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Chapter 15 
Disorders of the Eyes, Ears and Other 
Sensory Organs
Sensory Receptors 
 Classified into two major categories 
 General senses 
 Special senses 
• Include the eye and ear 
...
Sensory Receptors by Location 
 Exteroceptors 
 Located close to body surface (cutaneous 
receptors) 
• Examples—touch, ...
Sensory Receptors by Stimuli 
 Mechanoreceptors 
 Stimulated by mechanical force(s) 
• Touch, pressure, equilibrium, hea...
Sensory Receptors by Stimuli 
(Cont.) 
 Photoreceptors 
 Respond to light 
• Rods and cones in the retina (eye) 
 Nocic...
Eye 
 Light rays enter the eye through the cornea. 
 Pass through the lens to the receptor cells of 
the retina 
 Rods—...
Protection for the Eye 
 Protected by bony orbit of the skull 
 Bony protection of the eye 
 Eyelids and eyelashes 
 D...
Muscles of the Eyeball 
 Six extraocular skeletal muscles for 
movement of the eyeball 
 Muscles controlled by cranial n...
Eyeball 
 Outer layer 
 Touch fibrous coat 
 Posterior portion—sclera 
• “White” of the eye 
 Anterior portion—cornea ...
Eyeball (Cont.) 
 Middle layer—uvea 
 Choroid—dark vascular layer interior to the sclera 
 Absorbs scattered light 
 L...
Eyeball (Cont.) 
 Inner layer—retina 
 Contains no pain receptors 
 Multilayered—in posterior two thirds of the eye 
 ...
Structure of the Eye 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •12
Fluids in the Eye 
 Posterior cavity 
 Space between lens and retina 
 Contains vitreous humor 
• Formed during embryon...
Visual Pathway 
 Light rays pass through cornea 
 Refraction of rays 
 Through aqueous humor and pupil 
 To the retina...
Visual Pathway 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •15
Diagnostic Tests 
 Snellen chart (or similar test) 
 Measures visual acuity 
 Visual field test 
 Checks for central a...
Structural Defects of the Eye 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •17 
 Myopia 
 Ne...
Refraction Defects in the Eye: 
Myopia 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •18
Refraction Defects in the Eye: 
Hyperopia 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •19
Structural Defects of the Eye 
(Cont.) 
 Astigmatism 
 Irregular curvature in the cornea or lens 
 Strabismus (squint o...
Functional Changes 
 Nystagmus 
 Involuntary abnormal movement of one or both 
eyes 
 May result from neurological caus...
Infections and Trauma 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •22 
 Stye 
 Infection in...
Conjunctivitis 
 Superficial inflammation or infection 
 Allergens, irritating chemicals, bacteria, viruses 
 Redness, ...
Conjunctivitis (Cont.) 
 Other causes 
 Chlamydia trachomatis and Neisseria 
gonorrhoeae 
 Both cause infections in the...
Gonococcal Conjunctivitis 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •25
Pseudomonas aeruginosa 
Around Soft Contact Lens 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. ...
Bacteria Recovered from Contact 
Lenses and Solutions 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, ...
Trachoma 
 Caused by Chlamydia trachomatis 
 Follicles develop on inner surface of eyelids 
 Can occur in any age group...
Keratitis 
 Severe pain and photophobia 
 Develops when cornea is infected or irritated 
 Herpes simplex can be cause 
...
Glaucoma 
 Result of increased IOP caused by excessive 
accumulation of aqueous humor 
 Most common and preventable loss...
Acute Glaucoma 
 Acute or narrow-angle glaucoma 
 Angle between cornea and iris is decreased. 
 May be caused by aging,...
Glaucoma (Cont.) 
 Chronic or open-angle glaucoma 
 Higher incidence after age 50 years 
 Thickening of trabecular netw...
Glaucoma: Normal Flow of 
Aqueous Humor 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •33
Chronic Glaucoma 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •34
Acute Glaucoma 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •35
Cataracts 
 Progressive opacity or clouding of the lens 
 Interferes with light transmission 
 Size, site, and density ...
Appearance of Eye with Cataract 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •37
Cataracts (Cont.) 
 Blurred vision over visual field 
 Becomes darker with time 
 Night driving especially difficult 
...
Detached Retina 
 Acute emergency 
 Retina tears away from underlying choroid 
 Retinal ischemia can lead to irreversib...
