Chapter 16 - Ears
List 3 functions of the middle ear
(1) it conducts sound vibrations from the outer ear to the central hearing apparatus in the inner ear; (2) it protects the inner ear by reducing the amplitude of loud sounds; (3) its eustachian tube allows equalization of air pressure on each side of the tympanic membrane so the membrane does not rupture (e.g., during altitude changes in an airplane).
Abnormalities of the tympanic membrane
- Yellow-amber drum color occurs with OM with effusion (serous). - Red color with acute OM. - Absent or distorted landmarks. - Air/fluid level or air bubbles behind drum indicate OM with effusion - Retracted drum due to vacuum in middle ear with obstructed eustachian tube. - Bulging drum due to increased pressure in OM. - Perforation shows as a dark oval area or as a larger opening on the drum. - Vesicles on drum
Inner ear
- embedded in bone. - contains the bony labyrinth, which holds the sensory organs for equilibrium and hearing. - within the bony labyrinth, the vestibule and the semicircular canals comprise the vestibular apparatus, and the cochlea contains the central hearing apparatus. - although the inner ear is not accessible to direct examination, you can assess its functions.
Middle ear
- tiny air-filled cavity inside the temporal bone. - contains tiny ear bones, or auditory ossicles: the malleus, incus, and stapes. - has several openings. Its opening to the outer ear is covered by the tympanic membrane. The openings to the inner ear are the oval window at the end of the stapes and the round window. Another opening is the eustachian tube, which connects the middle ear with the nasopharynx and allows passage of air. The tube is normally closed, but it opens with swallowing or yawning.
Ear examination
1. Inspect external ear: Size and shape of auricle Position and alignment on head Note skin condition—Color, lumps, lesions Check movement of auricle and tragus for tenderness Evaluate external auditory meatus—Note size, swelling, redness, discharge, cerumen, lesions, foreign bodies 2. Otoscopic examination: External canal Cerumen, discharge, foreign bodies, lesions Redness or swelling of canal wall 3. Inspect tympanic membrane: Color and characteristics Note position (flat, bulging, retracted) Integrity of membrane 4. Test hearing acuity: Note behavioral response to conversational speech Whispered voice test
Branchial Remnant and Ear Deformity
A facial remnant or leftover of the embryologic branchial arch usually appears as a skin tag; in this case, one containing cartilage. Occurs most often in the preauricular area, in front of the tragus. When bilateral, there is increased risk for renal anomalies.
How should the whispered voice test be conducted?
A whisper is a high-frequency sound and is used to detect high-tone loss. - Stand arm's length (2 feet) behind the person. Test one ear at a time while masking hearing in the other ear to prevent sound transmission around the head. This is done by placing one finger on the tragus and pushing it in and out of the auditory meatus. - Move your head to 1 to 2 feet from the person's ear. Exhale fully and whisper slowly a set of 3 random numbers and letters, such as "5, B, 6." Normally the person repeats each number/letter correctly after you say it. - If the response is not correct, repeat the whispered test using a different combination of 3 numbers and letters. A passing score is correct repetition of 4 of a possible 6 numbers/letters. - Assess the other ear using yet another set of whispered items "4, K, 2."
What is presbycusis and what is it associated with?
Age-related hearing loss (presbycusis) is documented in 2/3 of adults over 70 years of age and is associated with communication problems, a decrease in health-related quality of life, and a loss of physical and cognitive function, as well as depression, dementia, an increase in falls, an increase in hospitalizations, social isolation and loneliness, and increased mortality. It is a sensorineural loss that affects the middle ear structures or causes damage to nerve cells in the inner ear or to cranial nerve VIII. The person first notices a high-frequency tone loss, such as difficulty hearing a phone ringing or a microwave beeping. Also it is harder to hear consonants than vowels, and words sound garbled. The ability to localize sound is impaired. This hearing loss is accentuated with competing background noise (e.g., with music, with dishes clattering, or at a large, noisy party).
