Equine Gastrointestinal Diseases & Sepsis

Front 1

What is:

a. systemic inflammation
b. systemic inflammatory response syndrome (SIRS)

Back 1

a. inflammatory response to blood borne microbial mols, tissue derived enzymes, pro-inflammatory mediators, etc.
b. 2 or more of the following: tachypnea, tachycardia, fever or hypothermia, neutrophilia or neutropenia

Front 2

What is

a. sepsis
b. endotoxemia
c. septic shock

Back 2

a. systemic inflammatory response triggered by a microbial mol (infection, damaged gut barrier, etc.)
b. systemic inflammation triggered by Gram (-) bacterial endotoxin
c. sepsis w/ signs of shock

Front 3

What is the pathophysiology of sepsis?

Back 3

infection or mucosal damage allows microbes (usually bacteria) to access systemic circulation

systemic inflammation triggered: most commonly by Gram (-) bacterial lipopolysaccharide (LPS)

poor perfusion: neutrophil & platelet aggregates, thrombi, hemodynamic shock (peripheral vasodilation, poor cardiac output)

tissue injury: ischemia, edema (d/t ↑ vascular permeability), leukocyte products (reactive O2 intermediates, degradative enzymes)

multiorgan dysfunction/failure: laminitis, CV, liver, kidneys

Front 4

What are the clinical signs of sepsis?

Back 4

tachycardia, tachypnea, pyrexia or hypothermia, leukocytosis or leucopenia

other: hyperemic mm, depression, edema

signs of shock: prolong CRT, poor peripheral pulses, hypotension, weakness, trembling, cool extremities

Front 5

What are common lab findings w/ sepsis?

Back 5

CBC: hemoconcentration (↑ PCV, TP), systemic inflammation (↑ fibrinogen, leukocytosis, neutropenia w/ L shift: classic, thrombocytopenia)

Chem: azotemia, ↑ liver enzymes, high gap lactic acidosis

U/A: concentrated, hematuria, proteinuria

Front 6

How is sepsis diagnosed?

Back 6

hx
typical clinical signs
typical lab findings
blood culture (lacks sensitivity in adults)
look for source

Front 7

What is the tx for sepsis?

Back 7

summary tx plan

SIRS
- 2-4 L J5 plasma
- flunixin IV TID-QUID
if hypotensive
- LRS bolus (20 L), then at 2x maintenance
- if still hypotensive: 10 ml/kg hetastarch, consider pressors (neonates)
monitor PE, BP, colic, feet, veins, PCV/TP, creatinine, LFTs, urine

ABs: if neutrophil count < 1000 OR septicemia suspected or documented

nutrition
- high quality diet if tolerated: high fat
- +/- parenteral nutrition

preventing laminitis
- circulatory support: incl. colloids
- anti-inflammatories: aspirin (↓ platelet clumping), pentoxifylline? (↑ deformability of RBCs & WBCs), hand walk, ice feet

Front 8

What are the principles of treating sepsis?

Back 8

stop absorption/tx source: hasten GI mucosal healing, drain abscesses, tx infections

antagonize LPS effects

↑ perfusion: ↑ BP, improve blood distribution, ↓ endothelial permeability (vascular leak syndrome)

control coagulation/platelet activation

Front 9

What are some causes of acute diarrhea in adult horses?

Back 9

infectious: Salmonella, Neorickettsia risticii, Clostridium difficile, Clostridium perfringens

toxic: NSAIDs, cantharidin, arsenic, ABs

misc.: grain overload, sand enteropathy

Front 10

What is the pathophysiology of diarrhea in adult horses?

Back 10

mucosal injury -->
- absorption of bacterial products: local inflammation, or endotoxemia/SIRS/sepsis
- enterocyte hypersecretion --> massive fluid loss (isotonic) --> dehydration, electrolyte & acid-base imbalances
- protein loss: albumin +/- globulin
- motility dysfunction: hypomotility early (colic), then hypermotility (diarrhea)

Front 11

What are the clinical signs of acute diarrhea?

Back 11

fever: usually 1st sign seen

scant to profuse diarrhea, +/- colic

sepsis & dehydration: depression, anorexia, tachycardia, tachypnea, tacky hyperemic mm, prolonged CRT, limb edema, weak peripheral pulses, cool extremities

Front 12

What are the lab findings assoc. w/ acute diarrhea?

Back 12

CBC: mature neutropenia w/ ↑ bands, ↑ fibrinogen, thrombocytopenia

Chem: hypoproteinemia, hypoglycemia, hyponatremia, hypokalemia, hypocalcemia (esp. cantharidin), metabolic acidosis, azotemia, +/- ↑ liver enzymes, bile acids, hyperbilirubinemia

Front 13

How is acute diarrhea diagnosed?

