Surgical Disorders of the GI Tract

Question 1

What is the most common approach to equine abdominal exploration surgery?

Answer 1

ventral midline with horse in dorsal recumbency

Question 2

What are considered “simple obstructions”?

Answer 2

1. stomach
2. ascarid impactions
3. ileal impactions
4. cecal impactions
5. small colon impactions
6. large colon impactions
7. meconium impactions

Question 3

What causes gastric impactions typically?

Answer 3

1. excessive dry fibrous ingesta

can also be: persimmon seeds or mesquite beans, other feeds that swell after ingestion such as wheat, barley, and beet pulp.

Note: dental disease and an inability to chew properly can predispose to impaction.

Question 4

how do you diagnose a gastric impaction?

Answer 4

can be diagnosed by endoscopy, but usually just diagnosed at the time of surgery.

Question 5

how do you treat a gastric impaction?

Answer 5

gastric lavage via NG tube.

it is too difficult to surgically exteriorize and evacuate the stomach. horses are incredibly sensitive to septic peritonitis and endotoxemia.

Question 6

what is the most common signalment for ascarid impactions?

Answer 6

foals and weanlings (4-24 months)

there is widespread resistance to ivermectin.

Question 7

T/F: a foal with an ascarid impaction is treated by doing enterotomy

Answer 7

false – you should milk the ascarids into the cecum and allow the patient to pass them in the feces. doing an enterotomy is more risky and should only be performed in severe cases and if the bowel is devitalized (R&A req).

Question 8

what is the prognsosis of ascarid impaction cases?

Answer 8

guarded.
The horse can get necrotizing enteritis, adhesion formation, peritonitis, and abscess formation leading to death.

Question 9

What is the most common NON-strangulating lesion of the equine small intestines?

Answer 9

ileal impaction

it is usually a primary condition in normal ileum.

Question 10

With what type of grass is there an increased prevalence in ileal impactions?

Answer 10

coastl bermuda grass.

Question 11

how can you diagnose ileal impaction?

Answer 11

rectal palpation – distention

ultrasound – distention

Question 12

how can we treat ileal impactions?

Answer 12

medically – IV lfuids and analgesics, massage the impaction and milk it into the cecum

if it doesnt break down on its own –> surgery

Question 13

which surgical technique can you use when handling the small intestine in order to decrease the chance of adhesions from irritating the serosal surface with your hands?

Answer 13

coat the bowel and the surgeons hands with carboxymethylcellulose (CMC) “belly jelly”

Question 14

how can you diagnose cecal impactions?

Answer 14

rectal palpation

Question 15

what are the 2 types of cecal impactions?

Answer 15

Type 1 - firm ingesta causing the impaction. risk factors include: diet, dentition, coastal hay, changes in feed, decreased exercise, decrease water intake, tapeworms, NSAIDs, and general anesthesia.
This type is more common

Type 2 - cecal dysfunction preventing cecal outflow into the right ventral colon. lumen is filled with gas, ingesta, and fluid and the wall may be edematous. they only start showing signs when cecum is extremely full/about to rupture.

Question 16

how do you treat cecal impactions?

Answer 16

medically – fluids, laxatives, NSAIDs, prokinetics

if not responding/difficulty controlling pain – surgical (typhlotomy +/- partial bypass +/- cecocolic anastamosis)

if the cecum ruptures –> euthanasia

Question 17

what is ‘large colon tympany’ and what causes it?

Answer 17

gas colic or spasmodic olic – the most common type of colic caused by excessive gas production

Question 18

T/F: large colon tympany is usually self-limiting

Answer 18

true

you can provide pain management (banamine), withold feed (12-24 hr), and give buscopan (antispasmodic)

Question 19

At what 3 locations do large colon impactions most commonly occur?

Answer 19

1. left ventral colon
2. pelvic flexure
3. right dorsal colon at junction of transverse colon

Question 20

what causes large colon impactions?

Answer 20

1. changes in management
2. recent/current musculoskeletal injuries
3. drugs – atropine, moprhine

Question 21

T/F: horses with large colon impactions will have decreased fecal output

Answer 21

true

Question 22

how do you treat large colon impactions?

Answer 22

medically – IV fluids, laxatives, analgesics

if not responding, surgical intervention is recommended.

Question 23

what are 2 indications of decline in the health of a portion of the GI tract that may be impacted?

Answer 23

lack of response to pain meds
changes in abdominal fluid

Question 24

how do you diagnose right dorsal displacement?

