PHARMACOKINETICS OF TRAMADOL AND O-DESMETHYLTRAMADOL IN GIANT TORTOISES (CHELONOIDIS VANDENBURGHI, CHELONOIDIS VICINA)

The objective of this study was to determine the pharmacokinetics of two orally administered doses of tramadol (1 mg/kg and 5 mg/kg) and its metabolite, O-desmethyltramadol (M1) in giant tortoises (Chelonoidis vandenburghi, Chelonoidis vicina). Eleven giant tortoises (C. vandenburghi, C. vicina) received two randomly assigned, oral doses of tramadol (either 1 mg/kg or 5 mg/kg), with a washout period of 3 wk between each dose. The half-life (t½) of orally administered tramadol at 1 mg/kg and 5 mg/kg was 11.9 ± 4.6 h and 13.2 ± 6.1 h, respectively. After oral administration of tramadol at 1 mg/kg and 5 mg/kg, the maximum concentration (Cmax) was 125 ± 69 ng/ml and 518 ± 411 ng/ml, respectively. There were not enough data points to determine pharmacokinetic (PK) parameters for the M1 metabolite from either dose. Tramadol administered orally to giant tortoises at both doses provided measurable plasma concentrations of tramadol for approximately 48 h with occasional transient sedation. Oral tramadol at 5 mg/kg, on average, achieves concentrations of >100 ng/ml, the reported human therapeutic threshold, for 24 h. Based on the low levels of M1 seen in this study, M1 may not be a major metabolite in this taxon.

Lidocaine constant rate infusion improves the probability of survival in rabbits with gastrointestinal obstructions: 64 cases (2012-2021)

OBJECTIVE

To determine the survival to discharge rate of rabbits with gastrointestinal obstructions treated with lidocaine constant rate infusion (CRI) and other factors associated with survival.

ANIMALS

Cases of gastrointestinal obstruction in rabbits (n = 56, including 64 events) that had presented to a veterinary teaching hospital from 2012 to 2021.

METHODS

This was a retrospective study in which data on rabbits with evidence of gastrointestinal obstruction were extracted from veterinary teaching hospital medical records over a 9-year period. Systemic lidocaine treatment, breed, sex, age, temperature at presentation, blood glucose at presentation, and time to discharge or death were evaluated with univariate and multivariate logistic regression to identify factors significantly associated with survival to hospital discharge in rabbits with gastrointestinal obstruction.

RESULTS

Comparatively, 89.7% of rabbits treated with lidocaine CRI (n = 39) survived to hospital discharge, while only 56% of rabbits that were not treated with lidocaine CRI (25) survived. In the final multivariate analysis, 2 factors were associated with survival to discharge: rabbits treated with systemic lidocaine and male rabbits had increased odds of survival compared to those not treated with systemic lidocaine and female rabbits, respectively.

CLINICAL RELEVANCE

Results demonstrated that rabbits with gastrointestinal obstruction and treated with a lidocaine CRI were more likely to survive compared to rabbits not treated with lidocaine CRI.

Treatment of Pain in Fish

This chapter provides an overview of our current understanding of clinical analgesic use in fish. Recently, the efficacy and pharmacokinetics of several analgesic drugs for use in fish have been investigated, and the most important data indicates that μ-opioid agonist drugs (e.g, morphine) are consistently effective as analgesics across fish species. In addition, bath application of some analgesic drugs may be useful, which affords multiple methods for delivering analgesics to fish. Although few published studies of non-steroidal anti-inflammatory drugs administered to fish show promise, we have much to learn about the analgesic efficacy of most drugs in this class.

Treatment of Pain in Reptiles

This chapter provides an overview of our current understanding of clinical analgesic use in reptiles. Currently, μ-opioid agonist drugs are the standard of care for analgesia in reptiles. Reptile pain is no longer considered a necessary part of recovery to keep the reptile from becoming active too early. Rather, treating pain allows for the reptile to begin normalizing their behavior. This recognition of pain and analgesia certainly benefits our reptile patients and greatly improves reptile welfare, but it also benefits our students and house officers, who will carry the torch and continue to demand excellence in reptile medicine.

Comparison of Thermal and Mechanical Noxious Stimuli for Testing Analgesics in White's Tree Frogs (Litoria caerulea) and Northern Leopard Frogs (Lithobates pipiens)

Determining the clinical efficacy of analgesic drugs in amphibians can be particularly challenging. The current study investigated whether a thermal nociceptive stimulus is useful for the evaluation of analgesic drugs in 2 amphibian species. The objectives of this study were 2-fold: 1) compare 2 models of nociception (thermal and mechanical) using 2 frog species; White's Tree Frogs (Litoria caerulea; WTF) and Northern Leopard Frogs (Lithobates pipiens; NLF) after administration of saline or morphine sulfate; and 2) evaluate antinociceptive efficacy of morphine sulfate at 2 doses in a common amphibian research species, the NLF, using a mechanical stimulus. Neither WTF nor NLF displayed consistent drug-dependent changes in withdrawal responses to a noxious thermal stimulus applied using the Hargreaves apparatus, but NLF exposed to the noxious mechanical stimulus demonstrated a significant dose-dependent antinociceptive response to morphine sulfate. These results indicate that morphine is not antinociceptive in WTF, supporting previously reported results, and demonstrate the importance of using an appropriate experimental antinociceptive test in amphibians. Our data suggest that nociception in amphibian species may be best evaluated by using mechanical nociceptive models, although species differences must also be considered.

