8/28 - Large Intestine Diseases

Large

Colic of which intestines, which include the cecum, large colon, and small colon, typically have low-moderate pain except in torsions, have no net gastric reflux, and have different blood work results based on the lesion?

Obstruction

Does a LI obstruction or strangulation occur due to cecal impaction, LVC impaction, LDD/RDD, enteroliths, fecoliths, small colon impaction, or thromboembolic colic?

Strangulation

Does a LI obstruction or strangulation occur due to large colon volvulus and strangulating lipoma?

Small

Which colon, large or small, will be affected by strangulating lipomas?

Cecum

An impaction of what component of the LI accounts for 2-5% of all colics, is often not painful until it is very severe, and produces partial anorexia and less manure production? It is associated with change in exercise or surgery, can be easily masked by banamine, and has a high fatality rate due to rupture before clinical signs. Treatment is through medical management (laxatives, IV fluids, cautious pain relief) or surgery (typhlotomy to empty contents), and prognosis is good if caught early.

Large

Impaction of which colon occurs due to luminal narrowing, such as at the pelvic flexure or right dorsal/transverse colon? Risk factors include sudden decrease in exercise, ingestion of coarse feed, meal feeding concentrates, inadequate mastication, poor dental health, insufficient water supply, and reduced water intake.

Pelvic Flexure

An impaction at which part of the large colon produces clinical signs such as mild intermittent colic, decreased appetite, reduced fecal output, dry fecal balls, mild tachycardia, GI sounds still present in the right quadrants, and mild dehydration on initial presentation? It is diagnosed based on history, rectal palpation (firm mass in pelvic inlet), normal ultrasound, NG tube with no reflux, and normal peritoneal fluid. Treatment is using enteral fluid to stimulate reflexes, checking for gastric reflux, using analgesics, and holding off feed until the problem resolves. Magnesium sulfate with the enteral fluids is also important, plus IV fluids if dehydrated, NSAIDs, serial rectal exams, cecal trocharization if serious, and it has excellent prognosis after resolution though feeding should be slow afterward.

Nephrosplenic

What type of entrapment occurs to the left dorsal colon when it is trapped between the spleen and left kidney? This may occur due to colonic gas distention, causing spleen contraction in response to pain, dorsal displacement of the colon, and reengorgement of the spleen hooking the displaced colon. Signs include mild-moderate-severe colic, rectal exam with a non-free nephrosplenic ligament and palpable bands on the LVC coursing dorsocranially to the kidney, visible colon near the kidney on ultrasound, and spleen-colon being the only tissues visible on ultrasound. Treatments can be conservative, phenylephrine/exercise, rolling under anesthesia, and surgical intervention. Prognosis is good with medical treatment.

Conservative

What type of treatment for nephrosplenic entrapment involves NPO, IV fluids, allowing the colon to empty over time, and allowing the horse space to roll around? This lets the problem resolve on its own.

Phenylephrine

What drug, an alpha-1 agonist, is a possible treatment for nephrosplenic entrapment? It causes vasoconstriction and splenic contracture, and can be given diluted in saline. Ideally, the spleen will shrink and allow the displaced colon to bounce off of the ligament, resolving the problem. There is higher risk of internal hemorrhage with this method in horses over 15 years old.

Rolling

Doing what to the horse under general anesthesia is one possible treatment method for nephrosplenic entrapment? It is positioned in right lateral recumbency, then rolled into dorsal recumbency, then rolled into left lateral recumbency. Large colon torsion is possible with this method.

Surgical

What type of intervention is the last method used to treat nephrosplenic entrapment, done only if the other three were unsuccessful? This is when there is persistent pain and severe distention. If the horse gets these chronically, you can ablate the nephrosplenic space.

Right

Displacement of the large colon to which side is relatively common, causing mild-moderate colic, minimal CV compromise, and often requires surgery?

Enteroliths

What substances can cause colic, and are stone formations within the GI tract, due to mineral deposits around a nidus, such as magnesium ammonium phosphate? Risk factors include alfalfa hay with minimal exercise and they are more common in areas with sandy soil, like california, texas, and southwest US. They present with intermittent colic, breed dispositions (Arabian), no palpation on rectal exam, possible visibility on x-ray, and treatment is with surgical removal through a pelvic flexure enterotomy.

Fecoliths

What substances are common causes of colic in miniature horses, due to dietary indiscretion and breed-associated dental problems? Small colon obstruction is the most common, along with concretions of feed material, gas distention/bloat/lack of feces, and treament is with surgical removal.

Small

Impactions of which colon are usually due to impaction of fecal material, such as after dehydration of feces, inspissated fibrous fecal material, or foreign bodies? They are often seasonal and are diagnosed through rectal palpation. Signs include colic (moderate-severe), tympany of the colon and cecum, and signs of endotoxemia. Treatment is with NPO, IV fluids, laxatives, anti-inflammatories, anti-endotoxemic therapy, and surgical resolution is often required.

S. vulgaris

Thromboembolic colic due to infection with what worm (genus letter and species name) whose larvae cause cranial mesenteric arteritis? Migration causes this condition, leading to a colonic infarct, thromboembolic colic, large colon gas distention, and often occurs in horses over a year old. Treatment is with surgical resection, prevention is with ivermectin, and the prepatent period is 6 months.

Ivermectin

What drug is given to prevent S. vulgaris infestation?

6

How many months is the prepatent period for S. vulgaris?