‫جـــــامعـــــة‬
‫‪SUEZ‬‬
‫الســــــــويـــــــــس‬
‫‪UNIVERSITY‬‬
‫‪RESEARCH‬‬
‫‪OTITIS MEDIA‬‬
1- Introduction
Otitis media (OM) is a serious disease with potential life-threatening complications;
means inflammation of middle ear and its complications are important causes of
preventable hearing loss, particularly in the developing world.
OM is pathology of the middle ear and middle ear mucosa, behind the ear
drum (tympanic membrane), any infection of the middle ear can spread to
surrounding structures with serious results.
The middle ear is lined by modified respiratory epithelium, with ciliated cells and
goblet cells; this epithelium produces mucin that is normally transported down the
eustachian tube.
Young children are more prone to acute otitis media (AOM) and otitis media
externa (OME) due to an anatomical predisposition; the eustachian tube is shorter,
more flexible, and horizontal which allows nasopharyngeal pathogens to enter the
middle ear(1).
It is thought that between 50% and 85% of children affected by AOM in first 3
years of age with the peak incidence between 6 and 15 months. The commonest
cause of hearing impairment in children in the developed world is the OME(1).
2- Research goal (objectives):
A- Structural components of the ear.
B- Relate the structure of different ear components to their function.
C- Describe auditory nervous pathway.
D- Discuss the mechanism of hearing.
E- Discuss clinical pictures of otitis media.
F- Discuss the causative agents, mode of transmission and lab Diagnosis of otitis
media.
G- Outline management of otitis media.
3- Literature review:
A- Structural components of the ear.
The ear consists of 3 parts:
1- External ear
2- Middle ear
3- Internal ear.
Related to the topic which discuss subject called (otitis media), defined as an
infection of the middle ear. In addition to describing the anatomy of the middle ear and
the function of each component of it, but first talking about brief anatomy about the
external and internal ear(2).
External ear
It is composed of (auricle, external auditory meatus and
Ear drum) (2).
The auricle: its elastic cartilage except its lobule, it
has a cutaneous nerve supply.
- The auriculotemporal nerve: supply the upper 1/2 of the outer surface.
- The lesser occipital nerve: supply the upper 1/2 of the inner surface.
- Great occipital nerve: supply the lower 1/2 of both outer and inner surface.
- Auricular branch of vagus which supply an area of the inner surface(2).
The external auditory meatus: one inch (24 mm). Consist of 2 parts outer 1/3
cartilaginous and the inner 2/3 is bony(2).
The ear drum: it’s a semi-translucent membrane
composed of (outer layer of skin, middle fibrous tissue
and inner mucous membrane).
- The middle fibrous layer called pars tensa but it absent in
the upper part which is called pars flaccida.
- The pars flaccida and tensa separated from each other
by 2 folds called the anterior and posterior malleolar folds.
The lower quadrant part of the outer surface of the ear drum is called the cone of
light (2).
The internal ear
It lies inside the temporal bone and consists of
2 parts: (bony labyrinth and membranous labyrinth)
Bony labyrinth: consists of 3 parts (semicircular
Canals, vestibule and cochlea) filled with perilymph.
Semicircular canals: (superior, posterior and
lateral) all the3 canals open in the posterior
aspect of the vestibule by 5 orifices(2).
The vestibule: it's the central structure of the bony labyrinth. It lodges the utricle and
saccule which are parts of the membranous labyrinth.
The cochlea: it's like the snail. The cochlear canal lodges the cochlear duct of the
membranous labyrinth(2).
Membranous labyrinth: consists of (semicircular ducts, utricle, saccule and
cochlear duct) filled with endolymph.
Nerve supply of the internal ear: vestibule-cochlear nerve.
Blood supply of the internal ear:
- Labyrinthine br. of basilar artery
- Stylomastoid br. of posterior auricular artery(2).
The Middle Ear
- The middle ear anatomically found in the temporal bone.