Analgesic Efficacy of Tramadol and Morphine in White's Tree Frogs (Litoria caerulea)

Published data are sparse regarding the recognition of clinically relevant pain and appropriate analgesia in amphibians. The amphibian analgesia literature has primarily focused on nociceptive pathways in a single species, the northern leopard frog (Rana pipiens). The objective of the current study was to assess the analgesic efficacy and safety of oral tramadol and subcutaneous morphine in a commonly maintained zoo and pet species, White's tree frog (Litoria caerulea). We hypothesized that tramadol and morphine would provide dose-dependent antinociception, as measured by significant increases in hindlimb withdrawal latency after exposure to a noxious thermal stimulus. Two randomized, placebo-controlled, complete crossover studies were performed, with tramadol (n = 12) administered at 15, 25, and 40 mg/kg PO and morphine (n = 12) administered at 5 and 10 mg/kg SC. Hindlimb withdrawal latency was measured for a maximum of 72 h. No adverse side effects or signs of sedation were observed with any dose or drug evaluated. No significant difference in withdrawal latency was detected between the control and either tramadol or morphine. These negative results were surprising, suggesting that the thermal nociceptive model may not be biologically relevant in amphibian species.

Pharmacokinetics of ceftazidime in Northern leopard frogs (Lithobates pipiens) at two different doses and administration routes

OBJECTIVE

To determine an optimal ceftazidime dosing strategy in Northern leopard frogs (Lithobates pipiens) by evaluation of 2 different doses administered SC and 1 dose administered transcutaneously.

ANIMALS

44 Northern leopard frogs (including 10 that were replaced).

PROCEDURES

Ceftazidime was administered to frogs SC in a forelimb at 20 mg/kg (n = 10; SC20 group) and 40 mg/kg (10; SC40 group) or transcutaneously on the cranial dorsum at 20 mg/kg (10; TC20 group). Two frogs in each ceftazidime group were euthanized 12, 24, 48, 72, and 96 hours after drug administration. Plasma, renal, and skin concentrations of ceftazidime were measured by means of reversed-phase high-performance liquid chromatography. Four control frogs were used for assay validation.

RESULTS

Mean plasma half-life of ceftazidime in the SC20, SC40, and TC20 groups was 9.01 hours, 14.49 hours, and too low to determine, respectively. Mean maximum plasma ceftazidime concentration was 92.9, 96.0, and 1.3 μg/mL, respectively. For 24 hours after drug administration in the SC20 and SC40 groups, plasma ceftazidime concentration exceeded 8 μg/mL. Renal and skin concentrations were detectable at both doses and routes of administration; however, skin concentrations were significantly lower than renal and plasma concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings indicated that ceftazidime administration to Northern leopard frogs at 20 mg/kg, SC, every 24 hours would achieve a plasma concentration exceeding the value considered effective against common amphibian pathogens. Transcutaneous administration of the injectable ceftazidime formulation at 20 mg/kg warrants further investigation but is not currently recommended because of a potential lack of efficacy.

Respiratory and antinociceptive effects of dexmedetomidine and doxapram in ball pythons (Python regius)

OBJECTIVE

To determine the effects of dexmedetomidine, doxapram, and dexmedetomidine plus doxapram on ventilation ([Formula: see text]e), breath frequency, and tidal volume (Vt) in ball pythons (Python regius) and of doxapram on the thermal antinociceptive efficacy of dexmedetomidine.

ANIMALS

14 ball pythons.

PROCEDURES

Respiratory effects of dexmedetomidine and doxapram were assessed with whole-body, closed-chamber plethysmography, which allowed for estimates of [Formula: see text]e and Vt. In the first experiment of this study with a complete crossover design, snakes were injected, SC, with saline (0.9% NaCl) solution, dexmedetomidine (0.1 mg/kg), doxapram (10 mg/kg), or dexmedetomidine and doxapram, and breath frequency, [Formula: see text]e, and Vt were measured before and every 30 minutes thereafter, through 240 minutes. In the second experiment, antinociceptive efficacy of saline solution, dexmedetomidine, and dexmedetomidine plus doxapram was assessed by measuring thermal withdrawal latencies before and 60 minutes after SC injection.

RESULTS

Dexmedetomidine significantly decreased breath frequency and increased Vt but did not affect [Formula: see text]e at all time points, compared with baseline. Doxapram significantly increased [Formula: see text]e, breath frequency, and Vt at 60 minutes after injection, compared with saline solution. The combination of dexmedetomidine and doxapram, compared with dexmedetomidine alone, significantly increased [Formula: see text]e at 30 and 60 minutes after injection and did not affect breath frequency and Vt at all time points. Thermal withdrawal latencies significantly increased when snakes received dexmedetomidine or dexmedetomidine plus doxapram, versus saline solution.

CONCLUSIONS AND CLINICAL RELEVANCE

Concurrent administration of doxapram may mitigate the dexmedetomidine-induced reduction of breathing frequency without disrupting thermal antinociceptive efficacy in ball pythons.

