Review of the Lesions of Psittacine Eyelids: 67 cases
Presenting Author: Drury Reavill, DVM, Dipl ABVP (Avian)
Pathologist for Zoo/Exotic Pathology Service, West Sacramento, CA
Interpretive Review and comments by Dr. Nemetz:
Disease lesions of the eyelids, nictitating membrane (3rd eyelid), and conjunctiva are often presented to an avian veterinarian. What are the causes for these lesions? How can we have a plan to rule out various disease processes? By knowing if the signs are primary or secondary is very helpful. Secondary diseases can arise from the periorbital skin, infections of the sinuses, or be part of a systemic disease. These are some of the issues Dr. Reavill tried to categorize in this paper.
But, we must not forget about noninfectious causes that can occur. Foreign bodies (i.e. feather follicles) are a common cause of localized reddening, inflammation, and discharge. Physical irritants such as smoke, aerosols, or chemical fumes (paint, urine) can cause nonspecific conjunctival inflammation. Vitamin A deficiency which is still often diagnosed at The BIRD Clinic, especially in South American species, can result in metaplasia (change in cellular growth) and hyperkeratosis (increase cornified cellular proliferation).
Proliferative lesions included conjunctival papillomas, conjunctival hyperplasia, neoplasms (adenoma, squamous cell carcinoma, carcinoma, adenocarcinoma, and lymphosarcoma) hyperkeratosis, and polyps.
Inflammatory lesions accounted for 39/67 cases. Etiologic causes included foreign material, fungal, pox virus, and mycobacterial (avian tuberculosis) infections.
Dr. Reavill looked at all the cases submitted to her service from July 1998 to January 2003. Of the various etiologies the most common lesion was of non-specific inflammation. The next most frequent cause of lesions was xanthomas, mycobacterial conjunctivitis, and tumors.