Aural haematoma

From Felipedia

Normal appearance of an aural haematoma in a cat, with a blood blister palpable. The ear is usually swollen, tender and hangs over

Longitudinal incision along the medial aspect of the ear, allowing drainage of subcutaneous blood

Subcutaneous placement of sutures above the auricular cartilage

Exposure of subcutanoue tissue and cartilage to ensure blood clots are removed

Suturing of the skin, leaving partial opening for drainage

Aural haematoma are a common ear disease of cats, and often occurs secondary to otitis externa. The most common causes include ear mites (Otodectes spp otitis), yeast (Malassezia spp) and immune-mediated/allergic dermatitis (see atopy). Regardless of cause, head scratching and secondary shaking of the head occurs^[1].

Aural haematoma are caused by the sheer forces induced when the head is violently shaken, causing whip-lesion injury to subcutaneous blood vessels within the pinna and resultant subcutaneous bleeding. In most cases, aural haematoma are sterile blood-filled cysts. Secondary infections are rare but can occur when trauma to the skin results in penetration of the skin by a claw, resulting in mechanical penetration of skin by debris^[2].

Diagnosis

Diagnosis is usually based on presence of a large fluid-filled cyst on the medial aspect of the pinna. In cats, aural haematoma can occur bilaterally but often is unilateral. A cause for the haematoma needs to be established to prevent further damage to the ear from ongoing pruritus in the ear canal. Removal of ear mites or secondary bacterial otitis is needed to ensure good recovery from haematoma repair^[3].

Treatment

Conservative

Conservative therapy usually involves needle drainage of the haematoma and injection of dexamethasone into the emptied space. Response to this is variable and a considerable proportion refill with blood within days or weeks^[4].

Surgical

A standard surgical approach is used with asepsis of both the ear and ear canal. Medial pinna approach is required due to most haematoma occurring on the medial aspect of the pinna. A longitudinal mid-pinnal incision of approximately half the length of the ear is made to release the blood cyst. Proper flushing of blood clots is essential to minimise a nidus for secondary bacterial infection. Subcutaneous approximation of tissue can be used but may cause scarring of the ear and resultant misshapen pinna. Skin sutures are placed either using side to side closure or from medial to lateral aspects of the pinna (full thickness, sometimes using 'buttons' or 'haematoma foam'). Good cosmetic outcome is dependent upon delay prior to surgery and type of surgical intervention used^[5].

References

1. ↑ Kuwahara J. (1986) Canine and feline aural hematoma: clinical, experimental, and clinicopathologic observations. Am J Vet Res 47(10):2300-2308
2. ↑ Euguere, E & Prelaud, P (2000) A practical guide to feline dermatology. Merial, France
3. ↑ Lanz OI, Wood BC. (2004) Surgery of the ear and pinna. Vet Clin North Am Small Anim Pract 34(2):567-99
4. ↑ Romatowski J. (1994) Nonsurgical treatment of aural hematomas. J Am Vet Med Assoc 204(9):1318
5. ↑ Weber HO. (1979) A technique for surgical treatment of aural haematoma in dogs and cats. Vet Med Small Anim Clin 74(9):1271