Detached Retina (Cont.) 
 Tear allows vitreous humor to flow behind 
retina 
 Increasing portion of the retina is lifted...
Macular Degeneration 
 Age-related macular degeneration (AMD) 
 Common cause of visual loss in older adults 
 Combinati...
Normal Vision 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •42
Age-Related Macular 
Degeneration 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •43
Parts of the Ear 
 External ear 
 Pinna and external auditory meatus (canal) 
 Middle ear 
 Tympanic membrane 
 Bony ...
Structure of the Ear 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •45
Pathway of Sound 
 Sound waves enter the external ear canals. 
 Vibration of the tympanic membrane causes 
the ossicles ...
Semicircular Canals 
 Three structures at right angles with each 
other 
 Crista ampullaris of each semicircular canal 
...
Hearing Loss 
 Two types 
 Conduction deafness 
• Sound is blocked in the external ear or middle ear. 
• Accumulation of...
Hearing Loss (Cont.) 
 Newborns are screened for hearing deficits. 
 Audiologists and otolaryngologists for consultation...
Cochlear Implant 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •50
Terminology 
 Deaf—congenital 
hearing deficit 
 Deafened— 
acquired hearing 
deficit 
 “Hearing-impaired” 
preferred t...
Ear Infections: Otitis Media 
 Inflammation or infection of the middle ear 
 Exudate builds up in cavity 
 Causes press...
Ear Infections 
 May spread along nasopharynx and 
respiratory structures 
 Caused by Haemophilus influenzae 
 Particul...
Ear Infections (Cont.) 
 May be asymptomatic in chronic stages 
 Most often—severe pain or earache 
 Tympanic membrane ...
Ear Infections (Cont.) 
 Treatment 
 Ibuprofen or acetaminophen to reduce discomfort 
in first 48 hours 
 Use of antiba...
Normal Tympanic Membrane 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •56
Tympanic Membrane 
with Otitis Media 
•Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •57
Otitis Externa 
 Also called swimmer’s ear 
 Usually bacterial (Pseudomonas aeruginosa) 
 May be fungal 
 Infection of...
Chronic Disorders of the Ear 
 Otosclerosis 
 Imbalance in bone formation and resorption 
 Development of excess bone i...
Chronic Disorders of the Ear 
(Cont.) 
 Meniere’s syndrome 
 Inner ear labyrinth disorder causing severe vertigo 
and na...
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Chapter 015

  1. 1. Chapter 15 Disorders of the Eyes, Ears and Other Sensory Organs
  2. 2. Sensory Receptors  Classified into two major categories  General senses  Special senses • Include the eye and ear •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •2
  3. 3. Sensory Receptors by Location  Exteroceptors  Located close to body surface (cutaneous receptors) • Examples—touch, pressure, temperature, pain  Visceroreceptors  Located internally around the viscera  Proprioceptors  Muscle sense •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •3
  4. 4. Sensory Receptors by Stimuli  Mechanoreceptors  Stimulated by mechanical force(s) • Touch, pressure, equilibrium, hearing  Chemoreceptors  Change in chemical concentration • Taste, smell  Thermoreceptors  Stimulated by change in the temperature • Warm and cold receptors •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •4
  5. 5. Sensory Receptors by Stimuli (Cont.)  Photoreceptors  Respond to light • Rods and cones in the retina (eye)  Nociceptors  Respond to any tissue damage • Results in pain  Osmoreceptors  Recognize changes in the osmolarity of body fluids • Concentrated in the hypothalamus •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •5
  6. 6. Eye  Light rays enter the eye through the cornea.  Pass through the lens to the receptor cells of the retina  Rods—black and white vision  Cones—color vision  Visual stimuli are conducted by the optic nerve to the occipital lobe.  Interpretation and processing • Information sent to other appropriate areas of the brain •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •6
  7. 7. Protection for the Eye  Protected by bony orbit of the skull  Bony protection of the eye  Eyelids and eyelashes  Deflect foreign material from eyes  Protect against excessive sunlight and drying  Conjunctiva  Mucous lining of eyelids  Covers sclera •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •7  Tears  Produced by lacrimal glands  Contain lysozyme—antibacterial enzyme
  8. 8. Muscles of the Eyeball  Six extraocular skeletal muscles for movement of the eyeball  Muscles controlled by cranial nerves (CNs) III and IV •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •8
  9. 9. Eyeball  Outer layer  Touch fibrous coat  Posterior portion—sclera • “White” of the eye  Anterior portion—cornea • Transparent portion • Light rays pass and are refracted • Does not contain blood vessels • Nourished by fluids around it • Oxygen diffusing from atmosphere •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •9