- It’s a small biconcave box; its vertical axis is parallel to the plane of the ear drum.
- It’s formed of roof, floor and 4 walls (anterior, posterior, medial and lateral) (2).
The roof: formed by a thin plate of bone called tegmen tympani. It separates the
middle ear cavity from the temporal lobe in the middle cranial fossa.
The floor: formed by a thin plate bone called jugular wall.
It separates the middle ear cavity from the jugular fossa which contains the
superior bulb of the internal jugular vein(2).
The lateral wall: formed by the ear drum.
The anterior wall: contain (opening of the canal of tensor tympani muscle,
opening of Eustachian tube and a plate of bone separating the middle ear cavity from
the internal carotid artery) arranged from above downwards(2).
The posterior wall: contain (aditus which lead to the mastoid antrum, pyramid
which contain the stapedius muscle and the vertical part of the facial canal) arranged
from above downwards(2).
The medial wall: it separates the middle ear from the internal ear. It shows (a
rounded bulge called the promontory formed by the first part of cochlea, oval window,
rounded window which is closed by 2ry tympanic membrane and the horizontal part of the
facial canal(2)).
Eustachian tube
- It is 36 mm long. The bony part is 12 mm while the cartilaginous part is 24 mm.
Superiorly: it's related to the base of the skull.
Inferiorly: it's related to the superior constrictor muscle of pharynx.
Medially: gives origin to the levator palati muscle.
Laterally: gives origin to the tensor palati muscle and related to the otic ganglion(2).
Contents of the middle ear
- 3 Ossicles
- 2 Muscles
- 2 Nerves
- Air
The ossicles:
Malleus: it's attached to the inner surface of the ear
Drum.
- It receives the insertion of the tensor tympani muscle.
- It articulates with the incus.
Incus: the intermediate ossicle.it has a body
and 2 Processes.
- The body articulates with the malleus.
- The long process articulates with the head of stapes.
Stapes: the medial ossicle.
- It has a foot which closes the oval window of the internal ear(2).
The muscles:
Tensor tympani muscle: its origin from the cartilaginous part of the Eustachian tube.
- It's inserted into the handle of the malleus by running in a small canal which opens in
the anterior wall of the middle ear.
- It’s supplied by a branch from the main trunk of mandibular nerve.
Stapedius muscle: its origin from the pyramid of the post wall of tympanic cavity.
- It's inserted into the posterior aspect of the stapes.
- It's supplied by nerve to stapedius from the facial nerve (2).
The nerves:
Chorda tympani: arises from the facial nerve which descends in the vertical part of
the facial canal.
- It leaves the middle ear cavity through the anterior canaliculus for chorda tympani to
reach the infratemporal fossa.
- It ends by joining the lingual nerve deep to the lateral pterygoid muscle (2).
Tympanic plexus: it lies on the promontory of cochlea on the medial wall of the
middle ear cavity.
- It supplies the mucous membrane of the tympanic cavity, Eustachian tube and
mastoid air cells(2).
Arterial supply of the middle ear
1- Anterior tympanic artery: branch from maxillary artery.
2- Posterior tympanic artery: branch from posterior auricular artery.
3- Superior tympanic artery: branch from middle meningeal artery.
4- Inferior tympanic artery: branch from ascending pharyngeal artery(2).
B- Relate the structure of different ear components to their function.
Organ
External ear
Function
Collect the sound waves from the air and transport it through the
external auditory meatus.
External auditory Transport the sound waves to the middle and internal ear.
meatus
Ear drum
-Vibrates in response to sound.
-Changes acoustical energy into mechanical energy.
Ossicles
Eustachian tube
Oval window
cochlea
Act as a lever system
Balance the air pressure at both sides of the ear drum.
It transmits the sound vibration from the middle ear to the inner ear.
- Converts mechanical energy into electrical energy.
- Transmission of signals via the vestibulocochlear nerve to the brain.
