1- Ears (Investigations and examination findings) Flashcards
How to use an otoscope
- Gently pull the pinna upwards and backwards to straighten the ear canal to best visualise the tympanic membrane. In children, pulling the pinna downwards and backwards may provide better visualisation
- Hold the otoscope like a pencil and use your little finger as a fulcrum against the cheek to avoid injury should the patient move suddenly
- Inspect systematically
Looking at: external auditory canal, tympanic membrane, ossicles
Normal auditory canal
- Some hair
- Often with yellow to brown
- Cerumen
Normal tympanic membrane
- Pinkish grey (pearly grey) in color, translucent and in neutral position
- Malleus lies in oblique position behind the upper part of the drum
- Mobile with air inflation
colour of TM
Colour
- A healthy TM should appear pearly grey and translucent.
- Erythema suggests inflammation of the TM which can occur in conditions such as acute otitis media.
shape of TM
- A healthy TM should appear relatively flat.
Bulging of the TM suggests increased middle ear pressure
- acute otitis media (there is
Retraction of the TM suggests reduced middle ear pressure
- pharyngotympanic tube dysfunction secondary to upper respiratory tract infections and allergies
- otitis media with effusion
Light reflex
- If a TM is healthy, the cone-shaped reflection of light should appear in the anterior inferior quadrant.
- In the left ear, the light reflex should be positioned at approximately 7 o’clock to 8 o’clock.
- In the right ear, the light reflex should be positioned at approximately 4 o’clock to 5 o’clock.
- Absence or distortion of the light reflex is associated with otitis media (due to bulging of the TM).
Perforations
- Size and position
- Cause: infection, trauma, cholesteatoma (superior part of TM), tympanostomy tube insertion
Scarring
- Scarring of the TM is known as tympanosclerosis and can result in significant conductive hearing loss if it is extensive.
- Tympanosclerosis often develops secondary to otitis media or after the insertion of a tympanostomy tube.
what is this?
cholesteatoma
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chronic supporative otitis media
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external auditory canal bleeding
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impacted cerumen
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otitis media with effusion
otitis
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tympanic membrane calcification
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tympanic membrane calcification
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otitis externa
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acute otitis media
Pneumatic otoscopy
Pneumatic otoscopy- can be used to assess tympanic membrane (this modified otoscope has an air-tight seal when placed in the ear canal and a rubber bulb (similar to that of a sphygmomanometer) which the user can squeeze which alters the pressure within the ear canal)
Hearing tests in order
- Field speech testing
- Webers and rinnes tests
- Pure tone audiogram
free field speech testing
- Free field testing is a good screening tool for hearing loss
- Use of masking improves the accuracy of testing:
o Rub the tragus of the contralateral ear whilst performing this to prevent sound being heard in the contralateral non-test ear - Use polysyllabic phrase (number or letter) e.g. ‘C5’, ‘37’ or motivational phrases in children e.g. ball, sweets, crisps
- Test normal ear first.
- Perform, in order of intensity at 60cm (arms length) and 15cm: whisper, conversational speech, loud voice.
- Patient should be able to repeat >50% of the letters/numbers correctly.
Webers and Rinnes test
Webers and Rinnes test
These tests assess air conduction (AC) and bone conduction (BC) and are used to help delineate whether hearing loss is sensorineural (SNHL)or conductive (CHL) in origin.
Webers test
- Vibrating 512Hz tuning fork applied firmly to the midline of the forehead, apex of head
- Ask the patient if they can hear a tone in the right ear, left ear or centre of the head
- The “louder” ear may be due to conductive hearing loss in that ear (sound travels through the bone), or sensorineural hearing loss in the other ear
- You can work out which this is by performing Rinne’s test
Rinnes test
- Place vibrating tuning fork with base on mastoid process (position 1, testing bone conduction).
- Then move the tuning fork so its prongs are adjacent to (but not touching) the external auditory meatus (position 2, testing air conduction).
- Ask patient to tell you which is louder, when the fork is placed behind the ear or in front of the ear
- Position 2 is louder than position 1 in the normal ear (Positive Rinne), as an intact hearing apparatus of the external and middle ear amplifies sound.
- When position 2 is quieter than position 1, (Negative Rinne), this indicates external or middle ear disease affecting the air conduction
intepreting Webers and Rinnes
Pure tone audiometry
is a subjective test that aims to evaluate the quietest sound that can be heard with each ear at various frequencies i.e. the hearing threshold.
Hearing is usually reported on the decibel scale, which is a logarithmic scale.
In general, a whisper from 1m has an intensity of 30dB, normal conversational voice is 60dB, shouting equates to about 90dB and discomfort can be felt at around 120dB.
Normal hearing is defined to be
20dB or better
Hearing Disability is defined as:
- Mild hearing loss is between 21-40dB.
- Moderate hearing loss is between 41-70dB.
- Severe hearing loss is considered to be 71-90dB.
- Profound hearing loss is worse than 90dB.
pure tone audiometry technique
Technique
- The audiometer is a machine which provides pure tone sounds at varying frequencies
- The test must be conducted in a soundproof room and the subject should not be able to see the machine or the tester adjusting the controls as this may influence the results.
- Before conducting the test, the ears must be examined to exclude an active infection, foreign body or occluding wax. The patient then wears headphones to test air conduction followed by a bone vibrator placed on the mastoid process to test bone conduction
- Air conduction is tested at 250, 500, 1000, 2000, 4000 and 8000 Hz while bone conduction is tested at 500-4000 Hz.
- Masking helps to deal with cross hearing, which occurs from bone conduction to the contra-lateral cochlea.
o It involves presenting a sound to the non-test ear (masking noise) to prevent it from detecting the sound being presented to the test ear
normal audiometry graph
all >20dB
audiogram form
diagnosis?
diagnosis?
