Keratosis obturans
| Keratosis obturans | |
|---|---|
| Classification and external resources | |
| ICD-10 | H60.40 |
| ICD-9-CM | 380.21 |
Keratosis obturans is a disorder of keratin formation that involves the external ear canal accumulating cholesterol granules, which may lead to bony erosion.
Etiology
The exact etiology is not known. It appears to be result of abnormal shedding of the epithelium and failure of migration of the cell from the surface of the tympanic membrane, which leads to accumulation of a mass. The keratin plugs are shed from all sides of ear canal. It looks like onion skin. A mass thus formed causes erosion and widening of the bony canal. It is sometimes associated with excess cerumen (wax) formation. Bronchiectasis, chronic sinusitis, and old age chronic smoking are risk factors.
Symptoms
- Severe pain
- Ear discharge
- Tinnitus (ringing sound in ear) along with discharge from ear.
- Deafness
- Granulation tissue formation
- In severe cases, the facial nerve may be exposed causing paralysis
- Otalgia
- Otorrhea
- Associated sinusitis or bronchitis may be present CT scan of temporal bones may reveal canal erosion and widenening
Diagnosis
The ear canal appears to be widened, making the ear drum stand out. CT scan of temporal bones may reveal canal erosion and widening. After surgical removal under general anesthesia the specimen must be sent for pathological evaluation to rule out malignancy.
Ear examination
On examination with the help of otoscope, it is very essential to differentiate keratosis obturans from cerumen (wax). Cerumen is the accumulated secretion from glands. It appears black or brown. However, if you examine a case of choleasteatoma with an otoscope, it looks like a pearly-white mass.
Investigations
- Examination under microscope : It may reveal presence of cholesteatoma, its site and extent, evidence of bone destruction, granuloma, conditions of ossicles and pockets of discharge.
- Tuning fork test and audiogram : essential for preoperative evaluation and to confirm the degree and type of hearing loss.
- X-ray mastoid/CT scan temporal bone : They indicate extent of bone destruction and degree of pneumatization. Choleasteatoma causes destruction in the area of attic and antrum better seen in lateral view.
- Culture and sensitivity of ear discharge : helps to select proper antibiotic.
Treatment
Removal of mass from the deep meatus to be performed under general anesthesia. Frequent cleaning may retard process of accumulation. Cleaning may be much easier if the typically inspissated and adherent material is softened with mineral oil. Surgical intervention rarely indicated, unless the erosion is very deep.
Surgery
The variation in technique in cholesteatoma surgery results from each surgeon's judgment whether to retain or remove certain structures housed within the temporal bone in order to facilitate the removal of cholesteatoma. This typically involves some form of mastoidectomy which may or may not involve removing the posterior ear canal wall and the ossicles.
Removal of the canal wall facilitates the complete clearance of cholesteatoma from the temporal bone in three ways:
- It removes a large surface onto which cholesteatoma may be adherent.
- It removes a barrier behind which the cholesteatoma may be hidden.
- It removes an impediment to the introduction of instruments used for the removal of cholesteatoma.
Thus removal of the canal wall provides one of the most effective strategies for achieving the primary aim of cholesteatoma surgery, the complete removal of cholesteatoma. However, there is a trade-off, since the functional impact of canal wall removal is also important.
Initial softening of mass with sodium bicarbonate/glycerine solution ear drops daily followed by syringing should be tried. Regular observation of patient is necessary to prevent the further accumulations. Two types of surgeries are possible, the canal wall down procedure or the canal wall up procedure.
See also
- Cholesteatoma, a different condition of external auditory canal disorder that has a more or less similar presentation
References
- ↑ brackmann, shelton. otologic surgery (3 ed.).
- Logan, Turner. Disease of Nose , Ear & Throat (10th ed.).
- PL Dhingra. Disease of Ear, Nose & Throat (2nd ed.).
- Glasscock, Shambaugh. Surgery of the Ear (5th ed.).