Gastroenterology, Pt. 6 (chronic diarrhea) Flashcards
Problem: Chronic small bowel diarrhea
- ways to classify
many ways to classify
- eg. primary GI vs. extra GI
- Maldigestion vs malabsorption
- Protein losing vs non-protein losing
- Specific cause
- Response to treatment
chronic enteropathy classification for maldigestion vs malabsorption - which is which? what does maldigestion look like and what animals are at risk?
Maldigestion (exocrine pancreatic insufficiency):
* Dog - young, thin, polyphagia, coprophagia
> German shepherds at risk
* Cats - any age, weight loss, only 2/3 have diarrhea
Malabsorption (all other causes)
chronic enteropathy classification for Protein-losing vs. non-protein losing
- how does this relate to panhypoproteinemia and Lymphangiectasia
- Panhypoproteinemia (albumin & globulin lost)
- Many causes of malabsorption may present either way
- Lymphangiectasia may be primary (idiopathic), and due to portal hypertension and thoracic duct obstruction
how can Lymphangiectasia arise? what are the different types and the associated signs?
Lymphangiectasia may be primary (idiopathic), and due to portal hypertension and thoracic duct obstruction
* In primary lymphangiectasia GI signs may be minimal, and ascites and pleural effusion may be pronounced
* Lymphangiectasia may also be secondary to causes of mucosal inflammation/infiltration (ex IBD, neoplasia)
mechinisms of protein losing enteropathy (3)?
- Lymphatic obstruction or rupture
- Increased mucosal permeability due to mucosal infiltrates
- Mechanical causes (ulcers, erosions, congestion)
Most common causes: of protein losing enteropathy
- IBD, lymphangiectasia, lymphoma
- Consider histoplasmosis or pythiosis in endemic areas
Classifications of chronic enteropathy based on specific cause
- Infectious
>bacterial
>protozoa
> helminth - neoplasia: lymphoma
- inflammatory bowel disease
> Lymphocytic-plasmacytic
> Eosinophilic
> Granulomatous - Villus atrophy
bacterial causs of chronic enteropathy
v Campylobacter jejuni
v Clostridium perfringens & C. difficile
v Yersinia
v Small Intestine Bacterial Overgrowth (SIBO, antibiotic-responsive enteropathy [ARE])
v Dysbiosis
protozoal causes of chronic enteropathy
Giardia, Cryptosporidium
helminth causes of chronic enteropathy
Toxocara sp., Ancylostoma sp., Uncinaria, Strongyloides
classifications of chronic enteropathy based on response to treatment
¡ FRE: Food-responsive enteropathy
¡ ARE: Antibiotic-responsive enteropathy
¡ IRE: Immunosuppressant (steroid)- responsive enteropathy
¡ NRE: Non-responsive enteropathy
IBD vs chronic enteropathy
Chronic enteropathy:
* Used in animals where intestinal inflammation is suspected but biopsies have not been taken
* Does not infer which treatment will be needed to control clinical signs
IBD:
* Implies treatment trials with diet, deworming, and antibiotics have failed
* Inflammation has been demonstrated histologically
* Immunosuppressant will be needed
should we do a work-up for chronic enterophathy
Work-up always indicated, how aggressive depends on earlier criteria
conservative work up for chronic enteropathy includes:
¡ Fecal parasitology
¡ Response to fenbendazole
¡ Dietary change (novel protein vs hydrolyzed protein)
¡ Risk for rendering more proteins antigenic with novel protein diet
* Can use hydrolyzed protein diet instead
* Often see improvement in 2 weeks if going to respond
how soon will we see improvements in chronic enteropathy from novel diet if the animal is a responder?
Often see improvement in 2 weeks if going to respond
chronic enteropathy work up bloodwork
¡ CBC, biochemistry
¡ Testing for hypoadrenocortism (resting cortisol)
¡ Consider bile acids to assess for hepatic dysfunction
chronic enteropathy work up - why look at TLI?
To assess for EPI
¡ TLI is decreased in patients with EPI
chronic enteropathy work up - why look at serum B12?
¡ Absorbed in ileum
* May be decreased with SIBO/ARE or severe mucosal inflammation/infiltration
chronic enteropathy work up - why look at serum folate?
