Lecture 7: Abnormal Conditions of Equine Small intestine Flashcards
What are the two classifications of obstructions
- Simple/ nonstrangulating vs strangulating
- Functional vs mechanical
What is a simple/ nonstrangulating obstruction
Blood supply to intestine involved in the obstruction remains patent
How does peritoneal fluid in a simple/ nonstrangulating obstruction look
Grossly normal
What is a strangulating obstruction
Blood supply is constricted/blocked which results in mucosal ischemia injury and endotoxemia
What is a functional obstruction
Lumen of the intestine involved remains patent but motility is altered
No blockage
What is a mechanical obstruction
Lumen is blocked
How does peritoneal fluid look in a strangulating obstruction
Serosanguineous
What are some causes of non-strangulating/ simple obstructions
Ideal impaction, ascarid impaction, enteritis
How does the ileum appear in an ileum impaction
Mostly normal but enlarged- doughy to solid tubular mass that extends ileocecal junction
What can cause ileal impactions
High prevalence related to feeding costal Bermuda grass hay
Regional: southeast US
Risk for ileal impactions increases by recent introduction to __ or feeding ____
Bermuda hay or poor quality hay
What is the pain for ileal impactions attributed to
Spasmodic bowel contraction around impaction- more severe and constant pain as small intestinal distention progresses
What would rectal exam reveal in an ileal impaction
Small intestine distention in right dorsal quadrant behind cecum
What are some rule outs for ileal impactions
Strangulating obstruction, enteritis
What is the treatment for ileal impactions
IV fluids, banamine, mineral oil via NG tube
What is the prognosis for ileal impactions
Favorable if treated early
If delayed: gastric rupture, mucosal necrosis, ileal perforation
What is the main ascarid that affects horses
Parascaris equorum
What age are ascarid impactions common
Foals and young horses
What do ascarid have widespread resistance to
Ivermectins
What is tx for ascarid impaction
Surgery
What is post-operative mortality for ascarid impactions and why
92%- focal necrotizing enteritis, peritonitis, abscess formation, adhesions
Why do you not want to deworm a foal less than 60 days for ascarids
- Want them to develop immunity ~1yr
- Don’t want all worms to die then cause blockage
What are the best drugs to tx ascarid impaction
Oxibendazole> fenbendazole > pyrantel pamoate
What is DPJ
Inflammation of the proximal portion of the small intestine leads to endotoxemia and ileus and thus fluid accumulation in SI and stomach
What type of obstruction is DPJ
Functional
How do you diagnose DPJ
- Large NG reflux
- Severe pain initially then depression
- Tachycardia, pre renal azotemia, dehydration, hypotension, electrolyte abnormalities
- After NG reflux should have pain relief
What is the primary rule out for DPJ
Strangulating lesions
What are the horses with DPJ more likely to have vs strangulating lesion
Fever, leukocytosis, greater volume gastric reflux
What diagnostic can you do to differentiate between DPJ and strangulating lesion
Belly tap
How is the uncleared cell count and total protein concentration in DPJ vs strangulating lesion
Increased to lesser extent in DPJ
What is treatment for DPJ
- Frequent NG tube decompression
- Correct dehydration and electrolyte imbalances- IV fluids with calcium, potassium and magnesium
- Restoration of normal intestinal function
- Tx endotoxemia- banamine and polymixin B
- Ileus- prokinetics- metoclopramide or lidocaine
- Maybe antibiotics
- Laminitis prevention- ice feet, sole support, deep bedding
What do you give horse to prevent/tx endotoxemia post DPJ
Banamine and polymixin B
What do you given horse to tx ileus post DPJ
Prokinetics- metoclopramide and lidocaine
What prognostic indicators associated with death in DPJ
Anion gap, peritoneal fluid total protein concentrations, and volume of gastric reflux in 24hrs
What happens in small intestinal volvulus
Rotation in a segment of jejunum +/- ileum about the mesentery so that the intestine becomes twisted into distinct spirals
What age group are small intestinal volvulus most prevalent in
Foals- most common cause of SI sx in foals
What is the most common indication of colic surgery in foals
Small intestinal volvulus
How do you diagnose small intestinal volvulus
- Degree of pain and heart rate
- Small intestinal distention on rectal palpation (adults) AUS in foals
Do foals have fever or not with small intestinal volvulus
No fever
If fever could be enteritis
What is the treatment for small intestinal volvulus
Surgery- manual correction of volvulus followed by resection and anastomosis
What is the prognosis for small intestinal volvulus
Good
What is an epiploic foramen entrapment
4cm wide entry into vestibule of omental bursa from peritoneal cavity- SI can become entrapped in this space
What are the boundaries for epiploic foramen
Dorsal boundary is caudate process of the liver, portal vein is cranial ventral border and gastropacreatic fold is ventral border
What are the risk factors for epiploic foramen entrapment
Cribbing, hx colic in last 12 months, increased time in stall, greater height
What is treatment for epiploic foramen entrapment
Surgery
What must you be cautious of when correcting epiploic foramen entrapment
Tearing portal vein- death
What is a pedunculated lipoma on SI
Benign, smooth walled fat tumor suspended by a thin mesenteric pedicure- causes strangulating obstruction when pedicure wraps around intestine and mesentery
What contributes to risk of strangulation for penduculated lipoma
Length of stalk
What age group is typically affected by pedunculated lipomas
Older horses
What breeds are at higher risk of pedunculated lipoma
Ponies, Arabians, saddlebreds
What are some rule outs for a pedunculated lipoma
Enteritis, especially if large volume of reflux
You have an Arabian that presents with colic, you suspect strangulating obstruction in SI, what is most likely dx
Pedunculated lipoma
What are the 4 types of intussception and which is most common
- Jejunojejunal
- Jejunoileal
- Ileoileal
- Ileocecal-most common
What are some predisposing factors to intussusception
- Segmental motility differences caused by enteritis
- Heavy ascarid burden
- Abrupt dietary changes
- Tapeworm infection
What is a mesenteric rent
Hole in the mesentery due to congenital, secondary mesodiverticular bands, primary lesion, trauma, mesenteric stretching
Who is most commonly affected by mesenteric rents
Mares- especially post partum
What is prognosis for mesenteric rents
Not good- long segments of bowel involved, hemorrhage, inability to close entire defect
What is the most common form of inguinal/scrotal hernias in horses
Indirect inguinal/scrotal hernias
What is an indirect inguinal/ scrotal hernias
Short segment of SI passes through inguinal ring into vaginal tunic, mild to severe colic and strangulating lesion
Is an indirect inguinal/ scrotal hernia acquired or congenital and nonreducible or reducible
Acquired and non-reducible
What is a direct inguinal/ scrotal hernia
Jejunum escapes through a rent in peritoneum to lie in SQ space of scrotum
T or F: direct inguinal/ scrotal hernias are more common in adults than foals
True
Is a direct inguinal/ scrotal hernia acquired or congenital and nonreducible or reducible
Congenital and reducible
What are some complications of SI strangulating obstructions
- Anastomotic obstruction
- Post-op pain
- Endotoxemia
- Ileus
- Adhesions
- Short bowel syndrome- leads to malabsorption
You are looking at section of ileum- what is wrong
Ileal impaction
What is wrong here? And what is a very concerning differential
small intestine distention- concern for intestinal volvulus
