Term 5 Week 10 DMN

What is included in the foregut and what is included in the hindgut in the horse

Foregut: mouth, esophagus, stomach, small intestines

Hindgut: cecum, large colon, small colon, rectum

What is the role of saliva in horses

Lube for swallowing and buffer stomach acids

Where does the stomach sit in horses

Rib space 9-12, holds 8-15 L

Why are horses at a risk for gastric rupture

Because they cannot vomit

What are the functions of the SI in horses

Digestion of starch, protein, fats

Absorption of glucose, AA, fatty acids, vitamins and minerals

What is the process of placing a nasogastric tube in horses

• Pass the tube through the ventral meatus to the marked line that signals you are at the pharynx

• Encourage a horse to swallow the tube: blow sharply into the tube​, “tap” the pharynx with the tube (advance and retract small amounts)​, turn the tube 180° to encourage advancing into the esophagus, ensure the horse is flexing at the poll ​

• To ensure you are in the esophagus once the horse has swallowed, you can try to withdraw air (suck) onthe tube to see if there is negative pressure = in the esophagus.​

• Once confirmed, you can then blow air into the tube to aide in passage of the tube. ​

• Once in the stomach (smell, sounds) a small amount of water is instilled via stomach pump or funnel and asiphon is created to check the volume and type of stomach content.​

• It is useful to know what is put in (liters of water) vs. what is obtained to know what the net reflux is.Typically, we expect no more than 1-2 liters of net reflux. ​

A litter of 5-day-old piglets develops pasty to watery diarrhea and poor weight gain. Morbidity is high, but mortality is low. At necropsy, no obvious gross lesions are observed. Histopathology reveals mild multifocal suppurative enteritis with abundant Gram-positive rods. Other common enteric pathogens have been excluded. What is the most likely diagnosis?

Clostridium perfringens type A infection. Typically affects piglets 2 to 10 days old, causes variable diarrhea with low mortality and often no gross lesions. Histology may reveal mild suppurative enteritis with abundant Gram-positive rods.

A group of 16-week-old grow-finish pigs presents with mucohemorrhagic diarrhea and progressive loss of condition. Gross lesions are confined to the large intestine and consist of severe mucohemorrhagic typhlocolitis. Microscopic lesions are restricted to the mucosa. A strongly beta-hemolytic spirochete is isolated from feces. What is the most likely etiologic agent?

Brachyspira hyodysenteriae 

How quickly does feed material pass through the small intestine

1 foot a minute (SI are 70ft)

What part of the SI is prone to impaction

Ileum

What are the goals of the SI

Nutrient absorption (CHO/fats/proteins)

Brush border created by SI villi

Malabsorption syndrome if absorption at vilous tip fails

What is the hallmark sign of malabsorption in the SI

Weight loss

What diagnostics can you do for the SI of horses

Hx (signalment) + PE

Bloodwork

US

Endoscopy

Absorption tests

Biopsies (rectal, endoscopic, laparoscopic)

Laparoscopy/ventral midline celiotomy

Ruminants will not eat unless there is what

Normal rumen motility

Normal rumen flora/environment

Normal vagal nerve function

What clinical signs can you see with acute SI disease in horses

Colic

Moderate/severe colic

On US or RE dilated SI loops

Copious gastric reflux

What clinical signs can you see with chronic SI disease in horses

Weight loss

Intermittent mild colic: acute episode of chronic dz

US thickened SI walls

What are CS of IBD in horses

Progressive weight loss despite good appetite

Protein losing enteropathy (hypoalbuminemia/peripheral edema)

Lethargy/performance loss

Intermittent mild colic

Diarrhea can be present

What are categories of IBD in horses

Granulomatous enteritis

Multisystemic eosinophilic epitheliotropic dz (MEED)

Eosinophilic enteritis (entercolitis)

Idiopathic focal eosinphilic enteritis (IFEE): IBD without chronic weight loss

Lymphocytic plasmacytic enterocolitis (rare and grave prognosis)

What is the definitive diagnosis for IBD in horses

Histopathology

Which horses get granulomatous enteritis

Young standardbred (genetic predispostition)

Maybe mycobacterium avium or abnormal host inflammatory response to bacterial antigens

What can you see on histology with granulomatous enteritis

Macrophages

Which horses get multi-systemic eosinophilic epitheliotrophic dz (MEED)

