Clinical characteristics and short-term outcomes for rabbits with signs of gastrointestinal tract dysfunction: 117 cases (2014-2016)

Therapies in Exotic Animal Gastroenterology

This article reviews treatment of gastrointestinal (GI) disorders in exotic companion mammal species, birds, reptiles, amphibians, and fish. Treatment of GI stasis involves fluids, nutrition, and analgesia; there is minimal evidence suggesting prokinetics are useful. Research has evaluated the efficacy of various appetite stimulants in several exotic animal species. Although rabbits and rodents cannot vomit, maropitant may be beneficial by providing visceral analgesia. Gastroprotectants may be indicated for patients at risk for GI ulceration, such as anorexic psittacine birds. Immunosuppressives may be indicated for GI neoplasia and inflammatory bowel disease.

Rabbit Gastroenterology

Gastrointestinal (GI) disorders are a common cause of emergency presentation in rabbits. Gastrointestinal stasis is a syndrome that is frequently caused by various primary conditions (including but not limited to affections of the GI tract itself). Over the last years, clinical features, diagnosis, management, and prognosis of GI disorders-such as GI obstructions, appendicitis, rabbit hemorrhagic virus disease, or liver lobe torsion-have been studied. Recent data about diseases of the stomach, intestine, liver, and pancreas in rabbits are reviewed in this article.

Unique Calcium Metabolism in Zoological Companion Animal Species

Regardless of species, calcium, vitamin D, and parathyroid hormone physiology are intricately linked. However, there are many unique differences between taxa that may affect husbandry recommendations, common disease processes, and effective treatment. This article aims to provide a basic overview of calcium metabolism and physiology then specifically delve into unique attributes of calcium homeostasis in common zoologic companion animal species.

Encephalitozoon cuniculi Infection in Rabbits (Oryctolagus cuniculus): Data from an International Survey of Exotic and Small Animal Veterinarians

In 2022-2023, the first survey of clinicians regarding Encephalitozoon cuniculi infection of rabbits was undertaken. The purpose was to assess the current worldwide knowledge of clinicians regarding influence of breed and age, clinical presentations, use of various diagnostic tools, and treatment regimens and to explore how responses may differ by geographic location. Identifying mostly as exotic animal clinicians, 339 respondents participated, with nearly half from the United States and the remainder from 35 other countries. Neurological signs were most consistently reported as associated with Encephalitozoon cuniculi and the most recurrent clinical case presentation. Other responses showed differences by geographic location. For example, age predilection for disease varied, with 71.1% of international respondents indicating that infection was more common in young rabbits versus 28.9% who suggested it was more frequent in older rabbits. This was significantly different (p = 0.001) from the information from respondents from the United States, where 48.0% indicated that younger rabbits had an increased incidence versus 52.0% who indicated that older age increased occurrence. While some differences may be related to the practice composition and the training level of respondents, many responses were in alignment with the existing literature. Future inquiries should focus more on these discrepancies to aid in generating guidelines for the diagnosis and treatment of this infectious disease.

Clinical diagnosis and outcome of cervicofacial cellulitis in pyrexic rabbits: six cases (2014-2021)

OBJECTIVES

To assess the signalment, history, exam findings, diagnostics, treatment and outcome of rabbits diagnosed with pyrexia and concurrent cervicofacial cellulitis.

MATERIALS AND METHODS

Retrospective evaluation of medical records of rabbits diagnosed with cervicofacial cellulitis and pyrexia based on physical exam, contrast-enhanced CT, clinicopathology and microbiology findings.

RESULTS

Six out of 1588 rabbits met the study inclusion criteria. Rabbits presented with a median age of 6 years (range, 8 months to 8 years) with a presenting complaint of anorexia or hyporexia. All rabbits had a rectal temperature >40.2°C (104.4°F). Physical exam and contrast-enhanced CT revealed unilateral submandibular and ipsilateral cervical diffuse soft tissue swelling in five of six rabbits. No antemortem evidence of periodontal or dental disease was found on physical exam or CT. Leucopenia was present in five of six rabbits. A left shift with marked toxic changes was present in all four rabbits, for which blood smears were reviewed. Bacterial cultures of the aspirated subcutaneous soft tissue swelling cultured Escherichia coli, Pasteurella multocida, Granulicatella adiacens, Streptococcus species, Haemophilus species and Bacteroides species. Treatment was pursued in five rabbits, where all rabbits received supportive care and four of five rabbits received systemic antibiotics. One rabbit was euthanased following a diagnosis of cervicofacial cellulitis. Three out of five rabbits continued to decline clinically despite medical management, and thus, euthanasia was pursued within 24 hours of starting treatment. Two rabbits responded to initial treatment and developed subsequent multi-focal abscessation. One rabbit was euthanased due to client cost constraints, and one rabbit died shortly after achieving clinical resolution of cervicofacial cellulitis.

