Dr Dave Collins, vet from SASH (the Small Animal Specialist Hospital in Sydney) presentation on Chronic Diarrhoea in Dogs

1. CHRONIC DIARRHOEA IN DOGS
Dave Collins BVSc FANZCVS
Registered Specialist in Small Animal Medicine
dcollins@sashvets.com

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Diarrhoea
• Increase frequency, fluidity, or volume of
faeces
• Large vs Small
• Acute vs chronic (>14d)

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Diarrhoea
• Mechanisms of diarrhoea:
• Osmotic: maldigestion or malabsorption eg EPI
• Secretory: abnormal ion transport due to
hormones, toxins, eg enteropath E Coli, IBD
• Increased Mucosal Permeability: eg erosive,
ulcerative enteropathies, IBD, neoplasia
• Deranged motility:eg abnormal ileal and
colonic motility in IBD

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DDx acute* or chronic diarrhoea
• Dietary: diet change *, overeating*, indiscretion*,
intolerance, allergy; type I IgE, type IV cell mediated
• Inflammatory: IBD, ARD, AHE*
• Infectious: parasitic – helminths, protozoa; bacteria*
– Salmonella, Campylobacter, C. perfringens, C.
difficile, E Coli; Viral* –parvovirus; Fungal?;
Rickettsial?

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DDx acute or chronic diarrhoea
• Extraintestinal:
pancreatitis, EPI, liver, kidney, hypoA
• Toxaemia, Septicaemia
• Neoplasia:
carcinoma, MCT, leiomyosarcomas, GIST, LSA
• Drugs & Toxins: eg NSAIDs, ABs

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Chronic Diarrhoea
• Signalment: IBD, PLE breeds, IBD rarely <12 months;
GSD, Shar Pei, Irish Setter, SCWT, Basenji, Yorkies,
Maltese, Rottweilers
• History: large vs small bowel, severity, weight
loss, parasites, diet
• Physical Exam
• Diagnostic tests: Non invasive first!
• CBC/biochem/TLI/ACTH stim

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Chronic Diarrhoea
• Faecal Exam: parasitology, bacteriology, Faecal PCR
• Folate/Cobalamin
• Dietary Trial
• Imaging
• Biopsy – endoscopic, laparascopic, surgical

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Giardia spp.
• Diagnosis:
• ZnSO4 floatation, SNAP Antigen, PCR
• Treatment:
• Metronidazole
• Fenbendazole

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Folate and Cobalamin

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Ultrasound: Intestinal wall thickness

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Ultrasound: Intestinal lymphoma

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Ultrasound: Intestinal lymphoma

13. Diarrhea Panel Prevalence Data
Australia US Canada Japan Brazil UK South Korea
Canine Distemper Virus 0.8% 1.1% 0.3% 1.5% 2.3% 1.4% 7.4%
Salmonella spp. 0.2% 0.6% 1.7% 0.7% 0.6% 0.7% 0.9%
Canine Parvovirus 2 4.7% 1.7% 0.3% 2.6% 6.3% 5.5% 1.9%
Cryptosporidium spp. 6.3% 5.6% 6.1% 7.3% 4.0% 6.2% 7.9%
Giardia spp. 7.8% 8.4% 9.3% 11.7% 10.8% 17.2% 21.9%
Canine Enteric Coronavirus 4.4% 11.8% 4.2% 20.7% 12.5% 19.3% 7.4%
C. perfringens alpha toxin (Q) 52.2% 51.6% 38.7% 57.5% 43.8% 7.8% 30.7%
C. perfringens enterotoxin 41.7% 22.7% 12.2% na na 0.0% 0.0%
Campylobacter jejuni 10.7% 4.5% 6.4% 3.1% 12.5% 20.7% 4.7%
Campylobacter coli 1.5% 1.4% 0.5% 1.1% 12.5% 1.4% 0.5%
Overall Infection Rate 78.8% 64.3% 69.7% 71.6% 62.5% 51.7% 47.0%
Coinfection Rate 29.5% 24.9% 47.5% 31.7% 40.0% 41.9% 36.6%
Samples included n=619 n=7829 n=2590 n=486 n=702 n=674 n=215
Canine Diarrhea Panel
Prevalence

