Vertigo

The inner ear is composed of two separate departments: the cochlea (for hearing), and the vestibule (for balance/positioning). The vestibular system consists of three semicircular canals, all at 90 degrees from each other. The semicircular canals contain an outer, “osseous”, labyrinth and an inner, “membranous” labyrinth. Inbetween the two labyrinths lies endolymphatic fluid. These canals detect and interpret rotational movement. The utricle contains hair cells as well as otoliths, which help to detect linear accelerations in the horizontal plane. Similarly, the saccule contains hair cells and otoliths, however, it detects linear accelerations in the vertical plane

Vertigo is different from lightheadedness/pre-syncope/syncope, however, a patient may not be able to reliably differentiate this while giving a history

Priority #1: Rule out a stroke

Stroke Red Flags: Central vertigo (see below), acute onset, new vertigo, associated auditory or neurological deficits

Central Vertigo (could potentially be a stroke)

• Posterior fossa (cerebellum/medulla oblongata)
• Spontaneous Nystagmus*: Multidirectional, vertical, or torsional upon primary gaze
• Dix-Hallpike Test: Nystagmus is immediate in onset, lasts >1 minute with no fatigability. It has vertical or horizontal directionality without a torsional component. The direction may vary depending on the direction of the patient’s gaze
• Differential Diagnosis
  • Cerebrovascular Accident
  • Migraine Headache
  • Multiple Sclerosis
  • Vertebrobasilar artery insufficiency/dissection

Peripheral Vertigo (will not be a stroke)

• Inner ear or vestibular nerve
• Spontaneous Nystagmus*: Unilateral, horizontal, contralateral of the affected side (though falls and “veering” will be ipsilateral to affected side)
• Differential Diagnosis:
  • Meniere’s Disease ₍₁₎
    • Pathophysiology: Buildup of endolymphatic fluid
    • Key Features: Vertigo, tinnitus, temporary hearing loss, “fullness” of the ear
    • Treatment: Diuretics, salt restriction
  • Labyrinthitis ₍₂₎
    • Pathophysiology: Viral infection (HHV, Influenza, Mumps, EBV, Varicella, etc.)
    • Key Features: Non-specific (vertigo, tinnitus, unilateral temporary hearing loss)
    • Treatment: Symptomatic treatment (antiemetics, antihistamines, or short-course of benzodiazepines) +/- glucocorticoids or valacyclovir
  • Vestibular Neuritis ₍₃₎
    • Pathophysiology: Inflammation, usually as a re-activation of virus
    • Key Features: Vertigo, balance issues, nausea/vomiting, NO hearing loss
    • Treatment: Symptomatic treatment (antiemetics, antihistamines, or short-course of benzodiazepines) +/- glucocorticoids or valacyclovir
  • BPPV (Benign Paroxysmal Positional Vertigo) ₍₄₎
    • Pathophysiology: Utricular otoliths get dislodged and are misplaced in the endolymph of the semicircular canals
    • Key Features: Vertigo with positional head change or looking straight up
      • Diagnostic: Dix-Hallpike maneuvre with torsional and/or vertical nystagmus
    • Treatment: Epley maneuvre (symptomatic treatment if this is not successful)
  • Migraine
    • Pathophysiology: Unclear pathophysiology
    • Key Features: Associated with migraine headache
    • Treatment: Abortive or prophylactic medications (see Migraine)
  • Ototoxicity
    • Pathophysiology: Medications (several, too many to list)
    • Key Features: May be associated with hearing loss, improves with cessation of offending medication
    • Treatment: Stop the offending medications

*Nystagmus is characterized by the quick-moving portion of the motion (i.e. if the eyes move left slowly, then snap back to the right, it is characterized as a right nystagmus)

References

1. U.S. Department of Health and Human Services. (2020, December 14). Ménière’s Disease. National Institute of Deafness and Other Communication Disorders. https://www.nidcd.nih.gov/health/menieres-disease. 
2. Labyrinthitis. Cedars. (n.d.). https://www.cedars-sinai.org/health-library/diseases-and-conditions/l/labyrinthitis.html. 
3. Smith, T. (2020, July 10). Vestibular Neuronitis. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK549866/#article-31140.s8. 
4. Hornibrook, J. (2011). Benign Paroxysmal Positional Vertigo (BPPV): History, Pathophysiology, Office Treatment and Future Directions. International journal of otolaryngology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144715/.