Fusus coli. Terminology. Regulation of gut motility. Gut motility. Ileus, stasis, bloat or blockagehow to tell the apart?

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1 Ileus, stasis, bloat or blockagehow to tell the apart? Terminology Gut stasis: stasis is a term that many people use to describe any rabbit that isn t eating Ileus- is a term that vets often use. May be called non-obstructive or obstructive Bloat- term that breeders use to describe a rabbit with a distended abdomen. Often attributed to clover or grass cuttings. Can be due to mucoid enteropathy Blockage- intestinal obstruction. Usually small intestine There is overlap between conditions Gut motility Gut motility is complex and important Supplies the caecum with nutrients and fluid Passage of food, especially large particles of indigestible fibre appear to have a direct effect on gut motility Regulation of gut motility Intestinal tissue will contract on its own Adrenaline will slow gut movement In rabbits, hindgut motility is complex Regulated by a specially adapted area of the colon- the fusus coli (another feature of lagomorphs) Fusus coli Causes of stress and slow gut motility Fusus coli is innervated and has a good blood supply Influenced by metabolites (glucose etc), hormones and the autonomic nervous system Rabbits seem more susceptible than other species to the effect of stress on gut motility Pain Illness So any clinical problem can slow gut motility Examples of other causes: Loss of companion Travelling Surgery is painfuleffective analgesia is very important in rabbits (it is in all species) 1

2 Gut stasis is not a diagnosis Signs of pain and stress in rabbits There is always a cause of gut stasis It doesn t just happen It is not a diagnosis? Influence of diet not proven My opinion: Gut stasis is as likely to occur in rabbits on a high fibre diet. However, rabbits on a high fibre diet are healthier and less like to suffer from some of the underlying causes Dental spur and tongue damage Immobile Unresponsive? Increased heart rate? Increased respiration Anorexia- most obvious to the owner Is it trivial or life-threatening Abdominal catastrophes Obstruction of gut e.g. by foreign body or tumour Strangulation of gut where part of gut is constricted e.g in a hernia or by a loop of intestine Torsion or twisting of a section of gut or other abdominal organ such as uterus Rupture of an abdominal organ e.g bladder, gut or uterus Peritonitis- can be result of any of above or due to infection e.g surgery, appendicitis (humans) or enterotoxaemia Signs of abdominal catastrophe in other species Complaining (humans) Whimpering Depressed and unhappy Colic Sweating Fast, weak pulse Vomiting Anorexia Absence of signs of abdominal catastrophe in rabbits Blood glucose measurement in rabbits Don t sweat Can t vomit Normal heart rate is bpm i.e. to fast to count easily Pulse is hard to find Hide and sit quietly when they are in pain Any signs of colic are subtle Anorexia may be the only sign that is obvious to the owner Glucose quickly rises in response to stress Can get very high in very painful conditions Can also be low if insufficient nutrients are absorbed from digestive tract NB: Diabetes is rare (and rabbit would be eating) 2

3 Blood glucose measurement Reference range: mmol/l <2mmol/l- significant e.g Insulinoma <2-4mmol/l- needs food (gut stasis) or terminal 4-8mmol- reassuringly normal 8-15mmol/l- probably due to stress > 15mmol/l severe stress, look for diagnosis > 20mmol/l severe stress and pain. Could need surgery > 25mmol/l- serious stress and pain-surgery is probably only hope This is only a guide: there are exceptions Gut stasis- Initial changes Food doesn t move through gut Stagnates Pockets of gas collect in gut because gas producing organisms are present Faecal output ceases Hard faeces may accumulate in colon Blood glucose in early stages of gut stasis Variable May be marginally high because rabbit is stressed by condition causing gut stasis May be marginally low because insufficient nutrients from GI tract Unlikely to be greater than 15mmol/l Demeanour of rabbit in early stages of gut stasis May be bright and responsive at outset unless there is serious illness or pain Left untreated- GI tract empties Demeanour of rabbit Small stomach Empty caecum and colon Reduced absorption of glucose from gut Reduced absorption of nutrients to and from caecum Blood glucose falls Often sitting quietly at back of cage Hunched posture No interest in eating on its own Will probably take syringe feed (why?) Glucose may be low, normal or slightly raised 3

4 After 2-3 days Formation of a hairball or Trichobezoar Gas continues to accumulate in stomach and caecum Dehydration Stomach contents become impacted Impacted fur and food forms in ball in the stomach Hairball or trichobezoar Used to be thought to be cause of anorexia Now it is known to be an effect Demeanour of rabbit Often sitting quietly at back of cage Hunched posture No interest in food May frantically chew paper or hay? Response to abdominal pain Rabbit has not eaten or passed faeces for 3-5 days. Next stage: Hepatic lipidosis After 4-7 days of untreated gut stasis Fat is mobilised and transported to liver as an energy source Metabolic bottle neck occurs Fat destroys liver cells Rabbit dies from liver failure Clinical features of hepatic lipidosis Gastric ulceration Rabbits are cold and wobbly Unresponsive Pale mucous membranes Won t take syringe feed- dribbles out of mouth Terminal Stage when some owners first notice a problem 1.5mg/kg meloxicam Can occur in rabbits with gut stasis Only diagnosed during post-mortem examination or laparotomy Role of NSAIDs (painkillers) is uncertain 4