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IBD – WSAVA, ACVIM
1. Chronic persistent or recurrent GI signs
2. Histopath evidence off mucosal inflammation
3. No evidence of other GI disease
4. Inadequate response to dietary, antibiotic and
anthelmintic therapy alone
5. Clinical response to anti-inflammatory or
immunosuppressive agents

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Inflammatory Bowel Disease
• Intestinal mucosa has a barrier function for “immune
exclusion”
• Controls exposure of GALT
• Protective immune responses to protect against
pathogens
• “tolerance” of harmless environmental antigens such
as commensal bacteria and food
• IBD develops when normal decision making process
breaks down → inappropriate immune responses
and uncontrolled inflammation

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Inflammatory Bowel Disease
• Loss of tolerance may result from:
i. Disruption of normal mucosal barrier leading to
antigen exposure to submucosal lymphoid tissue
ii. Dysregulation of normal mucosal immune system
or both
• Genetics of TLRs, NOD

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IBD

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Lymphocytic plasmacytic enteritis
• Most common
• Mucosal infiltrate of lymphocytes and plasma cells,
changes in mucosal architecture eg villous atrophy,
villous fusion, crypt abscessation
• Other causes of LP infiltration: enteropathogens,
Toxoplasma
• GSDs, Shar-Peis, pure bred cats
• Often causes PLE esp Basenjis

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Lymphocytic plasmacytic enteritis

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Lymphocytic plasmacytic enteritis

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Lymphocytic plasmacytic enteritis
• Chronic diarrhoea, weight loss
• Chronic vomiting may predominate
• Histopath: variation in interpretation; subjectivity;
localised inflammation - ileal; endoscopic vs full
thickness; severe LPE vs LSA –concurrent, pre-
neoplastic or misdiagnosis

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Eosinophilic Enteritis
• 2nd most common form of IBD
• Frequently involves SI, stomach and/or colon
• Variable changes eg villous atrophy
• Mixed inflammatory infiltrate, predominantly
eosinophilic
• Any breed and age, mostly younger adult
• Boxers, Dobermans, German Shepherds

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Eosinophilic Enteritis

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Eosinophilic Enteritis
• Vomiting, SI diarrhoea, LI diarrhoea
• +/- Mucosal erosion or ulceration
• May be associated with PLE
• DDX: dietary sensitivity, endoparasitism, visceral
larva migrans, MCT, idiopathic
• +/- hypereosinophilia (DDX MCT, parasitism, HypoA,
allegic cutaneous or respiratory diseases)

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Neutrophilic Enteritis
• May be neutrophilic infiltrate or granulomatous
inflammation
• Consider underlying bacterial infection
• May be secondary to bacterial invasion of mucosal
ulceration/erosion
• Caution: glucocorticoids

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Granulomatous Enteritis
• Rare form of IBD
• Mucosal infiltration with macrophages → granuloma
formation
• May be similar to human Crohn’s, granulomatous
colitis of Boxers
• Enteroadherent and invasive E Coli (EIEC)
• Yersinia, mycobacteria, fb rxn, fungal??

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Protein Losing Enteropathy
• Lymphangiectasia - primary (Yorkies, Maltese,
Rottweilers, secondary
• Inflammatory : IBD, esp Basenjis, SCWT, gluten
enteropathy Irish Setters
• Infectious: viral, bacterial, fungal, parasitic
• Neoplasia: LSA, ACA, GIST
• Obstructive: chronic fb, intussusception
• Haemorrhage: GUE, drugs, hepatic, renal, parasites,
neoplasia
• SLE, Hypoadrenocorticism
• Right heart failure, pericarditis, portal hypertension

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Protein Losing Enteropathy
• Most common:
• Lymphangiectasia – secondary
• Severe IBD
• Neoplasia
• GI haemorrhage
• Treatment considerations: aggressive treatment ,
dietary – hypoallergenic, low fat, prednisolone ,
chlorambucil, antithrombotics, +/- diuretics