CLINICAL SIGNIFICANCE

Cervicofacial cellulitis should be considered a differential diagnosis in pyrexic rabbits with facial or cervical swelling with medical and surgical management pursued for therapy.

Intramuscular Alfaxalone-Butorphanol-Midazolam Compared with Ketamine-Butorphanol- Midazolam in New Zealand White Rabbits

Rabbits are a common companion animal and research subject and frequently require sedation to facilitate procedures. The objective of this study was to compare the effects of intramuscular butorphanol and midazolam combined with either alfaxalone or ketamine in rabbits. In a complete crossover study, healthy New Zealand white rabbits (n = 9; age, 6 mo) randomly received midazolam (1 mg/kg IM) and butorphanol (1 mg/kg IM) combined with either alfaxalone (2 mg/kg IM; ABM) or ketamine (5 mg/kg IM; KBM). Time to first effects, recumbency, and standing (recovery) were recorded. Every 5 min during recumbency, an investigator who was blind to treatment group collected serial physiologic parameters and sedation scores. At 5 min after rabbits became recumbent, manipulations were performed to mimic 2-view radiography and a cephalic intravenous catheter was placed. At 30 min after drug injection, flumazenil (0.05 mg/kg IM) was administered for reversal. Food consumption and fecal output were measured for 3 d after each study day. Time to standing and duration of recumbency differed significantly between groups. The median (range) of the total sedation score for ABM was 10 (8 to 10) and for KBM was 10 (6 to 10). Sham radiographs were successful in all rabbits in both groups. Physiologic parameters were not significantly different between groups over time. At 24 h after drug treatment, KBM-treated rabbits showed reduced food intake and both groups showed reduced fecal output. Total sedation scores decreased significantly over time in KBM rabbits ( P < 0.001) but not in ABM rabbits (P = 1). The duration of recumbency was significantly longer in ABM rabbits than in KBM rabbits. Both protocols produced sufficient sedation for radiograph acquisition without clinically significant adverse effects.

Retrospective analysis of liver lobe torsion in pet rabbits: 40 cases (2016-2021)

BACKGROUND

Liver lobe torsion (LLT) in rabbits can be under-recognised and potentially fatal. The clinical features of cases presented to an exotic animal veterinary service in Australia were retrospectively reviewed.

METHOD

Medical records of confirmed rabbit LLT cases between 2016 and 2021 were reviewed for signalment, clinical signs and findings, diagnostic imaging results, management strategies and outcomes. Variables of interest were analysed for statistical association with outcome.

RESULTS

A total of 40 rabbits were included. The mean presenting age was 56.2 months (SD 30.5). Neutered males (23/40, 57.5%) were over-represented. Common clinical signs and findings included reduced appetite (40/40, 100%), lethargy (32/40, 80.0%), reduced faecal production (16/40, 40.0%), a doughy distended stomach (20/40, 50.0%), pale mucous membranes (19/40, 47.5%) and hypothermia (17/40, 42.5%). Anaemia and elevated plasma alanine aminotransferase and blood urea nitrogen were common clinicopathologic findings. Computed tomography (CT) was performed in 34 of 40 rabbits, confirming the presence and position of LLT (34/34, 100%), stenosis of the caudal vena cava or portal system (28/34, 82.4%) and increased free peritoneal fluid (29/34, 85.3%). Fifteen (15/40, 37.5%) rabbits were medically managed, and surgical intervention was performed in 23 of 40 (57.5%) rabbits. Overall, 30 of 40 (75.0%) rabbits survived. Surgical intervention did not confer a significant difference in outcome compared to medical management (odds ratio 0.77, 95% confidence interval 0.15-4.10, p = 0.761).

