GI Disease in Herbivorous Rodents Flashcards
What is food selection in rabbits based on?
Food selection based on smell and vibrissae (long stiff hairs growing around the mouth or elsewhere on the face of many mammals, used as organs of touch; whiskers)
How are end products of digestion separated in rabbits GI?
- End products of digestion are separated in proximal colon –> large indigestible fibre particles rapidly eliminated as hard pellets –> smaller particles passed to caecum for fermentation
Where does microbial fermentation occur in rabbits?
What happens after this?
Microbial fermentation in caecum –> caecotrophs –> ingested directly from anus and subsequently digested in a similar manner to other monogastric animals
When are caecotrophs usually passed in rabbits?
Caecotrophs usually passed overnight or early morning -> covered in protective mucus
What are the following:
- Sacculus rotundus
- Fusus coli
- Sacculus rotundus at junction of small and large intestines
- Fusus coli is a 8-10cm, specially adapted area of the colon –> acts as differential pacemaker –> alters depending on phase of faecal excretion
What is colonic motility regulated by in rabbits?
What can stress do to rabbits?
- Colonic motility is regulated by the autonomic nervous system, prostaglandins and aldosterone
- Stress of any kind –> adrenaline –> inhibits gastrointestinal motility –> GI stasis
What kind of diets are reccomended for rabbits and herbivorous rodents?
- A diet high in fibre is essential
- Natural diet –> mixed grasses, shoots, leaves, roots & bark
- Chinchillas –> hold food in paws
- Guinea pigs –> vitamin C
- Selectively eat higher quality/calorific foods and prefer sweet- tasting foods
- Recommended diet for pet rabbits _ 80-90% grass/hay, 1-2 tablespoons pellets, variety of leafy greens (preferably weeds)
- Unable to vomit –> though do see clinically especially in guinea pigs and during anaesthesia
What are some causes of GI disease in Rabbits & Herbivorous Rodents?
- In short, virtually anything can cause gastrointestinal disease!
- Deficiencies in diet, husbandry and environment
- Secondary to other diseases, pain and stress
- Infectious organisms and toxins
What are some key points of the history of rabbits and herbivorous rabbits that you should check/ask?
- Fully review the husbandry diet and environment
- Hutch, house, free-range or combination
- Access to grazing
- Type and quantity of hay and how is it offered
- Mix or pellets and how much is offered
- Fresh produce offered and how much
- Treats e.g. Yoghurt drops, seed sticks, biscuits…
- Supplements, vitamin C (guinea pigs)
- What is actually eaten
What should you check on the clinical exam of rabbits and herbivorous rabbits that you should check/ask?
- Remember _ assess from afar 1st; good restraint!!
- May require stabilisation, analgesia/sedation first
- Thoroughly palpate and examine skull & mouth
- Auscultate chest and abdomem
- Palpate abdomen thoroughly but gently
- Check body condition, limbs and perineum
- Unkempt coat or ectoparasites may be due to obesity, orthopaedic or dental disease and/or inadequate husbandry –> may predispose to GI obstruction
What is ocular discharge usually due to in rabbits?
Ocular discharge is often due to molar disease. Chinchillas may often just wink
What is wrong with these 3 images?
- Faecal soiling
- Anal-rectal papilloma
- Matted fur on foot pads
What is the investigation for GI disease of rabbits and herbivorous rodents?
- Haematology and biochemistry
- Urinalysis
- Faecal flotation & wet smear
- Radiography
- Ultrasonography
- Endoscopy
- Oral exam and abdominal palpation under heavy sedation/general anaesthesia when stable
How useful is haematology and biochemistry when investigating GI disease in rabbits and herbivorous rodents?
Haematology and biochemistry often non-specific
- Commonly –> anaemia and stress leukogram
- Hyperglycaemia –> stress, pain, advanced liver disease.