  10. 10. Eyeball (Cont.)  Middle layer—uvea  Choroid—dark vascular layer interior to the sclera  Absorbs scattered light  Located in anterior segment of the eyeball • Choroid is specialized as ciliary body that controls shape of the crystalline lens > accommodation for focus • Iris is pigmented muscle of pupil  Dilation occurs as a result of increased sympathetic nervous system (SNS) activity.  Constriction occurs as a result of increased parasympathetic nervous system (PNS) activity. •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •10
  11. 11. Eyeball (Cont.)  Inner layer—retina  Contains no pain receptors  Multilayered—in posterior two thirds of the eye  Photoreceptor cells • Rods—dim light, night vision (black and white) • Cones—color vision  Fovea centralis • Cones for most acute vision •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •11
  12. 12. Structure of the Eye •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •12
  13. 13. Fluids in the Eye  Posterior cavity  Space between lens and retina  Contains vitreous humor • Formed during embryonic development  Anterior cavity  Between cornea and lens  Divided into the anterior chamber and the posterior chamber  Filled with aqueous humor • Amount formed should be equal to the amount reabsorbed—maintenance of normal intraocular pressure (IOP) below 24 mm Hg •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •13
  14. 14. Visual Pathway  Light rays pass through cornea  Refraction of rays  Through aqueous humor and pupil  To the retina (rods and cones)  Nerve fibers form the optic nerve (CN II)  Nerve fibers of the ganglion cells of the retina  Optic chiasm  Fibers cross  Left occipital lobes receive images from right visual fields, right occipital lobes from left visual fields  Perception occurs in visual sensory and association areas of the occipital lobes of the cortex. •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •14
  15. 15. Visual Pathway •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •15
  16. 16. Diagnostic Tests  Snellen chart (or similar test)  Measures visual acuity  Visual field test  Checks for central and peripheral vision  Tonometry  Assessment of IOP  Ophthalmoscope  Examines internal structures  Gonioscopy—determines angle of anterior chamber  Muscle function and coordination tests •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •16
  17. 17. Structural Defects of the Eye •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •17  Myopia  Nearsightedness  Image focused in front of the lens  Hyperopia  Farsightedness  Eyeball is too short  Image focused behind the retina  Presbyopia  Farsightedness associated with aging  Loss of elasticity reduces accommodation
  18. 18. Refraction Defects in the Eye: Myopia •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •18
  19. 19. Refraction Defects in the Eye: Hyperopia •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •19
  20. 20. Structural Defects of the Eye (Cont.)  Astigmatism  Irregular curvature in the cornea or lens  Strabismus (squint or cross-eye)  Results from deviation of one eye  Double vision (diplopia)  May be caused by weak or hypertonic muscle, short muscle, neurological defect  In children • Must be treated immediately to prevent development of amblyopia •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •20
  21. 21. Functional Changes  Nystagmus  Involuntary abnormal movement of one or both eyes  May result from neurological causes, inner ear or cerebellar disturbances, drug toxicity  Diplopia (double vision)  May be caused by trauma to cranial nerves, resulting in paralysis of extraocular muscles  May occur in stroke  Loss of depth perception occurs. •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •21
  22. 22. Infections and Trauma •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •22  Stye  Infection involving a hair follicle on the eyelid  Usually caused by staphylococci  Swollen, red mass forms on eyelid  Purulent exudate  Other infections  Conjunctivitis, or “pink eye”  Trachoma  Keratitis
  23. 23. Conjunctivitis  Superficial inflammation or infection  Allergens, irritating chemicals, bacteria, viruses  Redness, itching, excessive tearing  Involves the conjunctiva lining of eyelids  Pink eye—Staphylococcus aureus  Frequently occurs in children  Sclera and eyelid appear red; purulent discharge  Spread by fingers or contaminated towels • Occurs with contact lens use, contaminated makeup, contaminated medication  Antibiotic treatment to prevent damage to cornea •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •23
  24. 24. Conjunctivitis (Cont.)  Other causes  Chlamydia trachomatis and Neisseria gonorrhoeae  Both cause infections in the reproductive tract.  May infect eyes of newborns  May be transferred by self-inoculation •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •24
  25. 25. Gonococcal Conjunctivitis •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •25
  26. 26. Pseudomonas aeruginosa Around Soft Contact Lens •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •26