CONCLUSION

CT can be an invaluable diagnostic modality for rabbit LLT. Favourable outcomes can be achieved in selected cases with medical management alone.

Clinicopathological findings in and prognostic factors for domestic rabbits with liver lobe torsion: 82 cases (2010–2020)

OBJECTIVE

To document clinicopathologic findings in domestic rabbits with liver lobe torsion and identify prognostic factors.

ANIMALS

82 rabbits.

PROCEDURE

Medical records of 4 institutions were reviewed to identify rabbits with an antemortem diagnosis of liver lobe torsion that were examined between 2010 and 2020.

RESULTS

The prevalence of liver lobe torsion was 0.7% (82/11,402). In all 82 rabbits, the diagnosis was made by means of abdominal ultrasonography. Fifty (60.1%) rabbits underwent liver lobectomy, 23 (28%) received medical treatment alone, and 9 (10.9%) were euthanized or died on presentation. Overall, 32 (39%) rabbits died within 7 days of initial presentation and 50 (61%) survived. Seven-day survival rate did not differ significantly between medical treatment alone and surgical treatment. However, median survival time following medical treatment (530 days) was shorter than that following surgical treatment (1,452 days). Six of 14 rabbits had evidence of systemic inflammatory disease on necropsy. Rabbits with right liver lobe torsion were less likely to survive for 7 days than were those with caudate torsions (P = 0.046; OR, 3.27; 95% CI, 1.04 to 11.3). Rabbits with moderate to severe anemia were less likely to survive for 7 days than were rabbits that were not anemic or had mild anemia (P = 0.006; OR, 4.41; 95% CI, 1.55 to 12.51). Other factors associated with a decreased 7-day survival rate were high heart rate at admission (P = 0.013) and additional days without defecation after admission (P < 0.001). Use of tramadol was associated with an increased survival rate (P = 0.018).

CLINICAL RELEVANCE

The prognosis for rabbits with liver lobe torsions was more guarded than previously described. Rabbits that underwent liver lobectomy had a longer median survival time than did rabbits that only received medical treatment.

Clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis: 19 cases (2015-2019)

OBJECTIVE

To report clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis.

ANIMALS

19 rabbits.

PROCEDURES

Medical records for client-owned rabbits that had a histologic diagnosis of appendicitis were reviewed.

RESULTS

Median age of the rabbits at presentation was 24.0 months (range, 4 to 84 months). Seventeen cases occurred during the summer and fall seasons. Decreased appetite (17/19 rabbits), abnormal rectal temperature (hyperthermia, 9/16 rabbits; hypothermia, 4/16 rabbits), hypocalcemia (8/11 rabbits), and hypoglycemia (7/15 rabbits) were common signs. Abdominal ultrasonography and CT findings were suggestive of appendicitis in 6 of 8 rabbits and in 1 of 2 rabbits, respectively. Of the 6 rabbits that received medical treatment, 3 died at 48 hours, 1 died at 24 hours after hospitalization, and 1 died at 10 days after presentation; 1 rabbit was alive at 1,030 days after presentation. Of the 8 rabbits that underwent appendectomy, 3 died before discharge from the hospital and 1 died 113 days after surgery; 4 rabbits were alive at 315, 334, 1,433, and 1,473 days after presentation. The remaining 5 rabbits either died or were euthanized before treatment could be instituted. In each of the 19 rabbits, the appendix had evidence of severe inflammation with mucosal ulceration, heterophilic inflammation, and necrotic debris.

CLINICAL RELEVANCE

For rabbits with decreased appetite and an apparently painful abdomen, hyperthermia, hypocalcemia, or hypoglycemia, appendicitis should be considered as a differential diagnosis. Further comparisons of medical and surgical treatments are required to establish treatment recommendations for rabbits with appendicitis.

Rabbit Sedation and Anesthesia

With the increasing frequency of rabbits as veterinary patients, the expectation for high-quality, intensive veterinary care, and resultantly an understanding of anesthesia has been increasing. Sedation and general anesthesia are commonly required for many routine and emergency procedures in rabbits, and this results in the need for a strong awareness of anesthetic principles, knowledge of limitations of anesthesia, and maintenance of high standards of anesthesia.