Evaluation of subcutaneous administration of alfaxalone-midazolam and dexmedetomidine-midazolam for sedation of ball pythons (Python regius)

OBJECTIVE

To evaluate SC administration of alfaxalone-midazolam and dexmedetomidine-midazolam for sedation of ball pythons (Python regius).

ANIMALS

12 healthy juvenile ball pythons.

PROCEDURES

In a randomized crossover study, each snake was administered a combination of alfaxalone (5 mg/kg [2.3 mg/lb]) and midazolam (0.5 mg/kg [0.23 mg/lb]) and a combination of dexmedetomidine (0.05 mg/kg [0.023 mg/lb]) and midazolam (0.5 mg/kg), SC, with a washout period of at least 7 days between protocols. Respiratory and heart rates and various reflexes and behaviors were assessed and compared between protocols. Forty-five minutes after protocol administration, sedation was reversed by SC administration of flumazenil (0.05 mg/kg) alone or in combination with atipamezole (0.5 mg/kg; dexmedetomidine-midazolam protocol only). Because of difficulties with visual assessment of respiratory effort after sedative administration, the experiment was repeated for a subset of 3 ball pythons, with plethysmography used to assess respiration.

RESULTS

Both protocols induced a similar level of moderate sedation with no adverse effects aside from transient apnea. Cardiopulmonary depression was more profound, but time to recovery after reversal was significantly shorter, for the dexmedetomidine-midazolam protocol than for the alfaxalone-midazolam protocol. Plethysmographic findings were consistent with visual observations and suggested that snakes compensated for a decrease in respiratory rate by increasing tidal volume amplitude.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that both protocols induced clinically relevant sedation in ball pythons and should be useful for minor procedures such as venipuncture and diagnostic imaging. However, caution should be used when sedating snakes with compromised cardiopulmonary function. (J Am Vet Med Assoc 2020;256:573-579.

Antinociceptive efficacy and respiratory effects of dexmedetomidine in ball pythons (Python regius)

OBJECTIVE To determine antinociceptive efficacy, behavioral patterns, and respiratory effects associated with dexmedetomidine administration in ball pythons (Python regius). ANIMALS 12 ball pythons. PROCEDURES Antinociception was assessed by applying an infrared heat stimulus to the cranioventral surface of snakes during 2 experiments. Thermal withdrawal latency was measured at 0, 2, and 24 hours after SC injections of dexmedetomidine (0.1 or 0.2 mg/kg) or saline (0.9% NaCl) solution and at 0 to 60 minutes after injection of dexmedetomidine (0.1 mg/kg) or saline solution. Behaviors were recorded at 0, 2, and 24 hours after administration of dexmedetomidine (0.1 mg/kg) or saline solution. Tongue flicking, head flinch to the approach of an observer's hand, movement, and righting reflex were scored. Respiratory frequency was measured by use of plethysmography to detect breathing-related movements after injection of dexmedetomidine (0.1 mg/kg) or saline solution. RESULTS Mean baseline withdrawal latency was 5 to 7 seconds; saline solution did not alter withdrawal latency. Dexmedetomidine increased withdrawal latency by 18 seconds (0.2 mg/kg) and 13 seconds (0.1 mg/kg) above baseline values at 2 hours. Increased withdrawal latency was detected within 15 minutes after dexmedetomidine administration. At 2 hours after injection, there were few differences in behavioral scores. Dexmedetomidine injection depressed respiratory frequency by 55% to 70%, compared with results for saline solution, but snakes continued to breathe without prolonged apnea. CONCLUSIONS AND CLINICAL RELEVANCE Dexmedetomidine increased noxious thermal withdrawal latency without causing excessive sedation. Therefore, dexmedetomidine may be a useful analgesic drug in ball pythons and other snake species.

Diagnosis and management of inflammatory bowel disease in a harpy eagle (Harpia harpyja) with suspected fenbendazole toxicosis

CASE DESCRIPTION A 14-year-old 4.1-kg (9.02-lb) male harpy eagle (Harpia harpyja) was evaluated because of vomiting, anorexia, lethargy, and weight loss (decrease of 0.35 kg [0.77 lb]) of 4 weeks' duration. The bird had previously been treated orally with fenbendazole after the initial onset of clinical signs. CLINICAL FINDINGS An initial CBC revealed marked heteropenia and anemia, but whole-body contrast-enhanced CT images and other diagnostic test findings were unremarkable. Clinical signs persisted, and additional diagnostic testing failed to reveal the cause. During celiotomy, a biopsy specimen of the duodenum was obtained for histologic examination, which revealed lymphoplasmacytic inflammation, consistent with inflammatory bowel disease (IBD). TREATMENT AND OUTCOME Prior to histopathologic diagnosis of IBD, barium sulfate administered via gavage resulted in a temporary improvement of clinical signs. Following diagnosis of IBD, corticosteroid administration was initiated in conjunction with antifungal prophylaxis. Cessation of vomiting and a return to normal appetite occurred within 3 days. Fifteen months after cessation of corticosteroid treatment, the eagle continued to do well. CLINICAL RELEVANCE To our knowledge, this was the first report of diagnosis and management of IBD in an avian species. For the eagle of the present report, results of several diagnostic tests increased clinical suspicion of IBD, but histologic examination of an intestinal biopsy specimen was required for definitive diagnosis. Although successful in this case, steroid administration in avian species must be carefully considered. Conclusive evidence of fenbendazole toxicosis was not obtained, although it was highly suspected in this bird.

