Treating Surgical GI Dz

Question 1

What is the most common surgical approach taken for equine abdominal exploratories?

Answer 1

(Ventral midline in dorsal recumbency)

Question 2

Why is it difficult to evacuate the stomach during surgery, resulting in horses needing to be woken up and treated medically?

Answer 2

(Bc you cannot exteriorize the stomach which means you cannot pack it off well enough from the abdominal cavity to prevent leakage and horses just need to look at a picture of a septic abdomen and they’ll get one)

Question 3

What is the typical signalment and presentation associated with an ascarid impaction?

Answer 3

(Foals and weanlings 2-24 months in age, will appear unthrifty, impacting usually occurs after anthelmintic treatment so a hx of recent deworming)

Question 4

Why is the prognosis for ascarid impactions guarded?

Answer 4

(Bc you have two options, milk the ascarids into the cecum which can cause bruising of the serosa leading to enteritis, adhesions formation, abscess formation or you can perform an R&A which can lead to contraction of the bowel lumen since the impaction is typically in the small intestines which already has a small diameter)

Question 5

Where do non-strangulating lesions of the equine small intestines most commonly occur?

Answer 5

(Ileum)

Question 6

What do you expect to see on ultrasound when there is an ileal impaction?

Answer 6

(Distended small intestines)

Question 7

What is used in exploratory surgeries to decrease the chance of adhesions from irritation of the serosal surface?

Answer 7

(Carboxymethylcellulose aka belly jelly)

Question 8

(T/F) Ileal impactions can be treated medically at first and then surgically as needed depending on the response to medical treatment.

Answer 8

(T)

Question 9

Compare and contrast type 1 and 2 cecal impaction.

Answer 9

(Type 1 is associated with normal function of the cecum that fills with firm ingesta that eventually causes an impaction, type 2 is associated with cecal dysfunction that results in decreased to no cecal outflow into the right ventral colon)

Question 10

Why is type 1 cecal impaction called a “silent killer”?

Answer 10

(Bc the horses cecum fills from the apex to the base (bc the apex is ventral and that’s how gravity works), horse will still be eating and defecating until the cecum fills up enough to block flow into the right ventral colon, cecum is usually very full and close to rupture at that time → if cecum ruptures it is a death sentence)

Question 11

How do you assess if medical treatment of a cecal impaction is successful?

Answer 11

(Serial rectal examinations to palpate the cecum and feel if the impaction is changing at all)

Question 12

Compare and contrast the surgical treatments for type 1 vs type 2 cecal impactions.

Answer 12

(Type 1 just needs a typhlotomy to evacuate the cecal contents, type 2 will be a typhlotomy with the addition of either a partial bypass or a cecocolic anastomosis)

Question 13

Where do large colon impactions occur most commonly? Two answers.

Answer 13

(In the left ventral colon at the entrance to the pelvic flexure OR in the right dorsal colon at the entrance to the transverse colon)

Question 14

How are large colon impactions typically diagnosed?

Answer 14

(Rectal palpation)

Question 15

(T/F) Medical management of large colon impactions is typically successful.

Answer 15

(T, entails IV fluids +/- oral fluids, laxatives, and analgesics, if unresponsive → surgery)

Question 16

Which portion of the large colon is the best option for an enterotomy and why?

Answer 16

(Pelvic flexure and because it can be removed from the abdominal cavity the most i.e. best approach for keep crap from getting into the abdominal cavity to cause septic peritonitis and adhesions)

Question 17

(T/F) Right and left dorsal colon displacements are non-strangulating lesions.

Answer 17

(T, can obstruct passage of digesta and gas but they do not disrupt blood supply)

Question 18

What do you expect to palpate per rectum in a case of right dorsal displacement?

Answer 18

(Tenia bands running right to left as opposed to cranial to caudal and you will be unable to palpate the pelvic flexure)

Question 19

If medical management of a right dorsal displacement fails (withholding food, IV fluids, analgesics, light exercise, lidocaine CRI) and surgery is not an option (just putting it back where it belongs, possibly performing an enterotomy to drain fluids from the colon), what else can you do to help the horse?

Answer 19

(Trocharize the colon with a 14G catheter and hope it slips back into place)

Question 20

This is the 3rd time you are seeing a particular horse for a right dorsal colon displacement, what might you suggest to the owner to prevent it from happening again?

