Colic in Horses - LA Exploratory Celiotomy

Question 1

6 causes of colic

Answer 1

1. Distension of a hollow abdominal viscus with fluid, gas, or solid material.
2. Tension on the mesentery.
3. Intestinal ischemia without 1 or 2 might cause pain.
4. Acute leakage of intestinal contents.
5. Gastric ulceration.
6. Combinations of 1 through 5.

Question 2

Signs of strangulating lesion-induced endotoxemia are due to what? What are some clinical signs?

Answer 2

when the lipopolysaccharide or endotoxin component of the outer wall of enteric gram-negative microorganisms from the intestinal lumen gains access to the circulation; profound vasoconstriction, pulm hypertension, incr RR, dyspnea, then vasodilation and hypotension

Question 3

What is repercussion injury and what is the proposed mechanism behind it?

Answer 3

exacerbation of tissue damage that occurs when ischemic
tissue is reoxygenated, as after surgical correction of a strangulating lesion and leaving the bowel in place; tissue damage is initiated by release of reactive oxygen molecules (xanthine dehydrogenase —-> xanthine oxidase) and exacerbated by neutrophils; seen in SI more often

Question 4

What parts of the horse’s GI tract cannot be exteriorized?

Answer 4

a. Stomach
b. Duodenum
c. Jejunum (first 10-12 inches)
d. Ileocecal junction
e. Ileum (distal 10-12 inches)
f. Transverse colon
g. Base of cecum
h. Cecocolic junction
i. Terminal part of right dorsal colon

Question 5

How many bands are on each segment of horse intestine?

Answer 5

• Cecum, R and L ventral: 4
• L dorsal: 1
• R dorsal: 3
• Small colon: 2 - fat, short mesentery

Question 6

What’s the most common cause of colic in horses?

Answer 6

impaction (pelvic flexure > small colon > R dorsal colon > cecal; ileal in SE US)

Question 7

Which type of impaction has the greatest risk of pressure necrosis? Rupture?

Answer 7

• Pressure necrosis: small colon >>>> R dorsal colon > pelvic flexure (Rare)
• Rupture: cecum >>> R dorsal

Question 8

What are the 2 types of cecal impaction?

Answer 8

• dehydrated mass fills the cecum and causes moderate distention, but gas or fluid can pass into the colon, producing scant soft feces.
• cecal dysfunction or cecal stasis- cecum is markedly distended with fluid contents.
• The dehydrated impaction should be treated medically if possible, whereas surgery is often needed for cecal dysfunction.

Question 9

Mesenteric volvulus typically occurs in what direction and at what level?

Answer 9

clockwise when looking at horse from the back and at the level of the cecocolic fold or at the start/end of the large colon

Question 10

What are two nonstrangulating infarctions of the large colon?

Answer 10

1. Thromboembolism
2. mesenteric adhesions and segmental ischemia of the small colon (postpartum mares)

*both present with peritonitis and low-grade comics

Question 11

The degree of pain a horse is in typically ______ when going into endotoxic shock

Answer 11

decreases

Question 12

Old horse with colic and small intestinal distension has what until proven otherwise?

Answer 12

Strangulating lipoma

Question 13

Cribbers are at risk for this disease more than any other horse

Answer 13

entraptment in the epiploic foramen

Question 14

In inguinal hernias, what critical structure must the bowel first traverse for this to occur?

Answer 14

the vaginal ring (passes in vaginal tunic thru inguinal canal > thru ext/int vaginal rings)

Question 15

What are your post-operative fever rule outs?

Answer 15

• incisional infection
• pneumonia
• thrombophlebitis
• enteritis/colitis
• peritonitis
• anhydrosis