techniques in Otology
Dr. T. Balasubramanian M.S. D.L.O.
Before proceeding with clinical
examination perse a good history taking is a must. Without proper
history taking it is not possible to come to a reasonably correct
diagnosis by clinical examination alone.
History should include:
- Previous ear surgery
- Previous head injury
- systemic diseases like diabetes / hypertension
- Use of ototoxic drugs
- Exposure to noise during work
- Family h/o deafness
- H/O atopy / allergy
The classic symptoms of ear disease are as
Deafness: The patient must be asked whether
deafness was sudden in onset, or gradual in onset. If deafness is
sudden in onset the triggering event if any must be sought for. For
example, deafness following head injury may be caused by a fracture of
petrous portion of temporal bone. If the damage occurs to the auditory
nerve the patient may have sensori neural hearing loss. Damage to 8th
nerve is common following transverse fractures of temporal bone.
Sometimes acute trauma may lead to dislocation of the ossicles causing
conductive hearing loss. Of the 3 ossicles incus is the most commonly
dislocated bone following trauma.
Conductive deafness can be differentiated from
sensori neural deafness in a consious patient easily by doing a tuning
fork test. Commonly used tuning fork tests are 1. Rinne, 2. Weber, and
3. Absolute bone conduction test.
Transient deafness after head injury may be
commonly caused by a haematoma in the middle ear cavity. Following head
injury the other common triggering event for deafness is viral
infections. Common among them are mumps, measles etc. Deafness
following viral infections are purely sensorineural in nature. The
presence of wax is sufficient to cause fluctuating hearing loss which
is conductive in nature.
Causes of fluctuating hearing loss are:
1. Presence of wax (conductive deafness)
- Patient will c/o severe itching in the affected ear
2. Menier's disease (sensorineural deafness)
3. Peri lymph fistula (sensorineural deafness)
In patients with deafness associated with ear
discharge the presence of perforation in the ear drum could be the
In all patients with c/o deafness a proper drug
history is a must. Ototoxic drugs like streptomycin, gentamycin and
aspirin may cause irreversible damage to the hair cells of the cochlea
causing sensori neural hearing loss. These drugs also sensitises the
hair cells of the cochlea to damage due to noise exposure, hence
occupational history of these patients is a must. H/O exposure to loud
noise must be sought.
Discharge: Ear discharge is one of the common
problems that brings the patient to the doctor. Before examining the
patient a detailed history regarding
1. Duration of the discharge
2. Quantity of discharge
3. Quality of discharge
4. Aggravating & relieving factors
must be sought for.
If the duration of discharge is short then acute
conditions must be borne in mind. Common acute conditions which can
lead to ear discharge are
1. A.S.O.M. - here the discharge is
serosanguinous in nature (blood tinged), preceded by an episode of
severe ear pain, pain subsides as soon as discharge starts, preceding
epiosode of upper respiratory infection.
2. Otomycosis - common fungi affecting the
external canal are candida and aspergillus fumigatus. Candida gives a
curdy appearance in the external ear canal. In a dried up state it
could appear like a cotton wool. Aspergillus fumigatus appears as a
black color patches in the external auditory canal. These patients have
ear discharge mostly just wetness, not profuse in nature, associated
with intense itching.
3. C.S.F. Otorrhoea - The disharge is watery in
nature, there is absolutely no mucoid elements in the discharge. This
clear discharge starts when the affected ear assumes a dependent
position. Biochemical analysis of this discharge will show that it
contains glucose which is normally absent in purulent ear discharges.
Bedside test - One useful bedside test for CSF
otorrhoea is Handkerchief test. If the secretion is mopped with a
handkerchief and allowed to dry, there will be stiffening of the
handkerchief if the discharge is from the middle ear because of the
presence of mucous, if the discharge is csf there is no stiffening seen.
Most sensitive diagnostic test is estimation of Beta
2 transferrin in the secretions. Beta 2 transferrin is seen only
in the CSF and is absent in other types of discharges.
Another important factor in the history taking
is asking for the quantity of discharge. If the discharge is profuse
the following conditions must be borne in mind : chronic mastoiditis,
mastoid reservoir, extra dural abscess. Of these three in extra dural
abscess the discharge is so profuse the external canal fills up with
pus immediatly after mopping. The presence of mastoditis or mastoid
reservoir can be ruled out by looking out for tenderness in the mastoid
tip area. In children with well pneumatised mastoids the pus may cause
erosion of the outer cortex and present as a collection just under the
mastoid periosteum. This condition is known as sub periosteal
abscess. If the ear discharge is scanty and foul
smelling osteitic reaction due to infection must be suspected. This is
frequently caused by the presence of cholesteatoma in the middle ear
cavity associated with bone erosion.
