Use of a Standing Computed Tomography Scan to Aid in the Diagnosis of a Pulmonary Adenocarcinoma in a Scarlet Macaw (Ara macao)
Primary respiratory neoplasia is a reported but uncommon finding in birds compared with other companion species.3 Computed tomography (CT) has been increasingly used in the diagnosis of intracoelomic disease in avian patients. However, a persistent drawback to performing CT exams is the need for general anesthesia, especially in compromised patients. A recent study experimentally showed the utility of sedated CT scans in birds.2 Another report detailed the use of non-sedated (standing) CT exams in mute swans to diagnose femoral fractures.1 The present case report is the first to describe the clinical use of a standing CT in a psittacine bird.
An adult female scarlet macaw (Ara macao) was referred for evaluation of pronounced respiratory noise. Previous treatment with antibiotics by the primary veterinarian did not improve clinical signs, and standard whole-body radiographs were non-diagnostic. When restrained, the patient would become severely tachypneic with increased respiratory effort. Because of the bird’s significant respiratory compromise and concerns over risks of general anesthesia, a standing CT scan was performed without sedation. The CT results showed the presence of a large, intrathoracic, soft-tissue mass with bony invasion. After attempts at supportive care with nebulization, antibiotics, and antifungal agents, the bird declined and was euthanized. Necropsy findings confirmed a 6.6x3.7x4-cm neoplasm with infiltration into the keel. Histologic examination led to the diagnosis of a pulmonary adenocarcinoma with local invasion and metastasis.
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2. Kusmiercyk J, Wall CR, Hoppes S, et al. Comparison of computed tomographic images of birds obtained with sedation vs general anesthesia. J Exotic Pet Med. 2013;22:251–257.
3. Lightfoot TL. Overview of tumors: section 1. Clinical avian neoplasia and oncology. In: Harrison GJ, Lightfoot TL, eds. Clinical Avian Medicine. Vol II. Palm Beach, FL: Spix Publishing; 2006:560–565.