Young horses (no breed predisposition)

What are CS of multi-systemic eosinophilic epitheliotrophic dz (MEED)

Dermatitis (first thing noted usually)

Tissue eosinophilia

Hypersensitivity response

What will you see on histology with multi-systemic eosinophilic epitheliotrophic dz (MEED)

Primary eosinophils

Lymphocytes + macrophages

What is eosinophilic enteritis (enterocolitis) in horses

Inflammatory eosinophilic cell infiltration at the level of the intestinal mucosa (diffuse and focal)

What can you see with diffuse eosinophilic enteritis (enterocolitis) in horses

Chronic weight loss- SI involvement

Diarrhea- LI involvement

Which form of eosinophilic enteritis (enterocolitis) comes with acute colic signs and not chronic weight loss

Focal idiopathic focal eosinophilic enteritis

What CS can you see with focal idiopathic focal eosinophilic enteritis

No weight loss

Protein normal

Acute severe colic- most common CS

What is the prognosis for lymphocytic plasmacytic enterocolitis

Grave prognosis

No age breed or gender predisposition

What can you see on histology from rectal biopsy in lymphocytic plasmacytic enterocolitis

Lymphocytes + plasma cells present in lamina propria with villous atrophy

How can you dx IBD

Signalment/hx/PE

Blood work (low protein/albumin)

US/rectal: evaluate SI wall thickness

Absorption tests: glucose absorption tests

Biopsy= definitive diagnosis

Laparoscopy/celiotomy/rectal

Differentiate IBD types

What can you see with glucose absorption test and how do you do it

18-24hr fasting/take sample 0

0.5-1g/kg glucose as 10% solution per NG tube

Blood glucose samples every 30 min

Expect glucose to elevate >85% over the baseline between 60-120min

What is glucose absorption test influenced by

Stress, drug, admin, delayed gastric emptying

How can you tx IBD in horses

Immunosuppressive dose of dexamethasone

Decrease exposure to possible dietary, parasitic or environmental antigens

Sx resection of intramural masses

What are potential causes of spasmodic colic in horses

Lush pasture

Drinking cold water after exercise

Heavy GI parasite load

Poor feed quality

What is the tx for spasmodic colic in horses

Buscopan and flunixin meglumine

What bacteria causes proliferative enteropathy in weanling foals

Lawsonia intracellularis

What are CS of lawsonia intracellularis in horses

Ill thrift

Poor haircoat/pot-belly appearance

Weight loss/lethargy/poor growth rate

Peripheral edema/ventral abdomen edema

Hypoproteinemia

Diarrhea

Colic sometimes

How can you dx lawsonia intracellularis in horses

SI wall thickness increase on US

PCR

Gold standard: isolation/culture, SI biopsy with Warthin Starry silver stain

How can you tx lawsonia intracellularis in horses

NSAIDs

Omeprazole

Fluids- colloids (hypoproteinemia)

Tetracyclines

What can macrolides and rifampin together cause in adult horses

Severe colitis

What are the typical important parameters for a presumed diagnosis of lawsonia intracellularis in horses

Low total protein and age

What is the typical age for weaning of horses

4-6 months

Why do some foals exhibit diarrhea with a lawsonia intracellularis infection

Enterocytes in the SI are affected, decreasing enzymatic activity and absorption resulting in an overload in CHO in the LI (osmotic diarrhea)

What happens in duodenitis proximal jejunitis

Syndrome of inflammation and edema of the duodenum and proximal jejunum causing excessive fluid and electrolyte secretion in proximal part of SI, high volume of enterogastric reflux and SI distension and abdominal pain

A type of functional gastrointestinal ileus

What are sources for accumulated fluid in duodenitis proximal jejunitis

Parotid saliva

Gastric secretion

Pancreatic secretion

Bile

Total 80-120 L/day for a 500kg horse

What are CS of duodenitis proximal jejunitis

Colic

Fever

Tachycardia

Endotoxemia

Decreased borborygmi

Copious amounts of gastric reflux

Dehydration and volume depletion

How can you dx duodenitis proximal jejunitis

Rectal exam- dilated loops of SI

NG tube- large volumes and improved comfort after decompression

US- dilated SI, increased wall thickness

Belly tap- dark yellow orange with elevated protein

What is the tx for duodenitis proximal jejunitis

NSAIDs/ 2% lidocaine CRI

IV fluids

Nutritional support when NP) >72hr

Frequent gastric emptying

Laminitis prophylaxis

What are possible complications with duodenitis proximal jejunitis

Laminitis

Thrombophlebitis

Peritonitis

Adhesion formation

Pharyngitis/esophagitis

Tx can becomes very expensive

What will you see with SI obstruction vs strangulation in horses

Obstruction: mechanical obstruction, luminal obstruction impedes flow or digesta, simple blood supply intact

