Idiopathic Sensorineural Hearing Loss

Definition:

• Loss of significant hearing (>30 dB in at least three adjacent frequencies) occurring over <72 hours.
• Diagnosis of exclusion.

Epidemiology:

• Incidence: 20 per 100,000 people per year.
• Accounts for up to 90% of sudden sensorineural hearing loss (SSNHL).
• Average age of onset: 40–50 years.
• Unilateral in 95–100% of patients.
• Bilateral loss tends to occur in older populations with lower recovery rates.

Symptoms:

• Frequently associated with tinnitus (70% of cases).
• Dizziness occurs in up to 40% of cases, sometimes leading to nausea and vomiting.
• Other symptoms: ear fullness, headache, and upper airway viral infection symptoms.
• Ménière’s triad: hearing loss, tinnitus, and dizziness.

Diagnosis:

• Often missed in children, especially if unilateral.
• Requires exclusion of other known causes.

Prognosis:

• Spontaneous recovery in 45-60% of patients.Detailed recovery estimates:
  • 25% experience total spontaneous recovery.
  • 50% experience partial recovery.
  • 25% experience no recovery.
• Better prognosis:
  • Low frequency hearing loss.
  • Less severe hearing loss at presentation.
  • Early commencement of treatment.
  • Severe hearing loss appears to respond better to steroid therapy.
• Worse prognosis:
  • Patients aged < 15 years or > 60 years.
  • Presence of vertigo.

Treatment:

• Mainstay of treatment: Early initiation of oral steroids.
• Prednisolone at a dose of 1 mg/kg/day (maximum 60 mg/day).
• Treatment duration: 7–14 days.
• Tapering is not required with shorter courses.