- Hypoglycaemia –> starvation
- Elevated TP & HCT +/- urea/creatinine indicate dehydration
- Reduced albumin –> production/loss/ingestion
- Liver –> TBIL, ALT, AST, GGT, ALKP
- Urea –> circadian rhythm = higher in the evening
- Lead –> toxicity most commonly occurs after chewing old painted woodwork
What is this?
Rabbit faecal smear demonstrating bacteria, yeasts (Saccharomyces guttulatus) and coccidia (Eimeria steidae)
Is this rabbit normal or abnormal?
What is it?
Normal (rabbit) lateral abdominal radiograph
‘hard faeces phase’
Is this rabbit normal or abnormal?
What is it?
Normal (rabbit) lateral abdominal radiograph
‘soft faeces phase’
What is wrong with this rabbit?
Lateral (rabbit) radiograph:
cardiomegaly and hepatomegaly
What is wrong with this radiograph?
Gastric Bloat
distension may be due to varying degrees of gas or fluid accumulation
What is wrong here in this guinea pig?
Gastric torsion in a guinea pig; a relatively common presentation that is often missed!!
What is wrong with this chinchilla?
Moderate gastrointestinal stasis in a chinchilla with dental disease
What is wrong in this chinchilla?
Severe gastrointestinal stasis in a chinchilla with dysbiosis after being treated with the antibiotic enrofloxacin
What is wrong with this rabbit?
Caecal impaction in a rabbit
What are some common causes of GI disease in Rabbits & Herbivorous Rodents?
- In short, virtually anything can cause gastrointestinal disease!
- Deficiencies in diet, husbandry and environment
- Secondary to other diseases, pain and stress
- Infectious organisms and toxins
What are some conditions of the oral cavity in rabbits and herbivorous rodents?
- Acquired Dental Disease
- Dental caries
- Tooth fractures
- Jaw fractures
- Foreign bodies –> wire, wood, grass awns etc.
- Electrical burns –> chewing through cables
- Congenital –> cleft palate, incisor malocclusion
Acquired dental disease is progressive.
What are the 5 stages?
- Stage 1 –> normal
- Stage 2 –> root elongation & deterioration
- Stage 3 –> acquired malocclusion
- Stage 4 –> cessation of tooth growth
- Stage 5 –> end stage:
- (a) osteomyelitis and abscess formation
- (b) calcification of teeth and surrounding bone
What stage of dental disease is this?
Contrast study of NL-duct demonstrating obstruction
Stage 2-3 dental disease
What stage of dental disease is this?
Stage 4 dental disease
What stage of dental disease is this?
Stage 5a dental disease
What stage of dental disease is this?
Stage 5b dental disease
What is wrong with this guinea pig?
Guinea pig with molar disease and mandibular abscess
What oesophageal disease is common in rabbits and herbivorous rodents?
- Megaoesophagus and foreign bodies are rare
- Gastro-oesophageal reflux and vomiting is in theory impossible but does rarely occur
How common in gastric ulceration in rabbits and herbivorous rodents?
What is advisable?
- Common –> secondary to anorexia and stress
- Clinical signs vary from anorexia, bruxism and depression to acute-abdomen and shock
- Routine administration of anti-ulcer drugs to anorexic rabbits is therefore advisable
- Ranitidine and omeprazole most effective
- Ranitidine is also prokinetic
What commonly causes gastric bloat in rabbits and herbivorous rodents?
Prognosis?
- Physiological obstruction –> gastric stasis as a result of pain, stress, dehydration, diet or toxins
- Physical obstruction –> foreign body, neoplasia or adhesions
- Subtle clinical signs may progresses slowly (physiological obstruction) or rapidly to an acute abdomen (physical obstruction)
- Aggressive stabilisation required in all cases –> surgical intervention required once stable if does not respond to medical therapy alone
- Prognosis is poor to grave, poor surgical patients
What is enteritis as part of GI disease of rabbits and herbivorous rodents?
Clinical signs?
