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.
what are the clinical signs of a sand impaction?
chronic poor performance
weight loss
diarrhea
chronic colic
how do you diagnose sand impactions?
- find sand in feces (sleeve)
- ausculte the ventral aspect of the abdomen (close to xiphoid)
- radiographs too
What are predisposing factors for developing sand impaction colic?
horses lower in social order
horses that are greedy eaters
living in sandy region
husbandry (feeding off ground)
how can you treat sand impaction?
medically - fluids, laxatives, NSAIDs, and psyllium for 4 consecutive days.
if unsuccessful, then surgical intervention necessary.
Almost 99% of horses with enteroliths have a history of being fed _________.
alfalfa
prevalence is highest in california
most horses with enterolithiasis have chronic colic signs. How do you diagnose?
radiographs.
what bodily locations are most common for enteroliths?
right dorsal colon**
transverse colon
small colon
what is the treatment for enterolithiasis?
surgical removal via pelvic flexure enterotomy ONLY if the enterolith is small enough.
the risk for peritonitis is very high.
how can you differentiate small colon impactions from ileal impactions?
Has broad tinea along the mesenteric border.
T/f: horses with small colon impactions are much more likely to have diarrhea at presentation compared to horses with large colon impactions
true
how do you treat small colon impactions?
medically – IV lfuids, oral laxatives (epsom salts), NSAIDs, anti-endotoxic tx
if fails, then surgical intervention is necessary.
what is the prognosis for small colon impactions?
good to excellent.
what are clinical signs of meconium impactions?
tenemus
pain
distention
how do you treat meconium impactions?
Enema (Fleet 1st, then acetylcysteine retention enema), laxatives, IV fluids
last resort – surgery.
what anatomic location is predisposed to foreign bodies/masses?
small colon
Adhesions cause (acute/chronic) (intermittent/ consistent) colic
chronic, intermittent
these horses typically have a history of prior surgery (<2 months)
What age horse is at highest risk for adhesion formation?
foals
small intestine is at highest risk.
in what cases would you choose to treat a patient ON THE FARM?
minimal physical exam changes
have a treatable diagnosis
easily manageable pain
short duration (not chronic)
when should you refer?
- nursing care inadequate
- mod-severe dehydration
- physical exam findings deteriorate
- pain increases
- duration longer than expected.
_________ is vascular compromise without strangulation. This can be caused by stongylus vulgaris, severe colitis, or coagulopathies.
thromboembolic colic
wht is the prognosis for thromboembolic colic?
poor/grave
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.?
signs of peritonitis (fever, anorexia, mild colic, scant feces)
what is the treatment for mesocolic rupture?
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)
T/F: the prognosis for all types of mesocolic ruptures is excellent
false –
prog is good if small colon is NOT involved, but guarded if it is involved and R&A has to be performed.
__________ is a benign smooth wall fatty tumor that suspends on a thin mesenteric stalk.
strangulating lipoma
what 2 locations are strangulating lipomas MOST common in?
jejunum
ileum
what are clinical signs and exam findings associated with strangulating lipomas?
severe colic (in acute stage)
serosanguinous abdominal tap
distended loops of small intestine
T/F: strangulating lipoma is one of the most common causes of colic in older horses (14-19y)
true
most are small intestinal, some are small colon.
T/F: in treating strangulating lipomas, you likely have to break the stlk blindly due to the inabiltiy to exteriorize the affected area
true
Why do you have to be extra cautious when reducing an epiploic foramen entrapment?
upard tension can cause damage to the portal vein resulting in death.
T/F: changes in the peritoneal fluid does not always reflect damage to the entrapped bowel in cases of epiploic foramen entrapment.
truue
_________ is the rotation of the jejenum and ileum around its mesentery resulting in ischemia to the bowel.
volvulus
what is the most common indication for surgery to repair volvulus?
being a foal (2-4 months)
in which breeds are inguinal hernias most common in?
standardbreds, tennesse walking, and american saddlebreds.
stallions!
T/F: most inguinal hernias are direct (no vaginal tunic layer involved)
false – most are indirect, within the vaginal tunic laying next to the testicle.
what is the treatment for inguinal hernias in stallions?
hemicastration and closure of the external inguinal ring
How do horses with large colon volvulus typically present?
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
Where does large colon volvulus typically occur?
at the base of the cecum, turns in a counterclockwise fashion
it can also occur at the sternal or diaphragmatic flexure.
what is the treatment for large colon volvulus?
surgery – simple correction +/- enterotomy
can infuse biosponge prior to closing the pelvic flexure enterotomy.
what is the prognosis for large colon volvulus?
guarded to favorable (50-70%)
what are 3 things that predispose horses to intussusceptions?
- enteritis
- parasites (ascarids, tapeworms)
- abrupt dietary change
how do you definitively diagnose intussusception?
surgery.
diagnosis is supported by small intestinal distention and abnormal abdominocentesis
which intussception type has the bets prognosis?
short intussusceptions (ileocecal is most common)
long intussusceptions have poor prognosis bc they are typically strangulating and require R&A
T/F: diaphragmatic hernias are difficult to diagnose pre-op, but they are always surgical cases.
true. they are not always repariable though.
How do you close the linea in horses?
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.
To reduce the incidence of infecton, what should you do with the linea prior to and after closure?
lavage with sterile saline. or bathe it with an antibiotic after closure.
What type of suture is used to close the subcutaneous and the skin layers?
2-0 monofilament absorbable (PDS) and staples (skin)
what type of things are involved in post-op care?
antibiotics
fluids
lidocaine CRI
NSAIDs
Ice boots
Belly Band
Polymixin B
Controlled refeeding
Stall rest 50-60 days with hand walking
T/F: prognosis of most GI cases depends on timely referral / surgery.
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.
