Ear, nose and throat surgery

Published on 11/04/2015 by admin

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21 Ear, nose and throat surgery

The ear

The ear is concerned with hearing and balance, and has three parts: the external, middle and internal ear (Fig. 21.1).

Figure 21.1 The anatomy of the ear.

Common symptoms of ear disease include:

• hearing loss (congenital or acquired)

• aural discharge

• otalgia (pain in the ear)

Investigations of auditory function

There are three types of hearing loss:

• conductive, due to disorders of the external and middle ear

• sensorineural, due to cochlear and retrocochlear lesions

• mixed conductive and sensorineural.

Tuning fork tests (Table 21.1)

• Rinne test – a vibrating tuning fork is placed near the external auditory meatus testing air conduction and then firmly on the mastoid process testing bone conduction. In a healthy ear, the sound is heard better by the ear (air conduction) than by the mastoid process (bone conduction).

• Weber test – a vibrating tuning fork is placed either on the vertex of the skull or on the forehead. The patient indicates on which side the sound is loudest.

Table 21.1 Interpretation of tuning fork tests

	Rinne	Weber
Normal	Air conduction better than bone conduction (test positive)	Both sides equal
Conductive deafness	Bone conduction better than air conduction (test negative)	Heard loudest on the affected side
Sensorineural deafness	Air conduction better than bone conduction but both reduced compared to normal (test positive but reduced)	Heard loudest on the good side

Pure tone audiometry and impedance audiometry, along with electric response audiometry, further refine the investigations (Fig. 21.2).

Figure 21.2 An audiogram. (a) Sensorineural loss with reduced hearing levels by both air and bone conduction. (b) Conductive hearing loss with reduced hearing level by air conduction and normal bone conduction.

Diseases of the external ear

Foreign bodies

Skilled personnel should always do extraction of foreign bodies to reduce the danger of forcing the foreign body further into the ear where it may damage the drum and middle ear.

Trauma to the auricle

Haematoma may occur, particularly in boxers and those who take part in contact sports. If blood extravasates between the cartilage and perichondrium, a cauliflower deformity composed of fibrous tissue ensues (classically seen in rugby forwards who damage ears in scrummages).

Otitis externa

Clinical features

There is discharge from the ear and occasional mild pain. In the spreading, necrotising variant, there is systemic disturbance with severe local symptoms which may include the development of a seventh nerve palsy.

Management

In the mild type, topical antiseptics and antibiotics are incorporated into eardrops containing steroids. Aural toilet is essential, best done by an ENT surgeon with a microscope and micro-suction equipment. In severe cases, therapy consists of intensive local treatment with excision of dead tissue and administration of systemic antibiotics.

Diseases of the middle ear

Acute otitis media

This is common in young children and rare after 5 years of age. There is usually a history of upper respiratory tract infection. Inflammation of the post-nasal space and adenoids spreads via the Eustachian tube to the middle ear. Oedema in the tube causes blockage. If secondary bacterial infection spreads in the tube, a middle ear abscess results. Haemophilus influenzae is isolated in 30% of cases in those under 5 years of age. As pressure builds, rupture of the tympanic membrane occurs in the pars tensa. A small proportion of cases develop complications and there is loss of hearing. Other complications include chronic middle ear effusion, scarring of the tympanic membrane (tympanosclerosis), chronic suppurative otitis media and progression to mastoiditis.

Clinical features are pain and hearing loss. If the drum perforates, a purulent discharge develops with the resolution of pain. There may be malaise and pyrexia. On examination, the drum is reddened and tense. Perforation may be visible. Amoxicillin is the preferred drug for children and is administered for 10 days.

Acute mastoiditis

Mastoiditis is a consequence of preceding otitis media. There may be cellulitis and osteitis in the air spaces, which develop into an abscess. Spread may occur through the temporal bone to cause intracranial complications, for example extradural abscess. Clinical features include pain, fever, aural discharge and hearing loss. There may be an erythematous, swollen mastoid and external canal on examination. Mastoid X-rays may show clouding of the air cells and formation of an abscess with erosion of bone. High-dose IV antibiotics are given. If resolution fails to occur, a cortical mastoidectomy may decompress the inflammatory process, preserving the posterior meatal wall and middle ear ossicles.