- Absorbed in proximal small intestine
- May be decreased with mucosal inflammation/infiltration
- May be increased in SIBO/ARE (production)
if a dog has EPI, what will we see for TLI, B12, and folate values?
decreased TLI, ± decreased B12, N folate
if a dog has SI malabsorption, what will we see for TLI, B12, and folate values?
N TLI, ± decreased B12 (distal), ± decreased folate (proximal)
if a dog has SIBO (ARE), what will we see for TLI, B12, and folate values?
N TLI, ± decreased B12 (distal), ± increased folate]
chronic enteropathy - what is the use of radiographs? barium series use?
- Abdominal radiographs often unrewarding in chronic diarrhea with normal PE
- May reveal mass, foreign body, plication
- Barium series not recommended
> Most useful to diagnose obstruction
> Expensive and tendency to over-interpret
> Superseded by ultrasound and endoscopy
chronic enteropathy - what is ultrasound good for?
¡ Distribution of lesion (enteritis more
diffuse)
¡ Thickness of intestine (neoplasia thicker)
¡ Loss of layering (neoplasia)
¡ Lymphadenopathy (neoplastic larger)
¡ Ultrasound in this case → enteritis
what infectious disease tests can we run in a chronic enteropathy case?
- Fecal culture for pathogens
> Campylobacter, Clostridium, Salmonella, Yersinia - IDEXX fecal PCR panel
> Parvovirus
> Coronavirus
> Canine distemper virus
> Salmonella
> Clostridium enterotoxin A gene
> Cryptosporidium
> Giardia
optional next steps for chronic enteropathy treatment (empiric)
Options:
* Empiric deworming
* Empirical treatment with dietary change
* Empirical treatment with tylosin or metronidazole?
* Gastrointestinal biopsies (endoscopic vs surgical)
* Empirical treatment with prednisone if biopsies declined
chronic enteropathy example plan / next steps
- complete bloodwork
> CBC, biochem, hypoadrenocorticism testing (dog), hyperthyroidism (cats) - endoparasitism testing
- fecal floatation
- empiric deworming - hypoallergenic vs novel protein dietary trial (2 weeks)
- surgical / endoscopic biopsies vs immunosuppressive trial
causes of IBD and treatment options that target them
- Genetics
> nothing much - Dietary antigens
> hypoallergenic diet - The microbiota
> fecal microbial transplantation - dysregulated immune response
>immunomodulatory therapy
how important is dietary therapy for chronic enteropathy? how successful can it be?
¡ ESSENTIAL!!!!!
¡ First-line treatment
¡ Remission rates of over 67% with diet alone (Mandigers, 2010)
¡ Many prospective studies demonstrating response to diet alone
chronic enteropathy (IBD) diet reccomendation? how soon do we often see improvement?
Dietary change:
* Highly digestible, novel protein, hydrolyzed protein
* Numerous brands with different proteins
* Easily digested carbohydrate (reduces osmotic effect)
* Fats may be reduced –unabsorbed fats aggravate diarrhea
* Strict diet trial for at least 2 weeks
* Often see some improvement within a few days to up to 2 weeks
SUMMARY
- highly digestible
- high fibre
- novel protein
- hydrolized protein
- etc…
if we get a poor response to a diet change for IBD does that mean we should give up on diet options? what should we do?
¡ Response to different diets varies
¡ Insufficient response to one diet does NOT exclude response to another
¡ Can consider a 2nd diet trial before additional diagnostics/treatment in stable patients
chronic enteropathy treatment options
- Dietary change
- Immunosuppression
> Prednisone - Treatment of dysbiosis
> Antibiotics
> Probiotics
> Fecal transplantation
methods of treating chronic enteropathy via immunosuppression
Prednisone:
- High quality evidence to support steroids for induction treatment of IBD
* If resistant, consider other immunosuppressives
> azathioprine, mycophenolate, chlorambucil, cyclosporine
* Budesonide – potentially less systemic side-effects than prednisone
methods of treating chronic enteropathy via treatment of dysbiosis
¡ Antibiotics
* Ex tylosin, metronidazole
¡ Probiotics
¡ Fecal transplantation
* Easy to perform and in some clinics is an early treatment
* Not standardized (dosage, administration method, donor screening)
are antibiotics a good choice for treating chronic enteropathy? possible drawbacks? what do we do if we dont see results in 2 weeks?
