Jörg Mayer

Productive thyroid follicular carcinoma in a wild barred owl (Strix varia).

An adult male barred owl (Strix varia) was found unable to fly on a pasture during the day. On presentation, several lacerations were noted on the left wing. The animal was anesthetized for radiographic examination, which revealed mild swelling and irregularity of the soft tissues of the left wing. Over the plane of the syrinx and great vessels, ill-defined soft tissue opacity was present. The anesthetic recovery was unsuccessful, and the patient died. On gross necropsy, a 1 cm in diameter, round, soft, red-tan nodule, with scattered light tan to white foci was noticed between the right subclavian artery and the syrinx. The histopathology of this structure was characteristic of a thyroid follicular carcinoma. Neoplastic cells were immunoreactive to thyroglobulin and pancytokeratin proteins. A blood sample, taken antemortem, was analyzed for total and free thyroxine. Due to the lack of reference intervals for the current species, 4 blood samples from other barred owls were taken, 2 of which were clinically normal and 2 with an unhealthy status. The thyroid values were higher than the controls (total thyroxine by radioimmunoassay [µg/dl] 1.1 vs. <0.2, <0.2, 0.6, <0.2; free thyroxine by equilibrium dialysis [ng/dl] >10 vs. <0.3, <0.3, 2.1, <0.3). Although the other 4 birds are not intended to serve as a reference interval because of the low number and unhealthy status, findings are indicative of a productive thyroid follicular carcinoma.

Zoonoses of Ferrets, Hedgehogs, and Sugar Gliders

With urbanization, people live in close proximity to their pets. People often share their living quarters and furniture, and this proximity carries a new potential for pathogen transmission. In addition to the change in lifestyle with our pets, new exotic pets are being introduced to the pet industry regularly. Often, we are unfamiliar with specific clinical signs of diseases in these new exotic pets or the routes of transmission of pathogens for the particular species. This article reviews zoonoses that occur naturally in ferrets, hedgehogs, and sugar gliders, discussing the occurrence and clinical symptoms of these diseases in humans.

Hyperthyroidism and Hyperparathyroidism in Guinea Pigs (Cavia porcellus)

Abnormal conditions of the thyroid and parathyroid in the guinea pig appear in the English-language scientific literature on an emerging basis. Although true descriptions of abnormal thyroid and parathyroid anatomy or morphology are not new findings, the clinical condition of abnormal thyroid or parathyroid function seems to be a more common observation by clinicians in recent years. This article is an overview of general clinical conditions and adequate diagnosis, and offers treatment options.

Prescription Diets for Rabbits

Dietary management can be used with drug therapy for the successful treatment of many diseases. Therapeutic nutrition is well-recognized in dogs and cats and is beginning to increase among other pet species, including rabbits. The nutritional component of some rabbit diseases (eg, urolithiasis) is not completely understood, and the clinician should evaluate the use of prescription diets based on the scientific literature and individual needs. Long-term feeding trials are needed to further evaluate the efficacy of prescription diets in rabbits. Prescription diets are available for selected diseases in rabbits, including diets for immediate-term, short-term, and long-term management.

Extralabel use of cabergoline in the treatment of a pituitary adenoma in a rat

CASE DESCRIPTION A 0.65-kg (1.43-lb) 24-month-old sexually intact male albino pet rat was examined because of a 3-week history of hypodipsia, apparent blindness, and sudden change in behavior. CLINICAL FINDINGS The rat was able to move around its cage but appeared unaware of its surroundings, was visually unresponsive, and seemed unusually aggressive. The rats hind limbs appeared mildly paretic, and it had sporadic difficulty placing its hind limbs on a flat surface. Given the rats age, history, and physical examination findings, the primary differential diagnosis was a pituitary tumor. Magnetic resonance imaging (MRI) of the rats brain was performed and revealed a large pituitary mass, which was indicative of a tumor. TREATMENT AND OUTCOME Cabergoline (0.6 mg/kg [0.27 mg/lb], PO, q 72 h) was administered. On follow-up MRI 2 months later, the pituitary mass had substantially decreased in size. For 6 months following the second MRI study, the rat continued to receive the same dosage of cabergoline and had no clinical signs of disease or unusual behavior. However, at 8.5 months after the start of the treatment, the rat was in poor condition and had clinical signs similar to those initially. A third MRI study was performed and revealed substantial regrowth of the mass. The rat was euthanized and a necropsy was performed; a histopathologic diagnosis of pituitary adenoma was made. CLINICAL RELEVANCE Pituitary adenomas have long been recognized as a common finding in geriatric rats (> 18 months old). Affected rats may respond favorably to oral administration of cabergoline.