Otitis Externa (Swimmer's Ear)
An infection of the outer ear, with severe painful movement of the pinna and tragus, redness and swelling of pinna and canal, scanty purulent discharge, scaling, itching, fever, and enlarged tender regional lymph nodes. Hearing normal or slightly diminished. More common in hot, humid weather. Swimming causes canal to become waterlogged and swell; skinfolds set up for infection. Prevent by using rubbing alcohol or 2% acetic acid eardrops after every swim.
Cholesteatoma
An overgrowth of epidermal tissue in the middle ear or temporal bone may result over the years after a marginal TM perforation. It has a pearly white, cheesy appearance. Growth of cholesteatoma can erode bone and produce hearing loss. Early signs include otorrhea, otalgia, unilateral conductive hearing loss, tinnitus.
A common cause of conductive hearing loss is: a. Impacted cerumen b. Acute rheumatic fever c. A CVA d. Otitis externa
Answer: A
While discussing the history of a 6-month-old infant, the mother tells the nurse that she took a significant amount of aspirin while she was pregnant. What question would the nurse want to include in the history? a. "Does your baby seem to startle with loud noises?" b. "Has your baby had any surgeries on her ears?" c. "Have you noticed any drainage from her ears?" d. "How many ear infections has your baby had since birth?"
Answer: A "Does your baby seem to startle with loud noises?" Children exposed in utero to a variety of conditions, such as maternal rubella or to maternal ototoxic drugs are at risk for hearing deficits. Aspirin can be ototoxic, so the nurse should ask if the baby seems to startle with loud noises.
The nurse is assessing a patient who may have hearing loss. Which of these statements is true concerning air conduction? a. Air conduction is the normal pathway for hearing. b. Amplitude of sound determines the pitch that is heard. c. Vibrations of the bones in the skull cause air conduction. d. Loss of air conduction is called a conductive hearing loss.
Answer: A Air conduction is the normal pathway for hearing. The normal pathway of hearing is air conduction, which starts when sound waves produce vibrations on the tympanic membrane. Conductive hearing loss results from a mechanical dysfunction of the external or middle ear. The other statements are not true concerning air conduction. The frequency of sound waves is what determines pitch, not the amplitude. Vibrations of the bones in the skull are bone conduction, not air conduction. Conductive hearing loss involves mechanical dysfunction of the external or middle ear and is caused by impacted cerumen, foreign bodies, a perforated tympanic membrane, pus or serum in the middle ear, and otosclerosis, not loss of air conduction
The nurse suspects that a patient has otitis media. Early signs of otitis media include which of these findings of the tympanic membrane? a. Hypomobility b. Fiery red and bulging of entire eardrum c. Retraction with landmarks clearly visible d. Flat, slightly pulled in at the center, and moves with insufflation
Answer: A Hypomobility An early sign of otitis media is hypomobility of the tympanic membrane. As pressure increases, the tympanic membrane begins to bulge. A fiery red color and bulging of the entire eardrum is not an early sign of otitis media but occurs a little later. A retracted tympanic membrane with landmarks clearly visible indicates a blocked eustachian tube which is not an early sign of otitis media. A tympanic membrane that is flat, slightly pulled in at the center, and moves with insufflation is a normal eardrum, not a manifestation of otitis media.
The nurse is testing the hearing of a 78-year-old man and is reminded of the changes in hearing that occur with aging that include which of the following? (Select all that apply.) a. Progression of hearing loss is slow. b. The aging person has low-frequency tone loss. c. Sounds may be garbled and difficult to localize. d. Hearing loss r/t aging begins in the mid-40s. e. Hearing loss reflects nerve degeneration of the middle ear. f. The aging person may find it harder to hear consonants than vowels.
Answer: A, C, FI8
You are assessing a patient's tympanic membrane and suspect an infection of acute purulent otitis media. Which of the following findings supports this? a. Absent light reflex, bluish drum, oval dark areas b. Absent light reflex, reddened drum, bulging drum c. Oval dark areas on drum d. Absent light reflex, air-fluid level, or bubbles behind drum
Answer: B Absent light reflex, reddened drum, bulging drum
A 31-year-old patient tells the nurse that he has noticed a progressive loss in his hearing. He says that it does seem to help when people speak louder or if he turns up the volume of a television or radio. What is the most likely cause of this hearing loss? a. Presbycusis b. Otosclerosis c. Trauma to the bones d. Frequent ear infections
Answer: B Otosclerosis Otosclerosis is a common cause of conductive hearing loss in young adults between the ages of 20 and 40 years. Presbycusis is a type of hearing loss that occurs with aging. Trauma and frequent ear infections are not a likely cause of his hearing loss.