Enteritis (Bacterial)
- Normal population –> Clostridia, Bacteroides, Enterococcus, Staphylococcus & E.coli
- Dysbiosis –> overgrowth of clostridia and/or coliformes secondary to diet change, stress or antibiotic administration
- Bacteroides appear to inhibit pathogenic bacteria
- Lactobacillus are absent in rabbits (probiotics?)
- Anorexia, diarrhoea, haematochezia, dehydration, shock and death
What can cause bacterial enteritis?
- E.coli _ Juvenile rabbits under stress
- Salmonellosis
- Pseudomonas
- Yersinia pseudotuberculosis –> acute and chronic forms.
- Latter = microabscess formation
- Lawsonia intracellularis
What can cause viral enteritis in rabbits?
- Neonatal and juvenile rabbits
- Coronavirus –> diarrhoea, abdominal distension and lethargy –> high morbidity and mortality
- Rotavirus –> mainly diarrhoea
- Concomitant infection with E.coli and/or coccidiosis
increases severity of clinical signs
What can cause parasitic enteritis in rabbits?
- Passalurus ambiguus (pinworm) is common
- Rabbit is intermediate host for Cysticercus pisiformis, Coenurus serialis & Echinococcus granulosus
- Coccidiosis (Eimeria spp) –> often subclinical except in juvenile rabbits under stress –> clinical signs include weight loss, diarrhoea +/- blood and in severe case –> death
What are some miscellanious things that can cause GI disease in rabbits and herbivorous rodents?
- Dysautonomia –> idiopathic –> clinical signs may include GI stasis, dry mucous membranes and conjunctiva, mydriasis, bradycardia, urine retention, megaoesophagus, large intestine impaction. May be found dead with food impacted in mouth; also occurs in hares.
- Mucoid Enteropathy –> idiopathic syndrome characterised by caecal impaction and large quantities of mucus in colon. Generally juvenile rabbits –> usually fatal
- Caecal Impaction –? occasionally occurs in adult rabbits (cf. mucoid enteropathy). Aetiology is often unclear but may be secondary to stress or ingestion of substances such as clay cat litter _ Poor prognosis, a small number rabbits have responded well to prostaglandin treatment
- Neoplasia –> papilloma, lymphoma, adenocarcinoma, squamous cell carcinoma…
- Anal Impaction –> common in aged male guinea pigs
What is wrong here?
Post-mortem of juvenile rabbit
Suffering From mucoid enteropathy
What can cause hepatic disease as part of GI disease in rabbits and herbivorous rodents?
- Lipidosis –> obesity, anorexia, and pregnancy are risk factors
- Liver lobe torsion –> presents as acute abdomen or death; prompt diagnosis and surgery required
- Coccidiosis (Eimeria steidae) –> weight loss, diarrhoea, ascites, jaundice and hepatomegaly; often older rabbits
What are some general goals for the treatment of GI disease of rabbits and herbivorous rodents?
- Restore circulatory volume
- Restore gastrointestinal hydration
- Eliminate pain
- Prevent/treat ulceration
- Restore gastrointestinal motility
- Eliminate stress
- Identify and treat underlying diseases
What nursing and hospitalisation is essential for GI disease of rabbits and herbivorous rodents?
- Good quality nursing is essential
- Keep away from sight, sound and smell of predators, general noise and people
- Hospitalise with cage mate(s)
- Encourage owners to bring normal food and utensils (especially guinea pigs)
- Ensure soft, dry bedding and plenty of fresh hay
- Provide hide box
- Gentle and patient restraint and handling
- Hand and syringe feeding
- Grooming and cleansing of soiling and discharges
- Especially clear nasal discharges
- Note faecal output –> type, consistency and size
- Gentle abdominal massage
- Allow to exercise daily if condition allows
Patient is stable, active, alert and swallowing
What is the treatment protocol?
