DISEASE OF EXTERNAL AUDITORY CANAL

BY-DR.SUDEEP K.C

DISEASES OF EXTERNAL AUDITORY CANAL

Diseases of external auditory canal are grouped as: Congenital disordersTraumaInflammationTumorsMiscellaneous conditions.

A)Congenital Disorders

1)Atresia of External canal : It may occur alone or in association with microtia . The outer meatus in this case is obliterated with fibrous tissue or bone while deep meatus and TM are normal.

2)Collaural fistula : It is abnormality of first branchial cleft. The fistula has two openings one in the neck just below and behind the angle of mandible, and other in external canal or middle ear.

B)Trauma to Ear canal : It may be minor or major lacerations.

c)Inflammations of Ear canalIt is also called as otitis externa.It is divided into infective and reactive group.1)Infective Group:Bacterial : -localised ottis externa(furuncle) -Diffuse otitis externa -Malignant otitis externaFungal : otomycosisViral :-Herpes zoster oticus -Otitis externa haemorrhagica

2) Reactive group:

Eczematous otitis Externa

Seborrhoeic otitis Externa

Neurodermatitis

A)Furuncle(Localised acute otitis externa) It is a staphylococcal infection of the hair follicle.Symptoms: severe pain and tenderness. Movements of pinna and jaw is painful. Oedema over mastoid with obliteration of retroauricular groove. Priauricular lymphnodes get enlarged.

Treatment: Without abscess formation-systemic antibiotics. -Analgesics -Local heat -10%icthammol glycerine.With abscess formation: Incision and drainage.

B)Otomycosis It is the fungal infection of ear canal. Causative agent: -Aspergillus niger - A. fumigatus - Candida albicans Symtoms: Intense itching,discomfort or pain in the ear,watery discharge and ear blockage.

Treatment:Thorough ear toilet to remove all discharge and debris.Antifungal agents – Nystatin,clotimoxazole , it should be continued for a week even after apparent cure to avoid recurrences.

C)Otitis externa haemorrhagica

It is caused by virus and characterised by formation of haemorrhagic bullae on TM and deep meatus .

Symptoms: Severe pain in the ear and blood stained discharge when bulla rupture.

Treatment: Analgesics and antibiotics for secondary infection of ear canal and middle ear.

D)Herpes zoster oticus

It is characterised by formation of vesicles on TM, meatal skin , concha and postauricular groove.the7th and 8th cranial nerves may be involved.

Miscellaneous Conditions1) Impacted wax: Wax is composed of secretion of sebaceous

gland , cerimunous glands, hair,desqumated epithelial debris, keratin and dirt.

It has protective function as it lubricates the canal and entraps any foreign body that enters the canal.

Treatment: Removal by syringing or instrumental manipulation. If wax is too hard it is softened by 5% soda bicarb

with glycerine and water.

2)Foreign bodies of ear

Methods of removing foreign bodies:Forceps removalSyringingSuctionMicroscopic removal with special instrumentsPostaural approach

Soft or irregular FB like paper , sponge _ removed by fine forceps.

Most of the seeds grains and smooth object –removed with syringing

Living objects like fly insects-first killed by instilling oil, spirit, choloroform water . Then can be removed by any of the methods.

Maggots in the ear : Instilling chloroform water to kill maggots and later removed by forceps.

3)Keratosis obturans

Collection of pearly white mass of desquamated epithelial cells in deep meatus . This , by its pressure effect , causes absorption of bone. Aetiology : Commonly seen between 5-20 yrs and may affect one or both ear. Failure or obstruction of migration of epithelium of TM .

Clinical features:Pain in the earDeafnessTinnitusEar discharge

Treatment : Keratotic mass is removed either by syringing or instrumentation . If secondary otitis externa present should be treated.

1)Retracted tympanic membrane:

It appears dull and lustreless , handle of malleus appears foreshortened, cone of light is interrupted.

It occurs as a result of negative intratympanic pressure when the eustachian tube is blocked.

Diseases of tympanic membrane

2)Myringitis bullosa : It is a painful condition characterised by formation of haemorrhagic blebs on TM and deep meatus.

3)Herpes zoster oticus: it is viral infection involving the facial nerve.there is vesicles on TM , deep meatus , concha and retroauricular sulcus.

4)Traumatic rupture: Rupture of TM may be due to trauma, sudden change in air pressure, fracture of temporal bone. The edges of perforation get inverted .

5)Tympanosclerosis : It is hyalinization and later calcification in fibrous layer of TM. It appears as chalky white plaque. Mostly, it remains asymptomatic but sometimes interferes in conduction of sound.

6)Perforations

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