2 ileus, stasis, bloat or blockage how to tell them apart

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Frances Harcourt‐Brown BVSc FRCVS, RCVS Recognised Specialist in Rabbit Medicine and Surgery

Ileus, stasis, bloat or blockage-how 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

• 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


Causes of stress and slow gut motility

• Pain• IllnessSo any clinical problem can slow gut motility

Examples of other causes:• Loss of companion• Travelling

Surgery is painful-effective analgesia is very important in rabbits (it is in all species)

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Gut stasis is not a diagnosis

• There is always a cause of gut stasis

• It doesn’t just happen • It is not a diagnosis• ? Influence of diet – not provenMy 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


Signs of pain and stress in rabbits

• 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

• Don’t sweat• Can’t vomit• Normal heart rate is

150-300bpm 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


Blood glucose measurement in rabbits

• 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)

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Blood glucose measurement

Reference range: 4.2-8.2 mmol/l

<2mmol/l- significant e.g Insulinoma<2-4mmol/l- needs food (gut stasis) or terminal4-8mmol- reassuringly normal8-15mmol/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 hopeThis 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

• Small stomach• Empty caecum and colon

• Reduced absorption of glucose from gut

• Reduced absorption of nutrients to and from caecum Blood glucose falls


Demeanour of rabbit

• 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

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After 2-3 days

• Gas continues to accumulate in stomach and caecum• Dehydration• Stomach contents become impacted


Formation of a hairball or ‘Trichobezoar’

• 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

• Rabbits are cold and wobbly

• Unresponsive• Pale mucous

membranes• Won’t take syringe

feed- dribbles out of mouth

• TerminalStage when some owners first

notice a problem


Gastric ulceration

• Can occur in rabbits with gut stasis• Only diagnosed during post-mortem examination or

laparotomy• Role of NSAIDs (painkillers) is uncertain

1.5mg/kg meloxicam

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Meloxicam

• Trend to use high doses (0.6-1.5mg/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

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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:

• Stomach is very distensible

• Strong cardiac sphincter-one 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


What happens if intestine is obstructed

4 hours later

• 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


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

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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

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Case report: 3yo MN Angora- Sunday afternoon

Sudden onset anorexia, palpable stomach, glucose 19.6 mmol/l


15 minutes later

After 15 minutes


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?

Shock, dehydration and electrolyte imbalances

Blood glucose goes dramatically high


Rupture of stomach or intestine

• Rabbit will definitely die

• Intestinal obstruction is a common cause of sudden death in pet rabbits

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Other causes of intestinal obstruction

• Strangulations• Spherical hard

objects- locust beans, sweetcorn kernels

• ? Carpet fibre• ? Other ingested

foreign bodies


Intestinal tumours

• 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. Euthanasia2. Surgery3. 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 29th 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

• Meloxicam and other painkillers• Motility stimulants• Massaging stomach• Infacol• Making him run around• Pineapple juice• Further investigations

Not Joe-Illustrative example of gastric dilation


Further investigations

• 6.15pm by time we arrived at practice

• Not our night on duty• Friday evening• Gave analgesic• Took radiograph• Confirmed gastric

dilation

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Options

• Meloxicam • Other painkillers• Motility stimulants• Fluid therapy• Surgery• Further investigations

It was Friday evening


Blood glucose measurement


Decision making

• 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 ownBUT• 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

intestineAnd it is my rabbit….


Surgery


Milking obstruction along


Pushing pellet into hindgut

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?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

• Having an obstruction seems to be just bad luck

• Many get better without surgery-motility stimulants, analgesia etc. etc.

• Others die• Makes treatment difficult


The end

2 ileus, stasis, bloat or blockage how to tell them apart

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