Semicircular
Balance of the body.
canal & vestibule
Auditory nerve
It transmits the signals from cochlea to brain.
(3) (4)
C- Auditory Nervous Pathway:
Auditory pathways take these steps:
1- Spiral ganglion.
2- Superior olivary nucleus complex, trapezoid
nucleus & nucleus of lateral lemniscuses.
3- Inf. Colliculus in the midbrain.
4- Medial geniculate body.
5- Auditory cortex.
Receptor: inner hair cells of the organ of corti.
1st order neuron: (cells of spiral
ganglion) Dendrites of bipolar cells innervate
hair cells. Axon: the cochlear division of 8th
cranial Nerve enters brain stem & ends in
medulla(4).
2nd order neuron: (dorsal & ventral cochlear nuclei)
Axon: pass medially in posterior part of pons, may cross to the opposite side & maybe
uncrossed.
The crossing fibers form mass called “trapezoid body” & some of them are separate
don’t form trapezoid body(4).
3rd order neuron:
1- Superior Olivary nucleus
Fibers of lat. Lemniscus
neuron)
2-trapezoid nucleus
midbrain
3-nucleus of lateral lemniscus
inferior Colliculus (4th order
Medial geniculate body (5th order neuron) (4).
Axon: form auditory (acoustic) radiation to cerebral cortex.
Primary auditory area (area 41, 42 in sup. Temporal gyrus) which important in
recognition of sound pitch, quality & loudness and detection of the direction of sound.
Auditory association area (area 22) which important to interpretation of the meaning
of heard sound(4).
NB: There are plenty of commissural fibers, which connect the auditory pathways on
both sides so: the auditory impulses from each ear are bilaterally represented in both
temporal lobes.
Therefore, unilateral cortical lesions affecting auditory areas or unilateral lesions of
the posterior limb of internal capsule lesions cause only reduction of hearing on both
sides(4).
D- Mechanism of Hearing:
Summarize mechanism of hearing in the following steps:
1( The sound wave travel through the external auditory meatus and produce
vibrations in the tympanic membrane(5).
2( The tympanic membrane acts as a resonator that reproduces the vibrations of sound.
3( Movements of tympanic membrane are transmitted by bone ossicles of middle ear to
the oval window (via foot plate of Stapes) (5).
4( The movement of the foot plate f the stapes lead to displacement of the
perilymph in the scala vestibula, he motion of this fluid move the vestibular membrane
which in turn lead to movement of the endolymph in the scala media, that causes the
basilar membrane to move in a pattern determined by the frequency and intensity of
the sound waves(5).
5( Movement of the stapes inwards lead to a downward displacement of the basilar
membrane. While, a movement of stapes outwards lead to upward displacement of the
basilar membrane and in both conditions, a shearing motion occurs between tectorial
membrane and the reticular lamina leading to bending of the hair processes of the hair
cells(5).
1- Mechanism of stimulation of hair cells:
The minute hairs, or stereocilia, project upward from the hair cells and either touch
or are embedded in the surface of the tectorial membrane, which lies above the
stereocilia in the scala media(5).
Bending of the hairs in one direction depolarizes the hair cells, and bending in
the opposite direction hyperpolarizes them(5).
- Each hair cell has numerous stereocilia on its apical border.
Movement of short strereocilia toward the direction of the longer one that causes
opening of opens 200 to 300 cation-conducting channels, allowing rapid movement of
positively charged potassium ions, causing their depolarization(5).
Depolarization of hair cells result in release of a chemical transmitter (glutamate
or aspartate) which stimulates the cochlear nerve at their bases(5).
E- Clinical Pictures of Otitis Media
The patient presents with ear pain, fever, malaise, coryzal symptoms. The ear hurts
and appears irritable.
On otoscopy the tympanic membrane looks
erythematous and may be bulging or perforated if the fluid
pressures on tympanic membrane. The fluid itself may
cause discomfort
And temporary hearing loss and when pus fills the middle ear cavity. The
pressure builds up the eardrum may burst. The pus and blood will then come out
and that is called ear abscess(6).
