bowel diarrhoea in dogs and cats.
| Cause | Examples | Comments |
|---|---|---|
| Diet related | Diet‐responsive disease or food‐responsive enteropathy (FRE) | Food intolerance is a non‐immunological reaction to a component of food, for example, gluten, preservative, bony material and other irritants.Food allergy/hypersensitivity is an immunological reaction to a component of food, for example, beef, chicken and dairy.Diagnosis of dietary allergy or intolerance is usually a process of trial and error by using elimination diets, as there is no sensitive or specific diagnostic test.Current evidence would suggest that blood tests for anti‐food antibodies are not specific and not clinically useful for dogs and cats with FRE. |
| Parasites/protozoa | Intestinal parasites (as previously mentioned)Protozoa (as previously mentioned) | See comment in Table 4.2. |
| ‘Infection’/bacterial/viral | Campylobacter/SalmonellaFeline infectious peritonitis | Note comments in Table 4.2 in relation to bacterial causes of diarrhoea. |
| Antibiotic responsive | Antibiotic‐responsive diarrhoea (ARD)Secondary small intestinal bacterial overgrowth (SIBO) | ARD: small intestinal diarrhoea that is responsive to antibacterials but no underlying cause can be identified.SIBO: secondary to an underlying problem such as exocrine pancreatic insufficiency, inflammatory bowel disease, partial obstruction or motility disorders. |
| Infiltrative | Immunosuppressive‐responsive or non‐responsive chronic enteropathy (IRE and NRE) – also termed inflammatory bowel disease (IBD), for example,Lymphocytic‐plasmacytic enteritisEosinophilic enteritisDiffuse or focal lymphomaAdenocarcinoma/adenomaMast cell tumour (feline)Smooth muscle/stromal cell tumours (canine) | Diarrhoea is the most common clinical signs of IBD in dogs.Vomiting is the more common clinical sign in cats.Intestinal biopsy is primarily required to characterise infiltrative inflammatory gut disease (IBD vs. neoplasia) and/or protein‐losing enteropathy. |
| Miscellaneous | LymphangiectasiaInherited selective cobalamin deficiencyChronic intussusceptionChronic partial obstruction | Lymphangiectasia is usually secondary to IBD but primary forms exist. |
| Secondary GI (not an exhaustive list) | Hypoadrenocorticism –dogsHyperthyroidism – catsExocrine pancreatic insufficiencyChronic pancreatitisLiver disease (hepatocellular failure, cholestasis, portal hypertension)Severe systemic disease |
Table 4.4 Causes of acute and chronic large bowel diarrhoea in dogs and cats.
| Parasites/protozoa | Giardia spp. (more commonly small bowel but can also cause large bowel diarrhoeaTritrichomonas foetus (cats)Entamoeba spp.Trichuris vulpis (whipworm)Ancylostoma caninum (hookworm) |
| Infection (bacterial/viral) | Campylobacter spp. (interpret positive results with caution)Clostridium perfringens; Clostridium difficile*Salmonella spp.*Yersinia enterocolitica*Feline infectious peritonitis (FIP)Granulomatous colitis (boxers, French bulldogs) – caused by invasive and adherent E. coli *These bacteria are rarely identified as causal agents in canine chronic diarrhoea; they may be more commonly identified in faecal samples from raw‐fed pets, but raw food is not currently proven to cause diarrhoea more often than commercial pet food. |
| Diet related | Food‐responsive enteropathy (FRE)Passing foreign materialFibre‐deficient diet |
| Inflammatory | Immunosuppressive‐responsive or non‐responsive enteropathy = inflammatory bowel disease (IBD), for example,Lymphocytic‐plasmacytic enteritis (colitis)Eosinophilic enteritis (colitis) |
| Neoplasia | Diffuse or focal lymphomaAdenocarcinoma/adenomaMast cell tumour (feline)Smooth muscle/stromal cell tumours (canine) |
| Miscellaneous | Stress‐induced colitis can occur relatively commonly in hospitalised or newly kenneled dogs, which may be due to an overgrowth of Clostridium perfringensStructural disease such as caecocolic intussusception (rare) |
Diagnostic approach to the patient with diarrhoea
Small bowel diarrhoea
Acute vs. chronic
It is important to ascertain the duration the diarrhoea has been present. Acute diarrhoea that is not severe, fulminating and potentially life threatening does not usually require extensive diagnostic investigation and will usually respond to non‐specific therapy. Fulminating acute diarrhoea, for example, viral and acute haemorrhagic diarrhoea syndrome (AHDS), may not require extensive diagnostic testing but will require intense supportive therapy and should not be treated on an outpatient basis if at all possible. In contrast, chronic diarrhoea persisting for weeks to months indicates that a structured approach to therapeutic trial and investigation is required.
When to investigate?
If diarrhoea persists despite symptomatic treatment or is chronic, severe and associated with significant weight loss and/or evidence of hypoproteinaemia, dehydration or systemic illness, then a more detailed investigation is indicated. Only a small proportion of diarrhoea cases require investigation as chronic disorders. An animal presenting with intermittent but repetitive episodes of diarrhoea over many months should also be considered for investigation unless there is a proven cause (e.g. regular garbage bin raiding).
The following is a general outline that can be used to approach stable cases of diarrhoea in adult dogs and cats in general practice. More severely affected animals and very young animals will require investigation and/or more intensive supportive treatment earlier in the course of their disease. Every case should be considered individually, and client factors such as budget must be taken into account.
1 Take a detailed history to assess for trigger factors (bin raiding, extra table scraps from the roast dinner, inappropriate diet or snacks, hunting etc). Perform a thorough physical examination to look for relevant abnormalities (e.g. palpable bowel lesion, dehydration, weight loss).
2 Ensure anthelmintic history is up to date, and if in doubt treat with an appropriate anthelmintic (usually more appropriate in young animals).
3 Recommend highly digestible food until diarrhoea resolves. If animal is not eating, monitor the situation in case intervention is needed (e.g. recheck in appropriate time period between 24 and 72 hours).
4 Antibiotic treatment is rarely indicated in acute diarrhoea unless the animal is systemically unwell, and even then it may not be warranted.
5 Consider
