Medical and Surgical Emergencies in Ferrets

Pharmacokinetics of methadone after intravenous and subcutaneous administration in domestic ferrets (Mustela putorius furo)

OBJECTIVE

To determine the pharmacokinetic profile of methadone after intravenous (IV) and subcutaneous (SC) administration in domestic ferrets (Mustela putorius furo).

STUDY DESIGN

Crossover experimental study.

ANIMALS

A group of eight healthy adult ferrets weighing 1.01 ± 0.23 kg (mean ± standard deviation).

METHODS

Methadone hydrochloride (0.3 mg kg-1) was injected IV or SC to each ferret with a 3 week washout period. Blood samples were collected via a jugular catheter before and 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 360 and 480 minutes after drug administration. Liquid chromatography-tandem mass spectrometry was used to determine plasma methadone concentrations. A nonlinear mixed effects model was used to analyze the data.

RESULTS

After IV injection, systemic clearance (Clss) and volume of distribution (Vdss) were 78.9 mL min-1 kg-1 and 9.8 L kg-1, respectively. Elimination half-life was 2.0 hours and SC bioavailability was fixed at 1. The maximum observed plasma concentration after SC injection was 92.1 ± 76.8 ng mL-1. Behavioral changes were observed after both routes.

CONCLUSIONS AND CLINICAL RELEVANCE

The pharmacokinetic profile of IV methadone was characterized by a high Clss and large Vdss, with high bioavailability and absorption rate after SC administration. Half-life was short and mean plasma methadone concentrations stayed above the minimum effective concentration (MEC) reported in humans only after SC administration for 5 minutes, but remained above that reported in dogs for 45 minutes following both routes. Further studies investigating the MEC and pharmacodynamics of methadone in ferrets are warranted.

Variation in mineral types of uroliths from ferrets (Mustela putorius furo) submitted for analysis in North America, Europe, or Asia over an 8-year period

OBJECTIVE

To compare mineral types of naturally occurring uroliths in ferrets (Mustela putorius furo) from North America, Europe, and Asia and to identify potential risk factors associated with cystine urolithiasis in ferrets.

SAMPLES

1,054 laboratory submission records of uroliths obtained from ferrets between January 1, 2010, and December 31, 2018.

PROCEDURES

For this cross-sectional study, the medical records databases at 4 diagnostic laboratories were searched for records of submissions of uroliths obtained from ferrets. Data collection included submission date; ferret sex, neuter status, and age; receiving laboratory and continent; and urolith mineral type. Regression analyses were performed to identify variables associated with cystine uroliths.

RESULTS

Of the 1,054 urolith submissions, 1,013 were from North America, with 92.6% (938/1,013; 95% CI, 90.8% to 94.1%) cystine uroliths, and 41 were from Europe and Asia, with only 26.8% (11/41; 95% CI, 15.7% to 41.9%) cystine uroliths. Median age was 2.0 years for ferrets with cystine urolithiasis versus 4.0 years for those with other types of uroliths. Submissions were more likely cystine uroliths for ferrets in North America versus Europe and Asia (adjusted OR [aOR], 59.5; 95% CI, 21.4 to 165.6), for ferrets that were younger (aOR, 0.67; 95% CI, 0.58 to 0.77), or for submissions in 2018 versus 2010 (aOR, 21.1; 95% CI, 5.1 to 87.9).

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that the proportion of submissions that were cystine uroliths dramatically increased in North America between 2010 and 2018. There is an urgent need to determine underlying causes and mitigate cystine urolithiasis in ferrets.

Diagnosis and surgical treatment of a primary splenic torsion in a domestic ferret (Mustela putorius furo)

A 4-year-old female spayed domestic ferret (Mustela putorius furo) presented with a history of vomiting over 24 hours. On physical examination, a significantly enlarged, firm spleen was palpated. Abdominal radiographs and abdominal ultrasound were suggestive of a splenic torsion or splenic infarction. An exploratory laparotomy confirmed the initial diagnosis and splenectomy was performed using a vessel sealing device. Histologic evaluation and culture of the spleen were consistent with primary torsion without evidence of infection or neoplasia. The patient recovered from surgery without complications. Based on a literature search, this is the first report of the clinical diagnosis and successful surgical treatment of a primary splenic torsion in a ferret. Although it appears to be a rare and potentially life-threatening disease in ferrets, splenic torsion should be considered as a differential diagnosis in ferrets that present with non-specific signs and a palpably enlarged spleen.

Ambulatory Emergency Medicine

While practicing exotic animal medicine as an ambulatory practitioner, veterinarians need to be prepared for the inevitable emergency call. Emergencies in exotic animal medicine come in all shapes and sizes and the veterinarian must be prepared for a variety of situations. With the proper training, equipment, and managing client expectations, an ambulatory exotics animal practitioner can successfully address emergencies. This article provides a brief overview in managing emergency cases in an ambulatory exotics animal practice.