The most common renal tumors in ducks include adenocarcinomas, adenomas, cystadenomas, fibrosarcomas, and lymphosarcomas.
Clinical Signs
The predominant clinical sign that points towards the possibility of renal tumor is unilateral or bilateral leg lameness or paralysis, with no history of trauma. This clinical sign results from compression on the ischiadic nerve of the lumbosacral plexus from the neoplastic mass.
The musculature in the affected leg(s) may atrophy from disuse, and the entire leg may become paretic. Affected birds may have trouble resting or sleeping due to discomfort. Their appetite, however, often remains relatively normal. Other less specific clinical signs which may occur are abdominal enlargement, apathy, weight loss, dyspnoea, and diarrhea, resulting from the intracoelomic pressure or organ displacement. Once clinical signs develop, most ducks can live an additional 3 to 6 months if they're provided proper palliative care.
Diagnosis
- Radiographs: Are useful in assessing the size, location, and radiopacity of the kidneys. Two views are recommended---right or left lateral and ventrodorsal. Correct patient positioning is essential.
- Ultrasound: Can be useful if the patient has ascites, which compresses the air sacs, allowing the ultrasonographic imaging of the kidneys. Otherwise, the presence of the air sacs makes it difficult to view kidneys in birds using ultrasound imaging.
Treatment
In mammals, nephrectomy is the treatment of choice for unilateral renal tumors. However, this is not the case in birds. Surgical removal of kidneys in birds is virtually impossible due to their location and intricate relationship with the surrounding blood vessels and nerves. There are also no effective medical management options for renal tumors in birds. Palliative care through the use of analgesics for pain management (for nerve compression by the renal mass), corticosteroids, and special care for immobility may help make the remainder of their lives more comfortable. Ultimately, euthanasia must be considered once husbandry modifications and analgesia fail to ensure appropriate quality of life for the bird.