Infection entering the middle ear through the perforation from the external

meatus. The perforation is always a central perforation, that is, it is

surrounded by part of the pars tensa throughout its circumference. The

perforation may be anterior, posterior, kidney-shaped or subtotal, but it is

always surrounded by drum remnant.

CLINICAL FEATURES. The main symptom of tubotympanic disease is mucopurulent

discharge which may be intermittent or persistent. There is also deafness which

may vary from trivial to moderately severe, that is, averaging about 40dB. More

severe deafness is unusual and is due to involvement of the ossicular chain

either by adhesions or by absorption causing a break in the link.

Examination of the ear will confirm the presence of a central perforation. It is

essential that all discharge be removed from the ear so that the tympanic

membrane may be completely examined. The discharge is removed by mopping or by

syringing. There may also be some otitis externa due to prolonged discharge. In

all cases the nasal cavities, nasopharynx and pharynx must be examined because

It is in the upper respiratory tract that the source of infection will be found.

The common causes of ascending infection are infected in tonsils and adenoids

and sinusitis. Hearing tests, including tuning-fork tests and pure-tone

audiometry will confirm the presence of conductive deafness. Radiography of the

nasal sinuses will frequently be required to exclude sinusitis. Radiography of

the mastoid will usually show that the mastoids are cellular, but if there has

been prolonged infection they may be of the sclerotic type but there will be no

evidence of bone destruction. A swab of the ear discharge will be submitted for

bacteriological investigation.

Complications are rare and are not serious. With prolonged discharge a polypus,

is a swelling of the middle-ear mucosa, may project through the perforation into

the external auditory meatus. This may require removal before the tympanic

membrane can be seen adequately and the true nature of the disease assessed.

Chronic discharge from the ear leads to otitis externa and this may require

treatment before the tympanic membrane can be adequately inspected. A much more

unusual complication is fixation of the ossicles by fibrosis. The ossicular

chain may be broken by absorption of bone, particularly the long process of the

incus. These lesions of the ossicular chain may cause more severe deafness.

TREATMENT. Treatment of the infection consists first of all of eliminating upper

respiratory tract infection. This may require the removal of tonsils or adenoids

or the treatment of sinusitis, etc. Provided this is done it is not usually

difficult to control the ear infection by local treatment. The local treatment

consists of thorough cleaning of the ear. After cleaning, antibiotics are

inserted, preferably on a pack. The choice of the antibiotic will depend on the

bacteriology. There will be a high incidence of Gram-negative infections such as

B. proteus or Pseudomonas pyocyanea so that antibiotics such as gentamicin or

neomycin will be required. It is usual to combine the antibiotic with

hydrocortisone to reduce the likelihood of skin sensitivity reactions. There is

a theoretical risk that these antibiotics which are ototoxic may penetrate the

oval or round window to cause sensorineural deafness, but there is no evidence

yet that this occur. Systemic antibiotics are given. In the vast majority of

cases the infection can be controlled by these measures.

However, once the ear is dry, there is always the risk of ascending infection

from the upper respiratory tract or infection from the outside via the external

meatus. These patients should be warned not to get water into their ears when

washing or swimming and, if the patient gets a cold, he should not blow his nose

as this may cause massive movement of nasal discharge up the Eustachian tube to

the middle ear. If there is recurring discharge or if the deafness sufficient to

cause disability, closure of the perforation by myringoplasty should be

considered.

The Dangerous-Type Tympanomastoid Otitis Media (Epitympanitis)

In this type of infection the bone of attic, antrum or mastoid process is

involved as well as the mucosa of the middle-ear cleft. An erosion of bone may

extend to adjacent vital structures there is always a danger of serious

complications. The bony involvement may give rise to granulations or polypi.

These may be true granulation tissue but are more often the result of

inflammatory swelling of the mucosa of the ear. Their presence, however, is

usually evidence of bony involvement.

CLINICAL FEATURES. The symptoms are very similar to those of the safe type of

otitis media. The main symptom is again the discharge from the ear which may be

persistent or recurrent. The discharge, however, is purulent rather than

mucopurulent and it is frequently foul-smelling. Deafness is again usually

present and may vary from trivial to severe because of frequent involvement of

the ossicular chain. If granulations or polypi are present, bleeding from the

ear may be note. The onset of symptoms is insidious so that the patient may be

unaware of the starting point of the disease, but in most cases the condition

commences in childhood.

On examination, purulent discharge which is frequently offensive has to be

mopped out before the tympanic membrane can be adequately seen. Polypi or

granulations may have to be removed by surgery before the nature of the

condition may be fully assessed. In contrast to the safe type of otitis media

the perforation in the dangerous type is usually attic or in the posterosuperior

segment of the tympanic membrane. The perforation is marginal, that is, it

extends to the bony annulus of the drum. Polypi or granulations may be seen to

occupy such perforation or may protrude through them into the ear canal.

