Investigation & Management of Diarrhea in Dogs & Cats Flashcards
what are dietary causes of diarrhea (3)
- abrupt dietary change
- dietary indiscretion
- dietary intolerance/allergy
what are inflammatory causes of diarrhea (3)
- inflammatory bowel disease
- colitis
- lymphangiectasia
what are infectious causes of diarrhea (4)
- parasitic: helminths, protozoa
- viral: parvovirus, distemper, coronavirus, rotavirus, FeLV
- bacterial: salmonella, campylobacter, C perfringens, C difficile, E. coli
- fungal and algal
what are neoplastic causes of diarrhea (4)
- alimentary lymphoma
- intestinal carcinoma
- leiomyosarcoma
- mast cell tumour
what are extra intestinal disorders of diarrhea (5)
- exocrine pancreatic insufficiency
- hypoadrenocorticism (Addison’s)
- liver disease
- pancreatitis
- peritonitis
what are miscellaneous causes of diarrhea (3)
- chronic intussusception
- irritable bowel syndrome
- acute hemorrhagic diarrhea syndrome
what drugs and toxins can cause diarrhea (3)
- NSAIDs
- antibiotics
- chemotherapy
how do you investigate diarrhea (3)
- signalment
- history
- physical examination
develop an appropriate ddx list based on these things
youre looking for distinguishing features that will help you to narrow down the potential cause of diarrhea
what questions should you ask about the history of diarrhea (6)
- is the diarrhea acute or chronic (chronic is >2 weeks duration)?
- is the diarrhea constant or intermittent?
- ask the owner to describe the characteristics of the diarrhea –> differentiate from small intestine vs large intestinal disease
- ask about any recent changes in diet or environment (could this be due to a change in diet, is the dog a scavenger, is the dog coprophagic?)
- ask about in contact animals
- ask about anthelmintic history and vaccination status
what are small intestinal diarrhea characteristics (6)
- normal to large volume
- frequency of defecation is normal to mildly increased
- melena
- concurrent weight loss (malabsorption)
- concurrent vomiting
- ascites if associated with protein losing enteropathy (PLE)
what are large intestinal diarrhea characteristics (6)
- variable but often small volume
- increased frequency of defecation associated with urgency
- mucus
- hematochezia (fresh blood)
- fecal tensmus
- dyschezia (pain associated with defecation)
what general history questions should you ask (3)
- what is appetite like (ex. dogs & cats with EPI typically have a ravenous appetite)
- has the dog/cat been vomiting (ex. if vomiting has developed in a patient that’s had acute diarrhea, consider the possibility of intussusception)
- has the owner noticed PUPD? (ex. you may be more likely to consider an extraintestinal cause of diarrhea like hypoadrenocorticism)
what are specific physical exam findings that may direct your investigation (4)
1. pyrexia: may be an indicator of an infectious cause or a systemic complication of underlying disorder
2. malnutrition: (poor BCS) may be an indicator of a chronic maldigestive or malabsorptive disorder
3. abdominal palpation: may suggest GI thickening or associated mass
4. presence of ascites: may suggest protein-losing enteropathy
what are differential ddx for acute hemorrhagic diarrhea (3)
- infectious: parvovirus, coronavirus, salmonella, C perfringens, E. coli
- acute hemorrhagic diarrhea syndrome
- abdominal catostrphe
what type of virus is parvovirus
enveloped DNA virus with a tropism for rapidly dividing cells
what cells does parvovirus have a tropism for
rapidly dividing cells
intestinal epithelium
hematopoietic cells (neutropenia)
how does parvovirus cause sepsis
bacterial translocation across an impaired intestinal epithelium coupled with neutropenia leads to a gram negative sepsis
what are the clinical signs of parvovirus infection
- anorexia
- vomiting
- severe hemorrhagic diarrhea
- pyrexia/hypothermia
- SIRS
- DIC
when should you suspect/consider parvoviral infection
- unvaccinated dogs with signs of acute and severe gastroenteritis
- patients are unwell: dehydration, signs of sepsis (neutropenia)
what type of organism is salmonella
entero invasive organism
what does salmonellosis cause
