Ear - Chapter 5 (Diseases of the middle ear)

Question 1

Congenital anomalies of middle ear

Answer 1

1- Dehiscence of the bony facial canal (horizontal portion) : Most common congenital anomaly of the middle ear. Predisposes to facial paralysis during middle ear infection or during ear surgery.
2- Dehiscence of the floor of the tympanic cavity : Predisposes to severe bleeding during operations e.g. myringotomy (due to possible injury of the jugular bulb).
3- Persistent stapedial artery : It should be recognized during stapedectomy since injury causes severe bleeding.
4- Fixation, deformity or absence of the ossicles.
5- Aplasia: Complete absence of the middle ear, causing conductive deafness since birth. Treatment is by hearing aid.

Question 2

Ossicular disruption

Answer 2

Etiology :
* Head injury (with or without temperature bone fracture).
* Surgical trauma during ear operations (myringotomy and mastoidectomy).
* During F.B removal.

Pathology :
Incudostapedial joint is the most common affected joint, but any joint may be involved.

Diagnosis :
* Otoscopy : usually intact tympanic membrane.
* Tuning fork tests : conductive deafness.
* Pure tone audiogram : air-bone gap (up to 50-60 dB loss).
* Tympanogram : hypermobile (type Ad tympanogram).

Treatment :
* Repositioning of the ossicles or interposioning of prosthesis (ossiculoplasty).

Question 3

• Otitic barotraumas

Answer 3

Physiology :
* At rest : the Eustachian tube is closed. It opens only during swallowing and yawning to allow inflow of air into the middle ear to equalize the middle ear and the atmospheric pressures.
* During airplane ascent : the atmospheric pressure decreases, the middle ear pressure becomes relatively positive. This can be easily corrected by passive outflow of air from the middle ear along the Eustachian tube.
* During diving and airplane descent : the atmospheric pressure increases, the middle ear pressure becomes relatively negative. This can be only corrected by active opening of the Eustachian tube (by swallowing) to allow inflow of air into the middle ear.

Etiology :
* Otitic barotraumas occurs when the patient fails to open the Eustachian tube during diving or descent in a non-pressurized airplane. This may occur when :
- The Eustachian tube is obstructed e.g due to upper respiratory infection or allergy.
- The patient does not swallow as during sleep.

Symptoms :
* Ear ache.
* Deafness.
* Tinnitus.

Signs :
* Retracted tympanic membrane (mild case).
* Effusion or blood (haemotympanum) in moderate cases.
* Rupture tympanic membrane (in severe cases).
* Conductive deafness :

Prophylaxis :
* Avoid diving or flying with nasal obstruction.
* Avoid sleep during airplane descent.
* Try to open the Eustachian tube by :
- Repeated swallowing, this is aided by chewing gum.
- Repeated auto-inflation of the middle ear by Valsalva’s manoeuvre i.e forced expiration with both mouth and nose closed.
- Use of vasoconstrictor nasal drops before flying in case of rhinitis.

Treatment :
* In mild cases (i.e retracted tympanic membrane) :
- Vasoconstrictor nasal drops to reduce edema around eustachian tube orifice.
- Auto-inflation of the middle ear by Valsalva’s manoeuvre.
* In moderate cases (i.e middle ear effusion) : Myringotomy.
* In severe cases (i.e ruptured tympanic membrane) : See before.

Question 4

• Fracture base of the skull

Answer 4

Two types of temporal bone fracture.
Fracture line :
- Longitudinal : along the longitudinal axis of the petrous bone (middle ear ossicles, tympanic m. and external auditory meatus).
- Transverse : along the transverse axis of the petrous bone (inner ear + internal auditory meatus).

Clinical picture:
- Incidence: 80% vs 20%
- Fracture line: In long axis of petrous bone VS At right angle to long axis of petrous bone
- Fracture involves: Tympanic cavity, Tympanic membrane ,External auditory canal VS Cochlea, Vestibular apparatus, Internal auditory canal
- Deafness: Conductive VS Sensorineural
- Facial paralysis: Rare 20% VS Common 80%
- Other symptoms and signs: Bleeding and C.S.F otorrhea VS Vertigo and nystagmus

Investigations :
1- CT scan : to show the fracture line.
2- Audiological : type of deafness.
3- Tests for facial nerve.

Treatment :
1- Complete rest and prophylactic antibiotic.
2- Treat CSF otorrhoea, traumatic rupture drum, Ossicular disruption.
3- Exploration of facial nerve in cases of immediate and total facial paralysis (as in transverse fracture).

Question 5

ACUTE OTITIS MEDIA

Answer 5

Acute inflammation of the mucoperiosteal lining of the middle ear cleft i.e. (the middle ear, Eustachian tube and mastoid air cells).

Etiology :
* Causative organisms: streptococcus pneumonia, Homophiles influenza and Moraxella catarrhalis
* Routes of infection :
- Through the Eustachian tube : the commonest route.
- Through tympanic membrane perforation : infected water enters the middle ear through tympanic membrane perforation.
* Sources of infection :
a- Through the Eustachian tube :
1- Upper respiratory infection :
- Nose : Rhinitis (commonest) e.g common cold and influenza.
- Sinuses : Sinusitis.
- Nasopharynx : Adenoiditis and pharyngitis.
2- Infected material passing through the tube :
- Vomitus and milk regurge in infants.
- Post-nasal packing.
b- Through tympanic membrane perforation : During bathing, swimming and ear wash.