Urethral diverticulum and urolithiasis in a female guinea pig (Cavia porcellus)

CASE DESCRIPTION A 5-year-old sexually intact female guinea pig was evaluated because of mild dysuria and a subcutaneous mass located cranioventral to the urogenital openings. CLINICAL FINDINGS Non-contrast-enhanced CT and surgical exploration of the distal aspect of the urethra revealed a urethral diverticulum with an intraluminal urolith. Analysis revealed that the urolith was composed of calcium carbonate and struvite. TREATMENT AND OUTCOME The urolith was surgically removed and ablation of the urethral diverticulum was attempted. Approximately 3 months later, the guinea pig was reevaluated for masses in the perineal region, and positive-contrast urethrocystography revealed 2 uroliths present in the same diverticulum. Uroliths were manually expressed with the patient under general anesthesia. Approximately 2 weeks later, urethroplasty was performed to create an enlarged stoma with the diverticulum, thereby preventing urine from pooling in the diverticulum and potentially reducing the risk of future urolith formation. The urethroplasty site healed well with no reported complications or evidence of urolith recurrence 6 months after surgery. CLINICAL RELEVANCE Urolithiasis is common in guinea pigs, and urethral diverticulum and intraluminal urolith formation should be considered as a potential differential diagnosis for a subcutaneous mass along the distal aspect of the urethra. Creation of a urethral stoma from a urethral diverticulum via urethroplasty achieved a successful outcome in this patient.

Antinociceptive and respiratory effects following application of transdermal fentanyl patches and assessment of brain μ-opioid receptor mRNA expression in ball pythons

OBJECTIVE To quantify plasma fentanyl concentrations (PFCs) and evaluate antinociceptive and respiratory effects following application of transdermal fentanyl patches (TFPs) and assess cerebrospinal μ-opioid receptor mRNA expression in ball pythons (compared with findings in turtles). ANIMALS 44 ball pythons (Python regius) and 10 turtles (Trachemys scripta elegans). PROCEDURES To administer 3 or 12 μg of fentanyl/h, a quarter or whole TFP (TFP-3 and TFP-12, respectively) was used. At intervals after TFP-12 application in snakes, PFCs were measured by reverse-phase high-pressure liquid chromatography. Infrared heat stimuli were applied to the rostroventral surface of snakes to determine thermal withdrawal latencies after treatments with no TFP (control [n = 16]) and TFP-3 (8) or TFP-12 (9). Breathing frequency was measured in unrestrained controls and TFP-12-treated snakes. μ-Opioid receptor mRNA expression in brain and spinal cord tissue samples from snakes and turtles (which are responsive to μ-opioid receptor agonist drugs) were quantified with a reverse transcription PCR assay. RESULTS Mean PFCs were 79, 238, and 111 ng/mL at 6, 24, and 48 hours after TFP-12 application, respectively. At 3 to 48 hours after TFP-3 or TFP-12 application, thermal withdrawal latencies did not differ from pretreatment values or control treatment findings. For TFP-12-treated snakes, mean breathing frequency significantly decreased from the pretreatment value by 23% and 41% at the 24- and 48-hour time points, respectively. Brain and spinal cord tissue μ-opioid receptor mRNA expressions in snakes and turtles did not differ. CONCLUSIONS AND CLINICAL RELEVANCE In ball pythons, TFP-12 application resulted in high PFCs, but there was no change in thermal antinociception, indicating resistance to μ-opioid-dependent antinociception in this species.

Comparative analgesic efficacy of morphine sulfate and butorphanol tartrate in koi (Cyprinus carpio) undergoing unilateral gonadectomy

OBJECTIVE

To identify pain-related behaviors and assess the effects of butorphanol tartrate and morphine sulfate in koi (Cyprinus carpio) undergoing unilateral gonadectomy. Design-Prospective study.

ANIMALS

90 adult male and female koi.

PROCEDURES

Each fish received saline (0.9% NaCl) solution (which is physiologically compatible with fish) IM, butorphanol (10 mg/kg [4.5 mg/lb], IM), or morphine (5 mg/kg [2.3 mg/lb], IM) as an injection only (6 fish/treatment); an injection with anesthesia and surgery (12 fish/treatment); or an injection with anesthesia but without surgery (12 fish/treatment). Physiologic and behavioral data were recorded 12 hours before and at intervals after treatment.

RESULTS

Compared with baseline values, the saline solution-surgery group had significantly decreased respiratory rates (at 12 to 24 hours), food consumption assessed as a percentage of floating pellets consumed (at 0 to 36 hours), and activity score (at 0 to 48 hours). Respiratory rate decreased in all butorphanol-treated fish; significant decreases were detected at fewer time points following morphine administration. In the butorphanol-surgery group, the value for food consumption initially decreased but returned to baseline values within 3 hours after treatment; food consumption did not change in the morphine-surgery group. Surgery resulted in decreased activity, regardless of treatment, with the most pronounced effect in the saline solution-surgery group. Changes in location in water column, interactive behavior, and hiding behavior were not significantly different among groups. Butorphanol and morphine administration was associated with temporary buoyancy problems and temporary bouts of excessive activity, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Butorphanol and morphine appeared to have an analgesic effect in koi, but morphine administration caused fewer deleterious adverse effects. Food consumption appeared to be a reliable indicator of pain in koi.

