cholesteatoma

Generality

Cholesteatoma is a pathology of the middle ear, characterized by an unusual collection of epithelial cells near the eardrum or the three ossicles.

Figure: a live cholesteatoma. From the site: www.ao.pr.it

The accumulation of this mass of cellular debris is very often due to bacterial infections of the ear canal, but not only.

The main symptom of cholesteatoma is hearing loss (hypoacusis): at the beginning, it is moderate; subsequently, when the formation expands, it becomes much more intense. Early diagnosis is essential, to prevent the patient from encountering complications, even unpleasant ones; the pressure exerted by the cholesteatoma could in fact damage the surrounding structures.

Surgery is used to remove the cholesteatoma. Despite the invasiveness of the intervention, the benefits, which derive from it, suggest to undergo the operation.

Anatomy of the ear

The ear is divided into three parts:

• External ear
• Middle ear
• Inner ear

The outer ear starts from the auricle and ends where the eardrum is located.

The middle ear is placed behind the eardrum and has three small bones: the hammer, the anvil and the stirrup. It communicates with the nose, through a duct called Eustachian trumpet . Therefore, air passes through the middle ear.

The inner ear is the area in which there are cochlea and semicircular canals . The cochlea is the organ of hearing; the semicircular canals, on the other hand, constitute the organ of balance.

THE THREE BONES OF THE MIDDLE EAR

The three little bones, hammer, anvil and stirrup, are so called because of their resemblance to the three tools used by the blacksmith during his craft work.

The hammer is the bone placed in contact with the eardrum. The bracket connects with the auger. Finally, the anvil connects the hammer and the bracket and interposes between them.

SOUND WAVES AND HEARING

How does the ear and the perception of sounds work?

Sound waves penetrate the outer ear and reach the eardrum. Struck by the sounds, the eardrum vibrates. This vibration is transmitted to the three ossicles, which set in motion. The hammer begins to move, then the anvil and, finally, the stirrup. In other words, the movement of a small bone determines the movement of the next one. It is the so-called ossicular chain .

From the bracket, the sound signal passes to the cochlea. The latter translates the sound into a nerve signal, which is directed to the brain for final identification.

What is cholesteatoma?

The term colesteatoma identifies an unusual collection of squamous epithelial cells, at a small niche, in the middle ear. This accumulation has the appearance of a pearly-white mass, which gradually increases its volume with time.

The presence of a cholesteatoma represents a threat to the hearing power of those who are afflicted, as it can also cause complete deafness.

What are squamous epithelial cells?

When we talk about epithelial cells, or epithelial tissue, we refer to covering cells, present both outside and inside the body. For example, there is the epithelium of the skin, mouth, vagina, pulmonary alveoli, etc.

Squamous (or paved) epithelial cells have a flat shape and have a slightly raised core, which reminds a scale. There are several subgroups of squamous epithelial cells: there are "keratinized", "non-keratinized", simple etc; their appearance depends on the position and the organ they are covering.

EVOLUTION OF COLESTEATOMA

How does the cholesteatoma evolve?

In its early stages, the cholesteatoma affects and damages the eardrum and the three ossicles of the middle ear. Subsequently, it expands, invading the structures of the inner ear (cochlea and semicircular canals) and, even, the mastoid portion (or mastoid process ) of the temporal bone of the skull. In fact, the worst forms of cholesteatoma penetrate to the brain, causing brain infections with unpleasant consequences.

THE COLESTEATOMA IS A TUMOR?

The name colesteatoma may suggest a malignant tumor pathology, but it is good to specify that it has no cancerous origin.

Epidemiology

Cholesteatoma is a rare disorder that affects an individual every 10, 000 every year. It can arise at any age, without any particular preference.

Some statistical studies report that, among 1, 000 people with various hearing problems, one case only presents the cholesteatoma.