The sensation of vertigo may indicate: a. Otitis media b. Pathology in the semicircular canals c. Pathology in the cochlea d. IV cranial damage
Answer: B Pathology in the semicircular canals
A patient in her first trimester of pregnancy is diagnosed with rubella. Which of these statements is correct regarding the significance of this in relation to the infant's hearing? a. Rubella may affect the mother's hearing but not the infant's. b. Rubella can damage the infant's organ of Corti, which will impair hearing. c. Rubella can impair the development of cranial nerve VIII and thus affect hearing. d. Rubella is especially dangerous to the infant's hearing in the second trimester of pregnancy.
Answer: B Rubella can damage the infant's organ of Corti, which will impair hearing.
A patient has been identified as having a sensorineural hearing loss. What would be important for the nurse to do during the assessment of this patient? a. Speak loudly so the patient can hear the questions. b. Assess for middle ear infection as a possible cause. c. Ask the patient what medications he is currently taking. d. Look for the source of the obstruction in the external ear.
Answer: C Ask the patient what medications he is currently taking. Sensorineural hearing loss may be caused by presbycusis, which is a gradual nerve degeneration that occurs with aging and by ototoxic drugs, which affect the hair cells in the cochlea. A simple increase in amplitude may not enable the person to understand spoken words. The middle ear and obstruction of the external ear are not associated with sensorineural hearing loss so the nurse should not assess for a middle ear infection or external ear obstruction.
A patient with a middle ear infection asks the nurse, "What does the middle ear do?" Which is the best response by the nurse? a. It helps maintain balance. b. It interprets sounds as they enter the ear. c. It conducts vibrations of sounds to the inner ear. d. It increases the amplitude of sound for the inner ear to function.
Answer: C It conducts vibrations of sounds to the inner ear. The inner ear, not the middle ear, helps with balance. Sound is interpreted in the cerebral cortex, not the middle ear. The middle ear reduces the amplitude of loud sounds, not increase them, to protect the inner year. The functions of the middle ear are to conduct sound vibrations from the outer ear to the central hearing apparatus in the inner ear; protect the inner ear by reducing the amplitude of loud sounds; and allow equalization of air pressure on each side of the tympanic membrane via the eustachian tubes so that the membrane does not rupture.
During an interview, the patient states he has the sensation that "everything around him is spinning." What part of the ear should the nurse recognize is responsible for this sensation? a. Cochlea b. CN VIII c. Labyrinth d. Organ of Corti
Answer: C Labyrinth If the labyrinth of the ear becomes inflamed, it feeds the wrong information to the brain, creating a staggering gait and a strong, spinning, whirling sensation called vertigo. The cochlea, which contains the central hearing apparatus, and cranial nerve VIII, the vestibulocochlear nerve, which conducts nerve impulses from the organ of Corti to the brain, are all involved with hearing.
A 70-year-old patient tells the nurse that he has noticed that he is having trouble hearing, especially in large groups. He says "I can't always tell where the sound is coming from" and that the words often sound "mixed up." What might the nurse suspect as the cause for this change? a. Atrophy of the apocrine glands b. Cilia becoming coarse and stiff c. Nerve degeneration in the inner ear d. Scar tissue in the tympanic membrane
Answer: C Nerve degeneration in the inner ear Presbycusis is a type of hearing loss that occurs in 60% of those older than 65 years of age, even in those living in a quiet environment. This sensorineural loss is gradual and caused by nerve degeneration in the inner ear. Words sound garbled, and the ability to localize sound is also impaired. This communication dysfunction is accentuated when background noise is present. Atrophy of the apocrine glands causes cerumen to be more dry and cilia becoming coarse and stiff may cause cerumen to accumulate and oxidize and reduce hearing but they do cause this patient's symptoms of not being able to locate the source of sounds or sounds being mixed up. Scarring of the tympanic eardrum are sequelae of repeated ear infections but do not necessarily affect hearing.