Answer 24

rectal examination
tinea are felt running horizontally
and you can palpate the absence of the pelvic flexure

Question 25

___________ is a non-strangulating malposition of the R dorsal colon resulting in obstruction to the passage of digesta and has without the disruption of blood supply. It occurs when the colon moves around the base on the cecum such that the section lies between the cecum and the body wall.

Answer 25

right dorsal displacement

Question 26

what is the treatment for right dorsal displacement?

Answer 26

medical -- withhold food, IV fluids, analgesics, light exercise, CRI lidocaine; also perform trocarization of the colon on the right side using a 14g catheter. surgical intervention is med management fails.

Question 27

T/F: the prognosis for right dorsal colon displacement is poor

Answer 27

false - the prognosis is excellent. horses can also undergo pexy surgery if they chronically displace their colons.

Question 28

_________ is colon displacement between the left body wall and the spleen without entrapment

Answer 28

left dorsal displacement it can migrate dorsally and become entrapped in the nephrosplenic space

Question 29

how do you diagnose left dorsal displacement?

Answer 29

rectal exam ultrasound (visualize left kidney against the spleen)

Question 30

how do you treat left dorsal displacement?

Answer 30

medically - rolling, phenylephrine (causes splenic contraction); successful in 75% of cases if med management fails -- surgical intervention is necessary.

Question 31

to treat left dorsal displacement, some vets give phenylephrine to cause splenic contraction. What should you warn the owners about administering this medication?

Answer 31

it causes significant hypertension.

Question 32

what is the most common location for sand impactions?

Answer 32

left ventral colon, but can occur anywhere along the GI tract.

Question 33

what are the clinical signs of a sand impaction?

Answer 33

chronic poor performance weight loss diarrhea chronic colic

Question 34

how do you diagnose sand impactions?

Answer 34

1. find sand in feces (sleeve) 2. ausculte the ventral aspect of the abdomen (close to xiphoid) 3. radiographs too

Question 35

What are predisposing factors for developing sand impaction colic?

Answer 35

horses lower in social order horses that are greedy eaters living in sandy region husbandry (feeding off ground)

Question 36

how can you treat sand impaction?

Answer 36

medically - fluids, laxatives, NSAIDs, and psyllium for 4 consecutive days. if unsuccessful, then surgical intervention necessary.

Question 37

Almost 99% of horses with enteroliths have a history of being fed _________.

Answer 37

alfalfa prevalence is highest in california

Question 38

most horses with enterolithiasis have chronic colic signs. How do you diagnose?

Answer 38

radiographs.

Question 39

what bodily locations are most common for enteroliths?

Answer 39

right dorsal colon** transverse colon small colon

Question 40

what is the treatment for enterolithiasis?

Answer 40

surgical removal via pelvic flexure enterotomy ONLY if the enterolith is small enough. the risk for peritonitis is very high.

Question 41

how can you differentiate small colon impactions from ileal impactions?

Answer 41

Has broad tinea along the mesenteric border.

Question 42

T/f: horses with small colon impactions are much more likely to have diarrhea at presentation compared to horses with large colon impactions

Answer 42

true

Question 43

how do you treat small colon impactions?

Answer 43

medically -- IV lfuids, oral laxatives (epsom salts), NSAIDs, anti-endotoxic tx if fails, then surgical intervention is necessary.

Question 44

what is the prognosis for small colon impactions?

Answer 44

good to excellent.

Question 45

what are clinical signs of meconium impactions?

Answer 45

tenemus pain distention

Question 46

how do you treat meconium impactions?

Answer 46

Enema (Fleet 1st, then acetylcysteine retention enema), laxatives, IV fluids last resort -- surgery.

Question 47

what anatomic location is predisposed to foreign bodies/masses?

Answer 47

small colon

Question 48

Adhesions cause (acute/chronic) (intermittent/ consistent) colic

Answer 48

chronic, intermittent these horses typically have a history of prior surgery (<2 months)

Question 49

What age horse is at highest risk for adhesion formation?

Answer 49

foals small intestine is at highest risk.

Question 50

in what cases would you choose to treat a patient ON THE FARM?

Answer 50

minimal physical exam changes have a treatable diagnosis easily manageable pain short duration (not chronic)

Question 51

when should you refer?

Answer 51

1. nursing care inadequate 2. mod-severe dehydration 3. physical exam findings deteriorate 4. pain increases 5. duration longer than expected.

Question 52

_________ is vascular compromise without strangulation. This can be caused by stongylus vulgaris, severe colitis, or coagulopathies.

Answer 52

thromboembolic colic

Question 53

wht is the prognosis for thromboembolic colic?

Answer 53

poor/grave

Question 54

What are clinical signs of mesocolic rupture of the small colon that can occur post-foaling, straining from diarrhea, intestinal parasites, proctitis, rectal tumors, etc.?

