Avian Common Clinical Presentations: Genetic and Nutritional Conditions
Teresa L. Lightfoot D.V.M., Diplomate ABVP - Avian
Numerous excellent texts on avian medicine and surgery now exist that give detailed information on various diseases of birds. Flow charts are included in many of these texts to proceed from clinical presentation (i.e. abdominal distention) through the dozens of possible etiologies. This lecture is designed to highlight the most commonly encountered clinical presentations and is arranged according to etiology, although overlap of causal factors willoccur. Hopefully, this disease-by- disease format will give practitioners an alternate view of frequently encountered avian syndromes, thereby facilitating their diagnosis and treatment.
First, a brief synopsis of a logical protocol when presented with a sick pet bird in practice. Due to the birds' ability to mask clinical signs until the late stages of disease and their faster metabolic rate, oxygen deprivation and death can occur during treatment or diagnostic sampling. Treatment and diagnostics must be performed in a step-wise fashion, with constant re-evaluation of the patient's ability to tolerate further procedures. Extensive client communication at the onset will allow the owner to understand the potential severity of the situation, and hopefully gain their permission for the necessary diagnostics to proceed in a specific treatment direction. Explain to the owner the myriad of conditions that can cause the general "sick bird" presentation. Collect a thorough anamnesis to help direct diagnostics and therapeutics. Assuming the bird remains stable, gather the diagnostic samples (bloodwork, gram stains, radiographs, etc.) necessary to narrow the diagnosis and initiate preliminary therapy as indicated.
Genetic, Congenital And Developmental Syndromes
Domestic breeding has greatly increased the frequency of diseases in this category. Birds that in the wild would have perished due to defects can often be treated in the captive environment. Unfortunately, domestic breeding has also increased the frequency of these syndromes, due to genetics, such as breeding for particular colors, and developmental problems created with artificial incubation and hand-feeding.
Young "poor-doer" cockatiels often have low body weights for their age (commonly 45 - 70 grams) and a stunted appearance. These birds may have underlying congenital or developmental problems, including decreased hepatic function and decreased immune competency. With supportive care, some of these birds will survive, but many will not. Owners seem to understand the "bubble child" immune suppressed nature if described in this manner. These birds, if they do survive, may have a fairly normal life, or may require repeated hospitalization due to relapses.
Some young cockatiels present with a classic one week post-pet-store-purchase syndrome. These babies were often purchased soon after arriving at the pet store. In nature, they would be eating some on their own, and still receiving supplementation from their parents. When sold as "weaned" to the uninformed owner, it generally takes about a week for the bird's insufficient food intake to create noticeable debilitation and weakness. The veterinarian is then presented with an emaciated, dehydrated baby that may or may not be beyond medical treatment.
Splay leg - actual etiologies are unknown. Parental "over-sitting", too slick of a nest box flooring, congenital ligamentous abnormalities, and nutritional deficiencies of the parents or diet being fed may all be contributory. Slides will be shown of various coaptation methods for correction of this condition.
Mandibular prognathism - commonly occurs in clutches. If detected early, many can be manually manipulated to avoid prosthesis application. The prosthesis is cumbersome, often needs to be re-applied and is painful for the baby. However, in extreme cases the various types of prosthesis are effective and necessary. 13
Constricted Toe Syndrome - is fairly common in baby birds, often affecting more than one digit. An annular band of fibrous tissue forms at a joint of the digit, impeding circulation. The etiology of this is not known, although both excessively low and high humidity have been proposed. When detected early many of these can be treated by debridement of the annular band, and moist dressings. Sometimes creating small longitudinal cuts on the medial and lateral surfaces to allow for swelling and circulation and suturing of the digit the over the incised area, followed by a dressing, are needed. If this condition presents after circulation loss is severe and necrosis is apparent, amputation may be necessary.
Various congenital diseases are appearing in our domestic species. Two cases of unusual presentations in juvenile African Grays will be presented.
Eyelid atresia is most common in cockatiels, usually occurring in several members of a clutch with varying degrees of affectation. If some eyelid margin remains and there is a sufficient opening for vision, the bird may lead a functional life. Attempts to slit the skin in this area and maintain patency of the margins is nearly always doomed to failure due to the propensity for the skin margins to heal together. One reported case of a vent tissue graft was partially successful and may hold promise.
