Labyrinthitis

Labyrinthitis Basics - Inner Ear Mayhem

• Inflammation of inner ear's membranous labyrinth; impacts hearing & balance.
• Types & Etiology:
  • Viral Labyrinthitis: Most frequent. Often follows Upper Respiratory Infection (URI) (e.g., influenza, measles, mumps, VZV).
  • Bacterial Labyrinthitis:
    • Suppurative: Direct bacterial invasion (e.g., from Acute Otitis Media (AOM), meningitis). Results in severe, often permanent, sensorineural hearing loss (SNHL) & vestibular dysfunction.
    • Serous (Toxic): Bacterial toxins diffuse from middle ear/meninges (e.g., AOM). Milder symptoms, often reversible.
  • Autoimmune: Rare; associated with systemic autoimmune disorders (e.g., Cogan's syndrome).
  • Traumatic: E.g., temporal bone fracture.

⭐ Suppurative labyrinthitis is a common cause of acquired profound sensorineural hearing loss, especially as a complication of bacterial meningitis in children; early cochlear implantation may be considered due to risk of labyrinthitis ossificans (LO).

Clinical Picture - The Dizzying Truth

• Onset: Acute, sudden, severe vertigo.
• Vertigo:
  • Continuous, prostrating; lasts days-weeks.
  • Worsened by head movements.
• Auditory:
  • Unilateral Sensorineural Hearing Loss (SNHL).
  • Tinnitus (affected side).
• Vestibular:
  • Nausea, vomiting.
  • Spontaneous nystagmus: horizontal-rotatory.
    • Fast phase beats away from lesion (usually).
    • Alexander's Law: ↑ intensity on gaze to fast phase.
  • Gait ataxia: falls towards affected side.
• Crucial: No focal neurological deficits (vs. central causes).
• Often follows: URI (viral) or otitis media (bacterial).

⭐ SNHL in viral labyrinthitis can be permanent; BPPV has no hearing loss.

Diagnostic Drilldown - Pinpointing the Problem

• Clinical Diagnosis: Acute vertigo, hearing loss, nausea/vomiting. Often post-URI.
• Key Exam Signs:
  • Nystagmus: Spontaneous, horizontal-rotatory; fast phase away from lesion. Suppressed by fixation.
  • Head Impulse Test (HIT): Positive (corrective saccade towards affected side).
  • SNHL: Audiometry confirms. (Tuning forks guide).
  • Gait: Ataxia, falls towards lesion.
• Stroke Mimic Alert!
  • HINTS exam (Head Impulse, Nystagmus, Test of Skew) to differentiate.
  • Central signs: Normal HIT, direction-changing nystagmus, skew → Urgent MRI.

⭐ Nystagmus in labyrinthitis: Unidirectional, horizontal-torsional, fast phase away from lesion. Intensifies with gaze towards fast phase (Alexander's Law), ↓ with fixation.

• Confirmatory/Exclusion Tests:
  • Audiometry: Essential to document SNHL.
  • MRI Brain (Gad): If CNS signs, stroke risk, atypical, no improvement.

Treatment Toolkit - Calming the Storm

• Immediate Goals: Control vertigo, nausea, vomiting.
  • Bed rest, hydration.
  • Vestibular Suppressants (short-term):
    • Antihistamines (Meclizine 25-50mg, Dimenhydrinate).
    • Benzodiazepines (Diazepam 2-5mg). ⚠️ Caution: limits compensation.
  • Anti-emetics (Ondansetron 4-8mg).
• Addressing Cause & Inflammation:
  • Corticosteroids (e.g., Prednisolone 1mg/kg, max 60mg, taper) for viral/idiopathic.
  • Antibiotics: If bacterial (e.g., IV Ceftriaxone).
• Long-term Recovery:
  • Vestibular Rehabilitation Therapy (VRT): Key for central compensation.
  • Avoid prolonged suppressant use.

⭐ Corticosteroids (e.g., Prednisolone) are often used in acute viral labyrinthitis to hasten recovery by reducing cochleovestibular inflammation.

High‑Yield Points - ⚡ Biggest Takeaways

• Labyrinthitis: Inflammation of the inner ear labyrinth, usually viral (post-URI).
• Presents with acute severe vertigo, sensorineural hearing loss (SNHL), and nausea/vomiting.
• Hearing loss is the key feature distinguishing it from vestibular neuritis.
• Bacterial labyrinthitis is rarer, more severe, often from AOM or meningitis.
• Nystagmus: Typically unidirectional, horizontal-torsional, fast phase beats away from the affected side.
• Treatment: Supportive care, corticosteroids to reduce inflammation. Antibiotics if bacterial_cause identified_or_suspected_