The Efficacy and Safety of Topical Rocuronium Bromide to Induce Bilateral Mydriasis in Hispaniolan Amazon Parrots ( Amazona ventralis ).

The efficacy and safety of topically applied rocuronium in Hispaniolan Amazon parrots ( Amazona ventralis ) was assessed in a group of 10 adult birds. A complete ophthalmic examination (including Schirmer tear test, ocular reflexes, applanation tonometry, fluorescein staining, and slit-lamp biomicroscopy) was performed, and rocuronium bromide (0.15 mg in both eyes) was administered. Pupillary light reflex (PLR) and pupillary diameter were recorded in a darkened room at the following time points: 0, 10, 20, 30, 40, 50, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 300, and 360 minutes, and 24 hours. Fluorescein staining in both eyes was performed at 24 hours. By 10 minutes, PLR was absent in all birds (at 5 minutes, 8 birds; at 10 minutes, remaining 2 birds). Pupil diameter differed significantly from baseline at all time points. Additionally, PLR was decreased in 7/10 birds at 360 minutes and normal in all birds at 24 hours. Superficial corneal ulceration was observed at 24 hours in the left eye of 2/10 of the birds after fluorescein stain application. This study demonstrated that rocuronium bromide was an effective mydriatic agent in Hispaniolan Amazon parrots with rapid onset and prolonged duration of action.

PROGRESSIVE SYRINGOHYDROMYELIA AND DEGENERATIVE AXONOPATHY IN A BOBCAT (LYNX RUFUS) FOLLOWING SURGICAL CORRECTION OF A CHIARI-LIKE MALFORMATION.

A 3-yr-old male captive bobcat (Lynx rufus) presented with chronic ataxia and right-sided head tilt. Magnetic resonance imaging (MRI) revealed cerebellar crowding and compression consistent with Chiari-like malformation. The clinical signs did not improve after surgical occipital craniectomy, and 2 mo postoperatively a second MRI showed hydromyelia and continued cerebellar compression. The bobcat was euthanized, and necropsy showed chronic focal cerebellar herniation and chronic multifocal atlanto-occipital joint osteophyte proliferation. Histology confirmed the presence of a thick fibrous membrane along the caudal aspect of the cerebellar vermis, suggestive of postoperative adhesions, and axonal degeneration of the cervical spinal cord, even in sections without a central canal lesion. These lesions appear to have been complications associated with surgical correction of the Chiari-like malformation.

Pharmacokinetics of Compounded Intravenous and Oral Gabapentin in Hispaniolan Amazon Parrots ( Amazona ventralis ).

Neuropathic pain is a manifestation of chronic pain that arises with damage to the somatosensory system. Pharmacologic treatment recommendations for alleviation of neuropathic pain are often multimodal, and the few reports communicating treatment of suspected neuropathic pain in avian patients describe the use of gabapentin as part of the therapeutic regimen. To determine the pharmacokinetics of gabapentin in Hispaniolan Amazon parrots ( Amazona ventralis ), compounded gabapentin suspensions were administered at 30 mg/kg IV to 2 birds, 10 mg/kg PO to 3 birds, and 30 mg/kg PO to 3 birds. Blood samples were collected immediately before and at 9 different time points after drug administration. Plasma samples were analyzed for gabapentin concentration, and pharmacokinetic parameters were calculated with both a nonlinear mixed-effect approach and a noncompartmental analysis. The best compartmental, oral model was used to simulate the concentration-time profiles resulting from different dosing scenarios. Mild sedation was observed in both study birds after intravenous injection. Computer simulation of different dosing scenarios with the mean parameter estimates showed that 15 mg/kg every 8 hours would be a starting point for oral dosing in Hispaniolan Amazon parrots based on effective plasma concentrations reported for human patients; however, additional studies need to be performed to establish a therapeutic dose.

Biometry, keratometry, and calculation of intraocular lens power for the bald eagle (Haliaeetus leucocephalus).

