SI Obstruction vs. Strangulation

A 16 year-old pregnant Standardbred mare presents with an acute onset of colic. HR = 64, RR = 32, and she is pawing. CRT = 3 sec, MM are red. Her rectal temp is 101.3F. GI sounds are completely absent, and gastric reflux yielded 16L of brown-yellow fluid. What is the most likely diagnosis?
A. Lawsonia infection
B. Gastric ulcer
C. Uterine Torsion
D. Duodenitis-Proximal Jejunitis
E. Small intestinal volvulus

D. Duodenitis-Proximal Jejunitis

Between obstruction and strangulation, which leads to devitalized bowel which can ultimately result in endotoxemia, hemoconcentration, and dehydration?

Strangulation

What is the major difference between a simple obstruction and strangulation?

Blood supply is intact with simple obstructions

Between obstruction and strangulation, which can see more severe pain that shows brief or no response to analgesia and/or gastric decompression?

Strangulation

In a strangulation case, what are clinical signs associated with cardiovascular deterioration?

- Endotoxemia

- Hemoconcentration

- Dehydration

Between obstruction and strangulation, which sees abnormal peritoneal fluid and gastric reflux?

Strangulation

Between obstruction and strangulation, which sees minimal CV compromise?

Obstruction

Between obstruction and strangulation, which is a surgical emergency?

Strangulation

What are three common differentials for a SI obstruction in a horse?

- Ascarid impaction
- Ileal hypertrophy
- Ileal impaction

What are four common differentials for SI strangulation in a horse?

- Intussusception
- SI volvulus
- Pedunculated lipoma
- Abdominal incarceration (Epiploic foramen, mesenteric rent, inguinal ring hernia, umbilical hernia)

What SI obstructive differential is seen in weanling foals before they develop immunity?

Ascarid impaction

What roundworm causes Ascarid intestinal impaction?

Parascaris equorum

Older foals and weanlings develop immunity to Ascarids by ______ months

18-24 months

What is a clinical history clue that a young horse may be dealing with an Ascarid impaction?

Heavy worm burden and "fast" kill dewormer used
(ascarids are ingested in the pasture by newly grazing horses)

What are four diagnostics to perform with a foal you suspect has an ascarid impaction?

- Simple Hx and signalment
- FEC
- Gastric reflux (with worms)
- Abdominal US

What is the prognosis for a foal with an Ascarid impaction?

Poor
(surgery often required, 10% long term survival due to adhesions)

What medication is there resistance reported in regards to Parascaris equorum?

Ivermectin

What is the TOC for Ascarid prevention?

Fenbendazole

What obstructive disease is associated with Coastal Bermuda Grass most commonly seen in the Southern US?

Ileal impaction

What is the biggest CS seen with an ileal impaction?

Colic
(spasm of the ileum around the impaction and distention of the proximal SI)

The SI will be ________ and peritoneal fluid will be __________ in cases of ileal impaction.

Distended; normal

What is a complication seen with ileal impaction?

Post-op ileus
(likely will see a decrease in feces)

What SI obstructive condition shows recurrent colic (low grade pain for years), inappetance, and weight loss?

Ileal hypertrophy

What is the only treatment for ileal hypertrophy?

Surgery
(ileo- or jejunocecostomy)

Presence of what embryonic remnant may become impacted, leading to chronic colic signs due to impaction or acute/severe colic if SI becomes strangulated?

Meckel Diverticulum