Aural haematoma in Guinea pig (Cavia porcellus).

Abstract

Aural haematoma occurs when blood accumulates under the skin of the pinna. It is usually caused by head shaking or ear scratching, often associated with an ear infection. It is well reported in dogs, cats and rabbits (Fossum 2007, Capello 2009, Csomos et al. 2016), but it is rare in rodents (Jepson 2015). In fact, to our knowledge, this clinical case is the first report in a Guinea pig (Fig. 1A). The treatment of choice, as described in previous species, consists of surgical drainage (Fossum 2007, Capello 2009, Csomos et al. 2016), and it is applicable to the Guinea pig as well. Our Guinea pig case was a 2-year-old male with concurrent otitis externa. Under general anaesthesia, after shaving and scrubbing the area, with the animal in lateral recumbency, an incision along the length of the inner surface of the ear was made to drain the haematoma (Fig. 1A). Fluid, blood clots and fibrin adhesions were removed, and transfixing mattress sutures were placed parallel to the incision to maintain the inner and outer surfaces of the ear pinnae against each other (Fig. 1C). In the meantime, a sample of purulent material from the external ear channel was submitted for bacterial and fungal culture and sensitivity testing. The animal was discharged with doses of 2 mg/kg meloxicam once a day for 5 days and 10 mg/kg enrofloxacin twice a day for 3 weeks. The culture and sensitivity test confirmed enrofloxacin as the treatment of choice. After treatment, there was no evidence of otitis externa, and sutures were removed (Fig. 1D). No recurrences were observed in the next 3 months. Care must be taken to not suture ear blood vessels and leave the incision open so that fluid can drain while the ear is healing. As in other species, treating the underlying ear infection is mandatory. In the Guinea pig, as in the majority of rodents, the ear pinnae is rounded, while in small animals and rabbits, it is elongated; for this reason, more mattress sutures are needed for the correct juxtaposition of the two aspects of the ear pinnae.