¡ Utility unclear:
¡ Response to antibiotics often short lived
¡ Antibiotic resistance
¡ **Granulomatous colitis of Boxers and French bull dogs
¡ If antibiotic trial not successful within 2 weeks, reassess
possible treatments for chronic enteropahty that are considered less often
¡ Vitamin B12 injections
¡ Vitamin D?
* Hypovitaminosis D negative prognostic factor
¡ Intestinal lymphoma
- Consider surgical removal of focal lesions
- Chemotherapy
> Diffuse GI lymphoma has a poor prognosis in dogs
> Indolent T-cell lymphoma has a good prognosis in cats
WHEN TO SUPPLEMENT COBALAMIN? for chronic enterophathy
- When measuring B12 levels isn’t an option
- When cobalamin measures low
- When cobalamin measures low- normal (<400ng/L)
EXOCRINE PANCREATIC INSUFFICIENCY (EPI)
- is due to:
¡ destruction of acinar cells due to chronic pancreatitis (dogs and cats)
¡ Depletion of acinar cells due to pancreatic acinar atrophy (dogs)
> GSD, rough coated collies
at what point do we see clinical signs of EPI?
¡ Clinical signs of EPI do not occur until more than 90% of the exocrine pancreatic function has been lost
exocrine pancreases is a major source of what that influences cobalmin?
Exocrine pancreas is major source of intrinsic factor:
¡ Assess for hypocobalaminemia
most common sign of EPI, and antoher common observatin
¡ Most common sign is weight loss*
¡ Loose stools commonly observed
EPI: DIAGNOSIS
TLI
¡ Low TLI is highly sensitive and specific for EPI
EPI: TREATMENT
¡ Pancreatic enzyme supplementation ($)
¡ Treat for concurrent SIBO/ARE/Dysbiosis
¡ May need to treat for concurrent IBD
¡ Diets with high fiber should be avoided (interferes with fat absorption)
¡ If patients not responding to therapy, antacid treatment can be considered
negative prognostic factor for EPI
marked hypocobalaminemia
PLE IN YORKSHIRE TERRIERS; what do we see?
- Emerging disease in Yorkshire terriers
¡ Females > males
¡ Median age 7 years (1 – 12)
¡ Diarrhea ± ascites
> Dyspnea (Ascites, pleural effusion, collapsing trachea) - Low albumin, globulin, magnesium, calcium
> Dogs with PLE may also have low iCa, occasionally signs of hypocalcemia - Response of Yorkie PLE to prednisone and diet change varies from none to good
LYMPHANGIECTASIA; what is primary vs secondary, and what signs are associated with each?
Can be primary or secondary
¡ Secondary to IBD, lymphoma
> Diarrhea a prominent feature
> Initial treatment of IBD more aggressive
¡ Primary
> Minimal GI signs
> Ascites
> Pleural effusion
LYMPHANGIECTASIA breeds at risk
small terrier breeds, rottweilers, lundehunds
LYMPHANGIECTASIA - what do we see on ultrasound? on endoscopy?
Ultrasound – may see speckling
Flexible or capsule endoscopy - dilated lymphatics
LYMPHANGIECTASIA - what will we see with diagnostic surgery?
- dilated lymphatics, serosal granulomas
> Full-thickness biopsies high- risk leakage
LYMPHANGIECTASIA TREATMENT and prognosis
¡ Dietary fat restriction
¡ Prednisone (anti-inflammatory dosage)
¡ ± medium-chain triglycerides
¡ Response to treatment unpredictable
¡ Guarded prognosis
Which of the following is NOT typically a cause of a protein losing enteropathy?
A) Lymphangiectasia
B) Histoplasmosis
C) Lymphoma
D) Campylobacter
D) Campylobacter
Identify the true statement in regard to EPI:
A) A high TLI is suggestive of EPI
B) High fiber diets are an important component of treatment
C) Chronic pancreatitis is a common cause of EPI in cats
D) Hypocobalaminemia is uncommon in patients with EPI
?C) Chronic pancreatitis is a common cause of EPI in cats?
