'The rabbit just stopped eating and died.' There are of course many reasons why rabbits become anorexic and die but a common cause is ileus. In fact, every sick rabbit will probably try and develop ileus and die. Sometimes they are emergency surgical cases and sometimes they will respond to supportive overnight care. If you are not routinely diagnosing and treating this condition in your practice, this lecture will review why it's so crucial to rabbit veterinary care.

What is ileus? Slowing or cessation of peristalsis is gastrointestinal stasis or ileus. It is important to remember that this is a serious problem that may prove fatal of itself but that it is often not a primary condition but a result of another underlying condition. Ileus can occur simply through pain, stress (fear), dehydration, intestinal blockage or even (chronic) fibre deficiency. If fewer pellets are produced, or they are smaller than normal, it is advisable that owners seek veterinary attention quickly. Once faecal production has completely ceased prognosis is poorer. Anorexia and lack of faecal production for 12 hours should be considered an emergency; the rabbit may be suffering from a life-threatening blockage, is at risk of developing clostridial overgrowth and toxicity and will be developing potentially irreversible hepatic lipidosis.

On clinical examination very small faecal pellets may be noted. The normal quiet sounds of peristalsis heard on abdominal auscultation will be replaced by loud gurgles or, more worryingly, complete silence. The rabbit will be lethargic, hunched and exhibit bruxism (teeth grinding - often mistaken for chewing of food; this animal is however anorexic and teeth grinding due to severe pain).

The ancient myth of rabbit stomach hairballs, or gastric trichobezoars, causing ileus has long been laid to rest. The rabbit's stomach is never empty even if it is dying of starvation; the stomach will always contain some food, hair from grooming and perhaps caecotrophs. The rabbit stomach never fully empties. Of course, in stasis the stomach contents may dehydrate as the rabbit dehydrates and on performing gastrotomy one finds a lump of fur matter, removes it and sometimes the patient moves on to full recovery. Ileus may also respond to pain relief (anaesthesia), fluid therapy and supportive care. Hair plugs may indeed lodge and block the gastric outflow; in that case the ileus is caused by blockage and urgent surgery is required. Hair-balls within the stomach per se do not cause ileus.

Diagnosis and examination, including radiography and ultrasonography, should quickly be used to differentiate surgical versus medical conditions. Intestinal blockage (e.g., fur plugs, seeds, string, neoplasia) requires surgical removal. True intestinal blockage is usually presented as severe acute abdominal pain and bloating. However, occasionally these cases can present as intermittent ileus seeming to respond to medical management before lapsing again days to week later. In some cases it may be that the foreign body is merely shunting along the intestine causing a blockage further on. If the foreign body reaches the caecum the issue generally resolves.

Medical therapy includes the use of gastrointestinal motility agents (cisparide, metoclopramide), pain relief (buprenorphine, butorphanol), anti-ulcer therapy (ranitidine), simethicone to relieve gaseous bloat, cholestyramine to absorb clostridial endotoxins, fluid therapy and nutrition (nasogastric tube may be required). Medical therapy will not work if the underlying cause requires surgical intervention of course; nor will it work if the underlying cause of pain, e.g., fracture, is not addressed. Even if the medical therapy appears to work it is good advice to work up the case to at least eliminate diagnoses using basic radiography (skull, thorax, abdomen, limbs). Dietary review is always advised with any sick rabbit; a high-fibre diet (at least 22% fibre) with plenty of fresh grass hay, exercise and a ready supply of water will help maintain optimum gut function.