Use of a Nitinol Wire Stent for Management of Severe Tracheal Stenosis in an Eclectus Parrot (Eclectus roratus)

Abstract: A 25-year-old, female eclectus parrot (Eclectus roratus) presented for dyspnea 3 weeks after anesthesia and surgery for egg yolk coelomitis. Radiography, computed tomography, and tracheoscopy revealed multiple tracheal strictures spanning a length of 2.6 cm in the mid to distal trachea. Histopathologic examination revealed mild fibrosis, inflammation, and hyperplasia consistent with acquired tracheal strictures. Tracheal resection was not considered possible because of the length of the affected trachea. The strictures were resected endoscopically, and repeated balloon dilation under fluoroscopic guidance over the course of 10 months resulted in immediate but unsustained improvement. Computed tomography was used to measure the stenotic area. A 4 × 36-mm, custom-made, nitinol wire stent was inserted into the trachea under fluoroscopic guidance. After stent placement, intermittent episodes of mild to moderate dyspnea continued, and these responded to nebulization with a combination of saline, acetylcysteine, and dexamethasone. Multiple attempts to wean the patient off nebulization therapy and to switch to a corticosteroid-free combination were unsuccessful. The parrot eventually developed complications, was euthanatized, and necropsy was performed. Histologically, the tracheal mucosa had widespread erosion to ulceration, with accumulation of intraluminal exudate and bacteria, severe degeneration of skeletal muscle and tracheal rings, prominent fibrosis, and mild to moderate, submucosal inflammation. Clinicopathologic findings in this case suggested tracheomalacia, which has not been previously described in birds. Custom-made tracheal stents can be used for severe tracheal stenosis in birds when tracheal resection and anastomosis is not possible. Complications of tracheal stent placement in birds may include tracheitis and tracheomalacia. To our knowledge, this is the first report of tracheal stent placement in an avian species.

Use of recombinant human thyroid-stimulating hormone for evaluation of thyroid function in guinea pigs (Cavia porcellus)

OBJECTIVE To evaluate the effects of administration of recombinant human (rh) thyroid-stimulating hormone (TSH) for evaluation of thyroid function in euthyroid guinea pigs (Cavia porcellus). DESIGN Prospective, experimental study. ANIMALS 10 healthy, sexually intact, pet guinea pigs (approx 1 year of age). PROCEDURES Guinea pigs were given rhTSH (100 μg, IM); plasma thyroxine concentrations were determined prior to and 3 and 4 hours after rhTSH injection. The animals were housed in 2 groups on the basis of sex and fed different commercial maintenance diets according to their husbandry. RESULTS There was no significant difference in thyroxine concentrations between males and females before or after rhTSH injection. There was also no difference between thyroxine concentrations at 3 versus 4 hours after rhTSH injection. There was a significant difference between thyroxine concentrations before (median, 9.05 nmol/L [0.70 μg/dL]; 10% to 90% range, 7.39 to 16.99 nmol/L [0.57 to 1.32 μg/dL]) and after (mean ± SD, 23.95 ± 4.2 nmol/L) rhTSH injection. Euthyroid guinea pigs had plasma thyroxine concentrations of at least 7.30 nmol/L (0.57 μg/dL) and an increase of at least 2.6 times prestimulation thyroxine concentrations at 3 or 4 hours after stimulation. CONCLUSIONS AND CLINICAL RELEVANCE The results suggested that rhTSH administered IM can be used for the TSH stimulation testing in guinea pigs. We suggest thyroxine concentration in a euthyroid guinea pig should at least double 3 to 4 hours after rhTSH injection.

