Avian Common Clinical Presentations - Traumatic, Bacterial and Fungal
Teresa L Lightfoot D.V.M., Diplomate ABVP-Avian
We must be vigilant in avian medicine not to cause nor accelerate a bird's demise with over-aggressive intervention. This is true in all presentations of clinically ill birds. The motto I use for this is "A tentatively diagnosed pet bird that lives is far preferable to a confirmed diagnosis at necropsy". When an owner presents a bird with a "bleeding" emergency, it is important to distinguish between frank hemorrhage occurring from an external site on the bird (i.e. wing, beak, foot) and blood on the cage and/or on the bird, but no active bleeding.. Continued frank hemorrhage requires intervention, whereas hemorrhage that has ceased is best left undisturbed. Birds in respiratory distress are initially placed in an incubator with oxygen. Unless they are showing signs of being overheated (panting, wings held out) the incubator is warmed and humidified. An antibiotic injection and subcutaneous fluids are administered as soon as it seems safe to do so. This may be before placement into the incubator, or done a step at a time, the antibiotic injection being less stressful than the subcutaneous fluid administration. Shock, (hypovolemic) with the respiratory reserve being exceeded is the initial concern. Septic shock or septicemia is of concern within a short period after stabilization in birds with penetrating or extensive wound trauma.
Minor or external trauma should be treated with the goal of patient survival first and addressing the traumatized tissue second. In other words, a bird that has struggled for hours in a cage with its band caught and may possibly have a fractured tibiotarsal bone, is in more danger of dying from stress related to the prolonged struggling than the fracture. Attention to reestablishing homeostatsis, with temporary stabilization of the traumatized tissue should occur first. When this has been accomplished, the traumatized site can then be addressed.
An ingluviotomy is performed in order to gain access to the mucosal surface and lumen of the crop, proventriculus or ventriculus. Removal of a foreign body, such as a feeding tube, is the most common indication for this procedure. In larger or older birds, a rigid endoscope may be necessary to visualize and extract ingluvial foreign bodies. The endoscope may be used either orally or through an ingluviotomy incision, depending on the accessibility of the foreign body.
Damage to the crop is most often from thermal burns caused by improperly heated hand-feeding formula. This presentation is generally seen in young, hand-feeding birds. The severity of the burn and the patient's reaction vary greatly. Some birds become ill from the tissue damage and may develop an endotoxemia and die despite intensive supportive care. Other birds are totally asymptomatic and are presented by their owners when either food or a hole is noticed in the area of the crop. In these avian patients, the crop has already fistulated, creating a demarcation between healthy tissue and necrotic tissue. It is not in the bird's best interest to perform surgery immediately after the burn has occurred. Wait until the area has begun to granulate, providing a healthy tissue bed for surgical reconstruction, will decrease the quantity of tissue that must be resected.
Miscellaneous traumatic conditions:
Avulsed pygostyle - opinions vary on whether surgical repair or confinement, granulation and improved nutrition is the treatment of choice. The preferred method will vary with the species, activity level, toleration of sutures, and chronicity.
Due to entrapment - illustrations will be shown.
Amazon mutilation syndrome - etiology is still unknown, although Dr. Walt Rosskopf has been reporting and following this syndrome for years. It is much more prevalent on the West Coast and seems to be less common than in previous decades. An allergic condition is suspected by histopathology of biopsy specimens and with the observation that most cases have recurred seasonally, but reduced in severity over time.
Quaker (Monk parakeet) Mutilation syndrome - etiology also unknown. No histologic evidence of an etiologic agent has been found. Onset is acute and generally unrelated to previous feather plucking. Over 50% of the cases seen at our hospital were either eventually fatal or euthanasia was elected due to the severe damage these birds inflict, include laceration of their jugular veins, crops, and severe skin trauma.
Acute onset dyspnea - traumatic. Differentiation of upper respiration dyspnea can often be made by the position of the bird (neck outstretched) expiratory noise and acute onset. See section of respiratory diseases for more information.
