Case report: head trauma in a tawny owl (Strix Aluco)

Head trauma is a common cause of emergent raptor presentations, as well as respiratory disease, toxin exposure, emaciation and other injuries such as fractures, wounds, electrocution, gunshot wounds. Emergency treatment should be aimed at stabilizing the patient and providing a low-stress environment to help facilitate rapid recovery and rehabilitation. Supportive care including thermal, oxygen support, fluid administration and nutritional support are particularly indicated. Diagnostic tests should be delayed until possible based on the patient status. Diagnostic tests that may be of value in determining the severity of lesions as well as the prognosis include ophthalmic examination, radiographs, auditory evoked potentials, electroencephalograms, Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). This case report concerns a mature tawny owl (Strix aluco), that was presented to a Wild Fauna Rehabilitation Center because of head trauma. At the clinical examination the animal appeared in good nutritional status, but it was unable to fly and showed a strong dulling of the sensorium. The left auricle appeared affected by a large hematoma that extended into the acoustic meatus. Moreover the oral mucosa was pale-rosy and the palatine fissure presented small blood clots. The animal was given first emergency care, including oxygen supplementation and fluid therapy (subcutaneous injection of normal saline solution and 5% glucose solution at a ratio of 1:1). An antibiotic was also administrated (cephalexin 100 mg/kg) and after about 12 hours the animal was fed by esophageal tube (Oxbow Carnivore Care®). The animal was so stabilized and the next day more specific diagnostic tests were performed to assess the severity of the trauma and thus establish a prognosis. In particular ophthalmic examination, CT and Brainstem auditory evoked response (BAER) were carried out. Ophthalmic examination revealed a mydriatic left eye without the pupillary reflex, furthermore edema, hemorrhage and retinal detachment were found. The right eye appeared normal. Inhalational anesthesia (isoflurane 1.5%) was then induced through the mask and an endotracheal tube was positioned. A CT scan of the head and one of the entire body were performed, which highlighted the presence of right cerebral edema. The BAER test highlighted a lesion outside the brainstem, more severe on the left side, with alteration of the BAER tracks. All the tests performed thus confirmed the presence of absolutely serious lesions, that could not be corrected and that would surely prevented the animal’s survival in the wild. Because of the severity of the damage, the tawny owl died during anesthesia. For wild animals the execution of these specific examinations is very useful, since in these cases it is important to consider the severity of the trauma in relation to the recovery possibility of the patient and its consequent ability to survive once released into the wild. A correct prognosis is also crucial to assess the possibility of maintaining the animal as a permanent resident and educational tool in a specific center or to perform the euthanasia, based on welfare, nonreleasability, or poor prognosis.