Fish Surgery: Presurgical Preparation and Common Surgical Procedures

Fish surgical procedures are commonplace in aquaria, zoos, laboratory facilities, and pet clinical practice. To incorporate fish surgery into a clinical setting, an understanding of anatomic differences between mammals and fish, bath anesthetics, and recirculating anesthesia techniques must be developed; a system or different size systems to accommodate anesthesia and surgery of particular species of concern at an institution or practice constructed; and familiar mammalian surgical principles applied with some adaptations. Common surgical procedures in fish include coeliotomy for intracoelomic mass removal, reproductive procedures, gastrointestinal foreign body removal, radiotransmitter placement, and integumentary mass excision.

Pharmacokinetics of subcutaneous versus intramuscular administration of ceftiofur crystalline-free acid to bearded dragons (Pogona vitticeps)

OBJECTIVE

To compare pharmacokinetics after a single IM or SC injection of ceftiofur crystalline-free acid (CCFA) to bearded dragons (Pogona vitticeps).

ANIMALS

8 adult male bearded dragons.

PROCEDURES

In a preliminary experiment, doses of 15 and 30 mg/kg, SC, were compared in 2 animals, and 30 mg/kg resulted in a more desirable pharmacokinetic profile. Then, in a randomized, complete crossover experimental design, each bearded dragon (n = 6) received a single dose of 30 mg of CCFA/kg IM or SC; the experiment was repeated after a 28-day washout period with the other route of administration. Blood samples were collected at 10 time points for 288 hours after injection. Plasma concentrations of ceftiofur and desfuroylceftiofur metabolites were measured via reverse-phase high-performance liquid chromatography. Data were analyzed with a noncompartmental model.

RESULTS

No adverse effects were observed. Plasma concentrations greater than a target minimum inhibitory concentration of 1 μg/mL were achieved by 4 hours after administration by both routes. Mean plasma concentrations remained > 1 μg/mL for > 288 hours for both routes of administration.

CONCLUSIONS AND CLINICAL RELEVANCE

A single dose of CCFA (30 mg/kg) administered IM or SC to bearded dragons yielded plasma concentrations of ceftiofur and its metabolites > 1 μg/mL for > 288 hours. The SC route would be preferred because of less variability in plasma concentrations and greater ease of administration than the IM route. Future studies should include efficacy data as well as evaluation of the administration of multiple doses.

Evaluation of rebound tonometry in red-eared slider turtles (Trachemys scripta elegans)

OBJECTIVE

To evaluate feasibility and accuracy of intraocular pressure (IOP) measurement by rebound tonometry in adult red-eared slider turtles and determine the effects of manual and chemical restraint on IOP.

ANIMAL STUDIED

Seventeen adult red-eared slider turtles.

PROCEDURES

Intraocular pressure was measured with TonoLab® and TonoVet® tonometers in conscious, unrestrained turtles. To evaluate the effects of manual restraint, turtles were restrained by digital pressure on the rostral head or proximal neck. The effect of two chemical restraint protocols (dexmedetomidine, ketamine, midazolam [DKM] and dexmedetomidine, ketamine [DK] subcutaneously) on IOP was evaluated. Triplicate TonoLab® and TonoVet® readings were compared with direct manometry in three ex vivo turtle eyes.

RESULTS

TonoLab® correlated better with manometry at IOPs < 45 mmHg than TonoVet® (linear regression slopes of 0.89 and 0.30, respectively). Mean (±SD) IOP in unrestrained conscious turtles was significantly lower (P < 0.01) with TonoLab® (10.02 ± 0.66 mmHg) than with TonoVet® (11.32 ± 1.57 mmHg). Manual neck restraint caused a significant increase in IOP (+6.31 ± 5.59 mmHg), while manual rostral head restraint did not. Both chemical restraint protocols significantly reduced IOP (DKM: −1.0 ± 0.76 mmHg; DK: −1.79 ± 1.17) compared with measurements in conscious unrestrained turtles.

CONCLUSIONS

Chemical and manual neck restraint affected IOP. Rostral head restraint had no significant effect on IOP and is, therefore, recommended as the appropriate restraint technique in red-eared slider turtles. TonoLab® measurements estimated actual IOP more accurately, within physiologic range, than measurements obtained using the TonoVet®.

Clinical management of an ectopic egg in a Timneh African grey parrot (Psittacus erithacus timneh)

CASE DESCRIPTION

A 13-year-old female Timneh African grey parrot (Psittacus erithacus timneh) was evaluated because of the presence of a bald patch of skin caudal to the sternum and increased territorial and nesting behavior of 2 weeks' duration.

CLINICAL FINDINGS

Whole-body radiography revealed a mineralized egg of normal size and shape. However, no oviposition occurred, and the bird had no signs consistent with dystocia. After 7 days, repeated radiography revealed that the egg had rotated by approximately 180° along its short axis, leading to a diagnosis of ectopic egg retention, which was supported by the results of ultrasonography.