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Treatment Approach
• Diet:
• Novel protein source
• Hydrolysed diets eg Hill’s z/d.
• Protein source? Size of particles too small for crosslinking of
IgE but type of immune response unknown; clinical efficacy
allergic dermatitis, IBD
• Antibiotic trial
• Immunosuppressives

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Antibiotics Trial
• Tylosin 10-15mg/kg PO q8h
• Oxytetracycline 20mg/kg PO q8h
• Metronidazole 10mg/kg PO q12h
• 28 day course
• Long term tylosin 5mg/kg/day

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Ciclosporin
• T-lymphocyte effects
• Efficacy in anal furunculosis
• Expensive, variable efficacy and toxicity
• 12 out of 14 steroid resistant enteropathies improved clinical
score (CIBDAI), 5mg/kg/day, also reduced T cell numbers in
duodenal biopsies (Allenspach JVIM 2006)

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Chlorambucil
• Long term use in severe IBD or small cell GI lymphoma in cats
• “Dogs are just big cats?”
• Chlorambucil (4-6 mg/m2/day for first 7 to 21 days)-
prednisolone (14 dogs) more efficacious for treatment of
chronic enteropathy and concurrent PLE than azathioprine-
pred (13 dogs)
Dandrieux JAVMA 2013

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Probiotics
• Probiotic strains of human or canine origin (Lactobacillus,
Bifidobacterium, and Enterococcus) may affect:
i. Intestinal microbial populations
ii. May reduce specific pathogens in faeces
iii. Immunomodulators
• Two overall positive studies on probiotics in management of
dietary sensitivity and food-responsive diarrhea have been
published to date
• Level 1 evidence for effectiveness of probiotics in treating
lactose intolerance/maldigestion, treating acute infectious or
nosocomial diarrhea in children, preventing or treating ARD,
maintaining remission of ulcerative colitis in adults

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Oscar
• 10MN Labrador
• 2 month history of inappetance, weight loss and
diarrhoea
• Mild hypoalbuminaemia 21 (22-39g/L), borderline
globulin 26 (26-45g/L)
• AUS: diffusely abnormal SI, thickened jejunum up to
7.0mm, thickened muscularis layer, distended loops,
similar changes in ileum
• Laparoscopic intestinal biopsies

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Oscar

38. Laparoscopic Intestinal Biopsies:

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Oscar
• Histopath:
• Moderate chronic enteritis of jejunum and ileum,
with mucosal oedema and lymphatic dilation
• Rx: Hill’s z/d, metronidazole, prednisolone, B12
• 2 weeks post op albumin 24, BAR, still diarrhoea!

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Sanka
• 3FS Border Collie
• Week long history of vomiting, lethargy, abdominal
pain and pyrexia
• Treated with clavulox, ranitidine
• Now diarrhoea, ropey intestines

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Sanka
• Abdominal ultrasound showed marked thickening
and lack of wall layering in ileum with grossly enlarge
jejunal lymph nodes (image next slide)
• Hypoproteinaemia: albumin 18 g/L
• Exploratory laparotomy with full thickened biopsies

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Sanka – Ultrasound Images

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Sanka
• Histopathology:
• 55% small lymphocytes, 3% medium lymphoid cells, 2%
large lymphoid cells, 2% plasma cells, at least 28%
macrophages and 10% neutrophils
• Ileum was abnormal with areas of erythematous
thickening
• MARKED CHRONIC MULTIFOCAL TO COALESCING
PYOGRANULOMATOUS MURAL ENTERITIS AND
LYMPHADENITIS.
• No bacteria, fungal elements or acid-fast organisms seen
on Gram, PAS or ZN sections respectively

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Sanka
• Culture negative, special stains negative
• No fungal elements or oomycetes seen on
methenamine silver sections.
• Fenbendazole
• Enrofloxacin, metronidazole
• Hill’s z/d
• Long term: tylosin

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Sanka – Ultrasound Images

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Phone - (02) 9889 0289 Fax - (02) 9889 0431
Level 1, 1 Richardson Place, North Ryde 2113, Sydney, NSW