Glandular Stomach through Intestine Pathology

What is the difference between primary and secondary gastric dilatation and rupture?

Primary: excess intake of carbs; lush pasture

Secondary: obstruction (colic)

True or False: Primary gastric dilatation and rupture is most common.

False! SECONDARY gastric dilatation and rupture is most common.

What are THREE major signs of gastric dilatation and rupture?

1. Colic

2. Muscle fasiculations

3. Sudden death

What kind of abomasal displacement is most common?

Left-sided displacement (down and to the left)

What direction would a right-sided abomasal displacement go?

Up +/- around

What TWO major risk factors are noted in postpartum dairy cows with abomasal displacement?

1. High grain diet

2. Atony

Name THREE clinical signs of abomasal displacement.

How would it appear from an acid-base standpoint?

1. Anorexia

2. Ketonuria

3. Ping on auscultation

Metabolic alkalosis and hypochloremia

True or False: Abomasal displacement is difficult to diagnose on necropsy.

True!

Name the TWO major causes of gastric impaction in horses.

1. Ingestion (phytobezoar, poor mastication, inadequate water intake, persimmons)

2. Vagal nerve damage

What substance, when unripe, contains soluble tannins that polymerize to form a gel and cause gastric impaction in horses?

Persimmons

What animal experiences gastric ulcers with bruxism, ptyalism, gastric reflux, and dorsal recumbency usually caused by stress and NSAID use?

Horses

What animal experiences gastric ulcers with subclinical to acute death due to hemoabdomen, usually caused by finely ground rations?

What region does this mostly occur in?

Pigs

Pars esophagea

What animal experiences gastric ulcers with anorexia, decreased milk production, and melena, usually caused by mechanical irritation, stress, or grain overload?

Cows

True or False: Viruses (BVD), fungi, lymphoma, and toxicants like arsenic can also cause gastric ulcers in cows.

True!

What bacterial gastritis develops in sheep and calves as a hemorrhagic abomasitis with submucosal emphysema and exotoxins?

Clostridium septicum (Braxy)

What bacterial gastritis occurs in calves and usually accompanies tympany, congestion, and hemorrhage?

Clostridium perfringens Type A

Name THREE parasites that cause parasitic gastritis in the horse.

1. Gasterophilus spp

2. Draschia megastoma

3. Trichostrongylus axei

Which Gasterophilus spp lives in the pyloric mucosa? Which is in the cardiac region mucosa?

G. Nasalis: pyloric mucosa

G. Intestinalis: cardiac region mucosa

True or False: Gasterophilus spp. are usually focal ulcerations and incidental in nature pathologically.

True!

What parasite causes submucosal nodules in the glandular region near the margo plicatus in the horse?

Which is a chronic gastritis in the glandular mucosa with proliferative nodules?

Draschia megastoma

Trichostrongylus axei

What cattle parasite, dubbed "Moroccan leather" histologically, causes irritation and mucosal hyperplasia?

Ostertagia ostertagi

What are TWO major sequalae of Ostertagia ostertagi infections in the cow stomach?

1. Loss of parietal cells and goblet cell hyperplasia

2. Protein losing enteropathy (malabsorption; leaky mucosa)

What TWO major parasitic gastritis exists in small ruminants and camelids?

1. Haemonchus contortus (Barber Pole Worm)

2. Teladoragia circumcinta

What are THREE physical exam/bloodwork findings are most consistent with Haemonchus contortus infections in small ruminants and camelids?

1. Anemia

2. Hypoproteinemia

3. Edema

What is the most common gastric neoplasia in the horse?

What is the most common abomasal neoplasia in the cow?

Horse: SCC

Cow: lymphoma

What is the occlusion of the intestinal lumen as the result of anomalous development?

Atresia

What is the major sequelae to atresia ani/coli?

Megacolon

What animal is atresia most common in?

Pig

What syndrome related to megacolon in horses involved an absence of myenteric or submucosal plexi in the colon and rectum?

What mutation is it related to?

Lethal White Syndrome

Endothelin receptor type B mutation

Horses form structures called —- that are formed from a concentration of ——————- around a central nidus.

Horses eating diet high in —-, —-, and —- are more predisposed.

Enteroliths

Ammonium magnesium phosphate (struvite)

Magnesium

Phosphorus

Protein

What TWO locations do enteroliths often lodge in the horse?

1. Pelvic flexure

2. Transverse colon

What are the THREE major causes of impactions in horses?

1. Ascarids

2. High roughage diet

3. Sand

What are the THREE major locations for an impaction in the horse?

1. Pelvic flexure

2. Right dorsal -> transverse colon

3. Base of cecum

Rectal strictures are common in what species?

What is it secondary to?

What does it cause?

(SHE WILL ASK THIS)

Pig

Salmonella

Thrombosis of hemorrhoidal artery

What is it called when one segment of intestine telescopes into the immediately adjacent segment?

Intussusception

What parasite is associated with ileo/cecal/colic intussusceptions in horses?

Anoplocephala perfoliata

True or False: Epiploic foramen entrapments and mesenteric rents are both examples of hernias or entrapments.

