Case Report: A 3-year-old, hand-raised, male hyacinth macaw wasexamined by an avian veterinarian because of loose, foul-smellingstools, anorexia, weight loss, lethargy, depression, ataxia andimpaired vocalizations of 4 day's duration. It had refused food andwater for 24 hours and its clinical condition was deterioratingrapidly.

The bird was housed alone in a cage and lived in the family roomwith 14 healthy psittacines. Its diet consisted of a variety ofnuts, monkey chow, fruits, vegetables and table food.

When healthy, it was in the habit of rocking its cage, running itsbeak up and down the chrome-plated cage bars and occasionallysnapping them off. Over the previous 6 months, it had destroyedthree different cage door padlocks.

On examination, the bird was lying down, fluffed, depressed andseverely dehydrated. It was thin and had voluminous, foul-smelling,bright lime-green feces with normal urates and urine.

The differential diagnosis included heavy metal poisoning(especially lead or zinc). Samples of blood, feces, and choanal and cloacal smears were taken for laboratory analysis.

The bird was treated initially with lactated Ringer's solution(IV and SC) and antibiotics and was placed in a hospital cage whereit was given oxygen. It responded to supportive care and was able tostand and drink within 6 hours, but it remained anorexic. It wastube fed and started on antifungal therapy.

After 20 hours of hospitalization, the bird was stable enough tohave x-rays taken. These revealed a metallic object measuringapproximately 6 x 2 x 2 mm in the ventriculus.

Laboratory results showed markedly high plasma zinc concentrations(24 ppm). Chelation therapy to bind the zinc and laxatives tohasten the passage of the metallic object were instituted. Surgicalremoval of the foreign body was contraindicated because of thebird's weakened condition and because the object was small enough topass.

By the morning of the third day, the bird was eating, drinking andvocalizing. The bird was discharged home with the owners withinstructions to continue with chelation therapy, laxatives,antibiotics and an antifungal drug.

When re-examined 12 days after admission, the bird was clinicallynormal and it had gained weight. An x-ray showed that the metallicobject had passed. Plasma zinc had dropped to 1.5 ppm (normalrange).

The macaw continued to improve and 40 days after admission, hadcontinued to gain weight (26 % increase). Plasma zinc had droppedto 1.0 ppm.

The potential sources of zinc were the destroyed padlocks and thechrome-plated cage bars. Analysis showed that the padlockscontained zinc, steel, brass and nickel and that the cage bars alsocontained zinc.

Discussion: Zinc toxicity in birds results in gastroenteritis,necrotizing ventriculitis, anemia as well as damage to the pancreas,kidneys and the liver. Increased thirst and increased urination may be observed. Treatment consists of supportive care, chelation therapy and endoscopic or surgical removal of the foreign body. Small foreign bodies may pass with the addition of laxatives to the diet.

Zinc is extremely toxic to birds. Sources include galvanized cagewire, quick links, clips or staples, bird toy snaps, zippers, keys, nails, plumbing nuts, nuts on animal transport cages, hardware cloth,padlocks, some antirust paints, shampoos and skin preparations.

Padlocks are frequently used on bird cages. Other types of lockingdevices should be considered on cages of large birds who may attemptto chew on the padlock. Chrome-plated cages should be avoided forlarger birds.

Reference: Romagnano A, Grinden, CB, Degernes, Mautino M. Treatmentof a Hyacinth Macaw with Zinc Toxicity. J Avian Medicine andSurgery. 1995;9:185-189.