- Warm, quiet environment with plenty of hay, greens and favourite food items
- Analgesia (opioid & NSAID)
- Subcutaneous and oral fluids
- Prokinetics & antacids
- Assist feeding
- Gently massage abdomen and allow exercise
Patient depressed, dehydrated and/or unwilling to swallow
What is the treatment protocol?
- Warm, quiet environment with plenty of hay, greens and favourite food items
- Analgesia (opioid)
- Intravenous/intraosseous fluids –> S/C & oral fluids
- Prokinetics & antacid (Ranitidine)
- Antibiotics ?
- Assist feeding (NG tube if unwilling to swallow)
- Gently massage abdomen
Your patient has gastric bloat
What is your treatment protocol?
- Critical patients!
- Intravenous crystalloids and colloids
- Analgesia and sedation (be prepared to intubate!)
- Decompress with orogastric tube SLOWLY _ CARE very easy to rupture!
- Administer liquid barium before remove tube and take lateral radiograph
- Proceed as per general protocol 2.
- Simethicone?
- If bloat recurs or barium does not pass into small intestine → requires surgery
What are some indications for surgery in Rabbits & Herbivorous Rodents?
Indications for surgery include lack of movement of barium from stomach and/or distension of small intestinal loop(s)
Your patient has Dysbiosis/enterotoxaemia - what is your treatment protocol?
- General protocol 2
- Warm, quiet environment with plenty of hay, greens and favourite food items
- Analgesia (opioid)
- Intravenous/intraosseous fluids –> S/C & oral fluids
- Prokinetics & antacid (Ranitidine)
- Antibiotics ?
- Assist feeding (NG tube if unwilling to swallow)
- Gently massage abdomen
- Colloids if hypotensive
- Stop any offending antibiotics
- Metronidazole +/- enrofloxacin?
- Cholestyramine
- Probiotics
- Transfaunation of caecotrophs?
What is the approach to Accumulated Caecotrophs?
- Clip and clean perineum (often require sedation!)
- Provide analgesia and antibiotics as required
- Correct underlying causes e.g. husbandry, obesity, perineal folds, DJD, teeth
- Exclude all treats, fruit and root vegetables from the diet
- Provide ad-lib hay and grass
- In stubborn cases can place on hay-only diet for 3 months (carefully monitor intake and weight); may not be appropriate if has oral/dental pain
What is wrong here?
What is the treatment?
- Faecal accumulation within excessive perineal skin folds
- Treatment is relatively simple by resecting redundant skin
- Weight management essential
What are some problems of surgery in rabbits and herbivorous rodents?
Which suture material should you not use?
- GI surgery in rabbits/rodents is often high risk
- Adhesions form readily in rabbit
- General principles and techniques as for cats
- Precise, delicate and minimal tissue handling
- Ensure tissues continually hydrated
- No powdered gloves
- Omentum small –> omentalisation is difficult
- PDS, Vicryl, Monocryl –> DO NOT USE CATGUT
- Verapamil reportedly reduces adhesions
- Sodium carboxymethylcellulose solution reduces adhesions
How should you perform dentistry in rabbits and herbivorous rodents?
- Deep sedation/general anaesthesia IS MANDATORY
- Good lighting +/- magnification (endoscopy helpful if available)
- Mouth gag, cheek dilators, tongue depressors
- Low-speed dental hand-piece with straight nose cone
- Diamond cutting disc (incisors) variety of burs for molars
- Avoid using hand-held rasps –> tend to be too traumatic
- Skull radiography is essential → will miss > 80% pathology without!
- Significant and very important species differences in anatomy & treatment!
- Straight lateral, lateral oblique x2, dorsoventral and rostrocaudal views
- Aim is to restore normal, pain-free occlusion as much as possible
- Important not to lower crowns too far especially if molars stopped growing
- Warn owners of need for multiple treatments
What is happening in these images?
- Large tooth-related abscess
- Exteriorise and remove as much of abscess as possible including diseased teeth & bone
- Remaining abscess capsule is sutured to skin (marsupilised) to allow topical therapy on remaining abscess tissue
