Diarrhoea

Investigation and Care Framework for Dogs with Gastrointestinal Problems (Including Diarrhoea)

1. Initial Assessment

   - Obtain a thorough history:

     - Duration, onset, and progression of clinical signs

     - Faecal characteristics (consistency, frequency, presence of blood/mucus)

     - Dietary history (recent changes, access to inappropriate foods, raw feeding)

     - Environmental factors (kennel/shelter, other affected animals, stress)

     - Vaccination and deworming status

     - Previous medical problems and current medications

   - Perform a complete physical examination:

     - Assess hydration status, mucous membranes, capillary refill time

     - Abdominal palpation (pain, masses, distension)

     - Rectal examination (faecal sample, masses, anal/perineal abnormalities)

     - Body condition scoring

2. Problem List and Initial Triage

   - Identify red flags requiring urgent intervention:

     - Shock, severe dehydration, hypovolaemia

     - Severe abdominal pain, palpable masses, intussusception

     - Profuse haemorrhagic diarrhoea, collapse, pyrexia

   - Stabilise as needed:

     - IV fluid therapy for hypovolaemia/dehydration

     - Analgesia if indicated

     - Hospitalisation for unstable patients

3. Differentiation of Diarrhoea Type

   - Small intestinal: large volume, weight loss, melena, vomiting, normal frequency

   - Large intestinal: increased frequency, small volume, mucus, fresh blood, tenesmus

   - Mixed pattern: features of both

4. Minimum Database and Diagnostic Work-up

   - In all moderate/severe or persistent cases:

     - Haematology, biochemistry, and urinalysis (assess for systemic/metabolic disease)

     - Faecal examination:

       - Parasitology (flotation, smear, ELISA for Giardia/Cryptosporidium)

       - Bacterial culture/PCR if infectious or zoonotic risk suspected (e.g. Salmonella, Campylobacter, Clostridium)

     - Imaging (abdominal radiographs/ultrasound) if:

       - Suspected foreign body, mass, intussusception, or non-responsive to initial therapy

     - Additional tests as indicated:

       - Canine trypsin-like immunoreactivity (cTLI) for EPI

       - Serum cobalamin and folate (chronic or weight loss cases)

       - Pancreatic lipase (cPL) for suspected pancreatitis

       - ACTH stimulation/basal cortisol for hypoadrenocorticism

5. Empirical Therapeutic Trials (in stable, non-severe cases)

   - Anthelmintic trial (e.g. fenbendazole) if parasitism not excluded

   - Dietary trial:

     - Highly digestible, low-fat, limited-ingredient or hydrolysed protein diet for 2–3 weeks

     - Avoid raw diets due to infection risk

   - Probiotics/prebiotics may be considered for mild cases or as adjunctive therapy

6. Specific Therapy

   - Treat underlying cause if identified (e.g. EPI, hypoadrenocorticism, neoplasia)

   - Infectious causes:

     - Antimicrobials only if indicated (e.g. confirmed bacterial infection with systemic illness, sepsis, or zoonotic risk)

     - Giardia: fenbendazole (first-line), metronidazole (second-line)

   - Supportive care:

     - Fluid therapy (oral/IV as appropriate)

     - Gastroprotectants (omeprazole, sucralfate) if GI ulceration suspected

     - Antidiarrhoeals (e.g. kaolin, loperamide) with caution and only in non-infectious, non-obstructive cases

     - Analgesia as required

7. Monitoring and Follow-up

   - Reassess hydration, clinical signs, and response to therapy

   - Adjust treatment based on progress and diagnostic results

   - Consider referral or advanced diagnostics (endoscopy/biopsy) if:

     - No response to empirical therapy

     - Severe weight loss, hypoproteinaemia, or abnormal imaging findings

     - Criteria of concern for chronic enteropathies

8. Infection Control and Biosecurity (especially in kennel/shelter settings)

   - Isolate affected animals if infectious or zoonotic cause suspected

   - Implement strict cleaning and disinfection protocols

   - Educate staff/owners on hygiene and zoonotic risks

This framework should be adapted to individual patient needs and clinical context. Early identification of severe or systemic disease is critical for appropriate intervention. Most mild, acute cases are self-limiting and respond to supportive care and dietary management. Chronic or severe cases require a methodical, stepwise diagnostic approach.

Idexx packages for investigation of diarrhoea

Parasitology - Faecal (FPAR)

Microscopical examination, Parasites

1-2 days   |   Faeces

Faecal Culture - swab (SWAF)

Yersinia, Salmonella & Campylobacter Culture

2-5 days   |   E-swab

PROPLAN FAECAL SAMPLE (PUP1)

Hookworm, roundworm, whipworm, flea tapeworm antigen immunoassays

Faecal sample

Faecal Parasitology and Giardia Antigen (PARG)

Faecal Parasitology (microscopy), Giardia Antigen

1-2 days   |   5 g Faeces

Faecal Dx® Antigen (Immunoassay) (FET)

Hookworm, roundworm, whipworm, cystoisospora, flea tapeworm antigen immunoassays

1-2 days   |   Faeces

Test then Treat Faecal (TNTF)

Parasitology, Salmonella, Campylobacter (Campylobacter isolates identified to species level where possible)

2-5 days   |   Faeces

Faecal Dx® Antigen Panel with Giardia (FECGP)

Faecal Parasitology (microscopy), Giardia Antigen, Hookworm, roundworm, whipworm, cystoisospora, flea tapeworm antigen immunoassays

1-2 days   |   5g Faeces

Camylobacter Culture plus Faecal Parasites & Giardia antigen (CFPAR)

2-5 days   |   Faeces

Faecal Parasitology, Giardia Antigen and Tritrichomonas RealPCR (PARGT)

Faecal Parasitology (microscopy), Giardia Antigen, Tritrichomonas foetus RealPCR

3-7 days   |   5 g Faeces

Faecal aerobic culture - Add on (AO2)

2-3 days   |   Faeces Can only be ordered with a faecal profile

Faecal aerobic culture - Add on (AO2)

2-3 days   |   Faeces Can only be ordered with a faecal profile

Basic Faecal Screen plus Giardia (Add On) (ASARCG)

Parasitology, Salmonella, Campylobacter, Giardia Antigen Immunoassay.

2-3 days (Campylobacter 2-5 days)   |   Faeces

Basic Screen - Faeces (SARC)

Parasitology, Salmonella, Campylobacter (Campylobacter isolates identified to species level where possible)

2-5 days   |   Faeces

Basic Faecal Screen plus Giardia (SARCG)

Parasitology, Salmonella, Campylobacter, Giardia antigen

2-5 days   |   Faeces

Canine Diarrhoea Screen (DIARCN)

Standard Screen + Cobalamin (B12) + Folate + Basal Cortisol + Faecal Parasitology + Selective Culture for Salmonella & Campylobacter + Giardia Antigen Immunoassay.

1-5 days   |   1ml EDTA + 1ml separated serum, faecal sample

Canine Diarrhoea Profile (DIARCI)

Standard Profile + Cobalamin (B12) + Folate + Basal Cortisol + Faecal Parasitology + Selective Culture for Salmonella & Campylobacter + Giardia Antigen Immunoassay.

1-5 days   |   1ml EDTA + air dried smear; 1ml separated serum, faecal sample