Back 13

Salmonellosis: fecal culture (5 consecutive samples) or fecal PCR

Potomac Horse fever: buffy coat PCR

C. perfringens: culture or PCR for toxins

C. difficile: fecal cytotoxin immunoassay

cantharidin toxicity: ID of blister beetles, cantharidin assay (urine, feces, GI contents)

Front 14

What is the tx for acute diarrhea?

Back 14

fluids
- crystalloids: maintenance + fluid deficit + on-going lossses
- colloids: if hypoproteinemic or evidence of septic/endotoxemic shock
- plasma: 6-8 L initially
- hetastarch: often used after initial plasma administration
- electrolyte/acid-base balance

mucosal protectant: bismuth subsalicylate BIP or psyllium TID-QID

tx sepsis

nutrition
- good quality grass hay/grass
- pelleted feed:
- AVOID enteral nutrition
- +/- parenteral nutrition

absorbent powders: only administer to horses w/ normal intestinal motility
- biosponge (di-tri-octahedral smectite) 0.5-1 lb BID: absorbs Clostridial toxins
- activated charcoal: 1 lb BID

specific therapy
- AVOID ABs if possible
- Clostridiosis: Metronidazole PO
- Poto. Horse fever: Oxytetracycline IV
- Salmonellosis: Enrofloxacin or Chloramphenicol

Front 15

What are some causes of chronic diarrhea in adult horses?

Back 15

parasitism (top ddx: always R/O), malnutrition, ulcerative colitis, IBD, sand enteropathy, Salmonellosis, neoplasia, chronic peritonitis, chronic liver dz/fibrosis (rare), chronic R heart failure (rare)

Front 16

What are the clinical signs of chronic diarrhea?

Back 16

wt. loss, +/- colic, +/- peripheral edema (if hypoproteinemic)

rarely dehydrated & rarely have systemic inflammation

Front 17

What lab findings are assoc. w/ chronic diarrhea?

Back 17

CBC/Chem: usually normal

+/- hypoproteinemia,+/- anemia of chronic inflammation, +/- electrolyte imbalances

Front 18

How is chronic diarrhea diagnosed?

Back 18

hard to dx

fecal float, sand test, peritoneal fluid analysis, fecal culture, abd. U/S, rectal bx

Front 19

What is the tx for chronic diarrhea?

Back 19

- parasites: fenbendazole for 5 d. followed by ivermectin for encysted cyathosomes
- sand: psyllium powder
- switch to all hay diet or pelleted feed
- chronic Salmonellosis: probiotics?
- metronidazole for 2 wks
- misoprostol, iodochlorhydroxyquin
- steroids: last resort

Front 20

What is the pathophysiology of right dorsal ulcerative colitis?

Back 20

- NSAID toxicity
- dehydration may play a role
- usually performance horses or sick horses in hospital being treated for something else
- mucosal injury d/t inhibition of PG production
- usually localized, but may be diffuse

Front 21

What are the clinical signs of acute & chronic R dorsal ulcerative colitis?

Back 21

acute: colic, mild to moderate diarrhea, anorexia, edema (d/t PLE)

chronic: intermittent colic, wt. loss, intermittent diarrhea, anorexia, edema

Front 22

What lab findings are assoc. w/ R dorsal ulcerative colitis?

Back 22

CBC: anemia of chronic inflammation or chronic blood loss, leukocytosis or leucopenia

chem.: panhypoproteinemia
peritoneal fluid: normal to ↑ WBCs

Front 23

How is R dorsal ulcerative colitis diagnosed?

Back 23

R/O other causes

U/S: not very sensitive (can only see ~1/3 or R dorsal colon): thickness > 5 mm: abnormal

Front 24

What is the tx for R dorsal ulcerative colitis?

Back 24

30-60 d. of tx
rest
low fiber roughage: pelleted feed; avoid hay, grain, & grass
psyllium mucilloid: promotes epi healing
misoprostol: promotes mucosal healing
colloids if hypoproteinemic
tx systemic problems: sepsis/endotoxemia
analgesia: butorphanol, fentanyl

Front 25

What is the pathogenesis of gastric ulcer dz (protective & harmful factors)?

Back 25

chemical damage d/t acid & bile salts

predominantly occurs at margo plicatus, but may also occur at antrum, duodenum

protective factors: saliva, roughage mat (buffer), mucus, epithelial integrity (PGs), gastric emptying

harmful factors: disruption of roughage mat, NSAIDs, mucosal ischemia, pooling of acid or bile salts

Front 26

What are some risk factors for

a. squamous gastric ulcers
b. glandular gastric ulcers

Back 26

a. occupation/training: 90% of racehorses, 50% of show horses; intermittent feeding, anorexia, or withholding food; stress
b. illness, post-op colics; gastric outflow obstruction; NSAID toxicity; Helicobacter infection?

