What Is Your Diagnosis? Author(s): Source: Journal of Avian Medicine and Surgery, 28(2):174-177. 2014. Published By: Association of Avian Veterinarians DOI: http://dx.doi.org/10.1647/2013-017 URL: http://www.bioone.org/doi/full/10.1647/2013-017

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Journal of Avian Medicine and Surgery 28(2):174–177, 2014 Ó 2014 by the Association of Avian Veterinarians

What Is Your Diagnosis? The parrot was placed in a warmed critical care unit supplied with supplemental oxygen and was administered an injection of meloxicam (1 mg/kg IM, Metacam, Boehringer Ingelheim, Saint Joseph, MO, USA), trimethoprim-sulfamethoxazole (40 mg/kg PO q12h), subcutaneous fluids (60 mL/ kg q24h lactated Ringer’s solution), metronidazole (30 mg/kg PO q12h) and was tube fed 30 mL/kg q8h of hand-feeding formula (Emeraid NutriSupport Lafeber Company, Cornell, IL, USA). No fecal material was observed overnight. Initial diagnostic testing included lateral and ventrodorsal whole-body radiographs and contrast radiographs. Blood was collected from the basilic vein for a complete blood cell count (CBC) and plasma biochemical analysis. Results of the CBC showed a mild anemia with a hematocrit of 30% (reference range: 35–45%)1 and moderate polychromasia. The biochemical result showed mild increased concentrations of aspartate transaminase 964 U/L (reference range: 135–365 U/L),1 creatine kinase 833 U/L (reference range: 100–300 U /L),1 and uric acid 24.2 mg/dL (reference range:, 3.5–10 mg/dL),1 which could be attributed to dehydration or renal disease.

History An 18-year-old, 194-g, female Maximilian pionus parrot (Pionus maximiliani) was referred to the Zoological Medicine Service of Kansas State University Veterinary Health Center as an emergency presentation. The bird was exhibiting signs of mild lethargy, weight loss, respiratory sounds, and constipation. The parrot’s diet included a mixture of table food, seeds, and pellets. The owner reported that bird had been straining to defecate for 5 days and was uninterested in food. Although the pionus was observed ‘‘defecating’’ by the owner, its droppings only consisted of urates and fresh blood. On presentation, the parrot was perched and alert but had a slightly increased respiratory rate and was noticeably straining. Physical examination revealed blood and urate staining around the feathers of its cloaca. A cotton swab was inserted into its cloaca and no obstruction or papillomatous lesions were detected. Abdominal distention was noted on palpation. No additional abnormalities were observed on the external physical examination.

Please evaluate the history, physical examination findings, test results, and Figures 1 and 2. Formulate a list of differential diagnoses and a treatment plan before proceeding.

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Figure 1. Ventrodorsal (A) and right lateral (B) radiographic views of the whole body of a 18-year-old female Maximilian pinous parrot that presented for lethargy, weight loss, respiratory sounds, and constipation.

Figure 2. Ventrodorsal (A) and right lateral (B) radiographic views of a whole-body contrast study of the parrot described in Figure 1, 6 hours after administration of barium.

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Diagnosis Whole body radiographic images revealed a soft tissue mass in the caudal abdominal ceolomic cavity most likely associated with the reproductive organs/tract, kidneys, or intestinal tract. The caudal thoracic and abdominal air sacs of the parrot were determined to be atelectic, due to mass effect. Polyostotic hyperostosis was also noted on the long bones. Contrast radiographs were performed to evaluate gastrointestinal motility and morphology, and to isolate the mass. Four milliliters of barium (25 mL/kg PO) in 6 mL of hand-feeding formula (Emeraid Nutri-Support Lafeber Company) was administered into the crop via a stainless steel gavage needle. Motility and transit time of the esophagus, proventriculus, ventriculus, and intestines appeared normal; however, a filling defect was apparent just cranial to the cloaca. Furthermore, the proventiculus and intestinal loops cranial to that defect were markedly distended, compressing the air sacs and cranioventrally displacing the liver and ventriculus. Because of the cost and poor prognosis, the owner declined surgery and elected euthanasia. At necropsy, a 1.231.231.1 cm whitish, firm, nodular mass was observed in the lumen of the distal colon proximal to the cloaca. Widespread intestinal hemorrhage was observed cranial and distal to the mass. The mass itself completely obstructed the lumen of the distal colon. Tissues were fixed in a neutral buffered 10% formalin solution. Representative tissue sections were trimmed and routinely processed. Histopathologic examination revealed that the mass was composed of pleomorphic cells that varied in shape, identified as cuboidal, columnar, and large round signet ring cells. Neoplastic cells had areas of vacuolated cytoplasm with a small amount of mucous present. Nuclei were round to oval with a significant number of mitotic figures present. The mass was determined to be a locally aggressive rectal adenocarcinoma. Discussion Gastrointestinal diseases are relatively common in avian species and can be challenging to diagnose. Many clinical signs observed in birds with gastrointestinal disease are nonspecific and include lethargy, anorexia, change in color of feces, and a ‘‘fluffed’’ appearance. Common gastrointestinal disorders can lead to a decrease in gastric and intestinal emptying times. Heavy metal toxicosis, inflammation, viral infections, foreign body ingestion, papillomatosis, and neoplasia are common