The quality of discharge may range from:
Mucoid - common in CSOM
Mucopurulent - comon in CSOM associated
Serous - Common in ASOM
Serosanguinous - ASOM and otitis
Watery - CSF otorrhoea
Fig showing various types of ear discharge
Tinnitus is defined as hearing
abnormal sounds in the ear. It can be classfied into objective tinnitus
and subjective tinnitus. Objective tinnitus is the one which is heard
by both the examiner and the patient eg palatal myoclonus. Subjective
tinnitus is heard only by the patient. Even a simple problem like
impacted wax can cause subjective tinnitus by the process of
amplification of endogenous sound (internal mileu sounds of the body
like the sound of circulating blood, contraction of muscle etc)
Commonly tinnitus (subjective) in the absence of impacted cerumen
indicates early sensori neural hearing loss. This is caused by damage
to hair cells of the cochlea. The damage could be due to the adverse
effects of medicines like those belonging to the group of antibiotics,
diuretics or cytotoxic drugs. Tinnitus associated with hearing loss is
commonly a manifestation of Menier's syndrome. Tinnitus in this
syndrome is roaring in nature and resolves within a day. It is also
associated with giddiness.
Tinnitus in a patient with
otosclerosis is an indication of active disease. These patients have
active foci of otosclerosis. A separate term is used to identify these
patients i.e. otospongiosis. Surgery if performed during this phase
carries an immense risk of sensorineural hearing loss.
Pain: is one of the common
complaints in patients with ear problem. Pain in the ear can arise from
2 sources, pain due to problems confined to the ear, and referred
otalgia i.e. pain that is referred to the ear from a problem arising
from other areas, i.e. pain associated with tonsillar infection has a
propensity to radiate to the ear due to common nerve supply i.e.
glossopharyngeal nerve. Pain due to inflammation in the external ear is
intense and is associated with swelling of the external auditory canal.
This can be differentiated from pain arising from middle ear
inflammation by the presence of tenderness on pressing the tragus. This
sign is known as the tragal sign. Tragal sign is negative in
otalgia due to middle ear causes. Pain due to mastoiditis (inflammation
of mastoid air cells) can be differentiated from pain due to otitis
externa by the presence of three point tenderness. Three point
tenderness is elicited by using the middle finger to apply pressure
over the well of the concha, index finger is applied over the mastoid
process, and the thumb is used over the mastoid tip. The pressure over
the well of the concha indicates tenderness over the antral area,
tenderness over the mastoid process indicates the presence of
mastoiditis, and tenderness over the tip of the mastoid process
indicate inflammation and thrombosis of mastoid emissary vein.
Fig showing various causes of otalgia
Vertigo: is defined as a sensation of
unsteadiness / rotation. The commonest peripheral causes for vertigo
are the diseases affecting the inner ear. It is always associated with
tinnitus/ blocking sensation in the ear. Peripheral
vertigo can be differentiated by central vertigo by its fatiguability.
In peripheral vertigo the vertigo tends to diminish with time because
the higher center learns to adjust with the problem. It is always
positional. The patient will have to assume the provoking position for
vertigo to manifest. Vertigo due to menier's disease is self limiting
and short lived. It never lasts for more than a day after which the
patient gradually improves. Periperal vertigo is always associated with
horizontal nystagmus, which is again fatiguing, where as central
nystagmus due to cerebellar pathology manifests with rotatory /
vertical nystagmus. They also show other postitive cerebellar signs
like past pointing, dysdiadokokinesis etc.
The external ear is inspected with the following
- size & shape of the pinna
- Presence of tags / preauricular sinuses / pits
- Evidence of trauma to pinna
- Skin condition of pinna & external
- Evidence of previous surgery / presence of
scars in the post aural / end aural region
- Discharge from the external canal
- Neoplastic lesions of pinna
The ear drum can be examined using an otoscope. The
pinna should be grasped between the index finger and thumb and is
pulled postero superiorly. This manouver straightens the external canal
bringing the ear drum into full view. This manouver should be done only
in adults. In infants the pinna must be pulled posteriorly and
downwards in an effort to straighten the external canal. This is
because of the fact the bony portion of the external canal is not fully
develped in infants.
Fig showing the manuver to straighten the external auditory canal
The use of Grubber's aural speculum itself is
sufficient to straighten the external canal. The status of the canal
skin / presence or absence of discharge is noted. The whole of the ear
drum is visualised by tilting and moving the otoscope in various
The ear drum is roughly oval in shape and about
1 cm in diameter. Normal ear drum is pearly white in color. The
following structures of ear drum are visualised:
1. Attic area
2. Pars tensa
3. Cone of light
4. Handle / lateral process of malleus
Rarely the following structures also can be seen:
Long process of incus
Head of stapes
Eustachean tube orifice
Perforations any must be identified, its
position clearly documented. Through the perforation the status of the
middle ear mucosa must be observed and documented. Presence of
tympanosclerotic plaque (chalky mass over the ear drum) is an indicator
of previous ear disease.
The cone of light must be observed for any
distortion. Cone of light is absent in perforated ear drums, is
distorted in retracted ear drums. It is also distorted when the ear
drum is bulging as in the case of Acute otitis media.