Front 27

What are the clinical signs of gastric ulcer dz in

a. adults
b. foals

Back 27

a. colic (chronic, intermittent, or after a meal), occasional hypersalivation, occasional bruxism (grinding teeth), reluctance to eat

b. colic (more common & more severe than in adults), hypersalivation, bruxism, mild non-hemorrhagic diarrhea

Front 28

How is gastric ulcer dz diagnosed?

Back 28

gastric endoscopy: only means of definitive dx

response to therapy

Front 29

What is the tx for gastric ulcer dz?

Back 29

drugs: 2-4 wks of therapy needed
- proton pump inhibitor (omeprazole): tx of choice
- H2 blocker (ranitidine)
- sucralfate: give if signs of colic (promotes healing of glandular mucosa)
- magnesium or aluminum hydroxide (antacid) to relieve acute signs: give if signs of colic
management/diet
- ↓ stall confinement
- frequent feeding: GRAZING
- less grain, more roughage: alfalfa hay
- corn oil (↑ PGE-2), high fat diet?
- modify training

prevention: low dose omeprazole PO daily during training/racing

Front 30

What is the pathophysiology of esophageal obstruction (choke)?

Back 30

functional or mechanical obstruction --> reflux of saliva & food material --> mucosal injury, possible ulceration, stretching of wall, rupture

Front 31

What are some clinical signs of esophageal obstruction?

Back 31

esophageal dysphagia: anorexia, hypersalivation (loss of bicarb, Na), nasal d/c (food material, saliva, water), cough, gagging, extension of neck when eating, swelling in cervical region, dehydration

Front 32

What lab findings are assoc. w/ esophageal obstruction?

Back 32

hemoconcentration: ↑ PCV, TP
electrolyte &

acid/base abnormalities: hyponatremia, hypokalemia, metabolic acidosis

mild azotemia

Front 33

How is esophageal obstruction diagnosed?

Back 33

establish obstruction: clinical signs, ability to pass NG tube (careful: risk of perforation), endoscopy, U/S, rads +/- contrast

look for underlying cause

Front 34

What is the tx for esophageal obstruction?

Back 34

obstruction relief
- lavage:
-single NG tube: standing, sedate w/ detomidine
-double NG tubes (ingress & egress tube), general anesthesia w/ ET tube
sx: rare (FBs, strictures, ruptures, masses)
diet: bran mashes, slurry from pelleted food, avoid hay or grass until function is normal
hydration: IV or rectal administration
- soften the impaction
- replace fluid deficits
- correct electrolyte/acid-base imbalances esophageal motility: ace, X/T, & detomidine or oxytocin

Front 35

What is the pathogenesis & signalment of proliferative enteropathy?

Back 35

- Lawsonia intracellularis infection
- transmission: fecal-oral
- organism promotes epithelial proliferation (hypertrophy) in SI --> malabsorption, PLE

- signalment: 1-6 mo. old

Front 36

What are the clinical signs of proliferative enteropathy?

Back 36

thin, +/- colic, diarrhea +/- melena, peripheral edema

Front 37

How is proliferative enteropathy diagnosed?

Back 37

- U/S
- definitive dx: serology or fecal PCR (specific but very insensitive)
- can do tissue PCR post-mortem

Front 38

What is the tx for proliferative enteropathy?

Back 38

Doxycycline: tx of choice

erythromycin, azithromycin, chloramphenicol also used

supportive care: fluids, colloids

Front 39

What is the pathophysiology & signalment for IBD?

Back 39

- inappropriate immune response to a pathogen or other Ag OR appropriate immune response to a persistent pathogen or other Ag
- depending on segment(s) involved, may have malabsorption syndrome, diarrhea, or both
- many horses w/ R dorsal ulcerative colitis have underlying IBD

signalment: 1-6 yrs old

Front 40

What are the clinical signs of each of these types of IBD?

a. MEED
b. EC
c. GE
d. LPE

Back 40

a. MEED: wt. loss, diarrhea (50%), dermatitis
b. EC: chronic intermittent colic
c. GE: wt. loss, diarrhea (33%), dermatitis
d. LPE: wt. loss, diarrhea (33%)

also peripheral edema, poor appetite

Front 41

What lab findings are assoc. w/ IBD?

Back 41

anemia of chronic inflammation or blood loss
possible leukocytosis: eosinophilia, lymphocytosis depending on dz
+/- ↑ fibrinogen
panhypoproteinemia

Front 42

How is IBD diagnosed?

Back 42

- abd. U/S: look for thick intestines
- carbohydrate absorption test: tests for malabsorption
peritoneal fluid analysis
- intestinal bx: definitive dx (transendoscopic or surgical)
- rectal bx: do if animal has diarrhea

Front 43

What is the tx for IBD?

