Diseases of external ear (cont..)

In this post we will discuss about few miscellaneous conditions affecting external ear.

• cerumen
• keratosis obturans
• external auditory canal cholesteatoma
• atresia of meatus

Cerumen or impacted wax:

composed of-

• sebaceous gland secretions
• apocrine sweat gland secretions
• desquamated epithelium & keratin
• dirt

function:

• protective as it lubricates the canal & due to its acidic nature

Motion of the ear canal provided by ordinary chewing movements together with the process of epithelial proliferation and lateral migration propel the cerumen outward in a self-cleansing manner.

complaints:

• hearing loss or blocked sensation
• tinnitus & giddiness due to impaction on tympanic membrane
• Reflex cough:Arnold's cough reflex-due to irritation of auricular branch of vagus nerve.also known as Ear cough.

Diagnosis

• Cerumen impaction is diagnosed by direct visualization with an otoscope.
• seen as brown to blackish mass

Treatment

Cerumen removal may be attempted by

1. irrigation of the external auditory canal, with or without the use of ceruminolytics;
2. by ceruminolytics alone;
3. or by manual removal using a curette, forceps, or suction.

Keratosis obturans:

• Keratosis obturans is characterized by a dense plug of keratin debris located primarily within the deep meatus.
• with no associated erosion or necrosis of the surrounding bone.{THIS IS PRESENT IN external auditory canal cholesteatoma}
• commonly seen b/w 5 & 20 years

etiology:

• due to defect in epithelial migration
• increased production of keratin debris
• both

Clinical features:generally BILATERAL & is PEARLY WHITE MASS.

• Severe ear pain
• Mild / moderate conductive hearing loss
• Associated bronchitis / sinusitis - common{due to shared etiology of defective ciliary function resulting in defective migration}
• Rarely otorrhea
• Thickened tympanic membrane due to pressure of the keratin
• Presence of granulations
• Ballooning of the ear canal (bony reabsorption circumferentially widens the external bony canal)
• On histological examination, the keratin plug displays a lamellar pattern(onion skin pattern) to the circumferential shedding of keratin squames from the auditory canal, with older layers being pushed centrally.

{note:

Keratosis obturans	external auditory canal cholesteatoma
generally bilateral	unilateral
younger patients	older patients
origin is diffuse(along circumference of canal)	focal
generally otorrhea absent	present
also associated with bronchiectasis & chronic sinusitis	not associated
no osteonecrosis	presence of osteonecrosis & focal overlying epithelial loss present
managed successfully by regular aural-toilet	surgical intervention required

Treatment

• Debridement of keratin debris (may require anesthesia)
• Treatment of any underlying inflammation and/or infection
• Periodical follow-up to remove reaccumulations

external auditory canal cholesteatoma:

we will deal with cholesteatoma in detail, in diseases of middle ear since more common in middle ear.

commonly involves post-inferior part of external auditory canal

etiology:

• may be due to trapping of epithelium below level of skin during previous episode of otitis externa.
• margins of it secrete enzymes & also due to pressure effects results in bone erosion
• so often Facial nerve is exposed & paralysed.

iatrogenic external auditory canal cholesteatoma:

• generally at anterior angle of tympanic membrane
• etiology:due to incorrect repositioning of skin flaps at end of procedure

Acquired atresia & stenosis of meatus:

causes-

1. infections:chronic otitis externa - important cause
2. burns
3. trauma

treatment:

meatoplasty {In a meatoplasty, an incision is made immediately behind the meatus, and a portion of the conchal cartilage is excised.}