The nurse is preparing to perform an otoscopic examination of a newborn infant. Which statement is true regarding this examination? a. An injected membrane may indicate an infection. b. The eardrum will appear in the oblique position. c. The normal membrane may appear thick and opaque. d. The appearance of the membrane is identical to that of an adult.
Answer: C The normal membrane may appear thick and opaque. During the first few days after birth, the tympanic membrane of a newborn often appears thickened and opaque. It may look injected and have a mild redness from increased vascularity. The eardrum of a neonate is more horizontal, making it more difficult to see completely. By one month of age the drum is in the oblique (more vertical) position as in the adult.
During an examination, the patient states he is hearing a buzzing sound and says that it is "driving me crazy!" What does this indicate? a. Vertigo b. Pruritus c. Tinnitus d. Cholesteatoma
Answer: C Tinnitus Tinnitus is a sound that comes from within a person; it can be a ringing, crackling, or buzzing sound. It accompanies some hearing or ear disorders. Vertigo is a strong spinning, whirling sensation; pruritus is itching; and cholesteatoma is an overgrowth of epidermal tissue in the middle ear or temporal bone that has a pearly white, cheesy appearance.
The nurse is reviewing the function of the cranial nerves (CNs). Which CN is responsible for conducting nerve impulses to the brain from the organ of Corti? a. I b. III c. VIII d. XI
Answer: C VIII (Vestibulocochlear nerve) Cranial nerve I, the olfactory nerve, is responsible for the sense of smell. Cranial nerve III, the oculomotor, innervates the superior, inferior, and medial rectus and the inferior oblique muscles of the eye. Cranial nerve XI, the accessory nerve, controls the muscles of the neck
The nurse is taking the history of a patient who may have a perforated eardrum. What would be an important question in this situation? a. "Do you ever notice ringing or crackling in your ears?" b. "When was the last time you had your hearing checked?" c. "Have you ever been told that you have any type of hearing loss?" d. "Is there any relationship between the ear pain and the discharge you mentioned?"
Answer: D "Is there any relationship between the ear pain and the discharge you mentioned?" Typically with perforation, ear pain occurs first and resolves after a popping sensation, then drainage occurs.
A 31-year-old patient tells the nurse that he has noticed pain in his left ear when people speak loudly to him. What does this finding indicate? a. A cerumen impaction b. Normal for people of his age c. Possible middle ear infection d. A characteristic of recruitment
Answer: D A characteristic of recruitment Recruitment is significant hearing loss occurring when speech is at low intensity, but sound actually becomes painful when the speaker repeats at a louder volume. A cerumen impaction and ear infection do not cause these symptoms and these are not normal findings.
The hearing receptors are located in which region? a. Vestibule b. Semicircular canals c. Middle ear d. Cochlea
Answer: D Cochlea
The nurse is conducting a child safety class for new mothers. Which factor places young children at risk for ear infections? a. Family history b. Air conditioning c. Excessive cerumen d. Passive cigarette smoke
Answer: D Passive cigarette smoke Exposure to passive and gestational smoke is a risk factor for ear infections in infants and children. A family history of ear infections, air conditioning, or excessive cerumen are at not risk factors for ear infections.
How should the nurse perform an examination of a 2-year-old child with a suspected ear infection? a. Pull the ear up and back before inserting the speculum. b. Omit the otoscopic examination if the child has a fever. c. Ask the mother to leave the room while examining the child. d. Perform the otoscopic examination at the end of the assessment.