Answer 54

signs of peritonitis (fever, anorexia, mild colic, scant feces)

Question 55

what is the treatment for mesocolic rupture?

Answer 55

if small colon not involved -- reduce and treat the primary problem if small colon is involved, resection is needed (kinda like an external R/A)

Question 56

T/F: the prognosis for all types of mesocolic ruptures is excellent

Answer 56

false -- prog is good if small colon is NOT involved, but guarded if it is involved and R&A has to be performed.

Question 57

__________ is a benign smooth wall fatty tumor that suspends on a thin mesenteric stalk.

Answer 57

strangulating lipoma

Question 58

what 2 locations are strangulating lipomas MOST common in?

Answer 58

jejunum ileum

Question 59

what are clinical signs and exam findings associated with strangulating lipomas?

Answer 59

severe colic (in acute stage) serosanguinous abdominal tap distended loops of small intestine

Question 60

T/F: strangulating lipoma is one of the most common causes of colic in older horses (14-19y)

Answer 60

true most are small intestinal, some are small colon.

Question 61

T/F: in treating strangulating lipomas, you likely have to break the stlk blindly due to the inabiltiy to exteriorize the affected area

Answer 61

true

Question 62

Why do you have to be extra cautious when reducing an epiploic foramen entrapment?

Answer 62

upard tension can cause damage to the portal vein resulting in death.

Question 63

T/F: changes in the peritoneal fluid does not always reflect damage to the entrapped bowel in cases of epiploic foramen entrapment.

Answer 63

truue

Question 64

_________ is the rotation of the jejenum and ileum around its mesentery resulting in ischemia to the bowel.

Answer 64

volvulus

Question 65

what is the most common indication for surgery to repair volvulus?

Answer 65

being a foal (2-4 months)

Question 66

in which breeds are inguinal hernias most common in?

Answer 66

standardbreds, tennesse walking, and american saddlebreds. stallions!

Question 67

T/F: most inguinal hernias are direct (no vaginal tunic layer involved)

Answer 67

false -- most are indirect, within the vaginal tunic laying next to the testicle.

Question 68

what is the treatment for inguinal hernias in stallions?

Answer 68

hemicastration and closure of the external inguinal ring

Question 69

How do horses with large colon volvulus typically present?

Answer 69

in unrelenting pain may display signs of hypovolemic shock and cardiovascular instability. they will be non-responsive to pain control they will have distended abdomens

Question 70

Where does large colon volvulus typically occur?

Answer 70

at the base of the cecum, turns in a counterclockwise fashion it can also occur at the sternal or diaphragmatic flexure.

Question 71

what is the treatment for large colon volvulus?

Answer 71

surgery -- simple correction +/- enterotomy can infuse biosponge prior to closing the pelvic flexure enterotomy.

Question 72

what is the prognosis for large colon volvulus?

Answer 72

guarded to favorable (50-70%)

Question 73

what are 3 things that predispose horses to intussusceptions?

Answer 73

1. enteritis 2. parasites (ascarids, tapeworms) 3. abrupt dietary change

Question 74

how do you definitively diagnose intussusception?

Answer 74

surgery. diagnosis is supported by small intestinal distention and abnormal abdominocentesis

Question 75

which intussception type has the bets prognosis?

Answer 75

short intussusceptions (ileocecal is most common) long intussusceptions have poor prognosis bc they are typically strangulating and require R&A

Question 76

T/F: diaphragmatic hernias are difficult to diagnose pre-op, but they are always surgical cases.

Answer 76

true. they are not always repariable though.

Question 77

How do you close the linea in horses?

Answer 77

Large absorbable multifilament (vicryl) suture (2 or 3) in a simple continous or interrupted pattern, bites placed 1.5 cm away from the wound margin.

Question 78

To reduce the incidence of infecton, what should you do with the linea prior to and after closure?

Answer 78

lavage with sterile saline. or bathe it with an antibiotic after closure.

Question 79

What type of suture is used to close the subcutaneous and the skin layers?

Answer 79

2-0 monofilament absorbable (PDS) and staples (skin)

Question 80

what type of things are involved in post-op care?

Answer 80

antibiotics fluids lidocaine CRI NSAIDs Ice boots Belly Band Polymixin B Controlled refeeding Stall rest 50-60 days with hand walking

Question 81

T/F: prognosis of most GI cases depends on timely referral / surgery.

Answer 81

true referral will be based on pain/worsening pain, declining CV status, and other PE findings such as mod-sev dehydration, reflux, severe distention, or changing abdominal fluid parameters.