TREATMENT AND OUTCOME

Surgical removal of the ectopic egg was performed by means of a ventral midline approach 14 days after administration of leuprolide acetate (800 μg/kg [364 μg/lb], IM). No intracoelomic abnormalities, such as coelomitis or oviductal disease, were diagnosed, and the bird recovered without complications. Physical examination and whole-body radiography at 8 months and a follow-up phone call with the owner at 16 months after surgical treatment revealed no evidence of ectopic egg recurrence or reproductive behavior.

CLINICAL RELEVANCE

Clinical management of ectopic egg retention differs considerably from treatment of intraoviductal egg binding. Therefore, careful evaluation of avian patients with radiographic evidence of egg binding should be performed to avoid possible iatrogenic deterioration of the patient's condition, secondary to inappropriate treatment attempts such as hormonal induction of oviposition or attempts to remove the retained egg via the cloaca. Repeated radiography and ultrasonography and close monitoring of the patient's general condition as well as the lack of clinical signs consistent with dystocia will facilitate the diagnosis of ectopic egg retention.

Endoscopically guided removal of cloacal calculi in three African spurred tortoises (Geochelone sulcata)

CASE DESCRIPTION

3 female African spurred tortoises (Geochelone sulcata) of various body weights (0.22, 0.77, and 2.86 kg [0.48, 1.69, and 6.29 lb]) were examined because of reduced food intake and lack of fecal output. Owners reported intermittent tenesmus in 2 of the tortoises.

CLINICAL FINDINGS

Physical examinations revealed no clinically important abnormalities in the tortoises. Cloacal calculi were diagnosed on the basis of radiography and cloacoscopy in all 3 tortoises. One tortoise had another calculus in the urinary bladder.

TREATMENT AND OUTCOME

Tortoises were anesthetized, and cloacal calculi were removed by use of a cutting burr (plain-fissure cutting burr and a soft tissue protector mounted to a dental handpiece that had a low-speed motor and a straight nose cone) and warm water irrigation with endoscopic guidance. Complete removal of calculus fragments was achieved by use of forceps and irrigation. In 1 tortoise, removal of the cloacal calculus was staged (2 separate procedures). In another tortoise, a second cloacal calculus (which had been located in the urinary bladder during the first examination) was successfully removed 25 days after removal of the first calculus. All 3 tortoises recovered uneventfully, and serious complications secondary to removal of the cloacal calculi were not detected.

CLINICAL RELEVANCE

Cloacoscopy combined with the use of a low-speed dental drill and warm water irrigation should be considered a simple, safe, and nontraumatic treatment option for removal of obstructive cloacal calculi in tortoises.

Diagnosis and management of oviductal disease in three red-eared slider turtles (Trachemys scripta elegans)

Three mature, female, red-eared slider turtles (Trachemys scripta elegans) were individually, and separately, diagnosed with different forms of oviductal disease. Case 1 presented with acute cloacal bleeding and was diagnosed with acute oviductal rupture and ectopic eggs in the coelom. Case 2 presented for repeated scratching in the direction of the cloaca and was diagnosed with chronic oviductal impaction and coelomitis. Both cases were treated successfully by endoscopy-assisted complete ovariosalpingectomy via a bilateral prefemoral approach. Case 3 presented with a reduced appetite and signs of nesting behaviour and was diagnosed with obstructive dystocia associated with bacterial salpingitis. Successful treatment consisted of transcloacal egg removal and systemic antibiotics. Complete recovery was achieved in all three turtles, which remained disease-free 23 to 33 months later. Oviductal disease can present with a variety of clinical signs, and an accurate diagnosis can be made based on a thorough history, physical examination and appropriate diagnostic techniques.

Evaluation of the analgesic effects of oral and subcutaneous tramadol administration in red-eared slider turtles

OBJECTIVE

To determine the dose- and time-dependent changes in analgesia and respiration caused by tramadol administration in red-eared slider turtles (Trachemys scripta).

DESIGN

Crossover study.

ANIMALS

30 adult male and female red-eared slider turtles.

PROCEDURES

11 turtles received tramadol at various doses (1, 5, 10, or 25 mg/kg [0.45, 2.27, 4.54, or 11.36 mg/lb], PO; 10 or 25 mg/kg, SC) or a control treatment administered similarly. Degree of analgesia was assessed through measurement of hind limb thermal withdrawal latencies (TWDLs) at 0, 3, 6, 12, 24, 48, 72, and 96 hours after tramadol administration. Nineteen other freely swimming turtles received tramadol PO (5, 10, or 25 mg/kg), and ventilation (V(E)), breath frequency, tidal volume (V(T)), and expiratory breath duration were measured.

RESULTS

The highest tramadol doses (10 and 25 mg/kg, PO) yielded greater mean TWDLs 6 to 96 hours after administration than the control treatment did, whereas tramadol administered at 5 mg/kg, PO, yielded greater mean TWDLs at 12 and 24 hours. The lowest tramadol dose (1 mg/kg, PO) failed to result in analgesia. Tramadol administered SC resulted in lower TWDLs, slower onset, and shorter duration of action, compared with PO administration. Tramadol at 10 and 25 mg/kg, PO, reduced the V(E) at 12 hours by 51% and 67%, respectively, and at 24 through 72 hours by 55% to 62% and 61 % to 70%, respectively. However, tramadol at 5 mg/kg, PO, had no effect on the V(E).

