Conductive deafness due to Chronic Ear infection
Chronic Otitis Media is a chronic infection (ear infection lingering on for over 3 months’ duration) of the middle ear cleft. It This includes disease of the middle due to infections by bacteria, virus etc. It may be Suppurative (with pus formation) or Non suppurative (without the formation of pus).
Anatomy and Physiology of the Ear Click here
Chronic Suppurative Otitis Media
1. Perforation of Tubo-tympanic type (Safe type).
2. Perforation of the Attico antral type (Unsafe type).
3 Perforation of the Marginal posterior marginal type (Unsafe type).
Chronic Non-Suppurative Otitis Media – Also known as Serous or Secretory Otitis Media or Otitis media with effusion (OME)
Chronic Suppurative Otitis Media of the Unsafe type
ATTICO – ANTRAL or MARGINAL TYPE (UNSAFE TYPE)
It is associated with formation of cholesteatoma and therefore regarded as unsafe. The term cholesteatoma is not an accurate description as it is not a tumour and always does not contain cholesterol chrystals. A cholesteatoma, truly speaking is ‘skin in the wrong place’ (Gray). This usually affects the postero-superior quadrant of ear drum (pars tensa) or the attic or epitympanum (Pars flaccida).
A cholesteatoma starts life as a dimple due to localised retraction of a portion of the tympanic membrane in the attic or postero superior quadrant of the pars tensa. It is in reality a retraction pocket and not a “perforation”. Epithelial squames (flat cells of skin) acumulate inside the dimple which soon shuts off and presents as an expanding bag. As more and more epethilium accumulates within the bag, the cholesteatoma forms an expanding erosive bag. This has the potential of eroding bone. Erosion of the small bones of the middle ear – ossicles result in conductive deafness. If it erodes the labyrinth, a sensori neural deafness ensues. Erosion of the facial nerve canal can lead to facial muscle paralysis. Erosion of the labyrinth can cause vertigo. When it grows superiorly, it can erode the tegmen tympani and cause intra cranial complications like meningitis and brain abscess.
1. Congential: - originates as embryonic rest cells, which eats away the bone until it breaks through the outer attic wall. The ear drum is normal in the initial stages. Derlaki and Clemis defined congenital cholesteatoma or Primary choleasteatoma as an embryonic rest of epithelial tissue in an ear without tympanic membrane perforation, in a patient without history of ear infection.
i. Primary - Type occurs following an eustachian tube malfunction resulting into retraction pockets into the attic (pars flaccida). Negative middle pressure causing retraction pocket
a) Immigration - Of tympanic epithelium on deep meatal skin in the posterior superior quadrant of the tympanic membrane occurs. This is possible following destruction of the annulus after a previous middle ear discharge.
b) Metaplasia - Is provoked by chronic infection in the ciliated mucous membrane of the middle ear. Here squamous metaplasia occurs as well as there can be a marginal migration of squamous epithelium from the meatus.
Over time, untreated cholesteatoma can lead to bone erosion and spread of the ear infection to localized areas such as the inner ear and brain causing deafness, facial muscle paralysis, brain abscess, meningitis, and even death can occur.
Formation of a Cholesteatoma (Pathogenesis)
A cholesteatoma usually occurs because of poor eustachian tube function as well as infection in the middle ear. The eustachian tube normally conveys air from the back of the nose into the middle ear to equalize ear pressure. When the eustachian tubes works poorly perhaps due to allergy, a cold or sinusitis, the air in the middle ear is absorbed by the body, and a partial vacuum results in the ear. The vacuum pressure sucks in a pouch or sac by stretching the eardrum inwards, especially the superior part of the pars tensa or pars flaccida of the ear drum or areas weakened by previous infections.
Cholesteatomas It usually takes the form of a cyst or pouch that containing scales of accumulated skin arranged in onion – like layers.
Symptoms of a Cholesteatoma
Initially, the ear may discharge off and on. The discharge may have a characteristic foul odour. As the cholesteatoma pouch or sac enlarges, it can cause a full feeling or pressure in the ear, along with hearing loss. Dizziness due to involvement of the balance organ and facial muscle weakness on the same side as the cholesteatoma can occur. Ideally, urgent evaluation is required as soon as the diagnosis of cholesteatoma is made.
Dangers of ignoring a Cholesteatoma
Ear cholesteatomas can be dangerous because of their ability to erode bone.They occur in an area crowded with important structures. There is only a thin plate of bone separating a cholesteatoma from the brain and meninges and lie close to the small bones (ossicles) of the middle ear, the organ of hearing and balance in the internal ear, facial nerve. should never be ignored. Bone erosion can cause the infection to spread into the surrounding areas, including the inner ear and brain. If untreated, deafness, brain abscess, meningitis, and rarely death can occur.
These are indicated by headache, giddiness, increasing deafness and noises in the ear and weakness of the facial muscles. Over time, the cholesteatoma sac increases in size, the mouth of the sac being blocked by skin flakes. With expansion, it starts eroding surrounding structures of the middle ear
Progression of Cholesteatoma & Chronic mastoiditis and Complications
Treatment of Chronic Mastoiditis and Cholesteatoma
Hearing and balance tests, CT scans of the mastoid bone may be necessary to determine the hearing level and the extent of destruction the cholesteatoma has caused.
A cholesteatoma usually requires surgical treatment to prevent serious complications. Surgery (called Tympano- Mastoidectomy involving extensive bone drilling of the mastoid bone and removal of disease from the middle ear is required. It may be performed under general or local anesthesia. The primary purpose of surgery is to remove the cholesteatoma and infection and achieve an infection-free, self-cleansing dry ear. Hearing preservation or restoration is a secondary goal of surgery. If the disease has been satisfactorily removed. The small bones of the middle ear are repositioned to restore the hearing. Various inert material prosthesis of teflon, stainless steel, silicone and hydroxyapetite as well as homo or auto graft of bone and cartilage may also be used. In cases of severe ear destruction, restoration of normal hearing may not be possible. Reconstruction of the middle ear to its normal anatomy is usually not possible in one operation; and therefore, a second operation (if deemed necessary) may be performed later. Facial nerve repair or procedures to control dizziness are rarely required.
Follow-up office visits after surgical treatment are necessary and important, because cholesteatoma sometimes recurs. In cases where an open mastoidectomy cavity has been created, office visits every few months are needed in order to clean out the mastoid cavity and prevent new infections. In some patients, there must be lifelong periodic ear examinations.
Complications of Chronic mastoiditis and Cholesteatoma