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TOPIC 2

TOPIC 2. CAUSES OF HEARING IMPAIRMENT. Outer and Middle Ear Disorders. Structural defects due to embryologic malformations Structural changes secondary to infection or trauma. Outer Ear Disorders. Microtia and atresia. Microtia. “an abnormal smallness of the auricle”. Atresia.

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TOPIC 2

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  1. TOPIC 2 CAUSES OF HEARING IMPAIRMENT

  2. Outer and Middle Ear Disorders • Structural defects due to embryologic malformations • Structural changes secondary to infection or trauma

  3. Outer Ear Disorders • Microtia and atresia

  4. Microtia “an abnormal smallness of the auricle”

  5. Atresia “the absence of an opening of the external canal”

  6. Outer Ear Disorders • Microtia and atresia • Impacted cerumen • Perforation of the tympanic membrane

  7. Perforation of the TM • An example of the audiogram illustrating the flat, mild, conductive hearing loss that can occur with a perforated tympanic membrane

  8. Outer Ear Disorders • Microtia and atresia • Impacted cerumen • Perforation of the tympanic membrane • Other

  9. Otitis Media Most common cause of transient conductive hearing loss in children Inflamation of the middle ear Caused by eustachian tube failure Middle Ear Disorders

  10. Otitis Media • Three examples of the usual characteristics of a conductive hearing loss arising from otitis media

  11. Ways to Classify Otitis Media • With or without effusion • Fluid type • Serous • Suppurative • Mucoid

  12. Ways to Classify Otitis Media • With or without effusion • Fluid type • Duration • Acute • Chronic • Subacute • Persistent • Recurrent

  13. Otitis Media Facts • 76-95% of all kids will have one episode of OM by age 6 • Prevalence is highest during the first two years of life • 50% of all kids with one episode before their first birthday will have 6 or more bouts within two years • Most episodes occur in winter and spring • Risk factors • Cleft palate • Down syndrome • Native Americans • Urban poor • Day care • Secondhand smoke

  14. Middle Ear Disorders • Otitis media • Otosclerosis

  15. Otosclerosis “a bone disorder that affects the stapes and the bony labyrinth of the inner ear. The disease process is characterized by resorption of bone and new spongy formation around the stapes and oval window”

  16. Otosclerosis • Facts: • Hereditary • Women are more likely to develop the disorder • Usually bilateral • progressive

  17. Middle Ear Disorders • Otitis media • Otosclerosis • Cholesteatoma

  18. Cholesteatoma “an epithelial pocket that forms on the tympanic membrane. Once the pocket forms, the normal shedding of epithelium results in growth of the tumor”

  19. Middle Ear Disorders • Otitis media • Otosclerosis • Cholesteatoma • Other • Physical trauma

  20. Physical Trauma of the Middle Ear Here’s an example of an audiogram resulting from disarticulation of the ossicular chain

  21. Middle Ear Disorders • Otitis media • Otosclerosis • Cholesteatoma • Other • Physical trauma • Barotrauma • Middle ear tumors • Glomus tumor

  22. Cochlear Disorders • Syndromes and inherited disorders • Syndromic disorders • Nonsyndromal disorders

  23. Syndromes and Inherited Disorders Resulting in Sensorineural Hearing Loss

  24. Types of Nonsyndromic Disorders • Dominant • Dominant progressive • Dominant progressive with adult onset • Recessive hereditary SNHL • X-linked

  25. Cochlear Disorders • Syndromes and inherited disorders • Noise induced hearing loss

  26. Noise Induced Hearing Loss The degree of SNHL depends on • The intensity of the noise • The spectral composition of the noise • The duration of exposure • Individual susceptibility

  27. OSHA Damage Risk Criteria

  28. Noise Induced SNHL • Noise notch • Cummulative • Progressive

  29. Cochlear Disorders • Syndromes and inherited disorders • Noise induced hearing loss • Other trauma • Infections

  30. Infections • Congenital • Cytomegalovirus • HIV • Rubella • Syphilis • Toxoplasmosis

  31. Infections • Acquired • Herpes Zooster Oticus (Chicken Pox) • Mumps • Syphilis

  32. Cochlear Disorders • Syndromes and inherited disorders • Noise induced hearing loss • Other trauma • Infections • Ototoxicity

  33. Ototoxicity • Some antibiotics that are often ototoxic: • Amikacin • Dihydrostreptomycin • Garamycin • Gentamicin • Kanamycin • Neomycin • Netilmicin • Streptomycin • Tobramycin • Viomycin

  34. Ototoxicity • Chemotherapy • Carboplatin • Cisplatin • Drugs that cause reversible hearing loss • Quinine • Salicylates (aspirin) • Loop diuretics • Drugs that may be harmful during pregnancy • Accutane • Dilantin • Quinine • Thalidomide

  35. Cochlear Disorders • Syndromes and inherited disorders • Noise induced hearing loss • Other trauma • Infections • Ototoxicity • Meniere’s Disease

  36. Meniere’s Disease • Symptoms • Tinnitus • Vertigo • Unilateral sensorineural hearing loss

  37. Cochlear Disorders • Syndromes and inherited disorders • Noise induced hearing loss • Other trauma • Infections • Ototoxicity • Meniere’s Disease • Presbycusis

  38. Presbycusis

  39. Central Auditory Disorders • VIII Nerve tumors • Other diseases of the VIII Nerve • Neural disorders • Cochlear neuritis • Diabetes mellitus • Brain Stem disorders • Infarcts • Gliomas • Multiple sclerosis • Temporal Lobe disorders

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