CONCLUSIONS AND CLINICAL RELEVANCE

Tramadol administered PO at 5 to 10 mg/kg provided thermal analgesia with less respiratory depression than that reported for morphine in red-eared slider turtles.

Proventricular Dilatation Disease Associated with Avian Bornavirus in a Scarlet Macaw (Ara Macao)

A case of proventricular dilatation disease is described in a scarlet macaw( Ara macao) from clinical presentation to diagnosis with molecular methods. The initial clinical signs were depression progressing to head pressing over several days. A leukocytosis with toxic heterophil changes, hypoalbuminemia, and increased serum activity of aspartate aminotransferase and creatine kinase were present. Lead and zinc assays were within reference ranges, and results from Chlamydophila and polyomavirus testing were negative. Contrast-enhanced fluoroscopy revealed normal gastrointestinal transit times and motility as well as the presence of 2 small metallic foreign bodies in the ventriculus. The macaw was treated with antimicrobials, analgesics, vitamins E and B complex, force-feeding, and fluid administration with little improvement. Euthanasia was elected, and histologic examination of brain tissue revealed a perivascular lymphoplasmacytic infiltration, while the lungs had evidence of a fungal pneumonia. Tissue samples from the brain and proventriculus tested positive for the presence of Avian bornavirus genotype 2, while serology confirmed Avian bornavirus infection.

Effects of opioid receptor activation on thermal antinociception in red-eared slider turtles (Trachemys scripta)

OBJECTIVE

To determine the effects of mu-, delta-, and kappa-opioid receptor (MOR, DOR, and KOR, respectively) activation on thermal antinociception in red-eared slider turtles Trachemys scripta.

ANIMALS

51 adult turtles.

PROCEDURES

Infrared heat stimuli were applied to the plantar surface of turtle hind limbs. Thermal hind limb withdrawal latencies (HLWLs) were measured before (baseline) and at intervals after SC administration of various doses of saline (0.9% NaCl) solution (SS), MOR, DOR, or KOR agonists (3 to 13 turtles/treatment). Treatment with a DOR antagonist SC prior to DOR agonist administration was also evaluated.

RESULTS

Treatment with an MOR agonist ([D-Ala(2), N-Me-Phe(4), Gly(5)-ol]-enkephalin acetate salt [DAMGO; 1.3 or 6.6 mg/kg]) increased HLWLs (from baseline) at 2 to 8 hours after injection; at the higher dose, the maximum mean increase was 5.6 seconds at 4 hours. Treatment with a DOR agonist ([D-Ala(2), D-Leu(5)]-enkephalin acetate salt [DADLE; 25 mg/kg]) increased mean HLWL by 11.3 seconds at 4 hours; however, treatment with DADLE (5.8 mg/kg) or with another DOR agonist ([D-Pen(2),(5)]-enkephalin hydrate [DPDPE; 1.2 or 6.3 mg/kg]) did not alter HLWL, compared with SS effects. Administration of a DOR antagonist (naltrindole hydrochloride; 10 mg/kg) prior to DADLE administration (25 mg/kg) increased mean HLWL by 2.7 seconds at 4 hours. One KOR agonist, U50488 ([-]-trans-[1S,2S]-U50488 hydrochloride hydrate; 6.7 mg/kg) decreased HLWL steadily from 2 to 24 hours (less than baseline value); another KOR agonist, U69593 ([+]-[5alpha,7alpha,8beta]-N-Methyl-N-[7-{1-pyrrolidinyl}-1-oxaspiro{4.5}dec-8-yl]-benzene-acet-amide; 6.7 or 26 mg/kg) did not alter HLWLs, compared with SS effects.

CONCLUSIONS AND CLINICAL RELEVANCE

Opioid-dependent thermal antinociception in turtles appeared to be attributable mainly to MOR activation with a relatively minor contribution of DOR activation.

Evaluation of liposome-encapsulated butorphanol tartrate for alleviation of experimentally induced arthritic pain in green-cheeked conures (Pyrrhura molinae)

OBJECTIVE

To evaluate injection of microcrystalline sodium urate (MSU) for inducing articular pain in green-cheeked conures (Pyrrhura molinae) and the analgesic efficacy of liposome-encapsulated butorphanol tartrate (LEBT) by use of weight load data, behavioral scores, and fecal corticosterone concentration.

ANIMALS

8 conures.

PROCEDURES

In a crossover study, conures were randomly assigned to receive LEBT (15 mg/kg) or liposomal vehicle subsequent to experimental induction of arthritis or sham injection. The MSU was injected into 1 tibiotarsal-tarsometatarsal (intertarsal) joint to induce arthritis (time 0). weight-bearing load and behavioral scores were determined at 0, 2, 6, 26, and 30 hours.

RESULTS

MSU injection into 1 intertarsal joint caused a temporary decrease in weight bearing on the affected limb. Treatment of arthritic conures with LEBT resulted in significantly more weight bearing on the arthritic limb than treatment with vehicle. Administration of vehicle to arthritic conures caused a decrease in activity and feeding behaviors during the induction phase of arthritis, but as the arthritis resolved, there was a significant increase in voluntary activity at 30 hours and feeding behaviors at 26 and 30 hours, compared with results for LEBT treatment of arthritic birds. Treatment with LEBT or vehicle in conures without arthritis resulted in similar measurements for weight bearing and voluntary and motivated behaviors.