Cholesteatoma may be seen as a greyish substance projecting from an attic or a

marginal perforation.

CHOLESTEATOMA. There are several theories as to how cholesteatoma arises.

1. Congenital Cholesteatoma

This is unrelated to chronic suppurative otitis media. It arises from embryonic

cell rests in the cranial bones and has been described in the region of the

internal auditory meatus.

2. Cell Rests

Some consider that cholesteatoma may arise from cell rests of squamous

epithelium in the middle-ear mucosa.

3. Metaplasia

It is well known that metaplasia can occur in mucous membrane, e.g. where a

nasal polypus protrudes from the nose or where an aural polypus protrudes from

the ear. It is, therefore, likely that metaplasia can occur in the middle-ear

mucosa and this may account for the multiple cholesteatomas which are seen

occasionally in cellular mastoids in young people.

4. Squamous Epithelium

This may grow through a perforation of the tympanic membrane to form a

cholesteatoma in the middle ear.

5. Retraction Pocket

The most widely accepted explanation of the origin of cholesteatoma is that it

starts as a retraction pocket of the Eustachian tube is blocked, the tympanic

membrane tends to be retracted in the posterosuperior segment and in the attic

region where the membrana flaccida is thin. This is frequently seen in the later

stages of secretory otitis media when the drum becomes atrophic. A simple

retraction pocket causes little trouble as the dead epithelium readily passes

into the meatus and is carried to the exterior by the normal migration. If the

retraction pocket becomes more marked as the process continues, a sac may be

formed with a narrow neck. At this stage the dead squames may not be able to

escape through the narrow neck and the condition is now a cholesteatoma. Once

formed a cholesteatomatous sac will continue to grow at the expense of any

structure in its path. Structures immediately at risk are the long process of

the incus, the Fallopian canal containing the facial nerve, and the dense bone

of the horizontal semicircular canal. Slightly more remotely, the tegmen may be

eroded to expose the middle fossa dura, the sigmoid sinus may be eroded with

risk of sinus thrombosis or the dura of the posterior fossa may be exposed to

allow direct access into the posterior fossa towards the cerebellum.

Problems of function of the Eustachian tube leading to secretory otitis media

are extremely common and it seems likely that, in most cases, cholesteatoma

arises from this cause during childhood.

6. Cholesterol Granuloma

This consists of cholesterol crystals surrounded by foreign-body giant cells and

granulations tissue. The granuloma occurs at the site of haemorrhage and may be

seen in any form of chronic otitis media. There is no significant relation with

cholesteatoma.

INVESTIGATIONS. Hearing tests, including tuning-fork tests and pure-tone

audiometry, will be required. Radiography will usually show a sclerotic mastoid.

The mastoid is small and poorly developed with a low middle fossa and a

far-forward lateral sinus. If the mastoid was previously cellular there may be

secondary sclerosis tending to obliterate the cells. A larger cholesteatoma sac

may be seen as an area of radio-translucency with a clearly outlined bony

margin. When discharge is present a swab should be taken to determine the

organisms and their sensitivity to antibiotics.

TREATMENT. Before treatment can commence, an accurate assessment of the nature

and degree of the disease process must be made. Examination of the ear using an

operating microscope will frequently be required. Aural polypi or granulations

may require removal before the underlying drum can be adequately visualized. If

there is no evidence of cholesteatoma the treatment described for the safe type

of otitis media may be used, and this may also be applicable after the removal

of granulations or polypi if no cholesteatoma is seen. If the infection is not

controlled by this conservative treatment, surgical treatment will be required.

In most cases of cholesteatoma surgical treatment will be required. If

cholesteatoma is seen in an attic perforation or in a posterosuperior

perforation it is not usually possible to assess the extent of the

cholesteatomatous sac unless there is also radiographic evidence of a bony

defect. Such evidence is usually only seen in the larger cholesteatomas. If the

hearing is good it is tempting to wait until it deteriorates before advising

treatment, lest the hearing be further damaged. However, if expectant treatment

is applied, there may be a sudden loss of hearing from trivial to severe if the

long process of the incus is eroded. It will then be very difficult to restore

the hearing to its previous level. It is more likely that a good level of

hearing will be maintained by early surgical treatment which will prevent

further extension of the cholesteatoma to the ossicles. Such surgery may require

removal of parts of the ossicular chain to make the ear safe, although this may

require sacrifice of the hearing. In addition to the risk to hearing there is

the distinct possibility of facial paralysis, labyrinthitis or an intracranial

complication if cholesteatoma is not controlled. It is for this reason that

surgical treatment will be required in the majority of cases to control the

cholesteatoma.

The surgical treatment of chronic otitis media