BPPV).

Common Etiologies and Management

1. Benign Paroxysmal Positional Vertigo (BPPV)

• Pathophysiology: Canalithiasis (calcium debris) in the posterior semicircular canal.
• Presentation: Brief episodes (<1 min) triggered by head movement (rolling in bed).
• Diagnosis: Positive Dix-Hallpike.
• Management: Epley Maneuver (Canalith repositioning). Pharmacotherapy (e.g., betahistine) is generally ineffective and not recommended.

2. Vestibular Neuritis / Labyrinthitis

• Pathophysiology: Viral inflammation of the vestibular nerve.
• Presentation: Acute, continuous vertigo (days), nausea, vomiting.
  • Neuritis: No hearing loss.
  • Labyrinthitis: Plus unilateral hearing loss.
• Management:
  • Acute (First 24-48h): Vestibular suppressants (e.g., dimenhydrinate, benzodiazepines).
  • Subacute: Early mobilization and vestibular rehabilitation to promote central compensation. Corticosteroids may be considered (controversial).

3. Meniere’s Disease

• Tetrad: Vertigo (20 min - 24 hours) + Hearing Loss (sensorineural, low frequency) + Tinnitus + Aural Fullness.
• Management: Salt restriction, diuretics (HCTZ), referral to ENT.

4. Posterior Circulation Stroke (Wallenberg Syndrome)

• Presentation: Vertigo + ipsilateral facial numbness + contralateral body numbness + Horner’s syndrome.
• Management: Stroke protocol (CT/CTA, aspirin, admission).

Canadian Guidelines and Context

Choosing Wisely Canada

Neurology / Family Medicine:

“Don’t order CT head scans for adults with simple dizziness or syncope in the absence of focal neurological features.”

• CT head has very low sensitivity for posterior fossa pathology.
• MRI is the imaging modality of choice for suspected central vertigo but has limited availability in some Canadian centers.

Access to Care

In the Canadian context, recognize that wait times for non-urgent MRI can be long.

• Red flags warrant ER referral for urgent imaging.
• BPPV should be managed in primary care to reduce burden on specialists.

Key Points to Remember for MCCQE1

• BPPV is the most common cause of peripheral vertigo. The treatment is mechanical (Epley), not pharmaceutical.
• Vertical Nystagmus is always pathological (Central) until proven otherwise.
• Head Impulse Test: A normal result in a patient with acute continuous vertigo suggests a central cause (Stroke). A positive (abnormal) result suggests peripheral (Neuritis).
• Imaging: CT is poor for the posterior fossa. MRI is gold standard.
• Elderly Patients: Dizziness is a major risk factor for falls. Address home safety (Health Advocate role).

Study Checklist

• Differentiate Vertigo, Presyncope, and Dysequilibrium.
• Master the HINTS exam interpretation.
• Memorize the steps of Dix-Hallpike and Epley maneuvers.
• Review the vascular supply of the brainstem (PICA, AICA).
• Understand the indications for neuroimaging in Canada.

Sample Question

Clinical Scenario

A 68-year-old female presents to her family physician complaining of “the room spinning.” She reports that the sensation lasts for approximately 30 seconds and occurs specifically when she rolls over in bed to her right side or looks up to reach a high shelf. She denies hearing loss, tinnitus, or focal weakness. Her blood pressure is 128/78 mmHg. A Dix-Hallpike maneuver performed on the right side elicits rotatory, up-beating nystagmus after a 5-second latency period.

Question

Which one of the following is the most appropriate initial management for this patient?

• A. Prescription for betahistine (Serc)
• B. Referral for MRI of the brain
• C. Performance of the Epley maneuver
• D. Prescription for meclizine
• E. Reassurance and observation only

Explanation

The correct answer is:

• C. Performance of the Epley maneuver

Detailed Explanation: The patient’s presentation is classic for Benign Paroxysmal Positional Vertigo (BPPV) of the right posterior canal. Key features include:

1. Triggered vertigo: Occurs with head movement (rolling in bed).
2. Short duration: Episodes last < 1 minute.
3. Positive Dix-Hallpike: Latency, fatigability, and characteristic nystagmus (rotatory/up-beating).

The Epley maneuver is the gold standard treatment for posterior canal BPPV, with a high success rate often after a single treatment. It repositions the canaliths from the semicircular canal back into the utricle.

• Option A (Betahistine): While used for Meniere’s disease, evidence for its efficacy in BPPV is lacking.
• Option B (MRI): Unnecessary. The history and physical exam are diagnostic for BPPV. MRI is indicated if there are red flags (central signs) or atypical nystagmus. Choosing Wisely Canada advises against imaging for simple dizziness.
• Option D (Meclizine): Vestibular suppressants are generally contraindicated in BPPV as they do not treat the underlying mechanical problem and may delay central compensation. They may be used briefly for severe nausea but are not “management” of the condition itself.
• Option E (Reassurance): While BPPV is benign, it causes significant morbidity and fall risk. Active treatment (Epley) is superior to observation.

References

1. Medical Council of Canada. MCCQE Part I Clinical Decision-Making and Multiple-Choice Question Objectives. Available at mcc.ca .
2. Choosing Wisely Canada. Neurology and Family Medicine Recommendations. Available at choosingwiselycanada.org .
3. Toronto Notes 2024. Otolaryngology and Neurology Sections. Toronto: Toronto Notes for Medical Students, Inc.
4. Kattah JC, et al. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009;40(11):3504-10.
5. Canadian Stroke Best Practices. Acute Stroke Management. Available at strokebestpractices.ca .