Intestine 3 (Test 1) Flashcards by Caleb Gwilliam

What diarrhea causing pathogens results in intracellular infection and all life stages can be seen?

Coccidiosis

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T or F

Coccidiosis cause cell lysis as part of lifecycle

TRUE

Loss of enterocytes

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What type of diarrhea do you see with coccidiosis?

Loss of enterocytes:

loss of absorptive surface area–>osmotic diarrhea
Mucosal damage–> exudative diarrhea

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When would you see coccidiosis in a calf?

Between 4-8 weeks

(has an 18 day pre-patent period)

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What will you see grossly with Coccidiosis?

Small and/or large intestine segmentally dark red

hemorrhagic contents

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What will you see microscopically with coccidiosis?

Segmental necrotizing enteritis

Villous atrophy

Crypt dropout

intracellular coccidial life stages

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Cryptosporidiosis is an intracellular or extracellular protozoal parasite?

Extracellular

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T or F

cryptosporidiosis attaches to apical surface of enterocytes (i.e. does not invade)

True

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What is the result of cryptosporidiosis infection?

It attaches to the apical surface of enterocytes (does not invade)–>does not cause loss of enterocytes/severe mucosal damage

Marked villous atrophy/fusion

loss of absorptive surface area: (malabsorption) osmotic diarrhea
loss of microvilli membrane-bound digestive enzymes–>maldigestion

Compensatory crypt hyperplasia

Possible secretory component (large-volume diarrhea is common)-Cholera-like enterotoxin affecting cAMP levels

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Who is most susceptible to cryptosporidiosis infecton?

Neonatal animals are most suceptible; adule animals likely immune but may shed oocytes

Most important in calves; sporadic in other ruminants

Can happen in horses

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List 3 clinical signs for cryptosporidiosis

Large volume diarrhea

anorexia

depression

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When do you see cryptosporidosis in calves?

Between 1-3 weeks

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Cryptosporidiosis results in what?

Acute, distal small intestine (large intestine), osmotic (loss of absorptive surface area), secretory (inflammatory mediators) due to enterocyte damage

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Crypto occurs along with what other pathogen infections sometimes?

Rota/coronavirus, ETEC

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Giardiosis is most important in what species?

Young Dogs, cats

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What type of diarrhea occurs as a result of giardiosis infection?

Results in diminished mucosal disaccharidase activity–>mucosal phase of digestion disrupted–>maldigestion

Some damage to microvilli–> malabsorption

Both of these mean Osmotic diarrhea

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What will you see microscopically with giardiosis?

Usually none, but sometimes you may see mild crypt hyperplasia, villous atrophy, mononuclear cell infiltrates

-pyriform trophozoites associated with enterocyte surface

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Giardiasis attacks what part of the GI?

Small intestine (chronic, intermittent)

Osmotic: maldigestion, malabsorption

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The following describe what pathogen?

Calves

Intracellular

Destruction of enterocytes

Hemorrhagic diarrhea

coccidiosis

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The following describe what pathogen?

Calves

Extracellular

Villous atrophy

Lamina propria Inflammation

Actue Diarrhea

Cryptosporidiosis

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The following describe what pathogen?

Dogs

Extracellular

Disaccharidase inhibition

Damage to microvilli

Chronic, intermittent diarrhea

Giardiasis

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Infiltrative disease cause what kind of diarrhea?

CHRONIC Diarrhea (accumulatio of cells in lamina propria)

2 Mechanisms:

Malabsorption: physical barrior + villous atrophy

Exudation: increased mucosal permeability due to: cellular infiltrate, inflammatory mediators (results in loss of water, electrolytes, often protein (PLE)

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Infiltrating cells may be:

Inflammatory or Neoplastic

what is a major consequence of infiltrative diseases?

Weight loss/Chronic Wasting

What is most common casue of chronic diarrhea and vomiting in dogs?

Inflammatory Bowel disease (IBD)

Describe the pathogensis of IBD?

Dysregulation of mucosal immune response leads to an imbalance between pro-inflammatory responses and down-regulatory responses-e.g. regulatory T-cells

What are possible factors that play into IBD?

Multifactorial: - genetic predisposition - environmental-e.g. diet - immunologic-breach of mucosal barrier may influence initiation of IBD - Dysbiosis-Alteration in GI flora

How do you diagnosis IBD?

It requires a Biopsy Severity of clinical signs does not correlate well with severity of lesions Forms: Lymphoplasmacytic, Eosinophilic

What are the 3 classifications of IBD?

