small mammals 4 - Diseases of Rabbits Flashcards
GI Stasis Syndrome or Dysbiosis - which smal mammals are susceptible?
Rabbits (and Hystricomorph rodents)
GI Stasis Syndrome or Dysbiosis - etiology
- Indigestible fiber stimulates intestinal (cecocolic) motility
- Lack of fiber, due to dietary deficiency or anorexia (e.g., stress, pain, disease), causes GI stasis
- Accumulation of ingesta in the stomach; fluid is absorbed
- Causes pain → further anorexia → cycle continues
GI Stasis Syndrome or Dysbiosis outcome
Result
* GI stasis disrupts the balance of cecal microflora → enterotoxaemia, intestinal gas distension, diarrhea, end-stage ileus, and death
GI Stasis Syndrome or Dysbiosis - specific causes
- Dental disease
- Antibiotic-associated enterotoxaemia – G-ve and Clostridium overgrowth
Gastrointestinal (GI) stasis summary
Gastrointestinal (GI) stasis is a syndrome of reduced or absent GI motility and its consequences.
* It is often caused by an inappropriate diet. Stress is a common initiator.
* It can rapidly become life-threatening.
The Role of Fiber
* Indigestible fiber stimulates intestinal (cecocolic) motility.
* Lack of fibre, due to dietary deficiency or anorexia, causes GI stasis.
* This results in the accumulation of hair and ingesta in the stomach; fluid is
absorbed.
* Compacted ingesta causes discomfort, contributing further to anorexia,
exacerbating GI hypomotility, and impaction of the stomach.
The Effect of Diet and Cecocolic Motility
* Cecal bacteria are vital for processing fiber entering the cecum into digestible nutrients, which are then reingested as cecotropes.
* An inappropriate diet or GI stasis can disrupt the balance of this complex cecal microflora and the environment in which it grows.
* Changes in cecal pH cause an increase in pathogenic bacteria, such as Clostridium and coliform species, resulting in enterotoxaemia, intestinal gas distension, diarrhea, end-stage ileus, and death.
GI Stasis Syndrome or Dysbiosis Clinical Signs
- Alert and quiet
- Anorexia
- Lack of fecal production
- Large/doughy stomach
- Decreased or absent gut sounds
- Tympanism, gas in GI tract
- Gastrointestinal pain
- But NOT a diagnosis
GI Stasis Syndrome or Dysbiosis
- History and Clinical Signs
- Diets of unlimited, good-quality, high-fiber grass or timothy hay, a moderate amount of fresh leafy greens, minimal pellets, and no or only occasional treats, are recommended.
- Stress alone, including stress caused by pain or concurrent disease, can cause GI stasis.
- The most common presenting complaint is a gradual decrease in appetite over 2 to 7 days and a subsequent decrease in fecal production.
- Also, a decrease in water intake; scant, dark, dry, and small feces; decreased activity; and signs of pain.
GI Stasis Syndrome or Dysbiosis
- Physical Examination Findings
- Generally, appears alert and quiet.
- Stomach contents feel firm, doughy, and remain pitted on compression.
- Little or no feces are palpable in the colon.
- Decreased or absent gut sounds.
- Contrast with obstructive disorders.
GI Stasis Syndrome or Dysbiosis
* Initial database for stabilization/clinical endpoints
- Blood pressure (reliable to diagnose hypotension on the front limb)
- Pulse, heart rate, CRT
- Body temperature
- Blood gases (collect enough blood for CBC and biochemistries, if possible)
- Urine specific gravity
GI Stasis Syndrome or Dysbiosis
* Rabbits – Bad Prognostic Indicators
- Hypothermia (<38oC, for each 1oC lower, odds of death x 2)
- Hyperglycemia (>20 mmol/L)
- Hypochloremic metabolic alkalosis suggestive of obstruction
- High lactates (>20 mmol/L),
- Hyponatremia (<129 mmol/L)
- Hypotension (<80 mmHg on Doppler, front leg)
- Hypoxemia (PvO2<30mmHg, SvO2<50%, SpO2<90-94)
GI Stasis Syndrome or Dysbiosis
- how do we stabilize?
- IV/IO catheter – crystalloid +/- norepinephrine (if no response/sepsis)
- If needed – heat, O2, dextrose, Ca, quiet
- Opioid analgesic
- If sepsis/enterotoxemia – IV enrofloxacin/ metronidazole antibiotic +/- biosponge
- If gastric obstruction – emergency surgery
GI Stasis Syndrome or Dysbiosis
- what to do once stable?
Investigatecause
* CBC and biochemistries, urinalysis, culture
* Imaging – x-ray/CT, US * Other…
diagnostic tests for GI Stasis Syndrome or Dysbiosis
- what will we see?