Diagnosis and treatment of proventricular nematodiasis in an umbrella cockatoo (Cacatua alba)

CASE DESCRIPTION A 16-year-old female umbrella cockatoo (Cacatua alba) was referred to the University of Georgia College of Veterinary Medicine for evaluation of a 3-year seasonal history of lethargy and weight fluctuation. CLINICAL FINDINGS Abnormalities detected via clinicopathologic analyses included mild leukocytosis, heterophilia, and lymphopenia consistent with a stress leukogram. Previous fecal examinations failed to diagnose enteric parasite infestation. Results of a fecal flotation test with Sheather sugar solution revealed spirurid eggs (Spiruroidea). Coelomic radiography revealed a widened cardiohepatic waist with increased soft tissue opacity at the level of the hepatic silhouette. The caudal thoracic and abdominal air sacs bilaterally appeared compressed against the coleomic wall. The proventriculus was increased in diameter, with a proventriculus-to-keel ratio of 1.0. Coelomic ultrasonography and positive-contrast upper gastrointestinal radiography revealed severe thickening and irregularity of the proventricular wall. The animal was anesthetized for an endoscopic examination of the upper gastrointestinal tract. Intralesional nematodes were identified on histologic examination of biopsy specimens from the proventriculus. TREATMENT AND OUTCOME Effective fenbendazole treatment (15 mg/kg [6.8 mg/lb], PO, alternating between 5 days of treatment and 5 days of no treatment, which continued for 4 periods) was confirmed by repeated endoscopy and fecal examinations. The bird remained free of clinical signs 27 months after diagnosis and treatment. CLINICAL RELEVANCE Antemortem diagnosis of proventricular nematodiasis has not been reported in psittacines. Spirurid nematode eggs are shed intermittently, which may lead to false-negative results on a single routine fecal examination. In this patient, radiography, endoscopy, and histologic evaluation facilitated antemortem diagnosis. This is the first report of successful treatment of this condition in psittacines.

Endocrine tumours in the guinea pig

Functional endocrine tumours have long been thought to be rare in guinea pigs, although conditions such as hyperthyroidism and hyperadrenocorticism have been documented with increasing frequency so the prevalence of hormonal disorders may have been underestimated. Both the clinical signs and diagnosis of hyperthyroidism in guinea pigs appear to be very similar to those described in feline hyperthyroidism, and methimazole has been proven to be a practical therapy option. Hyperadrenocorticism has been confirmed in several guinea pigs with an adrenocorticotropic hormone stimulation test using saliva as a non-invasive sample matrix; trilostane has been successfully used to treat a guinea pig with hyperadrenocorticism. Insulinomas have only rarely been documented in guinea pigs and one animal was effectively treated with diazoxide.

Antemortem Diagnosis and Successful Treatment of Pulmonary Candidiasis in a Sun Conure (Aratinga solstitialis)

Abstract An adult male sun conure (Aratinga solstitialis) was evaluated because of lethargy, ruffled feathers, and decreased appetite. Physical examination revealed hypothermia, dehydration, dyspnea, and crop distention. Results of a complete blood cell count revealed a marked inflammatory leukogram, and cytologic examination of a crop swab sample identified gram-negative bacilli and occasional yeast organisms. Radiographs demonstrated an opaque, ill-defined, soft tissue structure in the caudal coelom just cranial to the renogonadal silhouette, loss of serosal detail, and splenomegaly. Endoscopic examination revealed a pale, granuloma-like structure within the caudal aspect of the left lung, splenomegaly, and an enlarged proventriculus. Intraoperative cytologic examination of a biopsy sample of the lesion demonstrated yeast organisms, and a subsequent culture of the biopsy sample revealed Candida albicans. The bird was treated intraoperatively with intralesional amphotericin B. Postoperative treatment consisted of meloxicam, trimethoprim sulfa, amphotericin B by nebulization, and systemic itraconazole and fluconazole. The bird made a complete recovery, was discontinued from all medications, and has remained asymptomatic for 6 months. Although rare, pulmonary candidiasis should be on the list of differential diagnoses for any respiratory infection in birds. Endoscopic biopsy, cytology, and fungal culture were valuable in making the diagnosis.