Non-Obstructive Ileus – Rabbit

Also known as: Gastrointestinal Hypomotility

Introduction

This describes increased intestinal transit time and decreased frequency of caecocolonic segmental contractions.

Proper hindgut fermentation and gastrointestinal tract motility are dependent on the ingestion of large amounts of roughage and long-stemmed hay. Ileus can be caused by diets that contain inadequate amount of fibre, such as muesli-type diets.

When gastrointestinal motility slows down, ingesta accumulates in the stomach. Dehydration of stomach contents often occurs, which makes passing the contents even more difficult. If the hypomotility is not treated, electrolyte imbalances and shifts in the intestinal microbial flora can occur and can be fatal.

The rabbit stops eating, faecal pellet production slows and stops and there are alterations in the enteric microflora population. This can lead to overgrowth of E. coli and Clostridia spp which exacerbate the ileus.

Surgery, stress, changes in environment and anorexia due to other diseases can all precipitate ileus.

If a rabbit presents with ileus, the priority is to treat the condition, aggressively if necessary. Further investigations into the cause of the ileus can be performed once the rabbit is stable.

Clinical Signs

The rabbit may present due to decreased appetite or anorexia.

The owner may report: abnormal faecal production, with either no or a reduced amount of pellets, liquid faeces or mucoid pellets

Pain may be manifest as: hunched posture, tooth grinding, shallow rapid respirations, tender abdomen on palpation.

Intestinal sounds may be abnormal: negative or increased borborygmi, increased caecal resonance.

The rabbit may be hypothermic.

On abdominal palpation, the stomach may be hard, distended and remains pitted on compression.

Diagnosis

History and clinical signs are highly usually suggestive of the condition.

On radiographs there will be moderate to severe distention of the stomach with ingesta. A halo of gas may be present around the stomach contents. Gas distention is also common throughout the gastrointestinal tract, including the caecum.

Absence of faecal balls in the colon is also highly suggestive.

Investigation of Ileus

Investigation of the cause of ileus should include:

Full history: details of the diet fed, previous surgeries, any stressful situations

Clinical examination: dental examination, signs of musculoskeletal disease, neurological problems

Biochemistry: raised liver enzymes may indicate pathology causing pain

Haematology: may indicate chronic disease or infection

E. cuniculi serology: infection may be involved in neurological problems affecting food prehension or ingestion

Radiography: looking for signs of dental disease, osteoarthritis, neoplasia, foreign bodies

Ultrasound: allows more complete assessment of the liver, kidneys and bladder

Faecal analysis: may be difficult if there is a lack of faecal output, but once it returns may provide information on parasites, digestion etc..

Treatment

Aggressiveness of therapy depends on the severity of the presenting signs.

Aims should include:

Analgesia: NSAIDs like meloxicam or opioids like buprenorphine depending on the signs

Fluid therapy: the aim is to rehydrate the gut contents and/or to rehydrate the rabbit. Oral fluids can be given along with intra-venous fluid therapy. Intra-peritoneal and intra-osseous routes can also be used if venous access is impossible. Sub-cutaneous fluids are not particularly helpful.

Supportive nutrition: the aim is to provide long indigestible fibre to stimulate the fusus coli, however in the first instance, any food is better than none and the rabbit can be tempted with its favourites. It can be syringe-fed products made for critical care feeding of rabbirs.

Pro-kinetics: Ranitidine is the most useful, but metoclopramine and cisapride have also been used.

Exercise: this helps to stimulate gut motility and good hospitalisation away from predators, good analgesia and good nursing will all encourage the rabbit to exercise.

In the long term, the rabbit should be fed a diet high in fibre and low in carbohydrates to avoid the condition occurring again.

Owners should be taught to monitor faecal output so that small changes and early disease will be dealt with promptly.

Prognosis

Depends on the underlying cause.

Early medical management of animals with ileus carries an excellent prognosis.

Non-Obstructive Ileus – Rabbit Learning Resources
Flashcards Test your knowledge using flashcard type questions	Rabbit Medicine and Surgery Q&A 08

References

Girling, S. J. (2006) Diagnostic Imaging in BSAVA Manual of Rabbit Medicine and Surgery, eds Meredith A and Flecknell P, 2nd Edition 2006, published by BSAVA Quedgley Glocs

Oglesbee, B. (2006) The 5-minute veterinary consult: ferret and rabbit Wiley-Blackwell

Sayers, I. (2011) Ileus in Rabbits RVC Small Mammal elective student notes