- CBC and chemistries unremarkable other than dehydration.
- Radiographs help differentiate GI stasis (compact, ingesta-filled stomach)
from obstructive disorders (dilated, fluid-filled). Moderate to severe gas distention of the cecum and scant fecal pellets are commonly seen.
GI Stasis Syndrome or Dysbiosis treatment
- Rehydrate the patient and stomach contents, alleviate pain, provide
nutrition, and treat any underlying disorders. - Most rabbits will begin to eat and pass stool within 24 to 48 hours of
treatment. - Continue treatment for 3 to 5 days.
<><><> - Underlying cause
- Most medical
GI Stasis Syndrome or Dysbiosis
- treatment reginmen for mild case
Mild:
* SC fluids
* Ranitidine – motility enhancer, gastric protectant
* Opioid: hydromorphone or buprenorphine
* Meloxicam PO
* Metronidazole PO
* Syringe feeding q8h
* If possible, exercise
GI Stasis Syndrome or Dysbiosis
- treatment regimen for moderate / severe case
- IV fluids
- Correct electrolytic and acid- base disorders +/- potassium
- Lidocaine CRI (but hypotensive)
- +/- norepinephrine
- Fentanyl CRI
- After 12-24h, syringe feeding (or NG tube) q8h
- Metronidazole PO
- Enrofloxacin or TMS PO
- Ranitidine or famotidine
- +/- exercise
- If liquid diarrhea, biosponge, IV antibiotics, transfaunation
Dental Disease and Abscesses
* Rabbits (and Hystricomorph rodents)
> Risk Factors
- Metabolic bone disease
- Genetic factors, skull conformation (dwarf R)
- Diet, chewing patterns, dental wear, occlusal pressure
- Age
Dental Disease and Abscesses
* Presenting Signs
- Inappropriate diet
- Lethargy
- Selective feeding
- Anorexia/dysrexia
- Lack of stool production
- Hypersalivation
- Facial mass
- Epiphora
- Bruxism, abnormal mastication
- Nasal discharge/dyspnea /coughing
Clinical signs related to the primary dental problem:
- Reduced food intake
- Anorexia
- Dysrexia
- Dysphagia
- Changes in fecal quantity and size
- Weight loss
Clinical signs associated with complications of dental disease:
- Over-grooming
- Ptyalism
- Facial abscesses
- Epiphora
- Exophthalmos
- Nasal discharge
- Dyspnea
- Dermatitis (perineal or neck due to lack of grooming)
Dental Disease and Abscesses
- Lesions
- Malocclusion
- Elongation of clinical and/or reserve crowns
- Change in dental plane
- Curvature of teeth
- Dental spurs
- Infection, abscess
- Cavities
- Periodontal lesions
- Bone remodeling
- TMJ disease
Dental Disease and Abscesses
- how to investigate cause
- Oral examination
- X-ray/CT (head)
<><><> - Radiographs (if owner declines CT) - 5 standard projections (lateral, left-to-right oblique, right-to-left oblique, ventrodorsal/dorsoventral, rostrocaudal)
- CT (preferred)
Physical examination for dental disease and abscesses
- Palpate external maxilla and mandible for bony irregularities and swellings
- Incisor inspection - both frontal and lateral aspect
- Lateral-lateral motion of the mandible to assess the cheek teeth
arcades - Thorough oral examination with an otoscope
common dental issues
- crown elongation
- lack of wear
- buccal spurs
- lingual spurs
Dental Disease and Abscesses immediate treatment
- Shorten teeth
- Re-establish dental plane
- Extractions?
<><> - Anesthesia: on a mask, intubate if dyspneic. Always have a 3mm
endotracheal tube or V-gel available in case of emergency intubation - Provide pain medications
- Ongoing occlusal adjustments with the use of a straight handpiece and
dental burr guided by endoscopy
> Performed under general anesthesia
> Remove buccal and lingual point
> Perform coronal reduction
> Re-establish normal occlusal angle (may not be possible): 10 degrees in rabbits, 40 in guinea pigs, 0 in chinchillas and degus
> Clean periodontal pockets
> Remove very loose teeth, especially when pus at the base (use scaler or cheek teeth luxator and extractor)
Long-Term Treatment and Management for dental disease and abscesses
Antibiotics (if abscesses are present)
* Selected based on culture and sensitivity results
* Important to have good anaerobic, as well as Gram-positive and negative coverage
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Analgesia
* Meloxicam
* +/- Opioids
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* Assist feeding as needed
* Ongoing occlusal adjustments likely necessary
treatment for dental abscesses
- Wound-packing technique
> Weekly, 3-7 treatments - Marsupialization
- Long-term antibiotics (C&S, care with PO)
- Analgesia
- Assist feeding
