Diseases Of external Auditort Canal Flashcards
Atresia(abnormal closure or absence) of external canal. .
Congenital atresia of the meatus may occur alone or in association with microtia.
When it occurs alone, it is due to failure of canalization(new channels in tissues) of the ectodermal core that fillls the dorsal part of the first branchial cleft. The outer meatus(foramen), in these cases, is obliterated with fibrous tissue or bone while the deep meatus and the tympanic membrane are normal. Atresia with microtia is more common.
Treacher Collins
Pierre Robbins
Collaural fistula.
This is an abnormality of the fi rst branchial cleft. The fistula has two openings: one situated in the neck just below and behind the angle of mandible and the other in the external canal or the middle ear. The track of the fi stula traverses through the parotid in close relation to the facial nerve.
Wiki:
Collaural fistula or cervico-aural fistula is a type of fistula whose openings are at external auditory canal and the neck, usually in the upper part of anterior border of sternocleidomastoid muscle.
Trauma
Minor lacerations of canal skin result from Q-tip injury (scratching the ear with hair pins, needles or matchstick) or unskilled instrumentation by the physician. They usually heal without sequelae.
Major lacerations result from gunshot wounds, automo-bile accidents or fi ghts. The condyle of mandible may force through the anterior canal wall. These cases require careful treatment. Aim is to attain a skin-lined meatus of adequate diameter. Stenosis of the ear canal is a common complication.
Furuncle (localized acute otitis externa).
✓ staphylococcal infection of the hair follicle(only in cartilaginous part)Usually single, the furuncles may be multiple.
*Pain,tenderness. Move-ments of the pinna are painful. Jaw movements, as in chew-ing, also cause pain in the ear.
A furuncle of posterior meatal wall causes oedema over the mastoid with obliteration of the retroauricular groove. Periauricular lymph nodes (anterior,post and inf) are large and tender
Treatment without abscess
Antibiotics, painkillers,heat
W abscess
Incision and curettage
recurrent furunculosis, diabetes should be excluded, and attention paid to the patient’s nasal vestibules which may harbour staphylococci and the infection trans-ferred by patient’s fi ngers.
Diffuse otitis externa.
It is diffuse inflammation of meatal skin which may spread to involve the pinna and epidermal layer of tympanic membrane
> commonly seen in hot and humid climate and in swimmers. Excessive sweating changes the pH of meatal skin from that of acid to alkaline which favours growth of pathogens.
(i) trauma to the meatal skin (ii) invasion by pathogenic organisms.
Trauma in otitis externa(diffuse)
can result from scratching the ear canal with hair pins or matchsticks, unskilled instrumentation to remove foreign bodies or vigorous cleaning of ear canal after a swim when meatal skin is already macerated. Break in continuity of meatal lining sets the ground for organisms to invade.
Microorganisms in otitis Externa(diffuse)
invasion by pathogenic organisms.
Common organisms responsible for otitis externa are Staphy-lococcus aureus, Pseudomonas pyocyaneus, Bacillus proteus and Escherichia coli but more often the infection is mixed.
Some cases of otitis externa are secondary to infection of the middle ear, or allergic sensitization to the topical ear drops used for chronic suppurative otitis media.
Clinical features
Clinical features. Diffuse otitis externa may be acute or chronic with varying degrees of severity.
Acute phase is characterized by hot burning sensation in the ear, followed by pain which is aggravated by move-ments of jaw.
Ear starts oozing thin serous discharge which later becomes thick and purulent.
Meatal lining becomes inflamed and swollen. Collection of debris and discharge accompanied with meatal swelling gives rise to conductive hearing loss. In severe cases, regional lymph nodes become enlarged and tender with cellulitis of the surrounding tissues.
Chronic phase is characterized by irritation and strong desire to itch. This is responsible for acute exacerbations and reinfection.
Scanty discharge,crusts. Meatal skin which is thick and swollen may also show scaling and fi ssuring. Rarely, the skin becomes hypertrophic leading to meatal stenosis (chronic stenotic otitis externa).
Treatment
Treatment. Acute phase is treated as follows:
(i) Ear toilet. It is the most important single factor in the treatment of diffuse otitis externa. All exudate and debris should be meticulously and gently removed. Spe-cial attention should be paid to anteroinferior meatal recess, which forms a blind pocket where discharge is accumulated. Ear toilet can be done by dry mopping, suction clearance or irrigating the canal with warm, sterile normal saline.
Treatment (2)
Medicated wicks. After thorough toilet, a gauze wick soaked in antibiotic steroid preparation is inserted in the ear canal and patient advised to keep it moist by instilling the same drops twice or thrice a day. Wick is changed daily for 2–3 days when it can be substituted by ear drops. Local steroid drops help to relieve oedema, erythema and prevent itching. Aluminium acetate (8%) or silver nitrate (3%) are mild astringents and can be used in the form of a wick to form a protective coagulum to dry-up an oozing meatus.
(iii) Antibiotics. Broad-spectrum systemic antibiotics are used when there is cellulitis and acute tender lymphadenitis.
(iv) Analgesics. For relief of pain.
Chronic phase. Treatment aims at
(i) reduction of meatal swelling so that ear toilet can be effectively done andWhen the meatal skin is thickened to the point of obstruc-tion and resists all forms of medical treatment, i.e. chronic stenotic otitis externa, it is surgically excised, bony meatus is widened with a drill and lined by split-skin graft.
c) Otomycosis.
Otomycosis is a fungal infection of the ear canal that often occurs due to Aspergillus niger, A. fumigatus or Candida albicans. It is seen in hot and humid climate of tropical and subtropical countries. Secondary fungal growth is also seen in patients using topical antibiotics for treatment of otitis externa or middle ear suppuration.
Clinical features of otomycosis
✓intense itching
✓discomfort or pain in the ear, ✓watery discharge with a musty odour and ear blockage.
✓The fungal mass may appear white, brown or black and has been likened to a wet piece of filter paper.
Examined with an otoscope,
A. niger appears as black-headed fi lamentous growth, A. fumigatus as pale blue or green and Candida as white or creamy deposit. Meatal skin appears sodden, red and oedematous.
Treatment
•thorough ear toilet to remove all discharge and epithelial debris which are conducive to the growth of fungus.
It can be done by syringing, suction or mopping.
- Antifungal agents can be applied. Nystatin (100,000 units/mL of propylene glycol) is effective against Candida. Clotrimazole and povidone iodine. 2 pc salicylic acid in alcohol is also effective. It is a keratolytic agent which removes supeficial layers of epidermis, and along with that, the fungal mycelia growing into them. Antifungal treatment should be continued for a week even after apparent cure to avoid recurrences.
- Ear must be kept dry. Bacterial infections are often associated with otomycosis and treatment with an antibiotic/steroid preparation helps to reduce inflammation and oedema and thus permitting better penetration of antifungal agents.
Otitis externa haemorrhagica.
for-mation of haemorrhagic bullae on the tympanic membrane and deep meatus. viral in origin and may be seen in inf l uenza epidemics. severe pain in the ear and blood-stained discharge when the bullae rupture.
Treatment with analgesics Antibiotics are given for secondary infection of the ear canal, or middle ear if the bulla has ruptured into the middle ear.