OBJECTIVE: To document intraocular measurements and predict intraocular lens (IOL) power specific to the bald eagle. ANIMALS STUDIED: Eleven adult, captive bald eagles. PROCEDURES: Axial globe length (AGL), anterior chamber depth (ACD), crystalline lens thickness (CLT), and the distance from the cornea to the posterior lens capsule (CPLC) were measured in eight adult bald eagles using B-mode with vector A-mode ultrasound. Keratometry was done on four eagles. Two estimates for postoperative anterior chamber depth (PACD) were obtained from four aphakic eyes from three eagles by measuring from the apex of the anterior cornea to the center of an imaginary line that would connect the remaining edges of the anterior lens capsule across the capsulorhexis (PACD1) and from the apex of the anterior cornea to halfway between the anterior and posterior lens capsule (PACD2). IOL strength was predicted using the Colenbrander, Binkhorst, and Fyodorov theoretical formulas. RESULTS: Mean ± SD biometry for phakic eyes was AGL = 26.57 ± 0.45 mm, ACD = 4.45 ± 0.18 mm, CLT = 5.49 ± 0.14 mm, and CPLC = 10.00 ± 0.33 mm. Mean predicted PACD1 was 6.1 ± 0.66 mm, and PACD2 was 6.4 ± 0.70 mm. Mean horizontal and vertical corneal refractive power was 39.91 ± 0.43 diopters (D) and 40.02 ± 0.08 D, respectively. Calculated IOL power ranged from +16.4 to 17.4 D. CONCLUSIONS: Calculations using ultrasonographic biometry, keratometry, and theoretical IOL formulas suggest that the strength of an IOL necessary to return an aphakic bald eagle to emmetropia is between +16.4 and +17.4 D.

Flash electroretinography in the bald eagle (Haliaeetus leucocephalus).

Photopic and scotopic flash electroretinograms (fERGs) were done on 12 adult captive anesthetized bald eagles (Haliaeetus leucocephalus) following a complete ophthalmic exam. The b-wave amplitude in the bald eagle exceeds that seen in other species when using a similar protocol. This data may be used clinically as a reference for bald eagles undergoing fERG evaluation for retinal disease or as a preoperative screening tool before phacoemulsification.

Pharmacokinetics of cefovecin (Convenia) in white bamboo sharks (Chiloscyllium plagiosum) and Atlantic horseshoe crabs (Limulus polyphemus).

Cefovecin was administered to six healthy adult white bamboo sharks (Chiloscyllium plagiosum) and six healthy adult Atlantic horseshoe crabs (Limulus polyphemus) to determine its pharmacokinetics in these species. A single dose of cefovecin at 8 mg/kg was administered subcutaneously in the epaxial region of the bamboo sharks and in the proximal articulation of the lateral leg of the horseshoe crabs. Blood and hemolymph samples were collected at various time points from bamboo sharks and Atlantic horseshoe crabs. High performance liquid chromatography was performed to determine plasma levels of cefovecin. The terminal halflife of cefovecin in Atlantic horseshoe crabs was 37.70 +/- 9.04 hr and in white bamboo sharks was 2.02 +/- 4.62 hr. Cefovecin concentrations were detected for 4 days in white bamboo sharks and for 14 days in Atlantic horseshoe crabs. No adverse effects associated with cefovecin administration were seen in either species.

Hematologic parameters and hemoparasites of nonmigratory Canada geese (Branta canadensis) from Greensboro, North Carolina, USA.

Large flocks of wild, nonmigratory Canada geese (Branta canadensis) have established permanent residence throughout the eastern United States and have become a public concern. Few studies have assessed the hematologic parameters for these populations, which could provide useful information for monitoring individual and population health of Canada geese. This study measured the hematologic parameters and detected the presence of hemoparasites from 146 wild, nonmigratory Canada geese in central North Carolina, USA, during their annual molt. The age class, sex, and weight of each bird were recorded at capture. Values for packed cell volume (PCV), estimated white blood cell count, white blood cell differentials, and heterophil: lymphocyte ratios were calculated for each bird. Adults and female geese had higher estimated white blood cell counts compared with juveniles and males, respectively. The PCV increased with weight and age class. Adult geese had higher percentages of heterophils and heterophil: lymphocyte ratios, whereas juvenile geese had higher percentages of lymphocytes. Relative eosinophil counts in adults increased with decreasing bird weight, and relative monocyte counts in juveniles increased with increasing weight. Three percent of geese were infected with species of Hemoproteus blood parasites. Atypical lymphocyte morphology, including pseudopods, split nuclei, and cytoplasmic granules, was observed in 5% of the birds. The hematologic values reported for adult and juvenile nonmigratory Canada geese in this study may serve as reference intervals for ecological studies and veterinary care of wild and captive Canada geese.

Branchial Cyst With Carcinoma in an Umbrella Cockatoo (Cacatua alba).

