368.1 🎓 醫孞生版

368.1.0.1 📌 䞀頁重點

368.1.0.1.1 Four Types of Dizziness

368.1.1 1. Vertigo

  • Illusion of motion (spinning, tilting)
  • Vestibular origin (peripheral or central)

368.1.2 2. Presyncope

  • Near-faint sensation
  • Cardiovascular (orthostatic, arrhythmia, vasovagal)

368.1.3 3. Disequilibrium

  • Off-balance without rotation
  • Often gait-related
  • Cerebellar, sensory ataxia, parkinsonian, peripheral neuropathy

368.1.4 4. Lightheadedness/Vague

  • Anxiety
  • Hyperventilation
  • Hypoglycemia
  • Drug effects
368.1.4.0.1 Peripheral vs Central Vertigo

368.1.5 Peripheral

  • Inner ear or vestibular nerve
  • More common
  • Generally less dangerous
  • Severe N/V often
  • Unidirectional horizontal-torsional nystagmus
  • Reduced by visual fixation
  • Hearing symptoms common
  • No other neuro signs

368.1.6 Central

  • Brainstem or cerebellum
  • Less common but MORE DANGEROUS
  • Often less severe vertigo but more incapacitating
  • Direction-changing or vertical/pure torsional nystagmus
  • NOT reduced by fixation
  • Other neuro signs (CN, ataxia, diplopia, dysarthria, dysphagia)
  • Can have hearing loss if AICA stroke
368.1.6.0.1 Common Peripheral Causes

368.1.7 Benign Paroxysmal Positional Vertigo (BPPV) — Most Common

Pathophysiology: - Otoconia displaced into semicircular canal (posterior most common) - Movement triggers cupula deflection

Features: - Brief (< 1 min) - Positional (rolling over in bed, lying down, looking up) - Recurrent

Diagnosis: - Dix-Hallpike maneuver (posterior canal) - Latency, fatigability, geotropic torsional nystagmus

Treatment: - Epley maneuver (canalith repositioning) — very effective - Brandt-Daroff exercises - Avoid vestibular suppressants

368.1.8 Vestibular Neuritis

Features: - Sudden severe sustained vertigo (days) - N/V - No hearing loss - Often viral prodrome - Improves over days-weeks

Diagnosis: - Clinical - HINTS exam: peripheral pattern - Caloric testing: hypofunction on affected side

Treatment: - Steroids (methylprednisolone 100 mg taper, controversial but standard) - Vestibular suppressants short-term (≀ 72 hr — meclizine, diazepam, dimenhydrinate) - Antiemetics - Early vestibular rehab

368.1.9 Labyrinthitis

  • Vestibular neuritis + hearing loss
  • Same approach + audiology follow-up

368.1.10 Meniere Disease

Features: - Recurrent attacks (20 min - hours) - Tetrad: - Vertigo (recurrent) - Tinnitus - Hearing loss (sensorineural, low-frequency, fluctuating) - Aural fullness - Drop attacks (Tumarkin) in late stages

Pathophysiology: - Endolymphatic hydrops - Idiopathic

Treatment: - Diet: low salt - Diuretics (hydrochlorothiazide-triamterene) - Betahistine (used in Europe, mixed US evidence) - Vestibular suppressants for acute - Intratympanic steroid or gentamicin for refractory (gentamicin ablates vestibular function) - Endolymphatic sac decompression, labyrinthectomy for severe

368.1.11 Vestibular Migraine

Features: - Vertigo associated with migraine - May or may not have headache during episode - Recurrent attacks - Family history migraine - Light/sound sensitivity

Diagnosis: - Bárány Society + IHS criteria - Diagnosis of exclusion

Treatment: - Migraine prevention (β-blocker, topiramate, TCA, CGRP mAbs) - Acute as migraine

368.1.11.0.1 Common Central Causes

368.1.12 Brainstem/Cerebellar Stroke

  • Posterior circulation
  • AICA (anterior inferior cerebellar artery) — can have hearing loss (mimics labyrinthitis!)
  • PICA — lateral medullary (Wallenberg)
  • Cerebellar hemorrhage
  • Posterior fossa edema can cause obstructive hydrocephalus

368.1.13 Vertebrobasilar Insufficiency

  • TIA in posterior circulation
  • Recurrent brief episodes
  • Other brainstem symptoms

368.1.14 MS

  • Brainstem plaque
  • Other MS features

368.1.15 Posterior Fossa Tumor

  • Vestibular schwannoma (acoustic neuroma)
  • Cerebellar tumor
368.1.15.0.1 HINTS Exam (for Acute Vestibular Syndrome)

For sustained vertigo + nystagmus + nausea:

Component Peripheral Central
Head Impulse (HIT) Abnormal (catch-up saccade) Normal (no saccade)
Nystagmus Unidirectional horizontal Direction-changing or vertical
Test of Skew Absent Present (vertical misalignment)

Sensitivity for stroke: HINTS more sensitive than early MRI (within 48 hr).

368.1.15.0.2 Workup

368.1.16 History

  • Type of dizziness (vertigo, presyncope, disequilibrium, lightheadedness)
  • Onset (sudden vs gradual)
  • Duration of episodes
  • Triggers (position, motion, stress)
  • Associated symptoms (hearing, neuro, CV)
  • Medications

368.1.17 Exam

  • HINTS exam
  • Neurological (cranial nerves, cerebellar, gait)
  • Romberg
  • Orthostatic vitals
  • Cardiac
  • Audiometry

368.1.18 Imaging

  • MRI brain with DWI for suspected central
  • CT initial if hemorrhage suspected, but limited posterior fossa
  • MRA/CTA for vertebrobasilar

368.1.19 Vestibular Function Tests

  • Caloric testing (warm + cold water)
  • Videonystagmography (VNG)
  • Rotational chair
  • VEMP (vestibular-evoked myogenic potentials)

368.1.19.1 🩺 床邊速查

  • 4 types: vertigo, presyncope, disequilibrium, lightheadedness
  • Peripheral: BPPV, vestibular neuritis, labyrinthitis, Meniere, vestibular migraine
  • Central (dangerous): stroke, MS, tumor, VBI
  • HINTS exam: more sensitive than early MRI for posterior stroke
  • BPPV: brief, positional → Dix-Hallpike → Epley
  • Vestibular neuritis: sustained days, no hearing → steroids
  • Meniere tetrad: vertigo + tinnitus + hearing loss + fullness
  • Vestibular migraine: recurrent, migraine features