  27. 27. Bacteria Recovered from Contact Lenses and Solutions •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •27
  28. 28. Trachoma  Caused by Chlamydia trachomatis  Follicles develop on inner surface of eyelids  Can occur in any age group  “Scratchy” eye  Antibiotic treatment  Globally, most common cause of vision loss where water is scarce and inadequate hygiene occurs  Scarring of lid leads to eyelashes abrading cornea → loss of transparency •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •28
  29. 29. Keratitis  Severe pain and photophobia  Develops when cornea is infected or irritated  Herpes simplex can be cause • Transfer from herpes lesion around mouth • Transfer by fingers, dental office, spray of contaminated saliva  Keratitis—increased risk of ulceration eroding the cornea  Scar tissue formation interferes with vision.  Trauma to cornea  Damage from chemicals, splashes, fumes •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •29
  30. 30. Glaucoma  Result of increased IOP caused by excessive accumulation of aqueous humor  Most common and preventable loss of vision in developed countries  May be acute or chronic  Signs and symptoms  Halos around lights at night  Loss of peripheral vision  Pain may occur if IOP is greatly increased, as in acute form •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •30
  31. 31. Acute Glaucoma  Acute or narrow-angle glaucoma  Angle between cornea and iris is decreased.  May be caused by aging, developmental abnormalities, or scar tissue from trauma or infection • Iris pushed forward and to side • May block the outflow of aqueous humor • Sudden marked increase in IOP • May be triggered by pupil dilation • Treatment may include surgery. •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •31
  32. 32. Glaucoma (Cont.)  Chronic or open-angle glaucoma  Higher incidence after age 50 years  Thickening of trabecular network, which allows for resorption of fluid  Has insidious onset  Pressure increases over time • May cause ischemia and damage to the retinal cells • If pressure continues to increase, damage to the optic nerve occurs. • Irreversible, eventually can cause blindness  Treated by regular administration of eye drops •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •32
  33. 33. Glaucoma: Normal Flow of Aqueous Humor •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •33
  34. 34. Chronic Glaucoma •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •34
  35. 35. Acute Glaucoma •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •35
  36. 36. Cataracts  Progressive opacity or clouding of the lens  Interferes with light transmission  Size, site, and density of clouding vary among individuals.  May be different in individual’s two eyes  Changes may be  Age-related or caused by metabolic abnormalities  Excessive exposure to sunlight  Congenital  Traumatic •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •36
  37. 37. Appearance of Eye with Cataract •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •37
  38. 38. Cataracts (Cont.)  Blurred vision over visual field  Becomes darker with time  Night driving especially difficult  Rate of impairment varies.  One eye’s cataract may develop faster than the other’s.  May interfere with person’s ability to function or work  Outpatient surgery involves lens replacement. •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •38
  39. 39. Detached Retina  Acute emergency  Retina tears away from underlying choroid  Retinal ischemia can lead to irreversible loss of receptors.  No pain or discomfort  Visual field contains areas of blackness (scotomas), as if a curtain has fallen over the eye. •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •39
  40. 40. Detached Retina (Cont.)  Tear allows vitreous humor to flow behind retina  Increasing portion of the retina is lifted away form the choroid  Retinal cells cease to function.  Surgical intervention  Reattachment of retina •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •40
  41. 41. Macular Degeneration  Age-related macular degeneration (AMD)  Common cause of visual loss in older adults  Combination of genetic factors and environmental exposure  Dry or atrophic  More common—deposits form in retinal cells  Wet or exudative  Neovascularization  Central vision becomes blurred, then lost  New therapies being investigated •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •41
  42. 42. Normal Vision •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •42
  43. 43. Age-Related Macular Degeneration •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •43
  44. 44. Parts of the Ear  External ear  Pinna and external auditory meatus (canal)  Middle ear  Tympanic membrane  Bony ossicles  Auditory tube connects to upper respiratory tract •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •44  Inner ear  Cochlea • Organ of Corti—hearing  Semicircular canals • Balance and equilibrium
  45. 45. Structure of the Ear •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •45