The color of the ear drum must also be noted:
Red drum - is seen in acute otitis media,
Blue drum - is seen in haemotympanum, secretory
Flamingo drum - is seen in otospongiosis
Mobility of the ear drum must be tested using a
pneumatic otoscope, or a siegele's speculum. The mobility of the ear
drum is restricted in adhesive otitis media.
Fig showing siegles pneumatic speculum
A siegel's pneumatic speculum has an
eye piece which has a magnification of 2.5 times. It is a convex lens.
The eye piece is connected to a aural speculum. A bulb with a rubber
tube is provided to insufflate air via the aural speculum.
The advantages of this aural speculum is that it
provides a magnified view of the ear drum, the pressure of the external
canal can be varied by pressing the bulb thereby the mobility of ear
drum can be tested. Since it provides adequate suction effect, it can
be used to suck out middle ear secretions in patients with CSOM. Ear
drops can be applied into the middle ear by using this speculum. Ear is
first filled with ear drops and a snugly fitting siegel's speculum is
applied to the external canal. Pressure in the external canal is varied
by pressing and releasing the rubbur bulb, this displaces the ear drops
into the middle ear cavity.
Picture showing otomycosis in external canal (Black color Aspergillus
Picture showing otomycosis in external ear Cotton wool apperance
Picture showing retraction pocket involving the ear drum
Picture showing tympanosclerotic plaques
Picture showing large central perforation
Picture showing attic perforation
Tests for hearing:
Useful bedside test for hearing is performed
using a tuning fork. Ideally 3 frequencies are used 256 Hz, 512 Hz, and
1024 Hz. These three frequencies are used because they fall within
speech frequency range. An ideal tuning fork should have the following
It should be made of a good alloy.
It should vibrate for one full
It should not produce any over tones.
Tuning fork tests are performed to identify
whether the patient is suffering from conductive deafness,
sensorineural deafness, or mixed deafness. Three tests are performed
towards this end. They are 1. Rinnes test, 2. webers test, 3. Absolute
bone conduction test / ABC.
Rinnes test: Ideally 512 tuning fork is used. It
should be struck against the elbow or knee of the patient to vibrate.
While striking care must be taken that the strike is made at the
junction of the upper 1/3 and lower 2/3 of the fork. This is the
maximum vibratory area of the tuning fork. It should not be struck
against metallic object because it can cause overtones. As soon as the
fork starts to vibrate it is placed at the mastoid process of the
patient. The patient is advised to signal when he stops hearing the
sound. As soon as the patient signals that he is unable to hear the
fork anymore the vibrating fork is transferred immediatly just close to
the external auditory canal and is held in such a way that the
vibratory prongs vibrate parallel to the acoustic axis. In patients
with normal hearing he should be able to hear the fork as soon as it is
transferred to the front of the ear. This result is known as Positive
rinne test. (Air conduction is better than bone conduction). In case of
conductive deafness the patient will not be able to hear the fork as
soon as it is transferred to the front of the ear (Bone conduction is
better than air conduction). This is known as negative Rinne. It occurs
in conductive deafness. This test is performed in
both the ears.
If the patient is suffering from profound
unilateral deafness then the sound will still be heard through the
opposite ear this condition leads to a false positive rinne.
Rinne's test being performed (air conduction)
Here again 512 Hz tuning fork is used. The
vibrating fork is placed over the forehead of the patient and he is
asked to indicate on which side he is hearing the sound. Normally when
hearing level is equal in both the ears, it is heard in the middle, in
patients with conductive deafness the sound is heard in the left ear.
This is known as lateralisation of Weber test. If the patient is
suffering from sensorineural hearing loss then the sound is lateralised
to the normal ear or the better ear. Hence weber's test must always be
interpreted along with the Rinne's test. Weber's test is a sensitive
test, it can pin point even a 10 dB hearing difference between the ears.
Fig showing Weber test being performed
Absolute bone conduction test:
This test is performed to identify sensorinerual
hearing loss. In this test the hearing level of the patient is compared
to that of the examiner. The examiner's hearing is assumed to be
normal. In this test the vibrating fork is placed over the mastoid
process of the patient after occluding the external auditory canal. As
soon as the patient indicates that he is unable to hear the sound
anymore, the fork is transferred to the mastoid process of the examiner
after occluding the external canal. In cases of normal hearing the
examiner must not be able to hear the fork, but in cases of sensori
neural hearing loss the examiner will be able to hear the sound, then
the test is interpreted as ABC reduced. It is not reduced in cases with
Basic tests for hearing:
For making a basic assessment of patient's
hearing the ear opposite to the one tested is masked by occluding it.
The patient is asked to repeat random numbers uttered by the examiner.
Ideally patient is blind folded to prevent lip reading. The numbers are
uttered at various intensities, quiet whisper, loud whisper, quite
voice, loud voice and shout.
Rough estimation of hearing loss would be:
quite whisper - normal
Loud whisper - 20 - 30 dB
Quite voice - 30 - 45 dB
Loud voice - 45 - 60 dB
Shout - 60 - 80 dB
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