Lecture 11: GI III- diarrhea, SI dz, intestinal neoplasia, rectal/anal dz Flashcards
What is purpose of intestinal villi
absorption
what is purpose of intestinal crypts
proliferation
what is fx of SI epithelium
nutrient absorption
what is fx of colonic epithelium
absorb excess water
t or f: cecum/colon has no villi but lots of goblet cells
true
What tissue is this and identify 1-2
SI
1. Villi
2. Crypts
What part of intestine is this
Cecum/colon
What specialized enterocyte produces antimicrobial proteins
paneth cells
if you have no tight junctions in intestines what is consequence
no control of absorption and enhanced permeability—> diarrhea and dehydration
what is enteritis
inflammation of SI
what is typhlitis
inflammation of cecum
what is proctitis
inflammation of rectum
what is the pathogenesis of hypersecretion causing diarrhea
stimulation of enhanced ion (Cl-) transport at level of crypts—> increased osmotic pressure in lumen—> influx water into lumen
what mediates hypersecretion causing diarrhea
- Inflammatory mediators- prostaglandins
- Enterotoxins
what is the pathogenesis of malabsorptive diarrhea
damage to villi—> villus atrophy—> decreased surface area for absorption—> +/- crypt hyperplasia—> +/- enhanced secretion
what viruses can cause malabsroptive diarrhea
rotaviruses, coronaviruses
what bacteria can cause malabsoprtive diarrhea
EPEC and EHEC
what parasites can cause malabsorptive diarrhea
cryptosporidium parvum, coccidia
altered motility can be seen __ and is __ or __ mediated
hypersecretion, prostaglandin or cAMP
increased permeability component of enteritis can result from any __
epithelial damage/loss
Inflammation will result in increase ___ dump fluid and protein into lamina propria and subsequent loss into intestinal lumen
vascular permeability
Increased permeability is also associated with __
protein losing enteropathies (ex: IBD)
Maldigestion can be secondary to __, linked with __
villus atrophy, malabsorption
exocrine pancreas insufficiency is associated with what mechanism of diarrhea
Maldigestion
what is the consequence of any type of diarrhea
Water loss-> dehydration—> hypovolemia—> inadequate tissue perfusion and hypovolemic shock
what are some clinical signs of parvovirus
bloody diarrhea, vomiting, anorexia
what are some gross signs of parvo
segmental hyperemia, fibrin deposition on serosa
what is the pathogenesis of parvovirus
Cl- enters and damages crypts—> lack of replacement of absorptive enterocytes and loss of barrier function—> loss of fluids/bacterial translocation—> sepsis—> shock
what are some microscopic findings of parvo
severe crypt necrosis
what type of diarrhea does parvovirus cause
malabsoprtive diarrhea—> damages crypts so can’t regenerative villus tips
what virus likely cause this
parvo
Puppy with bloody diarrhea, anorexia, became septic and was euthanized. Histopath of intestines was performed and this was seen. What is likely cause and how do you know
Parvovirus- loss of crypts and secondary villus atrophy
What are the microscopic findings of coronavirus in intestines
villus atrophy, but crypts intact
What is the pathogenesis of enteritis caused by Pythian insidosum
dog ingest oomycete—> granulomatous enteritis—> obstruction
chronic enteropathies associated with hypoproteinemia that lead to __
weight loss, diarrhea, edema, ascites
what is the most common presentation of IBD
lymphoplasmocytic
what is the cause of lymphoplasmacytic IBD
immune mediated
what is cause of eosinophilic IBD
Food allergies vs parasite
what breeds are predisposed to histiocytic/ulcerative/granulomatous IBD
boxers, French bulldogs
What occurs during histiocytic ulcerative colitis
diffuse thickening/ulceration of colon due to influx of foamy histiocytes (macrophages) and contain PAS positive material
Boxer presents with chronic diarrhea, and weight loss- these were findings what is most likely dx and how do you know
histiocytic ulcerative colitis- diffuse thickening of colonic, PAS +, lots of macrophages
what is cause of histiocytic ulcerative colitis
Invasive E. Coli
define lymphangiectasia
dilation of lymph vessels/lacteals
what blood work findings are consistent with lymphagiestasia
lymphopenia, hypocholesterolemia, hypoalbuminemia
what dx
Lymphangiectasia
What neoplasia most likely
adenocarcinoma
What dx
Intestinal lymphoma
mass was very firm and following histo was taken- what are your top 3 differentials and what test should be done to find definitive dx
- Gastrointestinal stromal tumors
- Leiomyoma
- Leiomyosarcoma
Test: IHC
What breed most commonly gets perinatal fistulas
GSD
a perianal fistula forms a track between __ and __
perianal skin and rectum
what is the benign perianal tumor
adenoma
what is malignant perianal tumor and what is a bloodwork sign
Apocrine gland anal sac adenocarcinoma
BW: hypercalcemia
