Diagnostic techniques of equine GIT (Maxwell)

Question 1

Signs of colic in foals

Answer 1

• foal laying on their back “showing their belly”
• non-productive straining
• reluctance to stand and suckle

Question 2

colic etiologies in young horses

Answer 2

• ascarid impaction in SI (often post deworming)
• FB
• ileocecal intussusception (associated with nearby rivers or ponds)

Question 3

colic etiologies in stallions

Answer 3

testicular torsion; inguinal hernia –> entrapped piece of bowel in scrotum

Question 4

colic etiologies in post-partum mare

Answer 4

colon torsion (usually post foaling)

Question 5

colic etiologies in fat middle/old-aged horses

Answer 5

strangulating lipoma

Question 6

colic etiologies in older horses

Answer 6

epiploic foramen entrapment due to hepatic fibrosis & shrinkage

Question 7

colic etiologies in foals

Answer 7

• meconium impaction
• SI volvulus

“meconium” = newborn’s first poop

Question 8

colic etiologies in a horse with traumatic injury on the LEFT side

Answer 8

hemo-abdomen due to splenic trauma

Question 9

Signs of endotoxemia (gram negative infection)

Answer 9

• peripheral perfusion (muddy or purple-looking mm.)
• prolonged CRT
• muzzle cold, ears cold, periphery of limbs cooler to the touch
• horse = clammy (assess skin tent)

Question 10

Measuring lactate to determine perfusion relationship

Answer 10

Tissue hypoxia (due to poor perfusion) causes O2 delivery to exceed demand –> body switches to anaerobic glycolysis for ATP, where lactic acid is a by-product

Question 11

What parts of GIT can you auscultate on right side of horse’s body?

Answer 11

Large colon & cecum

Question 12

What parts of GIT can you ausculate on left side of horse’s body?

Answer 12

Large colon with SI sitting on top

Question 13

Where can sand impaction occur in the horse’s GIT?

Answer 13

ventral part of GIT –> sand impaction in sternal flexure

Question 14

Additional diagnostics that can be performed to determine colic & severity (5)

Answer 14

• Pass NG tube and look for reflux
• Perform a rectal exam
• BW (CBC/Chem, lactate)
• Abdominocentesis
• Abdominal U/S

Question 15

How much volume obtained when refluxing a horse’s NG tube is normal, slightly more than normal, and abnormal?

Answer 15

Normal = < 2L
Slightly High = 2-4L
Abnormal = more than 4L
- do not administer PO meds
- consider leaving NG tube in & refluxing (aspirating) q2h

stomach volume is ~14-16L

Question 16

What is the only true flexure in the equine GIT?

Answer 16

Pelvic flexure

sternal & diaph. flexures will straighten out if you take out intestines

Question 17

Things you may assess on rectal examination of a horse (7)

Answer 17

• position
• motility
• evidence of distension (gas, ingesta, GB)
• bowel wall thickness
• abdominal effusion
• presence of fibrin on serosal wall (feels like grit)
• mass associated w/ abd viscera or LN

Question 18

Risk of rectal exam

Answer 18

rectal tear (can be a life-threatening complication)

Note Grades 3a, 3b, and 4

Question 19

Minimum data base on a horse with suspected colic (4)

Answer 19

Hx, PE, palpation of abdominal viscera (rectal exam), NG intubation and reflux

Question 20

Bloodwork tests and findings for horse with suspected colic

Answer 20

• Leukopenia (due to neutropenia [marginate/stick to wall of vessels] with immature neutrophils//bands)
• PLE (TP shows hypoproteinemia)
• Lactate (increased)

Question 21

Where to tap for abdominocentesis

Answer 21

Low point behind the sternum, off midline, to the right (avoids the spleen)

sterile prep

Question 22

Use of abdominal u/s to assess GI disease in a horse

Answer 22

• nephrosplenic entrapment (none if spleen and LK are touching as normal)
• evaluate gut wall thickness, GI motility and any ascites

Question 23

Gastroscopy: the 5 steps

Answer 23

1. Fast for 12h and remove water 4h before
2. Alpha-2 agonist for sedation
3. Pass 3-meter endoscope tube (just like NG tube) and then inflate once in stomach
4. Examine stomach curvatures, margo plicatus, pylorus, proximal duodenum
5. Deflate stomach w/ active suction

e.g. sedation protocol: tomidine + butorphanol

Question 24

What drug is often administered for pain relief to treat colic in horses?

Answer 24

Flunixin meglumine (Banamine®)

NSAID & COX inhibitor