Strangulation: mechanical obstruction, both lumen and blood supply compromised, devitalized bowel (endotoxemia, hemoconcentration, dehydration)

What are clinical signs of obstruction of the SI in horses

Mild moderate pain

Good response to analgesia and or gastric decompression

Minimal CV compromise

Peritoneal fluid WNL

Sometimes gastric reflux

What are clinical signs of strangulation of the SI in horses

Moderate to severe pain

Brief or no response to analgesia and/or gastric decompression

CV deterioration: endotoxemia, hemoconcentration, dehydration

Peritoneal fluid abnormal

Gastric reflux

Which type of colic is a surgical emergency

Strangulating lesions

What are causes of obstructive colic

Ascarid (round worm) impaction

Ileal impaction

Ileal hypertrophy

What are causes of stragulative colic

Intussusception

SI volvolus

Penduculated lipoma

Abdominal incarceration: epiploic foramen, mesenteric rent, inguinal ring hernia, umbilical hernia

What type of ascarids do horses get in their gut and which horses normally get it

Parascaris equorum

Older foal and weanling

What are clinical signs of parascaris equorum impaction in horses

Unthrifty foal, colic and depression, increase HR, RR, febrile

Can see worms in gastric reflux

How do you tx parascaris equorum impaction in horses

Gastric decompression/lavage initially, anti-inflammatory therapy, dead worms cause damage to SI wall, surgery is often indicated (poor px)

How can you prevent parascaris equorum impaction in horses

Proper deworming protocol, pasture rotation managment, reported resistance to ivermectin (FECRT)

Fendbendazole

If large worm burden use non paralytic anthelcide and give mineral oil first through NGT

Which types of worms target young vs which for older

Ascarids (young) → strongyles → tapeworms (adult)

What is the ideal range for ascarid FECRT

4-6 months

How often should foals be tx for ascarids

Twice

2-3 months

5 months

With fendbendazole

What should weanling be dewormed with when out on pasture

Macrocyclic lactones for stronglyes 6-9 months

Praziquantel for tapeworm

What usually causes ileal impaction

Common in Southern US June-Novemeber due to coastal bermuda grass

What are CS and how do you dx ileal impaction

CS: spasm of ileum around impaction, distension of proximal SI

Dx: Rectal exam and NGT

How do you tx ileal impaction

Medical early in dz: IV fluids, NSAIDs, mineral oil if no reflux

Medical late in dz: gastric decompression

Chronic: sx, manual massage to break down impaction, enterotomy rarely needed

What is the complication you can see after sx for ileal impaction

Post op ileus

How can horses get adhesions

Scar tissue from previous colic sx

What can bastard strangles lead to

Internal abscessation leading to intra-abdominal dz and colic

What is the most common CS of IBD in horses

Weight loss

What are viral causes to neonatal and pre-weaning diarrhea in swine

Porcine epidemic diarrhea (PED)

Transmissible gastroenteritis (TGE)

Rotavirus infection

What are bacterial causes to neonatal and pre-weaning diarrhea in swine

ETEC E coli

C perfringens C

C perfringens A

C difficile

What are protozoal causes to neonatal and pre-weaning diarrhea in swine

Coccidiosis (cystoisospora suis)

What are bacterial causes to post-weaning and grow-finish diarrhea in swine

Post weaning colibacillosis (ETEC)

Salmonellosis (salmonella enterica)

Swine dysentery (brachyspira hydrodysenteriae)

Proliferative enteropathy (lawsonia intracellularis)

What are parasitic causes to post-weaning and grow-finish diarrhea in swine

Whipworm (trichuris suis)

Roundworm (ascaris suum)

What are protozoal causes to post-weaning and grow-finish diarrhea in swine

Coccidia (Eimeria spp)

