Heavy Metal Toxicosis
Lead and zinc intoxication are the most commonly encountered toxicities in caged birds. Paint, stained-glass lamps or windows, lead curtain weights, lead solder, and other lead metal objects are frequently sampled by pet birds. Galvanized cage wire and other metal objects coated with a shiny metal to prevent rust may be sources of zinc.
Clinical signs of heavy metal poisoning include passive regurgitation of water, polydipsia, depression, biliverdinuria, lethargy, and weakness. Amazona spp, Aratinga spp, Eclectus, and some other species may show hemoglobinuria with lead toxicity. Neurologic hyperexcitability or seizures may occur in lead toxicosis.
Diagnosis is based on serum levels of lead or zinc. The laboratory should be contacted for proper submission methods. In acute cases, and for tentative diagnosis pending heavy metal serum levels, radiographs often show metal-dense material within the ventriculus. In these cases, initiation of therapy prior to confirmation of the diagnosis may be life-saving. Calcium edetate (30–50 mg/kg, IM, bid-tid until asymptomatic) is indicated in all cases, and response to therapy is usually rapid. Concurrent fluid therapy is advisable. d-penicillamine (30–50 mg/kg, bid) and other oral chelation agents may be used once the bird is stable and can tolerate oral medications.
Nonstick bakeware coating may give off lethal acidic gases if pans are overheated. Other aerosols, including some carpet fresheners, plastics melted or burned in a microwave oven, perfumes, deodorizers, votive candles, and new heating duct systems may also be irritating or toxic to caged birds.
Iron Storage Disease
Hemochromatosis is the current popular scientific designation of this disease, but the specific histopathologic and physiologic changes that define hemochromatosis may not be the same as those seen in birds. Therefore, it is recommended that this condition be referred to simply as iron storage disease. It is common in pet mynahs and toucans, as well as in certain zoo birds such as the bird of paradise. It has been occasionally reported in pet psittacine species, particularly lories. Iron storage disease is reported to be associated with excessive intake of dietary iron. However, not all birds are affected when fed similar diets. Stress or genetic factors may also play a role. Certain foods rich in vitamin C, such as citrus fruits, increase dietary iron uptake. Current recommendations are that the diet for toucans and mynahs contain <50–100 ppm of iron. Once clinical signs appear, diets low in iron and vitamin C and periodic phlebotomy have been helpful. Recommending low-iron diets routinely for pet mynahs and toucans is prudent (commercial formulas are available).
Last full review/revision July 2011 by Teresa L. Lightfoot, DVM, DABVP (Avian)