Answer: D Perform the otoscopic examination at the end of the assessment. In addition to its place in the complete examination, eardrum assessment is mandatory for any infant or child requiring care for an illness or fever. For the infant or young child, the timing of the otoscopic examination is best toward the end of the complete examination because many young children protest vigorously during this procedure and it is difficult to re-establish cooperation afterward. When performing an ear examination on a 2-year-old child, with or without a suspected ear infection, the pinna should be pulled down (not up) and back. Rather than asking the parent to leave the room, the nurse should enlist the parent's help in holding the child to protect the eardrum from injury
During an examination, the nurse notices that the patient stumbles a little while walking, and, when she sits down, she holds on to the sides of the chair. The patient states, "It feels like the room is spinning!" What do this signs and symptoms indicate? a. Tinnitus b. Dizziness c. Objective vertigo d. Subjective vertigo
Answer: Objective vertigo With objective vertigo, the patient feels like the room spins; with subjective vertigo, the person feels like he or she is spinning.
Polyp
Arises in canal from granulomatous or mucosal tissue; redder than surrounding skin and bleeds easily; bathed in foul, purulent discharge; indicates chronic ear disease. Benign but refer for excision.
Romberg Test
Assesses the ability of the vestibular apparatus in the inner ear to help maintain standing balance, as well as the intactness of the cerebellum and proprioception. - ask patient to stand with feet at comfortable distance apart, arms at sides, and eyes closed - expected finding: client should be able to stand with minimal swaying for at least 5 seconds
When does the inner ear start developing?
At the 5th week of gestation
What does frank blood or clear, watery drainage (cerebrospinal fluid [CSF]) after head injury suggest?
Basal skull fracture, which warrants immediate referral.
Why isn't the otoscopic examination performed at birth?
Because at birth the canal is filled with amniotic fluid and vernix caseosa. After a few days the TM is examined. During the first few days it often looks thickened and opaque. It may look "injected," meaning having a mild redness from increased vascularity. The eardrum also looks injected in infants after crying.
Blue or dark red color on eardrum/tympanic membrane
Blood behind drum. Trauma, skull fracture
Absent or distorted light reflex on eardrum/tympanic membrane
Bulging of eardrum. May indicate acute OM.
Otosclerosis
Cause of conductive hearing loss in young adults between the ages of 20 and 40 years. It is a gradual bone formation that causes the footplate of the stapes to become fixed in the oval window, impeding the transmission of sound and causing progressive deafness.
Fungal Infection (Otomycosis)
Colony of black or white dots on drum or canal wall suggests a yeast or fungal infection.
Black or white dots on drum or canal
Colony of growth. Fungal infection.
What is the best indicator of OM in the newborn's first 6 weeks?
Drum immobility is the best indicator of middle ear infection for the newborn's first 6 weeks. Drum mobility/vibratility can be assessed in an infant or a young child using a pneumatic bulb attachment, which enables you to direct a light puff of air toward the drum. Normally the TM moves inward with a slight puff and outward with a slight release. An abnormal response is no movement.
What does the eardrum look like in an older adult?
During otoscopy the eardrum normally may be whiter in color and more opaque, duller than in the younger adult. It also may look thickened.
Macrotia
Ears larger than 10 cm.
Microtia
Ears smaller than 4 cm vertically
Furuncle
Exquisitely painful, reddened, infected hair follicle. It may occur on tragus on cartilaginous part of ear canal. Regional lymphadenopathy often accompanies a furuncle.
Tympanostomy tubes
In a child being treated for chronic OM, you may note the presence of a tympanostomy tube in the central part of the eardrum. This is inserted surgically to equalize pressure and drain secretions.
Motions used to straighten the ear canal when using an otoscope in adults x infants
Infants: pull the pinna straight down on an infant or a child younger than 3 years Adult: pull pinna up and back
Bright red color on eardrum/tympanic membrane
Infection in middle ear. May indicate acute OM.
Cellulitis
Inflammation of loose, subcutaneous connective tissue. Shows as thickening and induration of auricle with distorted contours.
