13.03.05 Hearing loss

Causes of sensorineural hearing loss

    • MS

    • Acoustic neuroma

    • Ménière's

    • Ototoxins

      • Streptomycin

      • Gentamycin

      • Salicylates

      • Thalidomide

      • Cis-platin

      • Vincristine

    • Infection

      • Meningitis

      • Mumps

      • Measles

      • Flu

      • Herpes

      • Syphilis

    • Metastatic cancer (brain)

    • Cochlear vascular disease

    • Presbycusis

Ménière's

    • Triad

    • Recurrent vertigo

      • Fluctuating sensorineural hearing loss (Low frequency loss initially, develops to full-range)

    • Tinnitus

    • Sensation of aural fullness

    • Usually unilateral but may extend to both ears in 25-75%

    • Genetic component

Weird/wonderful diseases causing hearing loss

    • Osteogenesis imperfecta

      • Blue sclera (very thin sclera, can see blood)

    • Waardenburg syndrome

      • Heterochromia

      • Wide-set eyes

      • Low hairlines

      • Monobrow

    • Usher syndrome

      • Visual as well as hearing loss (leading cause of deaf-blindness)

    • Pendred syndrome

      • Goitre / hypothyroidism

    • Alport syndrome

      • Type IV collagen deficiency => Poor basement membrane

      • Glomerulonephritis

      • Endstage kidney disease

    • Cogan syndrome

      • Recurrent corneal inflammation

      • Fever, fatigue, weight loss, dizziness

    • Behçet's disease

      • Mucous membrane ulceration and ocular problems

Patterns of hearing loss

    • Barotrauma => Mid-range

    • Presycusis => High-end

    • Otosclerosis => Low-end

    • Meniere's => Low-end then full-range

    • Acoustic neuroma => High-end (these fibres are on the outside of the nerve => hit first)

Auditory brainstem response

    • Recorded via electrodes placed on the scalp

    • Newborn hearing screening, auditory threshold estimation, intraoperative monitoring, determining hearing loss type and degree, auditory nerve and brainstem lesion detection

Otosclerosis

    • Bilateral

    • Progressive

    • Low-frequency dip

    • Stapidectomy + metal replacement

Blood supply of the ear

Notes

    • Facial nerve runs through the ear

      • cf Taste to anterior 2/3

    • Cochlear implant indications

      • Children

      • Bilateral deafness

      • Loss of another sense

    • Wax is skin