Causes

Figure: a live cholesteatoma. Modified from the site: //chroniclescamera.blogspot.it/

The exact cause of the cholesteatoma has not yet been fully clarified. According to the most accredited hypothesis, the anomalous collection of squamous cells is due to an incorrect cellular replacement of the internal epithelial lining of the ear canal. In other words, in the absence of the disorder, the auditory canal returns its epithelial cells, creating new ones and eliminating the old ones. In the case of cholesteatoma, instead, these cells instead of flaking and dispersing (as usual) accumulate in a point of the middle ear. This is how the white-pearly mass is created, of which we have said.

ORIGIN OF THE DISTURBANCE: WHY INSERT THE COLESTEATOMA?

Two types of cholesteatoma have been distinguished, different by origin:

• Congenital cholesteatoma . Present since birth, it is characterized by its growth, behind the eardrum of the epithelial mass.
• Acquired cholesteatoma . Typical of adulthood, it is the consequence of chronic and recurrent ear infections, which close and block the passage of air through the Eustachian tube. This impediment causes the eardrum to be sucked inwards, thus forming a sort of small housing. Here, the old squamous epithelial cells accumulate, after replacing them with new ones, and remain trapped there. It is a time-consuming process, explaining why it appears in adulthood.

The acquired cholesteatoma is the most common form of cholesteatoma; Congenital forms are rare.

Symptoms and Complications

The cholesteatoma usually affects only one ear, causing the following symptoms and signs:

• Hearing loss (hearing loss )
• Smelly otorrhea
• Tinnitus (the so-called "whistles" in the ear)
• Perforation of the eardrum
• Headache

These manifestations, when the cholesteatoma is in its infancy, are mild and do not cause any particular disturbance to the patient. Over time, however, the collection of epithelial cells expands, aggravating the entire symptomatology: first, the three ossicles are involved, and then the structures of the inner ear (cochlea and semicircular canals).

What is otorrhea?

When we talk about otorrhea, we are referring to any secretion of the ear canal due to an infection in the middle or external ear. On the basis of the pathology that originates it, the otorrhea can be blood, purulent, muco-purulent, malodorous, watery or mucoid. The possible causes of octopus are: trauma, ear cancer, acute ear infections and chronic otitis of the middle ear, loss of cerebrospinal fluid or eczema.

Often the erotrean goes unnoticed, until the causes that trigger it are not further aggravated.

Hearing loss

Hearing loss is classified as conductive, sensorineural or mixed ( conductive-sensorineural ). It is conductive when only the three ossicles (middle ear) are affected; sensorineural if only cochlea and semicircular canals are involved (inner ear); mixed when both middle and inner ear structures are affected.

In cases of cholesteatoma, hearing loss is always conductive. Subsequently, if the collection of squamous cells goes to affect also the cochlea, it can become a mixed type. Another pathology of the ear, also initially conductive and then mixed, is otosclerosis .

COMPLICATIONS

In light of the above, if the cholesteatoma is not treated properly, it can give rise to various complications; the main ones are:

• Damage and possible destruction of the three small bones of the middle ear .

  Characteristics: the colesteatoma, growing, goes to affect also the three ossicles.

  Consequences: possible complete and permanent deafness.

• Damage to the mastoid portion (or mastoid process) of the temporal bone .

  Characteristics: the mastoid bone is connected to the middle ear, through the tympanic cavity, and is composed of numerous cells full of air. When the cholesteatoma expands, it goes to invade these regions, infecting and destroying them.

  Consequences: brain abscess, meningitis, bone erosion, hearing loss, etc.

• Damage to the cochlea and semicircular canals .

  Consequences: permanent deafness, dizziness and loss of balance.

• Damage to the facial muscles .

  Consequences: paralysis of the muscles of the face.

• And rosion of other bony portions of the skull, located around the ear .

  Consequences: infections, meningitis, brain abscess etc.

Diagnosis

Preliminary diagnosis is based on the detection of typical symptoms of cholesteatoma: hearing loss, tinnitus and otorrhea. After that, further investigations are needed, such as:

• Otoscopic examination
• Audiometric tests
• Ear pad
• CT scan (computerized axial tomography)

WHAT SPECIALIST DO YOU SEE FOR?

