Vertigo

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• The Core Mechanism: Vertigo is the illusion of movement, typically generated by an asymmetry of signals in the vestibular system. Pathologically, it is strictly categorized into peripheral (benign) and central (life-threatening) etiologies.
• Peripheral Breakdown: Peripheral vertigo originates outside the central nervous system. In Benign Paroxysmal Positional Vertigo (BPPV), calcium carbonate crystals (otoliths) break loose and inappropriately enter the semicircular ear canals, altering fluid dynamics and triggering severe, episodic vertigo with head movement. In vestibular neuritis or labyrinthitis, viral inflammation of the vestibulocochlear nerve disrupts baseline firing rates, sending erratic signals to the brainstem.
• Central Breakdown: Central vertigo stems from direct mechanical, ischemic, or hemorrhagic destruction of the vestibular processing centers in the brainstem or cerebellum. The pathophysiology is driven by conditions such as a posterior circulation stroke, cerebellar hemorrhage, or vertebral artery dissection.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Immediate Stabilization: Secure the ABCs, assist the patient to a safe supine position to prevent falls, and obtain a bedside point-of-care (POC) glucose on arrival, as hypoglycemia is a critical, easily reversible mimic.
• Targeted Pharmacotherapy (Vestibular Suppressants & Antiemetics):
• Antihistamines: Meclizine 12.5–50 mg PO or Dimenhydrinate 50–100 mg IV/IM/PO.
• Benzodiazepines: Useful for vestibular suppression. Administer Lorazepam 1–2 mg IV/IM/PO or Diazepam 1 mg IV/IM/PO.
• Antiemetics: Administer Metoclopramide 5–10 mg IV/IM/PO, Ondansetron 4 mg IV/IM/PO, or Promethazine 12.5–25 mg IM/PO/PR.
• Therapeutic Maneuvers: For diagnosed posterior canal BPPV, perform the Epley maneuver. For horizontal canal BPPV, utilize the Barbeque roll or Gufoni maneuver.
• Monitoring Parameters: Evaluate orthostatic vital signs, assess ambulation status serially, and continuously monitor for the development of new focal neurologic deficits.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

• "Can't-Miss" Mimics & Etiologies:
• Posterior Circulation Stroke: Ischemia of the cerebellum or brainstem.
• Cerebellar Hemorrhage: Consider in patients with significant ongoing headache, ataxia, or decreased level of consciousness.
• Vertebral Artery Dissection: Highly suspect in patients presenting with vertigo and significant ongoing neck pain.
• Cardiovascular Dysrhythmia / Myocardial Infarction: Hypoperfusion can masquerade as dizziness/vertigo.
• Prioritized Diagnostic Workup:
• 12-Lead ECG & POC Glucose: Mandatory first steps to rule out dysrhythmias and metabolic causes.
• Non-Contrast Head CT: Indicated immediately if an intracranial/cerebellar hemorrhage is suspected (e.g., severe headache, trauma, altered mental status).
• CT Angiography (CTA) / MRA of the Head & Neck: Indicated for suspected vertebral artery dissection (neck pain) or to evaluate for stroke intervention (thrombolysis/clot retrieval).
• Emergent MRI: The gold standard imaging modality. Indicated if the patient has continuous vertigo for >48 hours without a clear peripheral cause, or if the HINTS exam points to a central etiology.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• The Clinical Visual Checklist (HINTS Exam): The HINTS exam (Head Impulse, Nystagmus, Test of Skew) is utilized to differentiate peripheral from central causes in acute, continuous vertigo. You must visually look for the following central red flags:
• Nystagmus: Direction-changing (bidirectional) nystagmus or purely vertical nystagmus strongly suggests a central lesion.
• Head Impulse Test: A negative (normal) head impulse test (the eyes remain perfectly fixed on the examiner's nose without a corrective catch-up saccade) points to a central etiology (brainstem stroke).
• Test of Skew: A vertical refixation of the eye during the alternate cover test (skew deviation) confirms a central lesion.
• Ambulation Assessment: Actively observe the patient's gait. Severe ataxia or being completely unable to sit or walk without support strongly points to a central process (e.g., cerebellar stroke).

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• Validated Scoring & Guidelines: Use the Sudbury Vertigo Risk Score to risk-stratify for a serious, central cause of vertigo. The GRACE-3 Guidelines (Guidelines for Reasonable and Appropriate Care in the Emergency Department) direct the evidence-based management of acute dizziness and vertigo.
• Clinical Decision Unit (CDU) Disposition Criteria:
• Exclusion: Patients are strictly excluded from ED observation/CDU if they have acute hearing loss, double vision, neuro deficits, severe headache/neck trauma, fever >38°C, abnormal vital signs, or a high clinical suspicion of stroke.
• Safe Discharge: Patients can be discharged home only if they have normal vital signs, a benign course, are able to tolerate PO medications, and are able to ambulate as well as they could before the onset of vertigo.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• Deadly Cognitive Trap (Relying on Head CT): Ordering a standard non-contrast head CT to "rule out" a posterior circulation stroke in a vertiginous patient. Critical Action: Head CTs have notoriously poor sensitivity for acute ischemic strokes in the posterior fossa. You must utilize the HINTS exam and order an emergent MRI if a central cause is suspected.
• Deadly Cognitive Trap (Misinterpreting the Head Impulse Test): Assuming an "abnormal" head impulse test means the patient has a stroke. Correction: A positive (abnormal) test showing a catch-up saccade actually indicates a peripheral problem (like vestibular neuritis). A perfectly normal (negative) head impulse test in a continuously dizzy patient is the deadly central finding.
• Premature Closure (Missing Dissections): Anchoring on benign vertigo in a younger patient complaining of neck pain. Critical Action: Vertigo paired with significant neck pain mandates a CTA to rule out a vertebral artery dissection.

7. MCQ MASTERCLASS (Written Exam Tips)

• The Classic Distractor (Symptom Duration): A question describes a patient with constant, unremitting vertigo for 2 days. The distractor options will include Ménière's disease or BPPV. Correction: Acute Vestibular Syndrome has an arbitrary cutoff of continuous vertigo for at least 1 day (24 hours). This rules out Ménière's disease and BPPV, which are characterized strictly by episodic vertigo.
• High-Yield Buzzwords: "Otoliths in the semicircular ear canals" (pathophysiology of BPPV). "Relieved by Epley maneuver" (Posterior canal BPPV).
• The Disposition Test: An exam question will ask who is safe for discharge. The correct answer will focus strictly on functional status: "The patient is able to tolerate PO fluids and ambulate safely".

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• The Initial Assessment Hook: "Given the patient's acute onset of severe vertigo, my immediate priority is to differentiate a benign peripheral etiology—such as BPPV or vestibular neuritis—from a life-threatening central cause, specifically a posterior circulation stroke, cerebellar hemorrhage, or vertebral artery dissection."
• The Diagnostic Command: "I will secure the ABCs, assist the patient to bed to prevent falls, and check a STAT point-of-care glucose and 12-lead ECG. I will perform a comprehensive neurologic exam, focusing on cranial nerves, cerebellar testing, and gait. Most importantly, I will perform the HINTS exam; if I see direction-changing nystagmus, a normal head impulse test, or skew deviation, I will presume a central etiology."
• The Definitive Disposition: "Because the patient demonstrates isolated peripheral findings and horizontal canal BPPV, I will perform the Gufoni maneuver, administer IV metoclopramide for their nausea, and assess their gait. If they can ambulate safely and tolerate oral intake, they meet criteria for safe discharge with outpatient follow-up."