Otitis externa (OE)
Inflammation of the external auditory meatus; also known as "swimmer's ear" Redness and swelling occur with otitis externa; canal may be completely closed with swelling. Purulent otorrhea suggests otitis externa or OM if the drum has ruptured. A sticky, yellow discharge accompanies otitis externa or may indicate OM if the drum has ruptured. Pain with movement occurs with otitis externa and furuncle. Crusts and scaling may occur with otitis externa,
Conductive hearing loss
Involves a mechanical dysfunction of the external or middle ear. It is a PARTIAL loss because the person is able to hear if the sound amplitude is increased enough to reach normal nerve elements in the inner ear. Conductive hearing loss may be caused by impacted cerumen, foreign bodies, a perforated tympanic membrane, pus or serum in the middle ear, and otosclerosis (a decrease in mobility of the ossicles). **A mixed loss is a combination of conductive and sensorineural types in the same ear.
Sebaceous Cyst
Location is commonly behind lobule in the postauricular fold. A nodule with central black punctum indicates blocked sebaceous gland. It is filled with waxy sebaceous material and painful if it becomes infected. Often are multiple.
What does pain at the mastoid process indicate?
Mastoiditis or enlarged posterior auricular node.
Tuning fork test
Measure hearing by air conduction (AC) or bone conduction (BC), in which the sound vibrates through the cranial bones to the inner ear. The AC route through the ear canal and middle ear is usually the more sensitive route. If hearing loss is identified by history or whispered voice test, tuning fork tests traditionally were used to distinguish conductive loss from sensorineural loss. However, up to 40% of normal hearing people lateralize the Weber test, i.e., hear the tone louder in one ear. The Rinne (pronounced RIN-neh) test is more accurate in detecting conductive hearing loss. Be aware that neither test can distinguish normal hearing from a sensorineural loss in both ears—you should rely on audiometry. **NOTE THAT with documented hearing loss, tuning fork test may help distinguish conductive loss from sensorineural loss, but they cannot screen a conductive loss from a mixed conductive/sensorineural loss.
Exostosis
More common than osteoma. Small, bony hard, rounded nodules of hypertrophic bone, covered with normal epithelium. Arise near the drum but usually do not obstruct the view of the drum. Usually multiple and bilateral, occur more frequently in cold-water swimmers. Needs no treatment, although may cause accumulation of cerumen, which blocks the canal.
Otitis media (OM) or middle ear infection
Occurs because of obstruction of the eustachian tube or passage of nasopharyngeal secretions into the middle ear. This creates a ripe environment for bacteria to grow. Acute OM is so common that up to 60% of children experience an episode during the 1st year of life, and by age 3 years up to 83% have suffered an episode. Risk factors (besides the anatomy of the eustachian tube): absence of breastfeeding in the first 3 months of age, preterm birth, exposure to secondhand tobacco smoke (SHS), daycare attendance, male sex, pacifier use, seasonality (fall and winter), and bottle-feeding
Equipment needed for ear examination
Otoscope with bright light (fresh batteries give off white—not yellow—light). Pneumatic bulb attachment, sometimes used with infant or young child.
Keloid
Overgrowth of scar tissue, which invades original site of trauma. It is more common in darkly pigmented people, although it also occurs in whites. In the ear it is most common at lobule at site of a pierced ear. Overgrowth shown here is unusually large.
Chondrodermatitis Nodularis Helicus
Painful nodules develop on rim of helix (where there is no cushioning subcutaneous tissue) as a result of repetitive mechanical pressure or environmental trauma (sunlight). They are small, indurated, dull red, poorly defined, and very painful.
Dark, round or oval areas on eardrum/tympanic membrane
Perforation. Drum rupture.
What is the most important side effect of acute OM (otitis media)?
Persistence of fluid in the middle ear after treatment. This middle ear effusion can impair hearing, placing the child at risk for delayed cognitive development.
Preparation for ear examination
Position the adult sitting up straight with his or her head at your eye level. Occasionally the ear canal is partially filled with cerumen, which obstructs your view of the TM. If the eardrum is intact and no current infection is present, a preferred method of cleaning the adult canal is to soften the cerumen with a warmed solution of mineral oil and hydrogen peroxide. Then the canal is irrigated with warm water (body temperature) with a bulb syringe or a low-pulsatile dental irrigator (Water-Pik). Direct fluid to the posterior wall. Leave space around the irrigator tip for water to escape. Do not irrigate if the history or examination suggests perforation or infection.