5 Meloxicam Trend to use high doses ( mg/kg) Based on a study of a small number of healthy (not ill) rabbits Showed that meloxicam is metabolised rapidly and rabbits are tolerant of high dose My opinion Lower doses (0.15mg/kg twice daily) are effective and safer Is the option to use higher doses if needed Prevention and treatment of gut stasis Vitally important in rabbit medicine and surgery Recognise any rabbit that is not eating and defaecating Identify and treat the underlying condition Provide effective analgesia Prevent negative energy balance by ensuring rabbit has food going through gut Stimulate gut motility Reduce stress MAKE A DIAGNOSIS (not always possible) Pineapple juice Traditional remedy for gut stasis Reputed to dissolve hair (doesn t) Does provide oral fluid Also source of absorbable sugars and electrolytes Syringe feeding Provides fluid and electrolytes Provides calories to prevent negative energy balance Provides fibre to nourish caecal microflora Safe and easy Provide tempting foods Medical treatment Analgesia Antiulcer medication Drugs to stimulate gut motility -cisapride -metoclopramide -domperidone -zantac (ranitidine) also anti-ulcer 5

6 Intestinal obstruction and bloat Gastric dilation (bloat) Common emergency Sudden complete anorexia Palpably enlarged stomach NOT just gut stasis NOT dietary Is usually due to physical obstruction in intestine Gas and fluid in stomach Recap: What happens if intestine is obstructed Stomach is very distensible Strong cardiac sphincterone way valve Saliva is continuously produced and swallowed Stomach contents contains caecotrophs with gas producing bacteria If exit to stomach is blocked, there is nowhere for gas to escape No exit for food Rapid fermentation of stomach contents and gas production Fluid continues to be swallowed and secreted No exit for gas and fluid Stomach becomes distended 4 hours later Gastric dilation Stomach is distended beyond normal limits Palpable behind ribs on left Rabbit is unwell Intestine fills with gas proximal to site of obstruction Blood glucose rises- >15mmol/l Causes of intestinal obstruction: 1. Pellets of impacted hair Most common cause of obstruction Only found during surgery or post-mortem examination Can pass through GI tract so no definitive diagnosis made Debate about origin 6

7 Theories about origin of pellets? Pieces of trichobezoars that have formed in stomach? Mats of hair that have been ingested during grooming Hard faecal pellets containing impacted hair Hairy poos Large amounts of hair is ingested during grooming Compressed during passage through colon Passed out as pellets of compresses hair Some rabbits eat hard faecal pellets as well as caecotrophs What happens if rabbit swallows a hard faecal pellet of compressed hair If it is small, the pellet will pass straight through If it is medium sized it can pass though but may obstruct intermittently If it is large, it will obstruct the small intestine completely Pain may influence process by slowing gut motility Moving pellets Pellets can move along and periodically obstruct gut Pain probably slows motility and passage through gut Analgesia might will help Prokinetics might help When pellet moves through ileocolic valve All the gas and fluid that has built up in stomach and small intestine is released into hindgut Pellet passes through colon and out through anus What happens when obstruction goes through? Either: 1.Pain resolves and rabbit feels better. Improvement in demeanour and return of appetite - may be interpreted as successful response to treatment 2.Or rabbit has been ill so long that shock, secondary paralytic ileus, acute renal failure and/or electrolyte imbalances kill it 7

8 Case report: 3yo MN Angora- Sunday afternoon After 15 minutes 15 minutes later Sudden onset anorexia, palpable stomach, glucose 19.6 mmol/l After 30 minutes After 2 hours Rabbit started to eat- could be interpreted as successful response to treatment. Analgesia probably helped What if the obstruction does not pass through to hind gut? Rupture of stomach or intestine Rabbit will definitely die Intestinal obstruction is a common cause of sudden death in pet rabbits Blood glucose goes dramatically high Shock, dehydration and electrolyte imbalances 8

9 Other causes of intestinal obstruction Intestinal tumours Strangulations Spherical hard objects- locust beans, sweetcorn kernels? Carpet fibre? Other ingested foreign bodies Common neoplasms of rabbits Often aggressive Usually inoperable May be minimal signs (reduced appetite, weight loss) until obstruction occurs Options for rabbit with gastric dilation 1. Euthanasia 2. Surgery 3. Treat in same way as gut stasis with fluids, analgesia and motility stimulants Each case is different Cost may be an issue Confidence with anaesthesia and surgery may be an issue Case example: My rabbit Joe 5.30 pm Friday 29 th March 2015 Moulting Suddenly unwell Had eaten well a few hours previously Sitting in a corner Unresponsive Palpably enlarged stomach behind ribs on left My options Further investigations Meloxicam and other painkillers Motility stimulants Massaging stomach Infacol Making him run around Pineapple juice Further investigations Not Joe- Illustrative example of gastric dilation 6.15pm by time we arrived at practice Not our night on duty Friday evening Gave analgesic Took radiograph Confirmed gastric dilation 9

10 Options Blood glucose measurement Meloxicam Other painkillers Motility stimulants Fluid therapy Surgery Further investigations It was Friday evening Decision making Surgery Surgery is expensive Friday night and inconvenient Probably a pellet of impacted hair causing the obstruction There is a chance that foreign body could move through on its own BUT Delaying surgery increase the risks as the rabbit becomes more unwell Rabbit is in pain with distended stomach Surgery will resolve situation Prevents the rabbit dying with a ruptured stomach or intestine And it is my rabbit. Milking obstruction along Pushing pellet into hindgut 10

11 ?Right decision to operate Concerns: Was surgery really necessary? Have I made him worse? BUT No longer obstructed Was able to remove some of stomach contents and relieve pressure under GA Outcome Intravenous fluids disconnected after surgery Needed syringe feeding for 36 hours Aggressive motility therapy Meloxicam (0.15mg/kg - 0.1mls/kg) twice daily Antibiotics Monday- less than 72 hours after surgery They are not all so lucky The end Having an obstruction seems to be just bad luck Many get better without surgerymotility stimulants, analgesia etc. etc. Others die Makes treatment difficult 11