Diarrhoea Flashcards
Explain diagnostic approach to diarrhoea
1st step: Determine if GI or non GI cause of DIarrhoea
Characterise the non GI causes….
- Non GI
- Often minor D+
- History
- PE findings
- lab +/- imaging changes
Cause:
- Pancreatitis
- Hepatic insufficiency
- Renal failure
- Hypoadrenocorticism
- Hyperthyroidism in cats
2nd step: deal with obvious problem.
Describe the GI causes….
- GI cause
Cause:
- Substantial parasite burden (can be difficult to diagnose)
- Poor-quality food
- Diet indiscretion
- Contagious disease
3rd step:
Determine if diarrhoea is Acute V Chronic
N.B. volume, frequency of bowel movements, vomiting is not helpful
Explain Acute V Chronic, and Large bowel V Small Bowel
Acute
= Non-episodic D+ < 7-14 days
May non-threatening or severe:
- Hemorrhagic gastroenteritis
- Infectious febrile
gastroentiris (e.g. parvovirus)
Tests:
- Fecal exam
- Lab tests: electrolytes &PCV
- or CBC & biochem (severe)
Treatment:
Symptomatic/supportive therapy (anthelmintic, diet)
Chronic:
= No improvement >14 days
Or episodes over 3-4 weeks
Large bowel
- Unusual to have weight loss unless severe and would find hematochezia and fecal mucus
- Tenesmus
Small bowel
- Weight loss
Steatorrhea is infrequent melena rare
4th Step: Determine if Maldigestion or Malabsorption is present.
Explain the causes of maldigestion nad malabsorptive disease and how to diagnose them
Maldigestion
Uncommon in cats but important to consider in dogs
EPI
Serum TLI is most sensitive and specific test for EPI
Malabsorptive disease
PLE:
Diagnosis of PLE by exclusion ->
Eliminate hepatic insufficiency & PLN with no severe cutaneous disease (burns, and ulcers)
- Severe or progressively decreasing hypoalbuminemia
- poor prognosis Panhypoproteinemia is not sensitivie or specific for PLE
Serum albumin (TP is inadequate) measurements and repeat at same lab
<2.0g/dL indicates hepatic insufficiency
Hepatic function testing & urinalysis
PLE & hepatic insufficiency patients are hypocholesterolemic
PLN
Most are hypercholesterolemic
Urinalysis
- Lymphangiectasia
- Lymphoma
- Fungal infections (regional), and IBD
- Ulcer/erosions
- ARD
- Intestinal crypt lesions
- Young dogs: Occult parasitism and chronic intussusception
- Cats: IBD and lymphoma mainly
- Imaging, endoscopy, and biopsy are desirable, but therapeutic trials (ultra low fat diet for lymphangiectasia) is done if anaesthetic risk is too great or there are client constrains
Advanced treatment:
1st - consider a treatment trial.
Who is safe to do a treatment trial?
If safe to do a 2-3 week therapeutic trial ->
- Dietary
- antibiotic-responsive
- parasitic disease
- Boxers & French Bulldogs should be biopsied earlier due to predilection for histiocytic ulcerative colitis
- If advanced disease or rapidly progressing disease then aggressive diagnostics should be done
Advanced diagnostics:
The second step is ultrasound. What is the purpose of abdominal ultrasound for a diarrhoea case?
Abdominal ultrasound
- Determines if local or diffuse
- Whether endoscope can reach lesion
- Focal lesions can be aspirated (lymphoma or fungal infection)
- Specific but not insensitive – absent changes doesn’t eliminate serious GI disease
Advanced Diagnostics
3rd Step: intestinal biopsy
How can an intestinal biopsy be taken? What are the pro’s and cons of each technique?
Endoscopic
- Faster, Safer Less expensive than surgery
- Able to find & biopsy focal mucosal lesions that cannot be seen from serosal surface at surgery => increased chance of histologic diagnosis
- Ileum important –> lymphoma, IBD, lymphangiectasia may be diagnosed when not diagnosable in duodenal samples
- Need to include full thickness of intestinal mucosa (with or without muscularis mucosa)
- Colonic biopsy is safer
Surgical
- Better if endoscopy operator is not trained
- If disease is not reachable by scope
- May get full thickness sample
- Patchy intestinal disease – may be not helpful if taken where there is no lesions
- Better for diffuse disease
- No good for colonic biopsy – full thickness incision is at risk of dehiscence and peritonitis
What are the causes of chronic canine lare bowel diseases? How could they be diagnosed/treated?
- Dietary responsive
- Fiber responsive
- ‘Clostridial’ colitis (e.g. tylosin responsive)
Unlikely to worsen if trial fails & otherwise normal except D+, normal serum albumin, no rectal lesion
- Therapeutic treatment trial
Polyp or mucosal thickening
Digital rectal exam for focal lesions
Parasites – whipworm
dogs whould be treated in whipworm endemic areas even if fecal exam does not reveal ova
giardiasis is small bowel problem buut may mimic large bowel diarrhoea
Regionally:
- Histoplasmosis
- Pythiosis
- Heterobilharziasis
If losing weight or becoming hypoalbuminemic -> undergo testing as they can become suddenly worse:
- Abdominal ultrasound
- Rectal scraping -> easy, quick, and specific (insensitivie) screening for histoplasmosis
- Colonoscopy/biopsy -> endoscope with rigid biopsy forceps to obtain large samples with lots of submucosa
- Urinary antigen testing -> for histoplasmosis (reasonably sensitive)
fecal PCR for heterobilharzia
What are the feline large bowel diseases?
How can they be managd?
Cats Tend to have :
- Dietary responsive
- Clostridial
Unlikely to worsen if trial fails & otherwise normal except D+, normal serum albumin, no rectal lesion
- Therapeutic treatment trial
Parasites (e.g. tritrichomonas)
IBD colitis
What are other tests for diarrhea that can be used?
Abdominal radiographs
Only yield unsuspected radiopaque foreign body
Fecal cultures
Low yield procedure unless history strongy suggest contagion
Pathogenic bacteria does not mean responsible for clinical signs
Faecal PCR
Can be difficult to interpred just like culture
Serum cobalamin and folate
Helpful in dogs and cats:
Dogs – hypocobalamenis is specific for SI disease but not sensitivite
Insensitive and non specific for canine antibiotic responsive disease – ‘dysbiosis’
Provides evidence for SI disease if weight loss is present without diarrhea
Normal values not helpful
Cobalamin supplement benefits cats
Hypocobalamenia may be prognostic in dogs
