Disseminated coelomic xanthogranulomatosis in eclectus parrots (Eclectus roratus) and budgerigars (Melopsittacus undulatus)

Prevalence, Anatomical Distribution, and Risk Factors of Adipocytic Tumors and Xanthomas in Psittaciformes: 1096 Cases (1998-2018)

Adipocytic tumors are mesenchymal tumors that are commonly reported in psittacine birds; however, large-scale studies evaluating their prevalence and associated risk factors are lacking. A retrospective study of adipocytic tumors in psittacine birds was performed by reviewing pathology submissions from the University of California, Davis-Drury Reavill Pathology Database, containing 26 013 submissions from psittacine birds (1998-2018). Age, sex, genus, anatomic distribution, and pathological diagnosis were collected for each case when available. The prevalence, risk factors, and association with other lipid-accumulation disorders were reported. A total of 450 cases of lipoma, 129 cases of myelolipoma, 35 cases of hemangiolipoma, 31 cases of liposarcoma, and 451 cases of xanthoma were identified. The prevalence of adipocytic tumors and xanthomas on necropsy was 1.3% (158/11 737, 95% confidence interval [CI]: 1.1-1.6). Adipocytic tumors were identified in 27 genera. Amazona (odds ratio [OR] = 1.93, 95% CI: 1.24-2.99, p = 0.004), Myiopsitta (OR = 2.3, 95% CI: 1.0-5.2, p = 0.041), Melopsittacus (OR = 3.4, 95% CI: 2.1-5.5, p < 0.001), and Agapornis (OR = 3.5, 95% CI: 2.0-6.1, p < 0.001) had significantly higher odds of developing adipocytic tumors compared with other genera, whereas Ara had significantly lower odds (OR = 0.5, 95% CI: 0.3-0.9, p = 0.030). Age was also a significant risk factor for many types of adipocytic tumors. There was no significant association between general adipocytic tumor formation and atherosclerosis or hepatic lipidosis. Xanthomas were associated with atherosclerosis (OR = 1.88, 95% CI: 1.01-3.51, p = 0.048), but not hepatic lipidosis (p = 0.503). On necropsy, the trunk and air sacs were the most common sites of xanthoma formation, whereas the trunk and liver were the most common sites of lipoma and myelolipoma formation, respectively.

Antemortem Diagnosis and Successful Long-term Management of Disseminated Intracoelomic Xanthogranulomatous Disease in an Eclectus Parrot (Eclectus roratus)

A 12-year-old male eclectus parrot (Eclectus roratus) was referred for evaluation of coelomic distention. Computed tomography and blood work revealed coelomic effusion with free coelomic mineral-attenuating material and elevations in the bile acids and aspartate aminotransferase activity, respectively. Coelomic effusion was consistent with macrophagic inflammation with abundant intracellular lipids. Initial treatment with meloxicam resulted in minimal patient improvement. Disseminated xanthogranulomatous inflammation was suspected based on imaging and diagnostic laboratory results, which were consistent with those previously reported. Biopsy samples of liver tissue and intracoelomic masses confirmed this diagnosis. Treatment was initiated with prednisolone 1 mg/kg/d for 6 months, followed by 0.5 mg/kg/d for 3 months. Clinical improvement was assessed based on owner evaluation, plasma bile acid concentrations, and repeated computed tomographic scans. After 2 months of treatment, the owner reported improved behavior and appetite; this persisted throughout treatment and when the bird was reexamined 17 months following the cessation of steroid therapy. Bile acid concentrations were normal 10 months after the prednisolone therapy was discontinued. Diagnostic imaging showed minimal coelomic effusion 10 months after the last prednisolone dose was administered, with improved ventilation of the air sacs and static to improved dystrophic mineral foci. This report describes the antemortem diagnosis and treatment of disseminated coelomic xanthogranulomatous disease in a psittacine species, with an observed measurable therapeutic response.

Case Series of Disseminated Xanthogranulomatosis in Red-crowned Parakeets (Cyanoramphus novaezelandiae) with Detection of Psittacine Adenovirus 2 (PsAdV-2)

Simple Summary

Lipometabolic disorders, such as xanthogranulomatosis, are common diseases in avian medicine. Various manifestations of lipometabolic disorders and risk factors for acquiring lipometabolic diseases have been described in the past years. Xanthogranulomas are usually limited to the skin and supposed to be associated with traumatic or inflammatory injuries in that area. Disseminated xanthogranulomatosis, appearing simultaneously in several internal organs, has been recently described in psittacine birds, the cause of the diseases was not known. Here, we describe a case series of disseminated xanthogranulomatosis in another psittacine species, the Red-crowned Parakeet (Cyanoramphus novaezelandiae) and a possible association with a concurrent psittacine adenovirus 2 (PsAdV-2) infection. Viral infections that trigger lipometabolic diseases have been described in human medicine in some species of small animals and in chickens. PsAdV-2- infections are widely distributed in avian species. A possible association between PsAdV-2- infections and lipometabolic diseases in the Red-crowned Parakeet should be considered. Individual birds and flocks with both or either of these diseases should be carefully examined and monitored.

Abstract

Xanthogranulomatosis is a common dermatological disease in birds. This form of inflammation, possibly associated with lipometabolic disorders, can also be seen in visceral organs, which as yet has only rarely been described in avian medicine. In general, diseases related to impaired lipid metabolism are frequently reported in avian medicine, with hepatic steatosis and atherosclerosis being the most common. In human medicine, infectious agents—especially some strains of adenovirus—were implicated in contributing to lipometabolic disorders; this has also been described for chicken. Here, a case series of six Red-crowned Parakeets (Cyanoramphus novaezelandiae) is presented, all cases being characterized by psittacine adenovirus 2 (PsAdV-2) infection with or without disseminated xanthogranulomatosis. The affected individuals were examined alive by clinical examination. Total body radiographs were taken of two birds, haematology and blood biochemistry results were achieved in one bird. The birds either died immediately after clinical presentation or within two days, two individuals were euthanized due to worsening of their clinical condition. All birds underwent a post-mortem examination. While four birds were finally diagnosed with disseminated xanthogranulomatosis, all six individuals had large eosinophilic intranuclear inclusion bodies in the epithelial cells of the collecting ducts of the kidney and tested positive for PsAdV-2. Further examinations are needed to clarify to what extent PsAdV-2 might elicit lipometabolic disease in birds, or psittacines in general, and, in particular, the Red-crowned Parakeet.