An individual who feels the classic symptoms of cholesteatoma can go to an otolaryngologist or a general practitioner .

Figure: CT scan of a patient with cholesteatoma. From the site: www.infirmus.es

Both, in fact, through the otoscope, are able to detect the pearly-white mass of squamous cells, located at the level of the middle ear, and an eventual perforation of the eardrum.

The otoscope is an instrument with a small light and a magnifying glass.

THE AUDIOMETRIC EXAMS

Audiometric examinations take place in a hospital and are handled by an audiometrist technician . The purpose of these tests is to define the degree of hearing loss (mild or severe).

The tests most commonly performed are the Rinne test and the Weber test ; they are both quick and non-invasive.

HEADPHONE

As we have seen, one of the typical signs of cholesteatoma is malodorous otorrhea. The bad smell is due to the presence, in the secretion, of a bacterium, Pseudomonas . To identify this germ, responsible for chronic infections at the level of the ear canal, you need a auricular swab on which to carry out the appropriate laboratory investigations.

TAC (COMPUTERIZED AXIAL TOMOGRAPHY)

This examination, which is slightly invasive because it uses ionizing radiation, shows whether the cholesteatoma has expanded and whether it has affected the mastoid process or other brain areas.

Treatment

Cholesteatoma therapy usually consists of surgical removal of the squamous cell mass. However, this operation is not suitable for all patients; therefore, in these cases, the attending physician is forced to resort to alternative countermeasures, less invasive but also less effective.

SURGICAL INTERVENTION

The operation to remove the coleasteatoma can be performed, after general anesthesia, through two procedures:

• Tympanoplasty associated with mastoidectomy . This technique involves the incision of the mastoid process (ie the portion of temporal bone located behind the ear), in order to have free access to the ear canal. Once the section is practiced, we proceed with the elimination of the cholesteatoma, contained in the ear. If this has also affected the eardrum and the three ossicles, the latter must be replaced with prostheses. Furthermore, if the infiltration of squamous epithelial cells has reached part of the mastoid bone, the affected areas are removed. The operation requires hospitalization and lasts several hours.
• Closed technique tympanoplasty . Through this procedure, the auditory canal is accessed without removing any bone wall. Many small incisions are made, which allow to gradually remove the cholesteatoma from the areas where it is wedged. If the eardrum and the three ossicles are damaged, they are repaired or replaced, as in the previous case. The operation requires hospitalization and lasts several hours.

The first surgical procedure is clearly much more invasive than the second one. However, it has more advantages than risks, especially when compared to the closed technique tympanoplasty. In fact, the danger of the cholesteatoma reforming is very low and the complications are very rare events. On the contrary, with the second surgical technique, it is possible that the mass of squamous cells is not completely removed and this can result in a recurrence after a short time.

NON-SURGICAL TREATMENT

If general anesthesia represents a risk to the patient's health, non-surgical treatment is chosen. The countermeasures, in these cases, consist of a sort of " ear washes ", which remove debris and cells from the cholesteatoma. Although not as invasive as a surgical operation, these interventions have three disadvantages:

• A regular practice
• Assistance by expert personnel, which helps to carry out the washing
• Variable effectiveness

ANTIBIOTIC COVERAGE

In the pre-operative period, once the disease is diagnosed, antibiotic drugs are administered. They serve to counter bacterial infections, which, as we have seen, often cause cholesteatoma and malodorous otorrhea.

Prognosis and prevention

The prognosis, for those suffering from cholesteatoma, depends on when the pathology is diagnosed and on how extensive the cholesteatoma itself is. In other words, an early diagnosis guarantees a greater percentage of successful surgery and a lower chance of relapse.

On the contrary, a late diagnosis and a lack of treatment of ear infections make the patient more easily subject to complications such as meningitis and permanent deafness .

After surgery, the patient should take care to regularly wash his ears (to remove debris and earwax), thus preventing the formation of another cholesteatoma.