  46. 46. Pathway of Sound  Sound waves enter the external ear canals.  Vibration of the tympanic membrane causes the ossicles to vibrate.  Motion of stapes against oval window initiates movement of the fluid in the cochlea.  Stimulation of hair cells in organ of Corti  Initiation of nerve impulses  Impulses conducted to the auditory area in the temporal lobe of cerebral cortex for interpretation of sound •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •46
  47. 47. Semicircular Canals  Three structures at right angles with each other  Crista ampullaris of each semicircular canal  Contain receptor hair cells  Stimulated by motion of the endolymph in response to head movements  Stimuli conducted by vestibular branch of the auditory nerve to cerebellum and medulla •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •47
  48. 48. Hearing Loss  Two types  Conduction deafness • Sound is blocked in the external ear or middle ear. • Accumulation of wax, foreign object, scar tissue • Otosclerosis of the ossicles  Sensorineural impairment • Damage to the organ of Corti or auditory nerve • Infection • Head trauma • Neurological disorders • Ototoxic drugs • Sudden very loud sounds or prolonged exposure to loud noise • Presbycusis and congenital defects •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •48
  49. 49. Hearing Loss (Cont.)  Newborns are screened for hearing deficits.  Audiologists and otolaryngologists for consultation  Hearing aids  Used if appropriate for individual hearing deficit  Cochlear implants  Used successfully in some cases of sensorineural loss •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •49
  50. 50. Cochlear Implant •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •50
  51. 51. Terminology  Deaf—congenital hearing deficit  Deafened— acquired hearing deficit  “Hearing-impaired” preferred to “hard of hearing” •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •51
  52. 52. Ear Infections: Otitis Media  Inflammation or infection of the middle ear  Exudate builds up in cavity  Causes pressure on tympanic membrane  Auditory tube may be obstructed by inflammation • May cause rupture of the tympanic membrane  Prolonged infection is likely to produce scar tissue and adhesion. • Can lead to permanent conductive hearing loss or speech problems  Chronic infection may lead to mastoiditis. • Infection involving mastoid cells of temporal bone •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •52
  53. 53. Ear Infections  May spread along nasopharynx and respiratory structures  Caused by Haemophilus influenzae  Particularly in young children  Pneumococci, b-hemolytic streptococci, staphylococci  Viral infections also common  Frequently complicated by secondary bacterial infections •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •53
  54. 54. Ear Infections (Cont.)  May be asymptomatic in chronic stages  Most often—severe pain or earache  Tympanic membrane red and bulging  Mild hearing loss or feeling of fullness  Fever, nausea might be present •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •54
  55. 55. Ear Infections (Cont.)  Treatment  Ibuprofen or acetaminophen to reduce discomfort in first 48 hours  Use of antibacterials if bacterial infection  Decongestant may be useful in draining auditory tube  Surgery may be done to Insert temporary tubes in tympanic membrane to allow for drainage. •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •55
  56. 56. Normal Tympanic Membrane •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •56
  57. 57. Tympanic Membrane with Otitis Media •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •57
  58. 58. Otitis Externa  Also called swimmer’s ear  Usually bacterial (Pseudomonas aeruginosa)  May be fungal  Infection of the external auditory canal and pinna  Often associated with swimming  Irritation when cleaning ear  Frequent use of earphones or earplugs  Pain usually increased with movement of pinna  Purulent discharge and hearing deficit •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •58
  59. 59. Chronic Disorders of the Ear  Otosclerosis  Imbalance in bone formation and resorption  Development of excess bone in middle ear cavity • Stapes becomes fixed to oval window.  Blockage of conduction sounds to cochlea  May be caused by genetic or environmental factors  Treatment—surgical removal of stapes and replacement prosthesis to restore hearing •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •59
  60. 60. Chronic Disorders of the Ear (Cont.)  Meniere’s syndrome  Inner ear labyrinth disorder causing severe vertigo and nausea  Intermittent, with remissions and exacerbations  Excessive endolymph produced  Attack may last minutes or hours • Change in barometric pressure may precipitate an attack  Balance test, electronystagmography, electrocochleography, MRI  Treatment with drugs • Home exercise programs to reduce sensitivity to motion •Copyright © 2014, 2011, 2006 by Saunders, an imprint of Elsevier, Inc. •60

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