Otitis media with effusion (glue ear)

Accumulation of non-purulent fluid is common in children between 2 and 6 years of age. This is most likely caused by low-grade inflammation with partial block of the Eustachian tube. Symptoms include impaired hearing, which may rarely lead to a delay in learning to speak, inattentiveness and recurrent earaches. Many children are diagnosed during routing audiometric screening. Examination demonstrates a lustreless, immobile tympanic membrane with occasional fluid levels.

Management

In over 90% of cases, the effusion resolves spontaneously. Unresolved middle ear effusions with hearing loss require an anterior inferior myringotomy, aspiration of the tube and decompression using a grommet. If there is nasal obstruction, the adenoids are curetted.

Middle ear effusions may occur in adults following an upper respiratory tract infection or allergic or vasomotor rhinitis. Chronic suppurative otitis media often follows acute otitis media which may be divided into tubotympanic suppuration limited to inflammation of the mucosa or atticoantral disease with destruction involving the mastoid bone. The latter may be complicated by cholesteatoma formation (a mass of keratinised squamous epithelium) which initially forms in the developed retraction pocket of a perforated tympanic membrane. Spread may occur, destroying middle ear ossicles and temporal bone causing marked hearing loss or vertigo if the cholesteatoma has eroded the bony wall of the most prominent lateral semicircular canal. CT scan may be helpful to demonstrate the extent of bony erosion. Radical mastoidectomy lays open the mastoid and excises the posterior meatal wall and contents of the tympanic cavity to create a safe cavity. Reconstruction using fascial grafts and artificial ossicles (tympanoplasty) may then be considered. The complications of otitis media are summarised in Box 21.1.

Otosclerosis

This is a localised disease of bone affecting the otic capsule. It is inherited as an autosomal dominant trait with incomplete penetration. New spongy bone develops. If this occurs in the area of the stapes, there may be ankylosis and deafness. There is a strong family history. Both ears are affected in 90% of patients, usually presenting in the second decade. Management includes hearing aids and stapedectomy, which restores the mobility of the ossicular chain.

Diseases of the inner ear

Sensorineural hearing loss

Causes include:

• genetic abnormalities

• maternal infections during pregnancy, for example rubella, cytomegalovirus and syphilis

• perinatal hypoxia

• viral and bacterial labyrinthitis

• ototoxic drugs, for example gentamicin, neomycin

• noise-induced hearing loss

• fractures of the temporal bone

• barotrauma to include rupture of the round window.

High audiometric frequencies are usually affected first. Tinnitus is often associated with sensorineural loss. Exposure to high intensity noise causes characteristic bilateral hearing loss on the audiogram.

Management includes hearing aids and air conduction aids consisting of miniature microphone, amplifiers and receivers. Bone conduction aids are used if there is a congenital absence of the pinna and atresia of the canal. Those who do not benefit from hearing aids may benefit from a cochlear implant.

Acoustic neuroma

Clinical features

There is unilateral or marked asymmetric sensorineural hearing loss and tinnitus. The audiogram reveals unilateral sensorineural hearing loss. MRI scan demonstrates the tumour.

Management

The tumour is removed by neurosurgery, hopefully with minimal damage to the facial nerve.

Menière’s disease

Distension of the membranous labyrinth caused by endolymphatic hydrops is thought to be the pathological feature of Menière’s disease. A characteristic triad of symptoms comprises vertigo, fluctuating sensory loss and tinnitus. Hearing gradually deteriorates over a period of time. Attacks of vertigo are treated with vestibular sedatives, for example diazepam and prochlorperazine. A salt-restricted diet may reduce the frequency of attacks. Decompression of the endolymphatic sac and vestibular neurectomy is indicated if medical treatment fails.

The nose and paranasal sinuses

Features of nasal and sinus disease

Symptoms include nasal obstruction, mouth breathing, discharge and post-nasal drip. Unilateral discharge in a child probably originates from a foreign body. Bloodstained discharge with unilateral symptoms may be associated with tumour. Copious, watery discharge may suggest CSF rhinorrhoea. Facial pain may also occur, occasionally radiating into the teeth, eyes or ear. There may also be headaches, loss of smell, bleeding and cosmetic nasal deformity.

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