CONCLUSIONS AND CLINICAL RELEVANCE

Experimental induction of arthritis in conures was a good method for evaluating tonic pain. Weight-bearing load was the most sensitive measure of pain associated with induced arthritis. Pain associated with MSU-induced arthritis was alleviated by administration of LEBT.

Deep fungal dermatitis in three inland bearded dragons (Pogona vitticeps) caused by the Chrysosporium anamorph of Nannizziopsis vriesii

The Chrysosporium anamorph of Nannizziopsis vriesii (CANV), a keratinophilic fungus that naturally and experimentally causes severe and often fatal dermatitis in multiple reptile species, was isolated in pure culture from skin samples of three inland bearded dragons (Pogona vitticeps) with deep granulomatous dermatomycosis. The first animal presented with a focal maxillary swelling involving the skin and gingiva. This lizard died while undergoing itraconazole and topical miconazole therapy. The second presented with focally extensive discoloration and thickening of the skin of the ventrum and was euthanized after 10 weeks of itraconazole therapy. A third lizard presented with hyperkeratotic exudative dermatitis on a markedly swollen forelimb. Amputation and itraconazole therapy resulted in a clinical cure. Histopathology of tissue biopsies in all cases demonstrated granulomatous dermatitis with intralesional hyphae morphologically consistent with those produced by the CANV. The second lizard also had granulomatous hepatitis with intralesional hyphae. Evidence in this report suggests that the CANV is the etiologic agent of an emerging condition in captive bearded dragons that has been called 'yellow fungus disease'.

Analgesic efficacy and respiratory effects of butorphanol and morphine in turtles

OBJECTIVE

To test the hypothesis that butorphanol or morphine induces antinociception with minimal respiratory depression in conscious red-eared slider turtles.

DESIGN

Prospective crossover study.

ANIMALS

37 adult male and female red-eared slider turtles (Trachemys scripta).

PROCEDURES

Antinociception (n = 27 turtles) and respiratory (10 turtles) experiments were performed. Infrared heat stimuli were applied to the plantar surface of turtle limbs. Thermal withdrawal latencies were measured before and at intervals after SC administration of physiologic saline (0.9% NaCl) solution, butorphanol tartrate (2.8 or 28 mg/kg [1.27 or 12.7 mg/lb]), or morphine sulfate (1.5 or 6.5 mg/kg [0.68 or 2.95 mg/lb]). Ventilation was assessed in freely swimming turtles before and after SC administration of saline solution, butorphanol (28 mg/kg), or morphine (1.5 mg/kg).

RESULTS

For as long as 24 hours after injection of saline solution or either dose of butorphanol, thermal withdrawal latencies among turtles did not differ. Low- and high-dose morphine injections increased latencies significantly by 8 hours. Ventilation was not altered by saline solution administration, was temporarily depressed by 56% to 60% for 1 to 2 hours by butorphanol (28 mg/kg) administration, and was significantly depressed by a maximum of 83 +/- 9% at 3 hours after morphine (1.5 mg/kg) injection. Butorphanol and morphine depressed ventilation by decreasing breathing frequency.

CONCLUSIONS AND CLINICAL RELEVANCE

Although widely used in reptile species, butorphanol may not provide adequate antinociception for invasive procedures and caused short-term respiratory depression in red-eared slider turtles. In contrast, morphine apparently provided antinociception but caused long-lasting respiratory depression.

Serum concentrations and analgesic effects of liposome-encapsulated and standard butorphanol tartrate in parrots

OBJECTIVE

To compare serum concentrations of liposome-encapsulated butorphanol tartrate (LEBT) and standard butorphanol tartrate (STDBT) following SC and IM administration, respectively, and to evaluate analgesic effects of LEBT and STDBT after parenteral administration to Hispaniolan parrots.

ANIMALS

11 adult Hispaniolan parrots.

PROCEDURE

The ability of LEBT to prolong the duration of analgesia in an avian species was tested. Blood samples were collected at serial time points after SC administration of LEBT (10 mg/kg or 15 mg/kg) or IM administration of STDBT (5 mg/kg). Serum concentrations of butorphanol tartrate were determined by use of a commercial immunoassay that measured parent drug and metabolites. Analgesic efficacy was evaluated in parrots exposed to electrical and thermal stimuli. Foot withdrawal thresholds were recorded at baseline and at serial time points after LEBT (15 mg/kg), liposome vehicle, STDBT (2 mg/kg), or physiologic saline (0.9% NaCl) solution administration.

RESULTS

LEBT had a prolonged in vivo release for up to 5 days. Negligible serum butorphanol and butorphanol metabolite concentrations were obtained at 24 hours after IM administration of STDBT. Analgesic efficacy of LEBT as measured by foot withdrawal threshold to noxious thermal and electrical stimuli persisted for 3 to 5 days following SC administration of LEBT.

CONCLUSIONS AND CLINICAL RELEVANCE

SC administration of LEBT provided analgesia and detectable serum butorphanol concentrations in Hispaniolan parrots for up to 5 days. The use of LEBT may allow for substantial improvement in long-term pain relief without subjecting birds to the stress of handling and multiple daily injections.