disease conditions that adversely affect the gastrointestinal tract.2 This report describes the clinical progression of antemortem signs and the postmortem diagnosis of rectal adenocarcinoma in a Maximilian pionus parrot. To our knowledge this is the first reported case of a rectal adenocarcinoma in psittacine species. Primary malignant neoplasias of the alimentary tract are relatively uncommon in birds.3 However, there have been a few cases of proventricular or ventricular adenocarcinoma reported in a grey-cheeked parakeet (Brotogeris pyrrhopterus),4 yellow-naped Amazons (Amazona auropalliata),5 cockatiels (Nymphicus hollandicus),6 green winged macaws (Ara chlorptera),7 blue-thighed lorries (Lorius tibialis),6 and a Humboldt penguin (Spheniscus humboldti).8 These tumors typically arise in the proventriculus or at the gastric isthmus. Intestinal adenocarcinoma have been also reported in a budgerigar (Melopsittacus undulatus), mandarin duck (Aix galericulata), gull,3 and at the pylorus and ileocecal junction in chickens.9,10 Gastrointestinal adenocarcinomas can produce thickened and irregular gastrointestinal mucosa and can cause narrowing or obstruction on the lumen with variable amounts of hemorrhage and necrosis. A few cases of gastrointestinal ulceration and sepsis have also been reported as a sequela to the neoplastic disease process.2 The rectum in birds lies in the dorsal part of the coelomic cavity and is a short tubelike structure that consists of numerous villi and a few goblet cells. However, in some species (eg, gallinaceous birds, ratites) the rectum is looped or folded. The only other reported case of a rectal adenocarcinoma occurred in a chicken.3 Clinical signs of gastrointestinal tumors consist of regurgitation, weight loss, weakness, inability to perch, head tilt, dark red-brown stools, and polyuria. The feces may test positive for occult blood. Clinicopathologic findings of intestinal obstructions are often nonspecific, but the most common diagnostic test abnormalities are metabolic alkalosis, hypochloremia, hypokalemia, hyponatremia, azotemia, hyperglycemia, and hemoconcentration.11 Survey radiographic images of the body may reveal a mass-like lesion as well as an increase of fluid and gas within the intestinal tract. Contrast radiography can help delineate irregular distention, thickening, and incomplete filling of the gastrointestinal tract. Antemortem diagnosis is rare and usually offers a poor prognosis. Surgical correction through excision of the affected intestinal tract and anastomosis is the only curative option. However, prognosis is reliant

WHAT IS YOUR DIAGNOSIS?

on early intervention, adequate exposure, location, and lack of metastasis of the neoplasm at the time of surgery.3 In summary, rectal adenocarcinoma should be considered a differential disease diagnosis in psittacine birds showing clinic signs of gastrointestinal obstruction. This case was submitted by Rodney William Schnellbacher, DVM, and James W. Carpenter, MS, DVM, Dipl ACZM, from the Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.

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References 1. Pollock CP, Carpenter JW, Antinoff N. Birds. In: Carpenter JW, ed. Exotic Animal Formulary. 3rd ed. St Louis, MO: Elsevier Saunders; 2005:268. 2. Lumeij JT. Gastroenterology. In: Ritchie BW, Harrison GJ, Harrison LR, eds. Avian Medicine: Principles and Application. Lake Worth, FL: Wingers; 1994:482–521. 3. Latimer KS. Oncology. In: Ritchie BW, Harrison GJ, Harrison LR, eds. Avian Medicine: Principles and Application. Lake Worth, FL: Wingers; 1994:640–672. 4. Schmidt RE, Dustin LR, Slevin RW. Proventricular adenocarcinoma in a budgerigar (Melopsittacus

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undulatus) and a grey-cheeked parakeet (Brotogeris pyrrhopterus). AAV Today. 1988;2:13–14. Leach MW, Murphy JP, Lowenstine LJ. Three cases of gastric neoplasia in psittacines. Avian Dis. 1989;33:204–210. Schmidt RE, Reavill DR, Phalen DN. Gastrointestinal system and pancreas. In: Schmidt RE, Reavill DR, Phalen DN, eds. Pathology of Pet and Aviary Birds. Ames, IA: Blackwell; 2003:41–65. Kennedy FS, Sattler-Augustin S, Mahler JR. Oropharyngeal and cloacal papillomas in two macaws with a pancreatic and an intestinal adenocarcinoma with hepatic metastasis. Proc Annu Conf Assoc Avian Vet. 1994:428–430. Yonemaru K, Sakai H, Asaoka Y, et al. Proventricular adenocarcinoma in a Humboldt penguin (Spheniscus humboldti) and a great horned owl (Bubo virginianus); identification of origin by mucin histochemistry. Avian Pathol. 2004;33:77–81. Turk JR, Forar AL, Gallina AM. Intestinal adenocarcinoma of the ileocecal junction in a chicken. Avian Dis. 1992;36:799–802. Reece RL. Some observations on naturally occurring neoplasms of domestic fowls in the State of Victoria, Australia (1977–87). Avian Pathol. 1996;23:407–447. Schmidt RE. Neoplastic diseases. In: Altman RB, Clubb SL, Dorrestein GM, Quesenberry K, eds. Avian Medicine and Surgery. Philadelphia, PA: WB Saunders; 1997:590–600.

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