Frostbite
Reddish-blue discoloration and swelling of auricle after exposure to extreme cold. Vesicles or bullae may develop, the person feels pain and tenderness, and ear necrosis may ensue.
Prominent landmarks on eardrum/tympanic membrane
Retraction of drum. May indicate vacuum in middle ear from obstructed eustachian tube.
White dense areas on eardrum/tympanic membrane
Scarring. Indicates sequelae of infections.
How do you screen for a hearing deficit?
Screening for a hearing deficit begins during the history; "Do you have difficulty hearing now?" If the answer is yes, perform audiometric testing or refer for audiometric testing. If the answer is no, screen using the whispered voice test.
Air/fluid level or air bubbles on eardrum/tympanic membrane
Serous fluid. May indicate OM with effusion
Yellow-amber color on eardrum/tympanic membrane
Serum or pus. May indicate otitis media with effusion (OME) or chronic otitis media.
Sensorineural/perceptive hearing loss
Signifies pathology of the inner ear, cranial nerve VIII, or the auditory areas of the cerebral cortex. A simple increase in amplitude may not enable the person to understand words. Sensorineural hearing loss may be caused by presbycusis, a gradual nerve degeneration that occurs with aging, and by ototoxic drugs, which affect the hair cells in the cochlea. **A mixed loss is a combination of conductive and sensorineural types in the same ear.
Osteoma
Single, stony hard, rounded nodule that obscures the drum; nontender; overlying skin appears normal. Attached to inner third, the bony part, of canal. Benign, but refer for removal.
Bullous Myringitis
Small vesicles containing blood are on the eardrum; it occurs with mycoplasma pneumonia and viral infections. Blood-tinged discharge and severe otalgia may be present.
Darwin tubercle
Small, painless nodule at the helix. This is a congenital variation and is not significant
Tophi
Small, whitish yellow, hard, nontender nodules in or near helix or antihelix; contain greasy, chalky material of uric acid crystals and are a sign of gout.
Sequela of repeated ear infections
Some adults may show scarring, which is a dense white patch on the drum.
How should the audiometric test be conducted?
The audiometric test is used to assess and diagnose conductive and sensorineural loss. An audiometer gives a precise quantitative measure of hearing by assessing the person's ability to hear sounds of varying frequency. A pure tone audiometer gives a precise quantitative measure of hearing by assessing the person's ability to hear sounds of varying frequency. This is a battery-powered, lightweight, handheld instrument that is available in most outpatient settings. - With the patient sitting, prop his or her elbow on the armrest of the chair with the hand making a gentle fist. Tell the patient, "You will hear faint tones of different pitches. Please raise your finger as soon as you hear the tone; then lower your finger as soon as you no longer hear the tone." - Choose tones of random loudness in decibels on the audioscope. Each tone is on for 1.5 seconds and off for 1.5 seconds. - Test each ear separately and record the results.
How does binaural interaction function and what part of the brain is responsible for it?
The brain stem. Binaural interaction permits locating the direction of a sound in space and identifying the sound. Each ear is actually one half of the total sensory organ. The ears are located on each side of a movable head. Cranial nerve VIII from each ear sends signals to both sides of the brainstem. Areas in the brainstem are sensitive to differences in intensity and timing of the messages from the two ears, depending on the way the head is turned.
What makes the visualization of the tympanic membrane more difficult in the neonate?
The eardrum is more horizontal in the neonate, making it more difficult to see completely and harder to differentiate from the canal wall. By 1 month of age the drum is in the oblique (more vertical) position as in the older child, and examination is a bit easier
Most efficient hearing pathway: air conduction (AC)
The function of hearing involves the auditory system at three levels: peripheral, brainstem, and cerebral cortex. 1) At the PERIPHERAL level the ear transmits sound and converts its vibrations into electrical impulses, which can be analyzed by the brain. Amplitude is how loud the sound is; its frequency is the pitch or the number of cycles per second. The sound waves produce vibrations on the tympanic membrane, which are carried by the middle ear ossicles to the oval window. 2) Sound waves travel through the cochlea, and are dissipated against the round window. Along the way the basilar membrane vibrates at a point specific to the frequency of the sound. The numerous fibers along the basilar membrane are the receptor hair cells of the organ of Corti, the sensory organ of hearing. As the hair cells bend, they mediate the vibrations into electric impulses. 3) The electrical impulses are conducted by the auditory portion of cranial nerve VIII to the brainstem. 4) The function at the BRAINSTEM level is BINAURAL INTERACTION, which permits locating the direction of a sound in space and identifying the sound. 5) The function of the CORTEX is to interpret the meaning of the sound and begin the appropriate response.
