Nasal adenocarcinoma and secondary chronic sinusitis in a hyacinth macaw (Anodorhynchus hyacinthinus).

An adult male hyacinth macaw (Anodorhynchus hyacinthinus) that presented for acute onset nasal discharge and dyspnea had purulent discharge from the right naris and serosanguineous discharge from the left naris on physical examination. Results of a complete blood count revealed severe leukocytosis with a mature heterophilia. Computed tomography scans showed a large amount of soft-tissue attenuating material within the infraorbital sinus and associated diverticula. Aerobic culture results of the nasal discharge showed a mixed population of Staphylococcus intermedius and Pasteurella species, including Pasteurella pneumotropica; all isolated bacteria were susceptible to enrofloxacin. Clinical signs did not resolve over the course of 9 weeks of antibiotic treatment. The macaw died after cardiopulmonary arrest while hospitalized. At necropsy, a 2 x 2 x 3-cm firm, tan, friable, space-occupying mass surrounded by a thick exudate was present in the left preorbital diverticulum of the infraorbital sinus. The cranioventral one-third of the trachea contained a 4 x 0.5-cm white-yellow plaque. On histologic examination, the sinus mass was diagnosed as a nasal adenocarcinoma, and the tracheal plaque was caused by fungal infection, most likely with an Aspergillus species.

Pharmacokinetics of zonisamide after oral single dosing and multiple-dose escalation administration in domestic chickens (Gallus gallus).

BACKGROUND: There are few effective drugs for treatment of seizures in avian species. OBJECTIVES: To investigate the pharmacokinetics and safety of zonisamide in chickens. METHODS: Phase 1: chickens (n = 4) received a single oral dose of zonisamide at 20 mg/kg. Blood samples were collected intermittently for 36 hr after dosing. Phase 2: chickens (n = 8) received zonisamide in a dose escalation protocol (20, 30, 60 and 80 mg/kg orally every 12 hr). The dose was increased weekly, and peak and trough blood samples were collected on Days 1, 3, and 7 each week. Two birds were randomly euthanized at the end of each week. Plasma zonisamide concentrations were analysed using a commercial immunoassay. Drug concentration vs. time data were subjected to non-compartmental pharmacokinetic analysis. RESULTS: For Phase 1, peak plasma zonisamide (Cmax ) was 15 ± 3 µg/ml at 2 ± 1 hr (Tmax ). The disappearance half-life was 6.5 ± 1 hr. Mean plasma concentrations remained within the (human) therapeutic range (10-40 µg/ml) for 6 hr. For Phase 2 of the study, plasma concentrations of zonisamide remained within or close to the recommended mammalian therapeutic range for birds in the 20 and 30 mg/kg dose. Area under the curve (AUC) and Cmax were dose dependent. Two birds developed immune-mediated haemolytic anaemia. CONCLUSIONS: Zonisamide appears to be a viable drug for use in chickens at a dose of 20 mg/kg orally every 12 hr.

Antemortem diagnosis of esophageal squamous cell carcinoma in a blue-fronted Amazon parrot (Amazona aestiva) and a mealy Amazon parrot (Amazona farinosa).

CASE DESCRIPTION: A 28-year-old blue-fronted Amazon parrot (Amazona aestiva) with a 1 -week history of regurgitation-like movement of the neck and a 34-year-old mealy Amazon parrot (Amazona farinosa) with a 1- to 2-day history of regurgitation and crop distention were evaluated. CLINICAL FINDINGS: Full-body radiography of the blue-fronted Amazon parrot revealed a soft tissue structure in the right side of the neck, cranial to the crop. Results of cytologic examination of a fine-needle aspirate specimen of the mass were diagnostic for an epithelial sarcoma involving the esophagus. For the mealy Amazon parrot, CT revealed diffuse esophageal thickening that was most consistent with esophageal squamous cell carcinoma on the basis of its location and appearance. Both parrots had secondary bacterial ingluvitis. TREATMENT AND OUTCOME: Given the location and extent of the neoplasm in each bird, surgical excision was not undertaken. Options of chemotherapy and radiation therapy were explored but declined by the owners owing to concerns regarding the parrots' quality of life. Both parrots were euthanized, and necropsy findings confirmed the diagnosis of esophageal squamous cell carcinoma in both cases. CLINICAL RELEVANCE: Both parrots of the present report had a palpable esophageal squamous cell carcinoma detected during physical examination. Although rare, esophageal squamous cell carcinoma should be included as a differential diagnosis for psittacines with upper gastrointestinal tract signs. Treatment to extend duration or quality of life of affected parrots hinges on antemortem diagnosis, which appears feasible in clinical practice.