Back 43

- colloids
- remove Ag source: ex. anthelmintics if eosinophilic dz
- resection of intestines if segmental (EC)
immunosuppression: Dex (tx of choice to begin therapy), prednisolone (long term therapy)

Front 44

What is the pathophysiology of peritonitis?

Back 44

- infection: acute or chronic
- intestinal rupture: acute & usually fatal
- intestinal abscess: Gram (-) enterics or others
- massive inflammatory response
- absorption of bacterial products --> endotoxemia
- fibrin deposition, pocket formation, intestinal adhesions

Front 45

What clinical signs are assoc. w/ peritonitis?

Back 45

wt. loss, pyrexia, anorexia, colic, diarrhea, +/- sepsis

Front 46

How is peritonitis diagnosed?

Back 46

- peritoneal fluid analysis: WBC, protein, glucose, pH
- U/S
- rectal exam

Front 47

What is the tx for peritonitis?

Back 47

broad spectrum ABs
- aminoglycoside + penicillin: 1st choice
- other possibilities: enrofloxacin, doxycycline, chloramphenicol
- add metronidazole if anaerobes suspected (ex. perforation)
tx systemic effects (sepsis), analgesia
abdominal lavage
- done if bacteria seen on cytology, if systemically ill or WBC in peritoneal fluid > 100,00 cells/uL

Front 48

What is the pathophysiology of proximal enteritis?

Back 48

- severe inflammatory dz of duodenum & proximal jejunum
- etiology unknown: Clostridium difficile?, mycotoxins?
- mucosal barrier damage --> inflammation --> hypersecretion, functional ileus, gastric fluid accumulation

Front 49

What are some clinical signs of proximal enteritis?

Back 49

acute colic, fever, signs of sepsis (depression, tachycardia, tachypnea, hyperemic mm, prolonged CRT), dehydration, nasogastric reflux (reddish orange), NO diarrhea

Front 50

What lab findings are assoc. w/ proximal enteritis?

Back 50

CBC: leucopenia followed by leukocytosis, hemoconcentration, ↑ fibrinogen, thrombocytopenia

Chem: hyponatremia, hypochloridemia, hypokalemia, hypocalcemia, metabolic acidosis, +/- abnormal organ function tests (ex. liver)

Front 51

How is proximal enteritis diagnosed?

Back 51

pyrexia, non-turgid distended bowel loops on rectal exam, peritoneal fluid analysis (normal WBC, RBC, ↑ TP), gastric decompression --> ↓ pain, ↓ HR, depression, gastric fluid (fetid, orange-red), large volume), U/S (diameter < 6 cm, wall > 6 mm, little motility)

Front 52

What is the tx for proximal enteritis?

Back 52

gastric decompression
fluid therapy
- IV isotonic fluids: deficit + maintenance + replacement of gastric reflux losses
- electrolytes: K, Ca gluconate, bicarb
- colloids
ABs
- metronidazole: Clostridiosis is possible etiology
- broad spectrum AB if severe neutropenia
analgesia/anti-inflammatory
- lidocaine: tx of choice
- flunixin: risk of potentiating mucosal damage
- butorphanol: CRI
tx sepsis/endotoxemia
mucosal protectants: ranitidine, omeprazole
prokinetics
- lidocaine: tx of choice
- metoclopramide: 2nd choice
- erythromycin: 3rd choice
nutrition
- NPO while refluxing > 2-4 L/4 hrs
- gradually put back on food
- parenteral nutrition if NPO > 72 hrs

Front 53

ddx for intermittent colic w/ or w/o weight loss

Back 53

R dorsal ulcerative colitis, obstructive GI dz, gastric ulcers, IBD, neoplasia, sand enteropathy, parasites (cyathosomes), peritonitis, dental dz, EIA

Front 54

ddx for intermittent colic w/ bruxism or salivation

Back 54

gastric ulcers, gastric neoplasia, gastric impaction, esophagitis, gastric outflow obstruction, R dorsal ulcerative colitis

Front 55

ddx for esophageal dysphagia

Back 55

obstructive
-intraluminal: simple impaction or FB
-extraluminal: intramural mass (ex. SCC), extramural mass (ex. abscess or tumor), vascular ring anomaly, congenital anomaly, stricture, diverticulum
-functional: esophagitis

neuromuscular: CN 9 or 10 dysfunction, botulism, selenium/vitamin E deficiency, megaesophagus

pain: esophagitis

Front 56

ddx for proximal enteritis signs

Back 56

proximal enteritis, peritonitis, small intestinal obstruction (strangulating or non-strangulating), gastric outflow obstruction, Salmonellosis

Front 57

ddx for weight loss w/ or w/o colic

Back 57

IBD, parasites, malnutrition, liver dz, renal failure, EIA, neoplasia, intra-abdominal abscess, dental dz, sand enteropathy, gastric ulcers, chronic dz of other systems