A 16-year-old female umbrella cockatoo (Cacatua alba) was presented for a fluctuant, right-sided cervical mass that extended from the caudolateral edge of the right mandible to the coelomic inlet. Results of initial diagnostic tests were consistent with a cystic mass containing hemorrhage. Surgical exploration and removal of the mass was done, but because the hyoid apparatus was incorporated in the base of the cyst, complete surgical excision was not possible. Histopathologic results were consistent with a branchial cyst with carcinoma. Five months after surgery, the cockatoo exhibited intermittent periorbital swelling and epistaxis, and cytologic results of a fluid aspirate from the right infraorbital sinus were consistent with carcinoma. Results of magnetic resonance imaging revealed extensive abnormal T2 and short-tau inversion-recovery hyperintense tissue associated with the right side of the head and neck, infiltrating between muscle planes and extending into the right retro-orbital tissue and nasal cavity. At 7 months after surgery, the bird was severely dyspneic and was euthanatized. To our knowledge, this is the first report describing the diagnosis, management, and histologic characteristics associated with a branchial cyst with carcinoma in an animal.

Diagnosis and treatment of a dermal malignant melanoma in an African lion (Panthera leo).

A 13-yr-old intact male African lion (Panthera leo) presented with a 4-mo history of left maxillary lip swelling. On physical examination, a 10-cm-diameter, ulcerated, round, firm, and pigmented mass at the level of the left maxillary canine tooth was noticed. All other organ systems examined were within normal limits. Multiple biopsies of the mass were collected and fixed in 10% neutral buffered formalin. Histopathologic evaluation of the biopsies revealed a malignant dermal melanoma. Hematologic and plasma biochemical parameters were within normal reference ranges. Thoracic radiographs taken 3 days following initial presentation showed no evidence of metastasis of the tumor. Computed tomography of the skull and neck was performed to evaluate local tumor invasion and to plan for hypofractionated radiation therapy. Therapy included four weekly treatments of 8 gray external-beam hypofractionated radiation and four bimonthly immunotherapy treatments. Following this treatment regime, the tumor size was reduced by 50%, and surgical excision was performed. No major side effects associated with radiation or immunotherapy were seen. Six months after diagnosis, hematologic and plasma biochemical parameters were within normal limits, thoracic radiographs showed no evidence of metastasis, and the lion showed no clinical signs of disease. The lion will continue to receive immunotherapy every 6 mo for the rest of its life. To the authors' knowledge, this is the first report of a successful treatment of a malignant dermal melanoma with external-beam hypofractionated radiation, immunotherapy, and surgical excision in an African lion.

Normal ocular parameters and characterization of ophthalmic lesions in a group of captive bald eagles (Haliaeetus leucocephalus).

Sixteen adult captive bald eagles (Haliaeetus leucocephalus) underwent a complete bilateral ocular examination to assess normal ocular parameters and describe ophthalmic lesions. Tear production was measured with the Schirmer tear test 1 and intraocular pressure was measured with applanation tonometry. The menace response was normal bilaterally in 13 of 16 eagles. Two birds had normal menace responses despite having fundic lesions, and 2 birds with an inconsistent or absent menace response did not have appreciable ophthalmic lesions. Mean (SD) tear production was 14 +/- 2 mm/min (range, 8-19 mm/min). Mean intraocular pressure was 21.5 +/- 1.7 mm Hg (range, 15-26 mm Hg). At least 1 ocular lesion was present in 50% of examined eyes. Cataracts, the most common lesion observed, were present in 8 eyes of 5 birds. Three of 4 known geriatric birds were or had been affected with bilateral cataracts. Overall, ocular lesions are common in captive bald eagles, and cataracts appear to be more prevalent in geriatric bald eagles. An obvious positive menace response is present in most visual birds but may be absent in some eagles that are either normal or that do not have appreciable ophthalmic lesions. Applanation tonometry and the Schirmer tear test 1 can be performed easily on adult bald eagles and provide reproducible results.

Diagnosis and treatment of a pharyngeal squamous cell carcinoma in a Madagascar ground boa (Boa madagascariensis).

A 15-yr-old female Madagascar ground boa (Boa madagascariensis) presented with a history of anorexia, wheezing, and occasional open-mouth breathing. On oral examination, a firm, caseous mass was noted in the right caudoventral pharyngeal region, which was confirmed as a carcinoma on incisional biopsy. Advanced imaging (computed tomography and magnetic resonance imaging) was performed to evaluate local tumor invasion and to plan for palliative radiation therapy. However, following the second treatment (10 Gy), the mass had increased in size, and the snake was euthanatized. Radiation-associated vasculitis was noted within the soft tissues surrounding the mass and within muscles and the lung, which was verified on histopathology. The squamous cell carcinoma of the snake in this report was resistant to palliative radiation therapy.