Diagnosis and clinical management of gastrointestinal conditions in exotic companion mammals (rabbits, guinea pigs, and chinchillas)

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.

Application of Diagnostic Imaging in Exotic Animal Gastroenterology

Imaging of an exotic animal with gastroenteric disease is often essential to make a diagnosis. The selection of a modality and its effective use needs careful consideration in each case. Obtaining a high-quality image and its interpretation are an acquired skill. This article describes how to obtain a high-quality image, and then presents guidelines for its interpretation.

Sectional Anatomy with Micro-Computed Tomography and Magnetic Resonance Imaging Correlation of the Middle and Caudal Abdominal Regions in the Syrian Hamster (Mesocricetus auratus)

The abdomen is a key region in small animal veterinary practice, with the middle and caudal sections housing various organ systems that are susceptible to dysfunction, necessitating medical intervention or surgery. Sectional imaging techniques like CT and MRI are commonly used in small mammals, but no studies have focused on rodent abdomen. This study aimed to correlate micro-CT and MRI images of the middle and caudal abdominal regions with corresponding anatomical sections in Syrian hamsters (SHs), which are popular pets and experimental models. Ten healthy male SHs were used, and anatomical structures from frozen sections were compared with corresponding MCT and MRI images. Clinically relevant structures identified in anatomical sections were discernible on MCT and MRI scans. The key findings include the presence of glandular and non-glandular stomachs, the stomach and cecum primarily located on the left side, the absence of ampulla coli, sacculus rotundus, and cecal appendix, and sacculation of the colon, as well as the jejunum, mainly on the right side. The vesicular, coagulating, and prostate glands were also present, and the right kidney did not extend to the last thoracic vertebra. The results were similar to abdominal anatomical and radiologic studies in rats, mice, and guinea pigs, regardless of the rat's and mice's sacculated cecum and the guinea pig's glandular stomach. However, significant differences were observed compared to the rabbit abdomen's sectional anatomy and CT findings. This study highlights the diagnostic value of MCT and MRI in SHs and provides a valuable reference for interpreting cross-sectional abdominal images in SHs.

Pain Management for Gastrointestinal Conditions in Exotic Animals

Gastrointestinal (GI) disorders are very common in exotic animals, such as reptiles, birds, mammals, and can be extremely painful. This review aims to provide the reader with a better understanding of the different pain mechanisms and manifestations across orders and species in order to provide the most updated information on pain recognition and management for GI conditions in exotic animals.

Pain management in pet guinea pigs (Cavia porcellus): a review of limitations of current knowledge and practice

OBJECTIVE

To describe recent evidence-based and peer-reviewed literature on the topic of pain assessment and pain management in guinea pigs in a systematic review. To consider impacts of current practice on guinea pig welfare and to identify areas in need of further research.

DATABASES USED

ScienceDirect, PubMed and CAB abstracts along with relevant information from books and ebooks were searched. Terms used were guinea pigs, cavies, Cavia porcellus, pain, surgery, surgical procedures, grimace, dental, bloat, analgesia, non-steroidal anti-inflammatories and opiates.

CONCLUSIONS

There are few studies available in the areas of pain assessment and pain management in guinea pigs. Grimace scales and in-clinic pain assessment scales are available for other species but have not been developed for guinea pigs. Doses of analgesic drugs are extrapolated from other species or used from anecdotal evidence in the absence of validated values. The specified dose for the only UK licenced analgesic drug for guinea pigs (meloxicam) is significantly lower than doses suggested in the reviewed literature which may have a negative impact on the welfare of this species. To improve the welfare of guinea pigs, further research into the pharmacokinetic (PK) and pharmacodynamic (PD) properties of analgesic drugs specific to this species are required. Further research into the development and validation of pain assessment methods is also indicated to promote better welfare of this species.

Computed tomographic diagnosis and clinical outcomes of small intestinal obstruction caused by trichobezoars in client-owned rabbits

Small intestinal obstruction in rabbits, although demonstrated to be common, is still poorly characterized. The objective of this study was to report features of small intestinal obstruction caused by trichobezoars in rabbits upon CT and their clinical outcomes. Rabbits with a diagnosis of intestinal obstruction that underwent CT scanning were included in this study. From each CT scan, obstruction location, appearance, Hounsfield units, size (mm), volume (mm3), distance from the stomach, and diameter of the small intestine proximal and distal to it, were extracted. Nine rabbits were included in the study. All rabbits presented for anorexia and had a distended or enlarged stomach (7) or abdomen (2). CT scan showed a non-contrast-enhancing, ovoid, smoothly marginated structure with a hyperattenuating rim, heterogeneous center, and variable amount of centrally located gas, in the duodenum (5), the jejunum (2), or the ileum (2). The density of the trichobezoars ranged from -156 to 58 HU (median, -44 HU) and volume ranged from 86.1 to 633.8 mm3 (median, 320.6 mm3). Three rabbits underwent medical management. Two of them survived, and one of them died. Six rabbits underwent surgery, of which three were successfully discharged from the hospital. CT proved to be a valuable imaging modality in rabbits with a suspected intestinal obstruction to provide the exact location of the obstruction and the characteristics of the obstructive material. The location and size of the trichobezoar may have relevant clinical implications.

Clinicopathological and radiographic indicators for orogastric decompression in rabbits presenting with intestinal obstruction at a referral hospital (2015-2018)

BACKGROUND

Orogastric decompression is regularly recommended as a part of both medical and pre-surgical treatment for small intestinal obstruction in rabbits. However, guidelines as to when orogastric decompression is indicated are sparse.

METHODS

The medical records of 35 rabbits diagnosed with gastrointestinal obstruction over a 3-year period were examined. Differences in presentation, clinicopathological and radiographic examination findings, treatments and outcome were evaluated.

RESULTS

Approximately 49% of the cases evaluated were considered to have non-life-threatening disease, while 51% were considered to have life-threatening disease. The severity of gastric obstruction was correlated with the severity of hyperglycaemia (average 25.7 mmol/L; 463 mg/dl) and corresponding hyponatraemia (Na < 138 mmol/L; 138 mEq/L). These patients were treated with orogastric decompression and medical management only.

LIMITATIONS

This is a retrospective study and there are inherent limitations involving the quality of the data and data collection. Additional studies should be completed that strive for larger sample sizes to compare the differences in outcome between surgical and medical management, as well as investigate the outcomes of rabbits with hyperglycaemia and hyponatraemia that did not have an orogastric decompression performed.

CONCLUSIONS

Blood glucose and sodium concentrations, in combination with radiographic findings, may aid clinicians in determining if orogastric decompression is indicated to stabilise rabbits with small intestinal obstructive disorders.

Diagnosis and surgical treatment of colonic obstructive foreign bodies in chinchillas (Chinchilla lanigera): a case series (2017-2020)

We describe a case series of colonic foreign bodies in seven chinchillas. These animals had all shown complete lack of fecal output. Ultrasonography was performed in each case, revealing a hyperechoic foreign body with strong acoustic shadowing in the bowel in 6 of the 7 cases (86%). Foreign bodies were removed under exploratory laparotomy in all cases, with a perioperative survival rate of 71% (5/7). The foreign bodies were extracted from the distal ansa of the ascending colon (n=3), descending colon (n=3), or intermediate part of the ascending colon (n=1). This case series suggests chinchillas are affected by colonic obstructive foreign bodies and surgical intervention may be necessary to pursue better prognosis in cases where medical therapies prove ineffective.