Gastric Stasis – Rabbit

Gastric stasis is reasonably common in pet rabbits.

Diagnosis of gastric impaction/stasis

• Careful palpation of the anterior abdomen
• Radiography: Barium, in a healthy rabbit
  • solid reaches caecum in up to 4 hours
  • liquids may take more than 12 hours
• General clinical assessment, especially for any likelihood of skin disease

Radiography confirms the presence of impacted gastric contents surrounded by a halo of gas (Hillyer 1994). The presence of a small gas “cap” in the fundus is normal. In gastric stasis a “halo” encircles the contents (Girling 2006). The contents vary but are usually composed of fur, fibre (from food), and/or foreign material (usually unsuitable fibre substitute eg. wood-based litter; grass cuttings from a lawn mower, paper). The intake of fur may be inversely related to the fibre content of the diet and mild cases involving gastric trichobezoars may be successfully treated by correcting the fibre content of the diet, but the clinician should also check for pruritic skin conditions and treat as required.

Clinical signs

• Gradually progressive inappetance
• Decrease in output and size of faecal pellets to zero
• Compensatory polydypsia
• Bright for a few days after anorexia
• Pica – the rabbit eats paper, cardboard, wood
• Not painful
• Depression, lethargy, dehydration and death

It is possible to palpate the "doughy" mass in the epigastric area – take care. Gastric rupture is easy to produce! As the condition progresses to non-obstructive ileus see below.

Treatment

Except on the extremely rare occasions when large trichobezoars can be confirmed possibly by endoscopy it is usually sufficient just to flush the offending material from the stomach. The use of a naso-oesophageal tube and administration of isotonic probiotic/electrolyte and monosaccharide solution is recommended. (Note: A small, flexible, atraumatic endoscope is required in this species but endoscopy of the rabbit stomach is difficult, due to the well-developed cardic sphincter and the fact that the stomach is nearly always full and contains material which is difficult to control so it gets in the way!)

The use of mild laxatives (Liquid Paraffin BPC, or preferably, MilPar; Sterling Health: given twice or three times a day, by stomach tube or by naso-oesophageal tube), may be considered.

Oral doses of metoclopramide and cisapride seem to work synergistically in assisting gastric emptying. Cisapride is now extremely difficult to obtain and some clinicians are using ranitidine.

Analgesia:

• Buprenorphine
• Butorphanol
• Carprofen

Assisted feeding:

• Oxbow Critical Care (PetLife email petlife@vetbed.co.uk)
• Hay, grass, high fibre foods – we find that nearly all rabbits will take Timothy hay in our hospital.

Simethicone if large amounts of gas are present.

Avoid antibiotics?

Exercise is important to promote gastrointestinal motility.

The administration of bromelain (10 ml of raw fresh pineap¬ple juice two or three times a day (Okerman 1988 for four to five days) – this is supposed to “tenderise” the keratin in fur-balls – it certainly doesn’t seem to do any harm and may even break down the protein matrix in small clumps of fur. Its main benefit is probably as a source of fluids.

Gastrotomy (recommended by Gentz et al 1995 if the signs are not resolved more than 2 weeks after the start of oral fluids) must be followed by all the medical treatments listed above and given 48 hours after surgery and immediate forced exercise (the rabbit is placed in a box with a fitted carpet on the floor and the box is tilted to make it walk to the opposite end and back again for several minutes several times a day) - Burke 1992

To apply a naso-oesophageal feeding tube, proceed as follows:

1. Take a FG 5 - 8 feeding tube. Make additional holes in the caudal aspect of the tube.
2. Apply local anaesthetic (Minims® Ophthalmic Amethocaine or Proxymetacaine; Bausch and Lomb Pharmaceuticals) drops to the nostrils and wait for 3 - 5 minutes for it to take effect.
3. Measure the tube length from external nares to the caudal end of the sternum and mark the position of the nostril with tape or pen.
4. Lubricate the tube with KY Jelly® (Johnson and Johnson). (If local anaesthesia is adequate the tube should move without resistance or discomfort).
5. Restrain the rabbit with or without a towel in sternal recumbency on the non-slip table-top.
6. Elevate the head. Place the lubricated tube in the ventral nasal meatus directing it medially and ventrally
7. Return the rabbit's head to the normal flexed position as the tip of the tube approaches the pharynx so that it passes down the oesophagus and avoids the larynx and trachea – the rabbit does not cough sufficiently obviously to give you warning that the tube may be misdirected. See step 9.
8. If there is resistance, remove the tube and use the other nostril (ie repeat steps 2, 5, 6 and 7).
9. If the tube is placed endotracheally, there may be a change in the breathing pattern, presence of breath sounds and intraluminal condensation. As this is not reliable, you should assess proper placement by radiography. Assessing the site of the caudal end of the tube by injection of saline is not appropriate as, in my experience, the rabbit does not always cough when the saline (or tube) is placed in the trachea. The distal end of the tube may be found in the stomach or distal oesophagus. If necessary, the tube should be withdrawn until it lies in and the end of the caudal oesophagus - not in the lumen of the stomach where it can be adversely affected by gastric acid. Suture or superglue the tube to the head of the rabbit (over the bridge of the nose and at the base of the ears). I use an Elizabethan Collar only if the animal shows signs of disturbing the tube. Natural caecotrophy is obviously not possible when the animal is wearing an Elizabethan Collar so caecotrophs have to be harvested and fed to the animal.
10. The tube may now be used for the administration of fluids or blended foods. To avoid blockage of the tube strain the dry blended food (shake it through a coffee strainer or flour sieve) prior to suspending it in fluid and flush the tube with water after administration. Administering blended caecotrophs may be attempted but should not be necessary as the rabbit should be able for caeotrophy (and feeding) with the tube in place, unless an Elizabethan collar has been fitted.
11. If the tube becomes blocked, it usually has to be replaced, but sometimes it can be flushed with warm water or even Coca-Cola® - the effervescence is supposed to relieve the blockages but I’ve never had to resort to it.

Offer Timothy hay and spring greens as if the tube was not fitted in the first place. The animal should be able to feed normally and it is imperative that it should be allowed to do so as the teeth continue to grow normally.