True!

What is another name for left dorsal colon displacement in horses?

Nephrosplenic entrapment

What is the difference between a torsion and a volvulus?

Torsion: intestine rotates on long axis

Volvulus: intestine twists around itself and mesentery

True or False: Most mesenteric lipomas are incidental, but some are pedunculated.

True!

Why are strangulating lipomas like really bad?

Lipomas wrap around intestine/mesentery -> ischemia, colic, death

What is an idiopathic condition of horses and pigs that is usually incidental and may be associated with impaction, especially involving ileocecal valve dysfunction?

Muscular hypertrophy of distal ileum

What intestinal condition occurs in horses and pink to black plaques on the serosal surface can be seen?

What is the cause?

Hemomelasma ilei

Unknown- maybe Strongylus edentatus migration

What are the FOUR basic mechanisms of diarrhea?

Which one is NOT commonly seen in large animals and is more a small animal thing?

1. Hypersecretion

2. Malabsorption

3. Increased permeability

4. Hypermotility

Hypermotility

True or False: Some diseases can cause diarrhea through more than one mechanism.

True!

What type of diarrhea involve excess of secretion over absorption of fluid and involves a derangement of normal secretory and absorptive mechanisms?

Where is it typically localized to in the bowel?

Hypersecretion

Small intestine

In hypersecretion diarrhea, postanoids and bacterial toxins (increase/decrease) cAMP, which (increases/decreases) Cl- secretion, (increases/decreases) sodium transport, and (increases/decreases) bicarbonate secretion.

Increase

Increase

Decrease

Increase

What diarrhea involves a net efflux of fluid and electrolytes independent of permeability changes, absorptive capacity, or exogenously generated concentration gradients?

Hypersecretion

Name ONE major example of hypersecretion diarrhea.

Enterotoxic E. Coli

What diarrhea is characterized by osmotic diarrhea and villus atrophy?

Malabsorption

Name the THREE major causes of malabsorption diarrhea.

1. Secondary to microvillous disruption

2. Crypt/villous enterocyte death

3. Space-occupying lesions of lamina propria

Name TWO examples of malabsorption diarrhea.

1. Rotavirus

2. Coronavirus

Diarrhea of increased permeability is seen with what FOUR things?

Which is the most important?

1. Extensive mucosal injury/necrosis

2. Increased hydrostatic pressure

3. Decreased plasma oncotic pressure

4. Decreased lymphatic drainage

Extensive mucosal injury/necrosis

E. Coli involves many genetic and environmental factors with multiple virulence factors and pathotypes.

What type of diarrhea forms from NONSTRUCTURAL alterations in cell membrane function?

What type of diarrhea involves STRUCTURAL alterations in cell membranes, leading to necrosis?

Nonstructural: secretory diarrhea

Structural: malabsorption diarrhea

Which pathotype(s) of E. Coli are related to nonstructural/secretory diarrhea?

Which are related to structural/malabsorption diarrhea?

Nonstructural/secretory: ETEC

Structural/malabsorption: EPEC and EHEC

Which pathotype of E. Coli invades mucosal enterocytes?

EHEC

What TWO major systemic effects can occur with bacterial enteritis caused by E. Coli?

1. Enterotoxemia (edema disease)

2. Septicemic colibacillosis (septic shock)

What pathotype of E. Coli involves K99 (F5) or F41 fimbriae binding to ganglioside and glycoprotein receptors on enterocyte microvilli?

ETEC

What TWO enterotoxins does ETEC secrete?

1. Heat labile (LT)

2. Heat stable (ST)

The heat labile and stable enterotoxins from ETEC interact with second messenger systems to increase —— (LT) and —— (ST). This causes —— channels to open, where ions flood into the lumen and water follows, resulting in —- diarrhea.

cAMP

cGMP

CFTR

Secretory

True or False: With ETEC, disease is most common in 1-4 days with calves and piglets.

True!

What would you expect to see on pathology with ETEC?

Histopath?

Dilated, flaccid intestine filled with yellow poo

No inflammation/necrosis but bacteria present on lumen

What is the MOST IMPORTANT pathologic finding of ETEC diarrhea on pathology?

(SHE SAID SHE WOULD ASK)

Chyle present in mesenteric lymphatics

True or False: There is still some capable of absorption seen with ETEC.

True!

True or False: EPEC produces LT and ST like ETEC.

False! EPEC does NOT produce LT and ST.

EPEC expresses additional adhesions to tightly bind to enterocytes, damaging the cytoskeleton of microvilli (attaching and effacing). This causes acute inflammation, leading to —- diarrhea.

Malabsorption

(Also a component of secretory due to ion transport but idgaf)

Some strains of EPEC produce ——, leading to mucosal necrosis.

Shiga/verotoxin

When does EPEC most commonly cause disease in calves and piglets?

2-3 weeks

You perform a necropsy on a suspected E. Coli bacterial enteritis. You find dilated, fluid-filled intestines with disruption of the brush border, acute inflammation, and enterocyte necrosis.

What pathotype is most likely?