Malnutrition is the underlying cause of many, if not most illnesses. The classic signs of Vitamin A deficiency, including submandibular abscesses and squamous metaplasia leading to secondary mucosal infections in the choana and respiratory tract are still encountered, although with less frequency than in prior years. More subtle nutritional problems with potential sensitivity to dyes or preservatives, especially in the Old World species and low-grade nutritional deficiencies are now encountered. It should be noted that the foods offered by an owner are not necessarily those consumed by the bird, which can lead to the incorrect impression that the bird is receiving a balanced diet.
Xanthomas, friable yellow fatty tissue accumulations, seem to be related to diet. If not advanced when first diagnosed, these may resolve with proper dietary correction. This tissue is extremely vascular and if surgical resection is deemed necessary, the practitioner should be prepared with adequate means of hemostasis.
The conjunctiva is also subject to the effects of nutritional deficiency, making the "seed" abscesses of cockatiels fairly common. Due to the caseated nature of purulent debris in birds, and the small area of confinement in the conjunctiva, many owners and veterinarians mistakenly identify the material removed from the conjunctiva as a seed or seed hull, when it is actually desquamated cellular debris. Concurrent infection is also common.
Quaker (Monk) parakeets have a tendency toward obesity, and exocrine pancreatic insufficiency. This stool is typical of the light colored, oily production of these birds. A more acute and rapidly fatal pancreatic condition has also been reported with some frequency. 10
In both cockatiels and African Grays with nutritional deficiency and subsequent poor hepatic function, a darker gray color with little or no powder down may be noted.
Hepatic lipidosis (pediatric) - The liver in neonates is typically larger relative to the total body weight than in adult birds, so some degree of hepatomegaly is normal in baby birds. However, the baby bird presented with hepatic lipidosis presents a fairly classic picture. It is usually still hand feeding - often with a commercial formula to which the owners have elected to add peanut butter, oil, or some other higher fat food. The baby is generally heavy for its age and exhibiting severe respiratory distress. These birds must be handled gently and minimally. COOL oxygenation, and nothing further, is the best first step. This allows time to discuss the situation with the owner. The first 48 hours with these birds is the most critical. Their lung and air sac capacity is virtually nil, and they have finally presented to you most likely because the stress of feeding and breathing at the same time has exceeded their oxygen reserves. Drastically reducing the quantity of crop food per feeding, adjusting the content of the formula, and adding lactulose to the formula are the general nutritional changes required. Parenteral fluid supplementation, when tolerated, should be added to keep the initially hyperthermic bird hydrated and to help detoxify the body, since the liver is generally not functioning adequately. When possible, bloodwork should be obtained to check for concurrent infection or other diseases.
Hepatic hematoma - can present much like the above hepatic lipidosis - and may present concurrently. Young birds have a prominent abdomen which provides very little keel protection for the underlying organs. When obese, the liver is more friable, AND extends farther into the unprotected region of the caudal abdomen. A history of overt trauma (i.e. - dropping the bird) may be present, but self trauma (getting exited and jumping in the incubator), may also cause this syndrome. Treatment varies with the degree of anemia, and the condition of the bird. Often the hematoma is visible through the abdominal skin. If the bird is stable, obtaining a PCV initially, then rechecking it within a short interval, will tell you whether the bleeding has stopped. Remember, if you elect to give fluid replacement, it will lower the PCV further, which may not only decrease the PCV below acceptable levels, but also give you a false reading of the current bleeding situation when the second sample is obtained. Homologous blood transfusions can be life-saving, or they can cause the death of the bird from stress. Both clinical judgment, experience and luck contribute to the proper course of action and outcome of this syndrome. Fortunately, it is not that common..
Hepatic Lipidosis (adult bird) - is most common in Amazon sp. This syndrome is often due to long-standing malnutrition in an obese bird, with secondary septicemia. CBC and serum chemistries will help direct treatment and confirm diagnosis. These birds frequently present with anorexia and a more quiet demeanor. Serum may be very lipemic, with consequent falsely high elevations in total protein. An elevated WBC is often encountered Supportive care with subcutaneous fluids, crop feeding with lactulose, antibiotics, a nutritional injection with Vitamin A, D3, B, E with selenium, and calcium, will pull many of these through. Diet change should not be forced until after the bird has returned to eating its customary food and is stable.
Egg binding - If a bird presents with rear end paresis or paralysis, thin, markedly depressed or with labored respiration, your prognosis must be guarded. Be sure to provide supportive care before attempting extraction of the egg. Hydrate the bird with fluids, give injectable calcium, and warmth. Genetic, nutritional and environmental factors all contribute to the predisposition to egg-binding, most notably in cockatiels. See reference # 12 for details on options for further treatment.
References are available after the final Avian Common Clinical Presentations article.
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