acute enterocolitis
mucosal sloughing and secretory diarrhea
when is salmonella infection most commonly seen
young and/or immunocompromised individuals or where concurrent GI infections occur
what increases the risk of salmonellosis
diarrhea with trend for feeding raw diets
when is campylobacter associated diarrhea likely to occur
more likely to be seen in young and/or immunocompromised individuals with conccurent GI infections
poor antibiotic therapy
poor hygeine
what does campylobacter cause
because its enteroinvasive it causes a superficial erosive enterocolitis
what are the pathogenic strains of E. coli (3)
- ETEC (enterotoxigenic)
- EPEC (enteropathogenic)
- EHEC (enterohemorrhagic)
what does ETEC cause
release toxins that result in secretory diarrhea
what does EPEC cause
attaching and effacing E. coli causes diarrhea by a combo of methods including malabsorption and secretion
what does EHEC cause
mediates disease via production of Shiga like toxins
can also go on to result in hemolytic uremic syndrome (HUS) characterized by acute renal failure, hemolytic anemia and thrombocytopenia
what clostridial species can cause diarrhea
clostridium perfringens
and
C difficile
how do clostridial species cause diarrhea
both cause diarrhea syndromes by production of toxins:
c. perfringens enterotoxin (CPE)
c. difficile toxins A (enterotoxin) and B (cytotoxin)
what does clostridium perfringens cause
implicated as a cause of an acute hemorrhgic diarrhea syndrome (AHDS) (previously known as hemorrhagic gastroenteritis or HGE)
what does c. prefringens cause to the epithelium
necrosis
what does acute hemorrhagic diarrhea syndrome present as
acute onset vomiting sometimes with hematemesis
severe hemorrhagic diarrhea progressing to severe dehydration
how do you investigate acute hemorrhagic diarrhea (3)
- exlusion of infectious disease
- exclusion of extra intestinal causes –> hematology & serum biochem, cortisol (ACTH), diagnostic imaging
- evaluation of potential consequences of diarrhea –> hematology & serum biochem including electrolytes, venous blood gas analysis, coagulation profile
how can you test for parvovirus (4)
- fecal antigen testing
- serology for anti CPV antibodies (covalescent titre)
- PCR on feces (detection of viral DNA)
- IFA on tissue specimens (post mortem)
how can you determine the infectious cause of acute hemorrhagic diarrhea (3)
- standard fecal culture and sensitivity
- fecal culture followed by further characterization of bacteria
- demonstration of enterotoxins
how do you exclude extra intestinal causes of acute hemorrhagic diarrhea (4)
- hematology and serum biochem profiles: acute liver disease (ALT, AP), acute pancreatitis (cPLI)
- cortisol (ACTH stimulation test): to exclude addison’s
- diagnostic imaging
- screeing for leptospirosis infection?
how do you manage acute diarrhea that you presume is from dietary indiscretion (3)
- dietary modification: low fat diet
- supportive IVFT if required
- probiotics
how would you manage paroviral enteritis (6)
- cyrstalloids
- +/- colloids +/- plasma
- IV antibiotics if neutropenic due to risk of gram - sepsis
- anti emetics (often combo therapy)
- early nutritional support (enteral +/- parenteral)
- interferon
how would you manage acute hemorrhagic diarrhea syndrome (4)
- IVFT (crystalloids, +/- colloids, +/- plasma)
- IV antibiotics, if signs of sepsis (neutropenia, due to risk of gram - sepsis)
- anti emetics (often combo therapy)
- early nutritional support (enteral +/- parenteral)
what are ddx for chronic diarrhea caused by dietary
- food responsive chronic enteropathy (FRD)
what are ddx for chronic diarrhea caused by infectious (5)
- parasitic: Giardia, trichuris, tritrichomonas (f), helminths
- viral: FeLV
- bacterial: campylobacter
- fungal: histoplasmosis (USA)
- algal: protothecosis (rare)
what are ddx for chronic diarrhea caused by neoplasia (3)
- alimentary lymphoma
- intestinal neoplasia
- mast cell tumour
what are ddx for chronic diarrhea caused by inflammatory (4)
- inflammatory bowel disease
- antibiotic responsive chronic enteropathy (ARD)
- colitis
- lymphangiectasia
what are ddx for chronic diarrhea caused by extra intestinal disorders (4)