Pathology and Clinical Picture :
1- Stage of tubal catarrh (salpingitis) : Inflammation of the Eustachian tube mucosa which becomes edematus → Eustachian tube obstruction → -ve middle ear pressure
Symptoms : Deafness and autophony.
Signs : Retracted tympanic membrane and conductive deafness.
2- Stage of catarrhal otitis media : Serous fluid exudates in the middle ear.
Symptoms : Deafness, Tinnitus, autophony and dull ear ache.
Signs : Congested tympanic membrane (around periphery and handle of malleus) + conductive hearing loss
3- Stage of suppuration :
A- Before drum perforation (pus under tension in the middle ear) :
Symptoms :
* Fever, headache, malaise.
* Ear ache: severe and throbbing.
* Deafness and Tinnitus.
Signs :
* Markedly congested and bulging drum.
* Conductive hearing loss.
B- After drum perforation : due to necrosis of central part of the drum.
Symptoms:
* General symptoms of inflammation diminished.
* Pain disappears.
* Discharge.
* Deafness.
Signs :
* Central perforation.
* Mucopurulent discharge.
* Conductive deafness.
4- Stage of resolution or complications, sequale (prognosis) :
A- Resolution means :
* Discharge disappears.
* Perforation heals.
* Hearing returns normal.
B- Incomplete resolution : Residual perforation, residual discharge (due to persistence of the predisposing factor and masked mastoiditis) and secretory or adhesive otitis media from repeated attacks.
C- Complications : may be :
* Cranial.
* Intracranial.
* Extracranial.

Question 6

MANAGEMENT OF ACUTE SUPPURATIVE
OTITIS MEDIA

Answer 6

Investigations :
1- Culture and sensitivity tests of the discharge.
2- Pure tone audiometer: conductive deafness.
3- Plain x-ray: clouding of mastoid air cells with intact intercellular bony septa.

Treatment :
A- Before perforation
Medical : Antibiotics for 10 days :
- Analgesics.
- Decongestant nasal drops.
Surgical : myringotomy… when?
- no improvement after 48 hours.
- markedly bulging drum.
- Development of complication e.g. Facial paralysis.
B- After perforation
* Antibiotics, avoid wetting of the ear and aural toilet.
* Myringotomy : if the perforation is small or high to improve
drainage.

Question 7

Acute Otitis Media in infants and children

Answer 7

It is different from that of adults and older children in the following :
I- Incidence :
More common in infants and young children due to :
a- Route of infection in easier because the Eustachian tube is wider, shorter, and more horizontal and its opening lies inferiorly close to the oropharynx.
b- Source of infection are common: upper respiratory tract infections, adenoid and tonsillitis.
c- General resistance is lower due to teething, artificial feeding (bottle fed more susceptible than breast fed because milk liable to be contaminated and position of infant during feeding which usually lie flat on his back and when regurgitate milk accumulate in the nasopharynx and pushed to Eustachian tube with swallowing).

II- Clinical picture :
* Symptoms: the infant cannot explain his symptoms, so the symptoms are of general disturbance :
- Pulling and rubbing ears or moving head from side to side.
- High fever which may be accompanied by convulsions.
- Vomiting and diarrhea which may be mistaken for gastroenteritis.
Signs :
* The drum is thick and doesn’t bulge easily, it appears dull and lusterless.

III- Treatment :
* Similar to adult, but myringotomy is done after failure of medical treatment for 48 hours – even if the tympanic membrane doesn’t obviously bulge.

IV- Prognosis :
Complications more common because :
* Misdiagnosis (see symptoms and signs).
* Open cranial sutures which facilitate spread of infection.
* Low resistance.

Question 8

CHRONIC SUPPURATIVE OTITIS MEDIA

Answer 8

Types :
I- Tubo- tympanic :
- Safe : as the infection is limited to the mucosa of middle ear and Eustachian tube , no bone erosion.
- Most common type.
II- Attico antral :
- Unsafe : the pathology involves the attic and antrum = cholesteatoma causing bone erosion.
- Most dangerous type.
Organisms : pseudomonas and proteus.

I- Tubotympanic disease :
Etiology :
Persistence or recurrence of acute suppurative otitis media due to :
* Inefficient treatment.
* Inadequate drainage.
* Low resistance of the patient.
* High virulence of the organism.

Symptoms :
Deafness and discharge.
Signs :
* Discharge: mucopurulent, odorless and may be profuse.
* Perforation: central (in pars tensa).
* Middle ear mucosa: congested and edematous.
* Polyps may be seen in the external canal.
* Conductive hearing loss.

Investigations :
* Culture and sensitivity of the discharge.
* C.T scan (if otitis media complicated).
* Audiometery.

Treatment :
A- Conservative :
- Aural toilet (either by dry mopping or suction)
- Antibiotics (topical and systemic)
- Avoid entry of water in ear canal.
B- Surgical :
- Removal of near by septic foci e.g. tonsils, adenoid.
- Removal of aural polyp to improve drainage and to allow application of ear drops.
- Myringoplasty if the perforation does not heal.
- Cortical mastoidectomy if the ear still discharging.