And in the chronic condition swollen adenoids may
lead to block the eustachian tube and prevent fluid
from draining and infection will spread to the mastoid
process(called mastoiditis), a network of thin, lacy bone located behind the ear(6) (9).
F- The causative agents, mode of transmission and lab Diagnosis of Otitis Media.
A: Bacteria.
Streptococcus pneumoniae
Hemophilus influenza
spread by droplets.
respiratory droplet.
Pseudomonas aeruginosa
spread to people who exposed to water or soil that is
contaminated.
Staph aureus
spread by direct contact with infected person or using
contaminated objects or droplets or via blood stream.
Moraxella catarrhalis
at hospital setting from person to person(7) (8).
Viruses:
Spread via coughing or sneezing
1- Adenovirus
2- Influenza & Para influenza virus
3- Respiratory syncytial virus(7).
Diagnosis:
Signs & symptoms:
- Cough
- Nasal discharge
- Fever
- Vomiting
- Otalgia & Otorrhea
- Hearing loss
- Bulging of TM
- Effusion (unilateral or bilateral) (7).
Physical examination:
1- Otoscope:
A tool shines beam of light which help examine ear canal & ear drum. elevation of
TM backword , upword & laterally to detect redness , swilling , bulging , blood . pus ,
perforation & tranlucency(7).
(normal TM is pale, ovoid, located at the end of external auditory canal & semitraslucent ).
2- Tympanomytry : by using a small
instrument which test the conuction of bones &
mobility of tympanic membrane by variation of
pressure(7).
3- Reflectometry: small instrument measures
sound waves which return from TM measuring
middle ear pressure.
4- Hearing test may perform(7).
G- Outline management of otitis media.
Acute suppurative otitis media in adults:
General: 1- Systemic Antibiotics like:
- Amoxicillin 20-40 mg/kg/day for 10- 14 days.
- Or Augmentin: 45 mg/kg/day for 10- 14 days.
- Or ampiclox or cephalosporins(9).
2- Simple analgesics, antipyretics and antihistamines
-
Auralgan: 2-4 drops as analgesic for ear pain.
Local : according to stage
NB: Attention
should be
given to any
nasal or
nasopharyngeal
1- In ET catarrh: decongestant nasal drops as xylometazoline.
pathology
2- In catarrhal OM: glycerin phenol warm ear drops.
3- In suppurative OM (bulging drum): stage of exudation
Myringotomy, Provides drainage to the pent-up secretions and relieves the
pain without the tissue necrosis of the tympanic membrane.
- Besides conservative line of treatment mentioned above (general).
- Culture media for the ear discharge(9).
4- In perforation:
- Myringotomy (see pic).
- Cleaning by suction or dry mopping.
- Local antibiotic ear drops(9).
NB: if there is a sub-periosteal abscess or no response to 48 intravenous antibiotic therapies,
mastoid surgery is reserved
Acute otitis media in infants and children:
The same as adults in addition to:
1- Myringotomy: may be needed early (if medical
treatment failed for 48 hours) to avoid any complications.
It is done in posteroinferior part of ear drum, followed by
suction and antibiotic ear drops.
Chronic non-suppurative otitis media
1- Secretory otitismedia
Medical
A- Treatment of cause: infection or adenoid.
B- Systemic antibiotic to prevent recurrent infection.
C- Steroid: withdrawal method.
D- Mucolytic: to dissolve mucous secretion.
E- Decongestant nasal drops to open ET.
F- To improve the drainage of effusion, we can use
Procedures like Valsalva's maneuver, politzerization
or eustachian catheterization (9).
Surgical (if medical treatment failed).
Myringotomy and insertion of ventilation tube with adenoidectomy if there is adenoid.
- The incision in the drum will be in anterosuperior part (as it is least migratory area
delay tube extrusion).