Answer 20

(RDC pexy)

Question 21

What drug is used to aid in medical management of left dorsal colon displacements, what does it do that is useful for these cases, and what does it do that can kill the horse?

Answer 21

(Phenylephrine, causes splenic contraction, also causes significant hypertension)

Question 22

This is the 3rd time you are seeing a particular horse for a left dorsal displacement, what might you suggest to the owner to prevent it from happening again?

Answer 22

(Laparoscopic closure of the nephrosplenic space)

Question 23

What portion of the colon is most commonly impacted with sand?

Answer 23

(Left ventral colon, but can accumulate anywhere along the GIT)

Question 24

Most horses with enteroliths have a history of being fed what legume?

Answer 24

(Alfalfa)

Question 25

How do you distinguish between the cecum and small colon per rectal palpation (since they both supposedly feel like sausages)?

Answer 25

(The small colon has an antimesenteric tenia band that the cecum does not have)

Question 26

Why should you make sure the small colon is empty after an R&A?

Answer 26

(Bc if there is feces, the small colon will continue to contract to make fecal balls and that can tear your R&A site, if it is empty it will rest and not do that)

Question 27

What is the most common cause of colic in newborn foals?

Answer 27

(Meconium impactions)

Question 28

What is the treatment for meconium impactions?

Answer 28

(Enema (can used Fleet, soapy water, and/or acetylcysteine), laxatives, and IV fluids; surgery is a last resort bc the chance of tearing something is extremely high)

Question 29

What diseases might result in thromboembolic clots leading to devitalized bowel?

Answer 29

(Strongylus vulgaris migration in the cranial mesenteric arteries, severe colitis, and coagulopathies)

Question 30

Rents in the mesocolon and damage to the mesenteric vessels, resulting in ischemia of the small colon, typically occurs after what event?

Answer 30

(Post foaling)

Question 31

How does the surgical plan and prognosis change for a mesocolic prolapse if the small colon is also prolapsed?

Answer 31

(Surgery is now a small colon resection (if just mesocolon can reduce and tx primary problem) and the prognosis goes from good (just mesocolon is prolapsed) to guarded (when small colon is involved)

Question 32

If a strangulating lesion has resulted in lots of dark bowel that you cannot entirely exteriorize from the abdominal cavity, what are some things you can do to determine whether the dark bowel needs to be removed or not?

Answer 32

(Remove the strangulating lesions and hope it pinks up again, flick it with your finger to try to stimulate peristalsis, inspect the arteries and veins for thrombi, and perform a small pelvic flexure enterotomy and examine the mucosa (if it is black = dead = need to try to remove or euthanize if cannot remove))

Question 33

What is the main determining factor for prognosis associated with strangulating lipomas?

Answer 33

(What portion of the GIT is affected, if you can easily exteriorize prognosis goes up, if not prognosis goes down)

Question 34

In what direction should you avoid pulling intestines that are trapped in the epiploic foramen and why?

Answer 34

(Avoid pulling up, can tear the portal vein and quite literally kill the horse → pull caudal instead bc there are no vessels in that direction)

Question 35

What portion of the GIT is most commonly involved in epiploic foramen entrapment?

Answer 35

(Ileum)

Question 36

Why is the incidence of inguinal hernias higher in standardbreds, Tennessee walking horses, and American saddlebreds?

Answer 36

(They have larger inguinal rings)

Question 37

What is the recommended surgical treatment for inguinal hernias?

Answer 37

(Hemicastration and closure of the external inguinal ring)

Question 38

How do horses with large colon volvulus typically present?

Answer 38

(Unrelenting pain, +/- signs of hypovolemic shock, +/- cardiovascular instability)

Question 39

Intussusceptions typically occur when GIT motility is altered, what are some things that can do that?

Answer 39

(Enteritis, parasites, and abrupt dietary change)

Question 40

(T/F) Diaphragmatic hernias are always surgical but not always repairable in surgery.

Answer 40

(T, sometimes the rents are too deep within the horse to be able to fix, can try but will be blind)

Question 41

What type of suture is most appropriate for closure of the linea alba (aka Dr. Holder’s preference, can be diff.)?

Answer 41

(2-0 or 3-0 absorbable multifilament → vicryl)

Question 42

How long should horses be stall rested post abdominal surgery?

Answer 42

(50-60 days)