Surgical Disorders of the GI Tract Flashcards
What is the most common approach to equine abdominal exploration surgery?
ventral midline with horse in dorsal recumbency
What are considered “simple obstructions”?
- stomach
- ascarid impactions
- ileal impactions
- cecal impactions
- small colon impactions
- large colon impactions
- meconium impactions
What causes gastric impactions typically?
- 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.
how do you diagnose a gastric impaction?
can be diagnosed by endoscopy, but usually just diagnosed at the time of surgery.
how do you treat a gastric impaction?
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.
what is the most common signalment for ascarid impactions?
foals and weanlings (4-24 months)
there is widespread resistance to ivermectin.
T/F: a foal with an ascarid impaction is treated by doing enterotomy
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).
what is the prognsosis of ascarid impaction cases?
guarded.
The horse can get necrotizing enteritis, adhesion formation, peritonitis, and abscess formation leading to death.
What is the most common NON-strangulating lesion of the equine small intestines?
ileal impaction
it is usually a primary condition in normal ileum.
With what type of grass is there an increased prevalence in ileal impactions?
coastl bermuda grass.
how can you diagnose ileal impaction?
rectal palpation – distention
ultrasound – distention
how can we treat ileal impactions?
medically – IV lfuids and analgesics, massage the impaction and milk it into the cecum
if it doesnt break down on its own –> surgery
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?
coat the bowel and the surgeons hands with carboxymethylcellulose (CMC) “belly jelly”
how can you diagnose cecal impactions?
rectal palpation
what are the 2 types of cecal impactions?
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.
how do you treat cecal impactions?
medically – fluids, laxatives, NSAIDs, prokinetics
if not responding/difficulty controlling pain – surgical (typhlotomy +/- partial bypass +/- cecocolic anastamosis)
if the cecum ruptures –> euthanasia
what is ‘large colon tympany’ and what causes it?
gas colic or spasmodic olic – the most common type of colic caused by excessive gas production
T/F: large colon tympany is usually self-limiting
true
you can provide pain management (banamine), withold feed (12-24 hr), and give buscopan (antispasmodic)
At what 3 locations do large colon impactions most commonly occur?
- left ventral colon
- pelvic flexure
- right dorsal colon at junction of transverse colon
what causes large colon impactions?
- changes in management
- recent/current musculoskeletal injuries
- drugs – atropine, moprhine
T/F: horses with large colon impactions will have decreased fecal output
true
how do you treat large colon impactions?
medically – IV fluids, laxatives, analgesics
if not responding, surgical intervention is recommended.
what are 2 indications of decline in the health of a portion of the GI tract that may be impacted?
lack of response to pain meds
changes in abdominal fluid
how do you diagnose right dorsal displacement?
rectal examination
tinea are felt running horizontally
and you can palpate the absence of the pelvic flexure
___________ 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.
right dorsal displacement
what is the treatment for right dorsal displacement?
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.
T/F: the prognosis for right dorsal colon displacement is poor
false - the prognosis is excellent.
horses can also undergo pexy surgery if they chronically displace their colons.
_________ is colon displacement between the left body wall and the spleen without entrapment
left dorsal displacement
it can migrate dorsally and become entrapped in the nephrosplenic space
how do you diagnose left dorsal displacement?
rectal exam
ultrasound (visualize left kidney against the spleen)
how do you treat left dorsal displacement?
medically - rolling, phenylephrine (causes splenic contraction); successful in 75% of cases
if med management fails – surgical intervention is necessary.
to treat left dorsal displacement, some vets give phenylephrine to cause splenic contraction. What should you warn the owners about administering this medication?
it causes significant hypertension.
what is the most common location for sand impactions?
left ventral colon, but can occur anywhere along the GI tract.