Types of ventilation tube: 1- Grommet tubes (temporary)
2- T-tubes (permanent) (9).
1- Adhesive otitis media
- Prophylactic: treat the cause.
- Grommet insertion.
- Curative:
Cartilage tympanoplasty
or Hearing aid (9).
3- Tympanosclerosis
- Surgery usually fails, Hearing aid is better.
- Silastic sheets may be put in to prevent adhesion formation.
- In fixation of the foot plate of stapes, stapedectomy may be helpful
- Fenestration is the method of choice for restoration of hearing in severe cases(9).
Chronic suppurative otitis media (CSOM)
1- Tubotympanic or Mucosal CSOM
Medical
We should pay attention to any abnormality of the nose, paranasal sinuses
and nasopharynx. And if we found, it should be adequately treated.
A- General : systemic antibiotics (given according to culture and sensitivity)
B- Local: 1- Local antibiotic ear drops like neomycin and gentamycin
2- Aural toilet by suction or by dry mopping
c- Prevention of re-infection by:
- Avoid wetting of the ear (keep it dry)
- Control upper respiratory tract infection as common cold(9).
Surgical:
The aim of surgery is to provide a safe, dry and a hearing ear.
-Adenoidectomy,
septoplasty and antrum washes may be required in some cases,
where the predisposing factors are in the nose and paranasal air sinuses.
-Aural
polypectomy should be done under general anesthesia using the
microscope.
-Myringoplasty(9).
MYRINGOPLASTY
For Myringoplasty
1- The ear should be dry for at least six weeks before myringoplasty is done.
2- The eustachian tube should bepatent.
3- There should be an adequate cochlear reserve(9).
Advantages of Myringoplasty
1- To prevent infection of ear.
2- To improve the hearing or to prevent deterioration in
hearing.
3- To prevent complications.
4- To prevent tympanosclerosis(9).
2- Attico-antral or bony COSM or Cholesteatoma
The aim of treatment in cholesteatoma is to make the ear safe by eradicating the
disease and to prevent its recurrence.
The treatment is surgical (9).
Tuberculous Otitis Media:
- Anti-tubercular therapy.
- Advanced cases may require surgical intervention (9).
References:
1- Qureishi, A., Lee, Y., Belfield, K., Birchall, J. P., & Daniel, M. (2014). Update on
otitis media - prevention and treatment. Infection and drug resistance, 7, 15–24.
https://doi.org/10.2147/IDR.S39637
2- Drake, Richard, A. Wayne Vogl, and Adam WM Mitchell. (2009): Chapter: Ear in
Gray's Anatomy for Students E-Book, 2nd ed, P.902:919. ISBN: 978-0-443-06952-9.
3- The physiology of hearing. Retrieved from
https://www.britannica.com/science/ear/The-physiology-of-hearing. Last accessed on
14/5/2020.
4- Khurana, I. (2018): Chapter: sense of hearing Medical physiology forundergraduate
students-E-book, 2nd ed. P. (856:871) (928-929). ISBN: 9788131228050
5- Sherman, J. H., Luciano, D. S., & Vander, A. J. (1985): Chapter: 9 Human
physiology: the mechanisms of body function, 9th Edition, P.253:254. ISBN: 9780072437935
6- Acute Otitis Media. Retrieved from https://teachmesurgery.com/ent/ear/acute-otitismedia/. Last accessed on 14/5/2020.
7- Nathan, P. (2015): Chapter: 8 ENT section 1 in Taylor’s Manual of Family Medicine,
4th ed, P.380-381. ISBN: 9781496317889
8- Mohan, H. (2015): Chapter 16 ENT in Textbook of pathology, 7th ed, P.511. ISBN:
9789351523697
9- Maqbool, M., & Maqbool, S. (2013). Chapter 9 to 13(otitis media) in Textbook of Ear,
Nose and Throat Diseases, 12th ed, P.40:57. ISBN: 9789350904954