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AURAL HEMATOMA
Overview
An aural hematoma is a collection of blood within the cartilage plate of the ear and the skin and usually arises as a self-inflicted injury from scratching and head shaking.
Causes
Underlying causes include all conditions that result in otitis externa (infection of the external ear canal). Hematoma formation has also been associated with increased capillary fragility (e.g., as seen with Cushing's disease).
Incidence and Prevalence
Aural hematoma is the most common result of physical injury to the pinna (the “flap” of the ear). The condition is common in dogs with chronic otitis externa, and less common in cats.
Signs and Symptoms
Swelling associated with aural hematoma is most apparent on the concave inner surface of the pinna (Figure 1). The swelling is soft and warm in the early stages. With chronicity, fibrosis and contraction will thicken and deform the ear, resulting in a cauliflower contracture.
Figure 1. A cat with an aural hematoma.
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Risk Factors
Sources of irritation to the ear have been implicated in the development of aural hematoma. These include inflammation, immune mediated diseases, allergies, parasites, and foreign bodies. Most patients usually have an associated otitis externa. Recurrence of the condition is common if the underlying condition is not resolved.
When to Seek Veterinary Surgical Advice
Veterinary surgical advice should be sought early in the disease process before chronic changes occur in order to achieve the best results. Most general practitioners are well equipped to manage the surgical treatment of an aural hematoma, and these cases are generally not referred to a surgical specialist. Find an ACVS Veterinary Surgeon
Exam, Screening Tests and Imaging
A fine needle aspirate and cytology of the content of swollen earflap may be necessary to confirm the diagnosis. Other tests performed are directed at identifying the underlying source of ear irritation and include cytology and culture of ear exudates, allergy testing, endocrine testing, and determination of immune status. Diagnostic imaging modalities that can prove helpful include radiography, computed tomography and magnetic resonance imaging. A biopsy may also be necessary in cases where a mass is identified around the ear or within the ear canal.
Differential Diagnoses
Aural hematoma must be differentiated from abscesses and tumors of the pinna.
Complications Caused by Disease
Deformity of the ear pinna, from fibrosis and contracture, can occur if the condition is left untreated. This typically will leave the animal with a “cauliflower” ear.
Treatment Options
Treatment options included needle aspiration and bandages, tube drainage systems and incisional drainage. Apposition between the tissues should be restored and maintained with bandages, with fibrin sealants, with the aid of sutures, or with tissue welding using laser. The goals of surgery are to remove the hematoma, prevent recurrence, and retain the natural appearance of the ears.
Potential Complications
Potential complications include cosmetic alteration of the ear, recurrence of the hematoma, and necrosis of the pinna. Infection can occur in the surgical site if surgical wound is not managed appropriately with bandages.
Aftercare
A bandage should be placed to protect the ear from contamination and self-inflicted trauma after hematoma repair. This will have to be changed a few times during the healing process. A protective collar is also useful in the postoperative period.
Prognosis
Aural hematoma seldom recurs if they are properly treated and the underlying disease is appropriately treated.
Prevention
This condition can be prevented by providing prompt attention to conditions that result in irritation of the ears.
—Abimbola O. Oshin, DVM, MS, MRCVS
Diplomate ACVS
Posted 8/13/2004
Updated 6/23/2008 by Dr. Oshin
Reviewed 10/1/2011 by Mitchell A. Robbins, DVM, Diplomate ACVS
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