Diet-Responsive Antibiotic-responsive Steroid/immunosuppressive- responsive

In which species is diffuse alimentary lympoma most common? A. Horses B. goats C. Dogs D. Cats

D. CATS

What breed is the poster child for IBD?

GERMAN shepherds often purebred dogs Classically produces small intestinal malabsorption syndrome with PLE, but can affect somach/large intestine as well

What is often associated with feline IBD?

Triaditis syndrome (IBD, cholangiohepatitis, panceatitis)

T or F Diffuse eosinophilic enteritis often idiopathic.

True: may also be associated with food allergy, RULE out parasites

Describe the alimentary lymphoma pathogenesis?

Diffuse or focal/multifocal proliferation of neoplastic lymphocyte/lymphoblasts--\> distortion and expansion of mucosa--\>transmural invasion--\>extraintestinal lesions (esp. mesenteric lymph nodes) Often accompanied by secondary inflammation

What other intestinal neoplasms are there along with alimentary lymphoma?

Adenoma/adenocarcinoma Leiomyoma/leiomyosarcoma Mastocytoma

What might you see clinically with Alimentary lymphoma?

Animal presenting with chronic small bowel diarrhea, weight loss, vomiting and palpably thickened loops of bowel

What do you see? What is your top differential with this slide?

Infiltation of the mucosa, submucosa, and tunica muscularis with neoplastic lymphocytes, villi distortion/atrophy Diffuse alimentary lymphoma

What is Lymphangiectasia?

It is a disease of abnormal lymphatic transport (dilation of mucosal and submucosal lymphatics)-TRANSPORT phase of digestion interrupted

What phase of digestion does lymphangiectasia disrupt?

TRANSPORT phase

What is the most common cause of PLE (protein-losing enteropathy)?

Lymphangiectasia

List three clincial signs of Lymphangiectasia:

- Diarrhea - Steatorrhea - Hypoproteinemia +/- ascites

Describe what you see: What is your top differential diagnosis from this? Hint: Hypoproteinemic dog

Dilated mesenteric lymphatic vessels Lymphangiectasia

What is primary lymphangiectasia? How can you get it?

Primary lymphangiectasia means there is no evidence of lymphatic vessel obstruction 1. Congenital-developmental disorder 2. Idiopathic (dogs)

What is acquired/secondary lymphangiectasia? How can you get it secondarily?

Secondary: inflammatory or neoplastic distorts and obstructs mesenteric lymphatic drainage 1. IBD 2. Johne's Disease 3. Lymphoma (Can be segmental or widespread)

How do you get ascites with lymphangiectasia?

Lymphatic stagnation--\>leakage of fluid, protein, lymphocytes into intestinal lumen Results in the following: 1. Lymphopenia 2. Hypoproteinemia 3. Hypocholesterolemia: also due to impaired absorption of lipid (steatorrhea)

Is lymphangiectasia acute or chronic?

CHRONIC

What type of diarrhea do you see with lymphangiectasia?

Osmotic (malabosorpative) Exudative (inflammatory)-increased hydrostatic pressure (PLE, fluids lost)

T or F Small intestinal bacterial overgrowth (SIBO) is an overgrowth of normal enteric bacteria

TRUE

T or F SIBO presents itself almost always with the same clinical signs

FALSE, Sometimes you will see all of the clinical signs reported other times you won't see anything

What does SIBO result in?

1. Decreased brush border enzyme activity 2. Disturbance of intraluminal solubilization/digestion 3. Bile Sale Deconjugation The top 3 cause maldigestion--\>osmotic diarrhea 4. Toxin production--\>stimulation of colonic secretion--\>SECRETORY diarrhea

What will you see microscopically with SIBO?

Usually little to none histologically

What can cause SIBO?

1. Increased entry of bacteria: reduced gastric acidity, gastrectomy, colonicjejunal fistula 2. Abnormality of intestinal loops 3. Reduced clearance of bacteria: motility disturbances, obstruction of intestine, immunodeficiency, cachexia

Is there more than one form of SIBO?

YEP, Primary: idiopathic; antibiotic-responsive diarrhea (ARD) Secondary to: IBD, EPI

What are the secondary causes of SIBO?

1. Decreased motility/partial obstruction: delayed intestinal transport--\>decreased flushing of normal intestinal flora 2. Secondary to mucosal lesions: IBD 3. Lesions that result in maldigestion/malabsorption--\>increased substrate EPI can also be a cause