Australian Doctor Australian Doctor 30th June 2017 | Page 18

Conditions of the pinna

How to Treat – Conditions of the external ear

from previous page
Physiology of the external ear
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B
Figure 2a and 2b.
Normal pinna.
The pinna acts as a funnel, directing sound waves into the external auditory canal. It not only assists in amplifying sound but also provides a directional element of hearing. The skin covering the outer third of the external auditory canal contains hair cells, sebaceous glands and ceruminous glands. The epithelium migrates laterally from the umbo of the malleus and is a natural cleaning mechanism preventing the accumulation of debris in the canal.
Cerumen or ear wax, is produced by the modified sweat
glands
known
as
ceruminous
glands. Cerumen protects the epithelium
of the external auditory
canal from breakdown; it has antimicrobial
lysozymes and contributes
to the normally acidic pH of
the ear canal.

Conditions of the pinna

Auricular haematoma AN auricular haematoma occurs when there is blunt trauma with shearing force to the pinna, resulting in the disruption of tissue layers. This disruption then allows for the accumulation of blood in between these layers, resulting in separation of the cartilage from the perichondrium. As mentioned above, the cartilage receives its blood supply from the perichondrium and this separation can result in death of the cartilage with subsequent infection and deformity, such as a‘ cauliflower ear’, often seen in rugby players.
Treatment should be undertaken as soon as possible to restore the blood supply to the cartilage and prevent deformity. A variety of methods are available for drainage of the haematoma but in general, patients should be referred to an ED for specialist review. Drainage can consist of an incision and drainage( see figure 3), followed by mattress sutures to ensure the potential space between tissue layers is eliminated, preventing the recollection of blood.
Perichondritis Perichondritis is inflammation of the perichondrium surrounding cartilage of the pinna. The term is a misnomer as the cartilage is also involved in most cases with subsequent abscess formation. An infected auricular haematoma is the most common cause of perichondritis, however, cases of infection have been documented following ear piercing, acupuncture, burns and ear surgery. 1 Perichondritis presents with a warm, erythematous, tender and swollen pinna with inflammation sparing the lobule. The most common organisms are Pseudomonas aeruginosa— with Proteus species, Staphylococcus aureus and Escherichia coli also implicated. 1 Patients require urgent referral to the ED for assessment. Treatment requires antibiotic therapy and occasionally surgical drainage if an abscess if present.
Cutaneous lesions of the pinna Given the protrusion of the pinna, it is exposed to increased UV
CONGENITAL EAR MALFORMATIONS CAN BE ASSOCIATED WITH RENAL TRACT ABNORMALITIES.
radiation when compared with other parts of the face. Due to the increased UV exposure, the skin over the pinna is at risk of developing pre-cancerous and cancerous lesions. 2 The management of cutaneous malignancy is beyond the scope of this article. However, the management of these lesions often includes complex surgical procedures( see figure 4), and referral to a head and neck surgeon should be considered.
Pre-auricular sinus The auricle develops in utero from six hillocks of cartilage. A series of
Figure 3. Auricular haematoma following incision and drainage, prior to mattress sutures. Note the pinna is still thickened with evidence of previous calcification.
congenital deformities involving the pinna occur when these hillocks fail to fuse. A pre-auricular sinus( also known as a pre-auricular pit) is a small pit that typically occurs in front of anterior margin of the helix. The shallow pit may be all that is present but the pit can also extend to form a sinus tract that can blend with the cartilage of the pinna.
Most pre-auricular sinuses are asymptomatic. However, congenital ear malformations can be associated with renal tract abnormalities. A renal tract ultrasound is recommended in patients who have other associated dysmorphic features, a family history of hearing loss or a maternal history of gestational diabetes. 3
Pre-auricular sinuses can become acutely infected and present with erythema, swelling, pain, fluctuance and discharge surrounding the tract( see figure 5). Depending on the extent of this infection, systemic antibiotics and drainage of the collection may be required. Refer these patients to the ED for further assessment and management. An incision and drainage should be avoided as this can disrupt the sinus tract and make future excision difficult. A nontraumatic needle drainage through the tract itself can be attempted in theatre to ensure adequate drainage of pus without disruption of the tract.
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Figures 4: a, b, c and d. Cutaneous malignancy of the pinna. The lesion is resected leaving a significant defect, however, this is filled with a skin graft from the neck.
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Figure 5. An infected right pre-auricular sinus. Note the surrounding erythema, swelling and discharge. This required a needle aspiration under a general anaesthetic.
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