What is the most important cause of neonatal and post-weaning diarrhea in pigs

Enterotoxigenic E coli (ETEC)

What are the major virulence factors of enterotoxigenic E coli (ETEC)

Fimbrial adhesins (F4/K88, F5/K99, F6?987p, F41)- allow attachment to enterocytes of the SI

Enterotoxin production (LT, Sta, STb, shiga)- secretory, dehydration, death

Which swine does ETEC affect and what are CS

Neonatal (0-4 days old)

Severe watery diarrhea

Yellow-green diarrhea

Hypothermia

Empty stomach and fluid filled intestines on necropsy

OR can cause post weaning diarrhea and edema dz in post weaning pigs (3-10 weeks)

How is ETEC transmitted

Sow fecal contamination to piglets

Is there a vaccine for ETEC

Yes K99 vx

What swine does clostridium perfringens type C affect and what does it cause

Piglets <7days old dz shortly after birth within 12-72hr

Sudden death in otherwise healthy piglets

Bloody diarrhea (dark red to hemorrhagic)

Weakness and depression

Abdominal distension

Rapid dehydration

High mortality 100%

How is clostridium perfringens type C transmitted

Fecal oral transmission

What can you see on necropsy with clostridium perfringens type C

Hemorrhagic necrotizing enteritis

Dark red intestinal contents

Segmental or diffuse small intestinal necrosis

Fibrin and blood within the intestinal lumen

What is the pathogenesis of clostridium perfringens type C

Ingestion of clostridium perfringens type C spores/vegetative cells → colonization of SI → production of beta toxin → severe mucosal necrosis and hemorrhage → rapid development of necrohemorrhagic enteritis

Is there a vaccine for clostridium perfringens type C? Who would you vaccinate?

Yes vaccinate sows/gilts 2-6 weeks before farrowing

What is a gram positive anaerobic spore forming bacterium that produces an alpha toxin

Clostridium perfingens type A

What swine are affected by clostridium perfingens type A and what are CS

Piglets 1-14 days old

Yellow to creamy pasty diarrhea

Mild dehydration

Reduced weight gain

Variable morbidity within litters- low mortality with mild catarrhal enteritis at necropsy

What is coccidiosis caused by in pigs

Cystoisospora suis (formerly isospora suis)

What swine are affected by coccidiosis (cystoisospora suis) and what are CS

Piglets 5-14 days old

Yellow to gray pasty to watery diarrhea

Dehydration and poor body condition

Reduced weight5 gain and growth performance

Rough hair coat

Variable response to abx

What swine are affect by rotavirus A and what are CS

Nursing and recently weaned piglets (1-8 weeks age) causing villous atrophy, malabsorption, osmotic diarrhea

High morbidity low mortality

Acute watery to creamy diarrhea

Dehydration

Reduced nursing or feed intake

Poor growth and reduced weight gain

Rough hair coat

Variable depression and lethargy

How can you dx rotavirus A

Fecal PCR for rotavirus detection

Antigen detection (ELIZA or immunochromatographic tests)

What will you see on necropsy with rotavirus A

Thin-walled, fluid filled small intestines

Villous atrophy of SI mucosa

No significant hemorrhage or necrosis

Villous atrophy

Villous blunting and fusion

Loss of mature enterocytes

What swine are affected by transmissible gastroenteritis (TGE) caused by coronavirus

All ages affected by most severe in piglets <2 weeks of age

What is the affect of transmissible gastroenteritis (TGE) caused by coronavirus

Destroy mature enterocytes lining the small intestinal villi causing severe villous atrophy developing through the small intestine

What can you see with transmissible gastroenteritis (coronavirus) in neonatal pigs

Acute onset profuse watery diarrhea

Vomiting

Severe dehydration

Rapid weight loss and weakness

Huddling and reduced nursing behavior

What can you see with transmissible gastroenteritis (coronavirus) in older pigs and adults

Watery diarrhea

Decreased appetite

Vomiting

Mild dehydration

Usually recover within several days

What causes porcine epidemic diarrhea

Corona virus

High morbidity but low mortality

How can you differentiate transmissible gastroenteritis and porcine epidemic diarrhea

PCR they are both coronavirus but different serotypes

TGE- severe, very high mortality, vomiting

PED- moderate, lower mortality, vomiting