Gastrointestinal Disorders in NTCA - VMS 3010

Gastrointestinal Disorders in Non-Traditional Companion Animals (NTCA)

• VMS 3010 course on the approach to gastrointestinal disorders in NTCA
• Course material provided by Dr Sharmini Julite Paramasiva
• Course content adapted and updated from previous work by Dan Horton and Will Wilkinson
• Includes learning outcomes, overview for mammals (including rodents and ferrets), birds, and reptiles.
• Learning outcomes include applying existing knowledge of structure, function, and pathophysiology to approach gastrointestinal tract disorders in NTCA
• Important to construct a differential diagnosis list of disorders based on clinical presentations.
• Essential to discuss principles of various diagnostic tests and determine common disease processes across species.

Learning Outcomes

• Apply existing knowledge of structure, function, and pathophysiology for gastrointestinal tract disorders in NTCA
• Construct a differential diagnosis list for disorders based on clinical presentations
• Discuss diagnostic test principles
• Determine shared disease processes across species.

NTCA - Non Traditional Companion Animals

• NTCA, also known as exotics, require consideration of their ecological niche for survival.
• Assess the value of the animal to its owner, as some live a long time and are highly valued.

Rodents (Hamsters, Rats, etc.)

• Anatomical Considerations:

  • Continuously erupting incisors (elodont)
  • Dental disease is acquired, not genetic
  • Some have continuously erupting cheek teeth
  • Rat teeth yellow from iron in enamel
  • Hindgut fermenters (e.g., guinea pigs and chinchillas)
  • Coprophagy or caecotrophy (extreme adaptations in some species)
  • High fur density (e.g., chinchillas) contributing to trichobezoars
  • Compound stomach (mice, rats)
  • Inability to vomit, but can regurgitate

• Presentations:

• Porphyrin staining around eyes (rats)- non-specific indication of stress or illness

• Bruxism (pain related)

• Reduced faecal output

• Lack of caecotrophy

• Wet rear end, smelly fur

• Loose stools

• Hypersalivation

• Dysphagia/inappetence

• Non-specific: hunched posture, lethargy; reduced gut motility on auscultation

• Differential Diagnoses:

  • Gastrointestinal stasis (primary or secondary)
  • Non-infectious diarrhoea
  • Antimicrobial enterocolitis
  • Nutritional issues
  • Infectious diarrhoea (e.g. bacteria - Salmonella, Tyzzer's Disease; parasites - Pinworm, Cestodiasis; protozoa - Hexamita; Viral enteritis)
  • Foreign body obstruction (e.g., trichobezoars)

• Diagnostic Approach:

  • History (recent antibiotic treatment, diet changes)
  • Physical exam (teeth, perianal soiling, abdominal auscultation, hindgut fermenters)
  • Faecal parasitology and bacteriology
  • Tape strips from rectum (pinworm)
  • Radiography/USG
  • Post-mortem (especially in animals from collections)
  • Specific tests (e.g., Tyzzer's disease PCR)
  • Blood tests (may not yield definitive diagnosis but could help with comorbidities)

Ferrets

• Anatomical Considerations:

• Anatomical similarity to humans

• Short transit time (<220 minutes)

• Spontaneous activity, even under anaesthetic

• Can vomit

• Presentations:

• Similar to dogs and cats: anorexia, vomiting, diarrhoea (green slime disease)

• Hunched posture (sign of abdominal pain)

• Grinding teeth

• Differential Diagnoses:

• Bacterial/viral/parasitic enteritis (e.g., epizootic catarrhal enteritis, coronavirus)

• Inflammatory bowel disease (IBD)

• Lymphoma

• Hairballs (don't vomit them up)

• Stomach ulcers (associated with Helicobacter mustelae)

• Diagnostic Approach:

• Bloods (lipase raised in IBD)

• Radiography

• Ultrasound

• Faecal examination

• Endoscopy, biopsy, PCR for Helicobacter mustelae

Birds

• Anatomical Considerations:

• Beak similar to teeth and lips

• Crop (oesophagus expansion for food storage)

• Stomach pluricavity and compound structure

• Shorter and simpler intestines than mammals

• Paired caeca (important in chickens, ducks)

• Cloaca (end of gastrointestinal, urinary, and reproductive tracts)

• Presentations:

• Anorexia

• Vomiting

• Diarrhea

• Weight loss/failure to gain weight

• Abnormal faeces (e.g., urates)

• Dysphagia

• Crop distension

• Itchy crop

• General signs of pain

• Sudden death

• Differential Diagnoses:

• Endoparasites (e.g. Mycobacteriosis, Chlamydia psittaci, Avian Bornavirus, PDD)

• Candidiasis

• Capilaria

• Crop stasis

• Crop fistulae/abscesses

• Foreign bodies

• Toxins (e.g., lead, zinc)

• Diagnostic Approach:

• Bloods (haematology & biochemistry)

• Faecal examination

• Radiography

• PCR & serology (e.g., PDD)

• Crop swab (C&S)

• Biopsy of crop

• CT scan (expensive, but can provide good outcomes)

Reptiles

• Anatomical Considerations:

• Abdominal fat in discrete bodies

• Affects radiography

• No muscular diaphragm

• Distensible oesophagus (snakes) or no cardiac sphincter (snakes)

• Regurgitation

• Hindgut fermentation in large intestine (herbivores)

• Presentations:

• Anorexia (especially in snakes and carnivorous lizards)

• Dehydration

• Weight loss

• Emesis (regurgitation)

• Diarrhoea

• Distension around the midbody (coelomic)

• Differential Diagnoses:

• Husbandry-associated anorexia

• Stomatitis

• Foreign body impaction

• Gingival proliferation (lizards)

• Parasitic diseases

• Bacterial/viral/infectious diseases (e.g., PDD in birds)

• Diagnostic Approach:

• Similar to mammals (abdominal auscultation usually unrewarding in reptiles)

• USG at prefemoral fossae in Chelonians (lack of contrast)

• Endoscopy (more useful for bigger reptiles)

• Defecation frequency consideration