Myringosclerosis
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Tympanosclerosis is a condition caused by hyalinization and subsequent
calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature M ...
of subepithelial connective tissue of the
tympanic membrane In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit changes in pressur ...
and middle ear, sometimes resulting in a detrimental effect to hearing.


Signs and symptoms

Myringosclerosis rarely causes any symptoms. Tympanosclerosis, on the other hand, can cause significant
hearing loss Hearing loss is a partial or total inability to hear. Hearing loss may be present at birth or acquired at any time afterwards. Hearing loss may occur in one or both ears. In children, hearing problems can affect the ability to acquire spo ...
or chalky, white patches on the middle ear or tympanic membrane.


Causes

The aetiology for tympanosclerosis is not extensively understood. There are several probable factors which could result in the condition appearing, including: *Long term
otitis media Otitis media is a group of Inflammation, inflammatory diseases of the middle ear. One of the two main types is acute otitis media (AOM), an infection of rapid onset that usually presents with ear pain. In young children this may result in pullin ...
(or 'glue ear') *Insertion of a
tympanostomy tube Tympanostomy tube, also known as a grommet, myringotomy tube, or pressure equalizing tube, is a small tube inserted into the eardrum via a surgical procedure called myringotomy to keep the middle ear aerated for a prolonged period of time, typic ...
. If aspiration is performed as part of the insertion, the risk of tympanosclerosis occurring increases. Risk also increases if a larger tube is used, or if the procedure is repeated. *
Atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...
*There is ongoing research as to whether or not
cholesteatoma Cholesteatoma is a destructive and expanding growth consisting of keratinizing squamous epithelium in the middle ear and/or mastoid process. Cholesteatomas are not cancerous as the name may suggest, but can cause significant problems because of the ...
is associated with tympanosclerosis. If there is an association, it is likely that the two conditions co-exist.


Pathophysiology

Increased
fibroblast A fibroblast is a type of cell (biology), biological cell typically with a spindle shape that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and ...
activity results in deposition of
collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...
.
Calcium phosphate The term calcium phosphate refers to a family of materials and minerals containing calcium ions (Ca2+) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white ...
plaque Plaque may refer to: Commemorations or awards * Commemorative plaque, a plate, usually fixed to a wall or other vertical surface, meant to mark an event, person, etc. * Memorial Plaque (medallion), issued to next-of-kin of dead British military p ...
s then form in the
lamina propria The lamina propria is a thin layer of connective tissue that forms part of the moist linings known as mucous membranes or mucosae, which line various tubes in the body, such as the respiratory tract, the gastrointestinal tract, and the urogenital ...
of the tympanic membrane.


Diagnosis

If lesions are typical, non-extensive and with no detriment to hearing, investigation into the condition is rarely required. Audiometry is used to determine the extent of hearing loss, if any. Tympanometry produces tympanograms which can be different when tympanosclerosis is present.
Computerised tomography A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...
(CT) can be used to determine if disease is present in the middle ear. Whilst hearing loss is a common symptom in many diseases of the ear, for example in
otosclerosis Otosclerosis is a condition of the middle ear, middle and inner ear where portions of the dense enchondral layer of the bony labyrinth Tissue remodeling, remodel into one or more lesions of irregularly-laid spongy bone. As the lesions reach the s ...
(abnormal bone growth in the ear), the white, chalky patches on the tympanic membrane are fairly characteristic of tympanosclerosis. Cholesteatoma is similar in appearance but the whiteness is behind the tympanic membrane, rather than inside.


Classification

''Myringosclerosis'' refers to a calcification only within the
tympanic membrane In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit changes in pressur ...
and is usually less extensive than ''intratympanic tympanosclerosis'', which refers to any other location within the middle ear such as the ossicular chain, middle ear
mucosa A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...
or, less frequently, the mastoid cavity.


Treatment

Hearing aids are a common treatment for hearing loss disorders. A more specific treatment is surgical, involving excision of the sclerotic areas and then further repair of the ossicular chain. There are several techniques, sometimes involving two surgeries; success rates are, however, variable. Damage to the inner ear as a result of surgical procedures is a possible and serious concern, as it can result in forms of
sensorineural deafness Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear, sensory organ (cochlea and associated structures), or the vestibulocochlear nerve (Cranial nerves, cranial nerve VIII). SNHL accounts for a ...
.


Prognosis

In most cases, tympanosclerosis does not cause any recognisable hearing loss up to ten years after the initial disease onset. Sclerotic changes seem to stabilise, but not resolve or dissolve, after 3 years.


Epidemiology

Myringosclerosis seems to be more common than tympanosclerosis. Most research has not been conducted upon the general, healthy population, but rather those with otitis media or patients who have had tympanostomy tubes in prior procedures. Of the children studied who had 'glue ear', and who were treated with tympanostomy tubing, 23-40% of cases had tympanosclerosis.
-
One study suggested that people with
atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...
were more likely to have tympanosclerosis than otherwise healthy individuals.


References


External links


Tympanosclerosis
- Image of tympanosclerosis as revealed by
otoscopy An otoscope or auriscope is a medical device used by healthcare professionals to examine the ear canal and eardrum. This may be done as part of routine physical examinations, or for evaluating specific ear complaints, such as earaches, sense o ...
. {{Diseases of the ear and mastoid process Diseases of middle ear and mastoid