Bite wounds from other birds & evaluation of beak tissue - Much has been written concerning treatment and repair of beak trauma injuries. Some will heal with just supportive care until the beak is again able to withstand the pressure that is applied during eating. Others will require surgical repair. Some species and individual birds will be able to function without an upper beak by eating soft foods. Other birds with severe beak damage will either succumb or require euthanasia.
Bacterial infection, often from bacterial flora that exists normally in low numbers and proliferates under certain circumstances, is common in pet psittacines. The circulatory system of birds contains a renal shunt that can drain venous blood from the caudal gastrointestinal tract directly into the circulation without hepatic filtration, exacerbating this potential. The decreased hepatic function and suppressed immune system in many individual psittacines due to nutritional deficiencies and genetic or congenital compromise as discussed earlier add to the incidence of septicemia.
Bacterial infections can be primary or secondary. Often feather plucking birds develop a secondary folliculitis. While treatment of this condition may not eradicate the plucking behavior, it must be accomplished to ensure the general health of the bird. Left untreated, this bacterial infection can lead either to a septicemia or a severe local infection.
Rhinitis and sinusitis are common in Amazons as a primary disease, though they can also occur in other psittacine species. The etiologic agent may be bacterial, fungal, or both. Often, chronic Vitamin A deficiency and squamous metaplasia have occurred and have compromised the nasal mucosa. Desquamated cells and bacteria accumulate in the nares, occluding the opening to the opposite nare, lacrimal duct, and choanal slit. With time, deformation of the nare occurs and permanent changes in bony architecture can arise.
Flushing of the nares and infraorbital sinus is both diagnostic and therapeutic. Cytology and bacterial/fungal culture and sensitivity can be obtained from the samples. A gram stain should be performed to give immediate preliminary results.
In cases where the infraorbital sinus is impacted with inspissated material, lancing and debridement may be necessary. Care must be taken to avoid aspiration of the pathogenic bacteria, which could result in lower respiratory involvement. A CBC to check for systemic infection and preliminary treatment with antibiotics may be warranted.
Bacterial infection involving the skin and soft tissues may not provide a source for culture. Blood cultures are seldom performed in practice on psittacines due to both financial and blood volume constraints. Therefore, the choice of antibiotics in a septicemia is usually empirical;. Enrofloxacin is often selected due to its broad spectrum and less frequent dosing. Combinations of a broad spectrum B-lactam such as Piperacillin or cefitazidime, in combination with an aminoglycoside, are also often utilized. Response to antibiotic therapy should be monitored closely, both by the condition of the patient (weight gain, attitude) and by serial CBCs.
Fungal infections are generally causes by Aspergillus fumigatus. An opportunistic organism, it is often found in the same locations and under the same conditions as many bacterial secondary invaders. Malnutrition, especially Vitamin A deficiency is a common predisposing factor. Poor hygiene and inadequate ventilation, especially in warm, humid climates, can increase the incidence of this disease.
Clinically, rhinitis with Aspergillus involvement is similar in appearance to bacterial rhinitis or sinusitis. A gram stain or Dif Quik will often demonstrate the fungal elements.
Antibody titers are of use in some species for aid in diagnosis of this condition. Antigen tests may also be helpful. False negatives and false positives both still occur with these tests.10
Lower respiratory disease, including air saculitis, often involves invasion by Aspergillus. Granulomas of the air sacs or coelomic cavity are also common.
Treatment of Aspergillosis has advanced greatly in recent years. Amphotericin-B is still utilized in nebulization, nasal flushes, intra-tracheal and I.V. administration, and is the only fungicidal agent available. Itraconazole is the most commonly used azole for oral administration for systemic Aspergillus infections in the US. Clotrimazole is being used more frequently for nebulization in birds, dosed empirically at 10 mg/ml. Terbinafine (LamisilR) is used orally in conjunction with or in lieu of itraconazole for severe or resistant Aspergillus infections, with a reported dose of 10mg/kg q 24 hrs. Newer azoles are likely to be approved for use in the United States, and will further enhance our ability to treat this condition. See reference #11 for the ranges of dosages applicable to the various types and routes of antifungal drug administration.
References are available after the final Avian Common Clinical Presentations article.
ACVC Contact Information