EPEC

Which pathotype of E. Coli is similar to EPEC and secretion Shiga/verotoxins to create an acute immune response and necrosis?

Does it produce LT or ST?

EHEC

No

What is the major pathogenesis of EHEC that differs from the other pathotypes?

LPS absorbed into lamina propria/submucosa -> vasculitis

When do calves and pigs typically get EHEC?

2 weeks

Necrohemorrhagic or mucohemorrhagic diarrhea is characteristic of what E. Coli pathotype?

EHEC

What pathogenic, zoonotic enteroinvasive Gram-negative bacteria produces enterotoxins, cytotoxins, and endotoxins?

Salmonella spp

Salmonella is associated with —- and —- diarrhea and its endotoxins induce —-.

Malabsorptive

Secretory

Thrombosis

When do calves, piglets, and foals get Salmonella?

4-5 days and older

What is the unique pathologic finding of Salmonella enteritis?

Button ulcers

True or False: Salmonella spp. cause diffuse catarrhal enteritis with fibrinonecrotic ileotyphlocolitis, and Aeromonas spp. can cause similar lesions in horses.

True!

What is the Gram-positive, anaerobic bacteria that is uniquitous and overgrowth is often seen with diet change, stress, or disease?

Clostridium perfringens

What are the FOUR exotoxins produced by Clostridium perfringens that are encoded on plasmids and determine "type?"

1. Alpha

2. Beta

3. Epsilon

4. Iota

Name the major toxins associated with each type of Clostridium perfringens. (NEED TO KNOW THIS)

A

B

C

D

E

A: alpha

B: alpha, beta, epsilon

C: alpha, beta

D: alpha, epsilon

E: alpha, iota

Match the disease description with the type of Clostridium perfringens:

A

B

C

D

E

Diarrhea; necrotic enteritis in fowl

Enterotoxemia in lambs/sheep/goats/calves

Enterotoxemia in calves

Dysentery lambs; hemor enteritis calf/foal, enterotox sheep

Necrotic enteritis piglets/lambs/calf/foal; enterotox sheep

A: diarrhea; necrotic enteritis in fowl

B: dysentery in newborn lambs; hemorrhagic enteritis in neonatal calves and foals; enterotoxemia in sheep

C: necrotic enteritis in piglets, lambs, calves, foals; enterotoxemia in sheep

D: enterotoxemia in lambs, sheep, calves, goats

E: enterotoxemia in calves

Which type of C. Perf is associated with enteritis in foals, necrotizing enterocolitis in piglets, enterotoxemia and hemorrhagic enteritis in lambs, and neonatal calves and older cattle?

C. Perf Type A

Which type of C. Perf is associated with hemorrhagic enterotoxemia of neonatal lambs, calves, piglets, goat kids, and foals?

What age range are they typically?

What is this infection called in adult sheep, goats, and feedlot cattle?

C. Perf Type C

1-14 days

Struck

Pulpy kidney disease is associated with what type of C. Perf?

C. Perf Type D

What is the most frequent type of C. Perf?

Does it normally have mild or severe disease?

C. Perf Type A

Mild

True or False: C. Perf Type A is a part of the normal microbiota.

True!

What type of C. Perf is associated with acute necrohemorrhagic enteritis in neonates?

C. Perf Type C

What is the Gram-positive, anaerobic bacillus associated with dysbiosis?

C. Difficile]

What are the TWO toxins produced by C. Diff?

1. Toxin A: enterotoxin

2. Toxin B: cytotoxin/enterotoxin

What are the pathology findings of C. Diff in suckling pigs and horses, respectively?

Pigs: mesocolonic edema and enterocolitis

Horses: colic, diarrhea, enterocolitis

What is the Gram-negative intracellular bacteria that affects crypt enterocytes?

What TWO major impacts does this have?

Lawsonia intracellularis

1. Bacteria/crypt enterocyte hyperplasia

2. Dysregulation of growth signals

What is the classic manifestation of Lawsonia intracellularis in pigs and horses?

Proliferative enteropathy/enteritis/ileitis

What are the FOUR major clinical signs of Lawsonia intracellularis?

1. Mucoid to watery to hemorrhagic diarrhea

2. Anorexia

3. Vomiting

4. Pyrexia

What bacteria is associated with death of villous enterocytes and can be seen with silver stains (Warthin-Starry)?

Lawsonia intracellularis

What is the causative agent of Johne's disease?

Mycobacterium avium subspecies paratuberculosis

Johne's disease is typically associated with a subclinical period of what time?

2-5 year

What are the clinical signs in cattle and sheep/goats, respectively, with Johne's disease?

Cattle: pipe stream/hose pipe diarrhea; hypoproteinemia; emaciation

Sheep/Goats: emaciation; diarrhea uncommon

What is the major pathologic finding of Johne's disease?

Granulomatous enterocolitis with acid-fast bacilli in macrophages

You are presented a necropsy with diffuse or segmental thickening of ileum and proximal colon with thickened rugae mucosa, granulomatous enterocolitis with acid-fast organisms, and granulomatous lymphadenitis.

What is your primary differential?

Johne's disease