16. Damages of the inner ear caused by noise, infectious diseases and toxic lesions.

What are the causes of noise induced hearing loss

cochlear damage from noise

What are acute noise traumas

• occurs when ear is exposed to sudden intense sound

• >140 dB for less than 1.5ms

• eg gunshot, airbags, firecrackers, fireworks

What is chronic noise trauma

• occurs when ear is exposed to loud sound

• >90dB for months or years

• eg noise at workplace, loud music

What are the clinical signs of noise induced hearing loss

• bilateral SNHL → difficulty with speech discrimination, especially in situations with competing noise

• often accompanie by tinitus

How do you diagnose noise associated hearing loss

• history

• hearing tests

  • Weber, Rinne

  • PTA

    • AC=BC, but lower threshold

    • BC shows characteristic boilermarkers notch on audiogram

What is the treatment of noise induced hearing loss

hearing aids

What is ototoxicity

medication side effect involving toxic damage to inner ear

What are the causes of ototoxicity

• exogenous

• endogenous

What are the causes of exogenous ototoxicity

• drugs

  • aminoglycosides, diuretics, cytostatic drugs- cisplatin, salicylates, quinine, heavy metal, tabacco, alcohol, heroin, cocain

What are the causes of endogenous ototoxicity

• Metabolic disorders: DM, renal disease, hyperlipidemia, uremia

• Bacterial toxins

• Viruses: herpes zoster (Ramsay Hunt syndrome), influenza, measles, mumps, adenovirus, coxsackievirus, chicken pox (varicella)

What are the clinical signs of ototoxicity

• bilateral SNHL

• vertigo, nausea, tinnitus

• oscillopsia- illusion that environment is moving

• disequilibrium

What is the treatment of otoxicity

Treatment of underlying cause:

• Drug withdrawal

• HSV: acyclovir, gammaglobulin and antibiotics to prevent superinfection