Diagnosis

Labyrinthitis

Etiology

Cause [wdi]

• Usually unknown cause

• Infections of the ear:

  • Virus: Rubella, CMV, mumps, measles, herpes zoster oticus

  • Bacterial labyrinthitis: arising from menigitis or otitis media

• Autoimmune: Polyarteritis nodosa and granulomatosis with polyangiitis

• Head injury

• Extreme stress

• Allergy

• Systemic disease: Syphilis, HIV

• Reaction to medication:

  • Aminoglycosides and other ototoxic medications

  • Antihypertensives: amlodipine.

  • Antidepressants (abrupt discontinuation)

  • Tranquilisers: benzodiazepines

  • Anti-epileptics

  • Carbon monoxide

Pathophysiology

1. The bony labyrinth situated within the temporal bone comprisse of three main parts:

   • The vestibule

   • The cochlea

   • The 3 semicircular canals

2. All three structures contain perilymph (sodium as the primary cation)

3. The membranous labyrinth is situated within the bony labyrinth and contains Endolymph (potassium as the primary cation)

4. The gradient across Reissner's membrane, created by the opposing concentrations of endolymph and perilymph, is responsible for generating the electrical impulses of the hair cells, known as the endocochlear potential

5. Labyrinthitis cause an imbalance of neuronal input between the left and right inner ears --> Nausea, vomiting, and severe spinning vertigo

Complications [wdi]

• Persistent hearing loss

• Complete deafness

• Persistent tinnitus

Epidemiology

Incidence per 100.000

Approach

• Otoscopy

• Neurologic exam: Cranial nerve, cerebellum, gait, balance

• Examination for nystagmus, electronystagmography, caloric testing

• Audiometry

• CT caput

• MR caput

Treatment

A self-limiting disease. Treatment with drugs is neither necessary nor possible. [wdi]

1. Supportive: hydration and bed rest

2. Treatment of underlying condition:

   • Bacterial infection: Antibiotics

   • Autoimmun condition: Corticosteroids, azathioprine, etanercept, or cyclophosphamide

3. Symptomatic treatment: Antihistamin, antiemetic, prochlorperazine

4. Vestibular rehabilitation exercises: neural adaptation and compensation

   • Gaze stability exercises: keeping eyes fixated on a target while moving the head

   • Habituation: provoke symptoms and then reduce response upon repetition

   • Functional retraining – including postural control, relaxation, and balance training

5. Surgical treatment:

   • Myringotomy and evacuation of effusion secondary to otitis media

   • Mastoidectomy for mastoiditis or cholesteatoma

Differential diagnoses

Acoustic neuroma, Benign paroxysmal positional vertigo, Brain tumor, Cholesteatoma, Herpes zoster, Intracranial hemorrhage, Meniere disease, Meningitis, Migraine, Multiple sclerosis, Otitis media, Spondylolysis, Stroke, Subarachnoid hemorrhage, Temporal bone fracture, Transient ischemic attack, Vestibular neuronitis, Wernicke encephalopathy