What anatomic differences place the infant at greater risk for middle ear infections?
The infant's eustachian tube is relatively shorter and wider, and its position is more horizontal than the adult's, making it is easier for pathogens from the nasopharynx to migrate through to the middle ear. The lumen is surrounded by lymphoid tissue, which increases during childhood; thus the lumen is easily occluded. The infant's and the young child's external ear canals are shorter and have a slope opposite to that of the adult's.
What are the normal characteristics of the eardrum/tympanic membrane?
The normal eardrum is shiny and translucent, with a pearl gray color. The cone-shaped light reflex (from the otoscope) is prominent in the anteroinferior quadrant (at the 5 o'clock position in the right drum and the 7 o'clock position in the left drum). Sections of the malleus are visible through the translucent drum: the umbo, manubrium, and short process. (Infrequently you also may see the incus behind the drum; it shows as a whitish haze in the upper posterior area.) At the periphery the annulus looks whiter and denser.
Contrast 2 pathways of hearing
The normal pathway of hearing is air conduction (AC), the most efficient one. An alternate route of hearing is by bone conduction (BC). Here the bones of the skull vibrate. These vibrations are transmitted directly to the inner ear and to cranial nerve VIII (vestibulocochlear)
What is the function of cerumen?
The presence and composition of cerumen are not related to poor hygiene. Cerumen is supposed to be present—to lubricate, waterproof, and clean the external auditory canal. Cerumen also is antibacterial, and it traps foreign bodies. Impacted cerumen is a common cause of conductive hearing loss. Excessive cerumen may show as round ball partially obscuring drum or totally occluding canal. Even when canal is 90% to 95% blocked, hearing stays normal. But when last 5% to 10% is totally occluded (when cerumen expands after swimming or showering), person has ear fullness and sudden hearing loss. **NOTE THAT there are 2 distinct types of cerumen: wet, honey-brown wax occurs in Caucasians and African Americans, and a dry, flaky white wax is found in East Asians and American Indians.
Hearing assessment in infants and children
The room should be silent and the baby contented. Make a loud, sudden noise (hand clap or squeeze toy) out of the baby's peripheral range of vision of about 30 cm (12 in). You should note these responses: - Newborn—Startle (Moro) reflex, acoustic blink reflex - 3 to 4 months—Acoustic blink reflex, infant stops movement and appears to "listen," stops sucking, quiets if crying, cries if quiet - 6 to 8 months—Infant turns head to localize sound, responds to own name - Preschool and school-age child—Child must be screened with audiometry A young child may be unaware of a hearing loss because the child does not know how one "ought" to hear. Note these behavioral manifestations of hearing loss: The child is inattentive in casual conversation, reacts more to movement and facial expression than to sound, child's facial expression is strained or puzzled, child frequently asks to have statements repeated, child confuses words that sound alike, etc.
Diminished or absent landmarks on eardrum/tympanic membrane
Thickened drum. Indicates chronic OM.
Battle Sign
Trauma to the side of the head may lead to a basilar skull fracture involving the temporal bone. This shows as ecchymotic discoloration just posterior to the pinna and over the mastoid process. A look inside the ear canal may show hemotympanum as well
Carcinoma
Ulcerated, crusted nodule with indurated base that fails to heal. Bleeds intermittently. Must refer for biopsy. Usually occurs on the superior rim of the pinna, which has the most sun exposure. May occur also in ear canal and show chronic discharge that is either serosanguineous or bloody.
Atresia
absence or closure of the ear canal.