- exocrine pancreatic insufficiency
- hypoadrenocorticism (atypical Addison’s)
- chronic liver disease
- renal disease
what are ddx for chronic diarrhea miscellaneous (2)
- chronic intussusception
- irritable bowel syndrome
how do you investigate chronic diarrhea (5)
- fecal analysis
- hematology & serum biochem (+/- urinanalysis)
- diagnostic imaging
- endoscopic assessment of GI mucosa
- histopathology
why is hematology and serum biochem useful to investigate chronic diarrhea (4)
- exclusion of non-GI disorders that may be causing or contributing to diarrhea
- assessment of clinical status/sequelae of chronic GI disease (ex. PLE)
- therapeutic planning
- prognosis
why is fecal analysis useful in chronic diarrhea investigations
- fecal parasitology: to exclude giardia
- bacterial culture and sensitivity
what non GI disorders could cause chronic diarrhea (4)
- liver disease (portal hypertension and/or cholestasis)
- endocrine diseases (hypoadrenocorticism, hyperthyroidism in cats)
- pancreatic disroders (exocrine pancreatic insufficiency)
- renal disease (PLN causing hypoalbuminemia)
how would you exclude liver disease as a cause of chronic diarrhea
hematology and serum
liver function testing including bile acids and bilirubin
reactive elevations in ALT and AP with primary GI disease
how would you exclude renal disease as a cause of chronic diarrhea
- hypoalbuminemia and hypercholesterolemia
- urine protein:creatinine ratio
how would you exclude hypoadrenocorticism as a cause of diarrhea (3)
- electrolyte disturbances
- absence of stress leukogram should highlight the possibility of atypical Addison’s as a cause of chronic diarrhea, particularly if concurrent hypoproteinemia is observed
- basal cortisol or ACTH stimulation test to confirm
how would you exclude hyperthyroidism as a cause of chronic diarrhea in cats
T4 levels
how would you rule out exocrine pancreatic insufficiency as a cause of chronic diarrhea
trypsin like immunoreactivity (TLI)
? cPL and fPLI
how do you rule out lymphangiectasia as a cause of chronic diarrhea
may lead to combo of hypoproteinemia, hypocholesterolemia and lymphopenia
how would you assess the clinical status of the patient with chronic diarrhea using hematology and serum biochem (3)
- serum protein (albumin)
- serum folate and cobalamin
- calcium, phosphate, magnesium balance
in what ways would diagnostic imaging help you diagnose cause for chronic diarrhea (2)
- identify or rule out neoplastic processes or disorders such as partial bowel obstruction
- inform decision making about whether endoscopy or exploratory coeliotomy should be performed to obtain a diagnosis
what histopathological changes would be seen with idiopathic inflammation (IBD) (3)
- epithelial alterations
- architechtural abnormalities
- inflammatory cell population, PLE – lymphangiectasia, crypt abscessation
how do you manage chronic idiopathic food responsive enteropathy (FRD)
dietary modification
how do you manage chronic idiopathic antibiotic responsive enteropathy (FRD)
antibiotic responsive diarrhea
manipulation of intestinal flora – probiotics and prebiotics
how do you manage chronic idiopathic glucocorticoid responsive enteropathy (FRD)
immunosuppressive drug therapy
what dietary modifications can you do to manage chronic idiopathic enteropathies (5)
- allergen restriction: elimination diets
- hydrolyzed protein diets
- prebiotics: fructo-oligosaccharides
- low fat diets
- supplementation with soluble fibres (psyllium)
what antibiotics can manage antibiotic responsive diarrhea (3)
- metronidazole
- tetracyclines
- tylosin
what can be used to manipulate the intestinal flora (3)
- lactobacillus spp
- enterococcus spp
- bifidobacterium spp
what drugs can manage chronic idiopathic enteropathies (6)
- prednisolone
- azathioprine
- cyclosporine
- chlorambucil
- sulphasalazine (ASA)
- budesonide
what adjunctive therapy can be given to manage chronic idiopathic enteropathies (2)
- vitamin B12 (GI dysfunction, chronic wasting/failure to thrive, malaise, cobalamin)
- thromboprophylaxis (clopidogrel) in dogs with PLE (risk of thromboembolic disease)