Colitis and Enterocolitis

Question 1

Acute Equine Colitis

Answer 1

A general term referring to inflammation of the cecum (typhlitis) and/or colon (colitis) with or without SI involvement (enteritis) with subsequent rapid onset of diarrhea in adult horses and foals

Question 2

Characteristics of colitis-enterocolitis

Answer 2

The horse can have sudden, massive fluid loss and severe electrolyte imbalances that can result in death in a matter of hours

• Unique GI physiology
• Large populations of Gr- bacteria, particularly in the cecum, that are endotoxin sources
• Exquisite sensitivity to endotoxin
• Intestinal prostaglandin production that leads to chloride hypersecretion
• Large population of gastrointestinal leukocytes that initiate and then promote the positive feedbavk cascade of proinflammatory cytokines

Question 3

Colitis-Enterocolitis in adults

Answer 3

Acute adult equine colitis-associated diarrhea:
- Horses between the ages of 2 and 10 years
- Sporadic in occurrence
- Intraluminal sequestration of fluid
- Moderate to severe colic
- Profuse, watery diarrhea
- Endotoxemia, leukopenia, and hypovolemia
Disease onset is sudden with a rapid progression and is often preceded by a stressful event
Definitive Dx is obtained in only about 30-50% of cases

Question 4

Colitis-Enterocolitis in foals

Answer 4

Acute colitis-associated diarrhea:
- Foals of all ages, although specific diagnoses can be age-grouped
- Can occur in outbreaks of in individual cases
- Intraluminal sequestration of fluid
- Moderate to severe colic
- Pasty or profuse, watery diarrhea
- Endotoxemia, leukopenia, and hypovolemia
Disease is often associated with bacteremia or other adverse neonatal conditions
Definitive diagnosis is more common

Question 5

Colitis-Enterocolitis Diarrhea

Answer 5

A result of abnormal fluid and ion transport by cecal and colonic mucosa. Loss of fluid by the large intestine can result from malabsorptive or hypersecretory processes and is often a combination of both

Question 6

CS of colitis- enterocolitis

Answer 6

Depression
Anorexia
Fever
Tachycardia
Dry/sticky mucous membranes
'Toxic' to brick red mucous membranes
Increased skin tent
Prolonged capillary and jugular refill times
Colic
Watery, profuse, frequent, sometimes fetid diarrhea

Question 7

Clin path/biochem of colitis-enterocolitis

Answer 7

Increased PCV
Normo to hypoproteinemia
Acidemia, metabolic acidosis, hyperlactatemia, increased anion gap
Electrolyte derangements (hyponatremia, hypochloremia, hypokalemia, hypocalcemia)
Leukopenia with a left shift, toxic neutrophils, lymphopenia
Azotemia

Question 8

T/F: Fibrinogen concentrations decrease in cases of colitis-enterocolitis and are a useful diagnostic tool

Answer 8

False; normal to increased, so not useful

Question 9

T/F: Hyperammonemia may be seen in colitis-enterocolitis and is a useful diagnostic tool

Answer 9

False; may be seen but is misleading -makes one think hepatoencephalopathy

Question 10

Salmonellosis

Answer 10

Salmonella spp associated colitis is of particular concern and should always be ruled out:
- Zoonotic potential
- Potential to lead to a hospital or farm outbreak
Salmonella organisms are intermittently shed and multiple cultures or PCR tests may be necessary for diagnosis:
- Samples for culture or PCR should contain at least 5-10g of feces

Question 11

Potomac Horse Fever Agent

Answer 11

Neorickettsia risticii

Question 12

Potomac Horse Fever CS, Dx, Tx

Answer 12

CS: Biphasic fever, laminitis, and colitis of variable severity
Widespread seasonal disease: associated with proximity to freshwater ponds and streams
Dx: Paired serum titers using immunofluorescent antibody testing techniques, isolation of N risticii from WBCs, PCR of WBCs or feces
Tx: IV oxytetracycline

Question 13

Clostridial/antimicrobial colitis

Answer 13

Clostridium difficile and perfringens have been implicated as etiologic agents of colitis in:

• Farm outbreaks in foals
• Horses treated with antimicrobials
• Mares when their foals are being treated with erythromycin and rifampin for Rhodococcus equi pneumonia
• Untreated horses with diarrhea

Question 14

T/F: Clostridium spp are not common inhabitants of the equine GIT

Answer 14

False; quantitative culture is useful

Question 15

Differentiating C. difficile from other clostridial organisms

Answer 15

• Send several grams of feces
• Immediate submission
• Transporting samples frozen or on ice in airtight containers

Question 16

T/F: Commercially available cytotoxin assays , if positive, may be more suggestive of C. diff associated diarrhea

Answer 16

True

Question 17

T/F: Cryptosporidium and Giardia should not be implicated as a cause of adult acute colitis

Answer 17

True; foals only

Question 18

Common clinical presentation of a horse with colitis-enterocolitis

Answer 18

Electrolyte imbalances, fluid loss, endotoxemia/septicemia

Question 19

Which forms of colitis-enterocolitis are curable?

Answer 19

PHF and possibly Clostridium spp.

Question 20

Fluid therapy for colitis-enterocolitis

Answer 20

Aggressive IV polyionic fluid therapy should be instituted immediately
Total deficit is subjective:
Percent times BW in kg = L deficit
Include estimated on-going losses and normal maintenance with an aim of correction within 12h

Question 21

What is the maximum safe rate of fluid administration in a 450kg adult horse?

Answer 21

10L/h

Question 22

What helps determine if normovolemia has been established?

Answer 22

Central venous pressure (CVP) and serial lactate determinations

Question 23

What are some fluid mixtures that can be made for horses to consume?

Answer 23

Water with baking soda (10g/L)
Water with NaCl/potassium chloride (Lite salt, 6-10g/L)
Water with a commercial electrolyte solution

Question 24

T/F: IV sodium bicarb is a useful solution for acidosis

Answer 24

Falswe; may worsen intracellular acidosis and cause paradoxical CSF acidosis