Chapter 35 - Jejunum and ileum Flashcards
1
Q
What is the average length of the equine small intestine?
A
The equine small intestine varies from 10 to 30 m in length, with an average length of approximately 25 m.
2
Q
- Where is the duodenojejunal flexure located, and what does it mark the junction of?
A
The duodenojejunal flexure is located on the left side of the dorsal abdomen, marking the junction of the duodenum and jejunum.
3
Q
Describe the location of the jejunum in the equine abdomen.
A
The jejunum is situated mainly in the left dorsal quadrant of the abdomen, between loops of the small colon.
4
Q
What provides arterial supply to the jejunum, and what is the structure of the vascular arcades in the mesojejunum?
A
The cranial mesenteric artery provides arterial supply to the jejunum. Vascular arcades in the long mesojejunum are composed of a major jejunal vessel, an arcuate vessel, and several vasa recta.
5
Q
A
5
Q
How is the length of the ileum marked, and what attaches its antimesenteric side to the dorsal band of the cecum?
A
The length of the ileum is marked by the distinct ileocecal fold, and its antimesenteric side is attached to the dorsal band of the cecum.
6
Q
What forms the papilla of the terminal ileum, and where is the ileal orifice located?
A
7
Q
Describe the muscle composition of the ileocecal papilla.
A
The muscle of the ileocecal papilla is composed of 3 layers:
an inner circular layer,
a central longitudinal muscle layer from the ileum,
and an outer layer formed from the circular muscle of the cecum
8
Q
```
Does the ileocecal papilla have a true sphincter?
A
No, the ileocecal papilla lacks a true sphincter, although the lumen of the ileum appears reduced at the ileocecal junction.
9
Q
What cells constitute about 90% of the small intestinal epithelial cells, and what is their turnover time?
A
Columnar absorptive cells or enterocytes constitute about 90% of the small intestinal epithelial cells, and their turnover time is usually 2 to 3 days.
10
Q
What is unique to the small intestine in adults regarding its epithelial surface?
A
Unique to the small intestine in adults are fingerlike projections of the epithelial surface called villi, each surrounded by approximately six to nine crypts of Lieberkühn.
11
Q
What is the primary function of the villi in the small intestine?
A
Villi in the small intestine function in the digestion and absorption of nutrients.
11
Q
What are the primary components of the small intestinal epithelial cells, aside from enterocytes?
A
Aside from enterocytes, small intestinal epithelial cells include mucous (goblet) cells, enteroendocrine cells, Paneth cells, and undifferentiated columnar cells.
12
Q
How are mature absorptive cells (columnar cells) formed, and what is their turnover time?
A
Mature absorptive cells migrate onto the villus as mature absorptive cells after at least two divisions within the crypt, and they are extruded at the villous tip with a turnover time of 2 to 3 days.
13
Q
What structures form the brush border membrane on the apical surface of a mature enterocyte?
A
Microvilli form the brush border membrane on the apical surface of a mature enterocyte.
14
Q
What is the function of tight junctions in enterocytes?
A
ight junctions restrict the transmucosal flux of large molecules but are permeable to water and many low-molecular-weight substances.
14
Q
What is the primary mechanism for absorption of Na+ and Cl− in the small intestine?
A
The cotransport of Na+ and Cl− through a carrier mechanism on the luminal membrane is the primary mechanism for absorption of these ions in the small intestine.
15
Q
How is the release of secretin stimulated, and what is its role in pancreatic secretion?
A
Secretin is released from S-cells in the duodenal mucosa in response to hydrogen ions in the duodenum. Secretin stimulates the pancreas and liver to secrete bicarbonate (HCO3−) and water.
16
Q
What is the role of cholecystokinin (CCK) in pancreatic secretion?
A
Protein and fat in the duodenum stimulate the release of cholecystokinin (CCK) from I-cells in the duodenal mucosa. CCK causes the pancreas to secrete enzymes for the digestion of carbohydrates, fat, and protein.
17
Q
How do bile salts aid in fat absorption, and what is the fate of bile salts in the small intestine?
A
Bile salts aid in fat absorption by emulsifying fat in the small intestine.
Approximately 94% of bile salts are reabsorbed by the small intestinal mucosa, pass to the liver, and are resecreted, creating enterohepatic circulation.
18
Q
Where does the bulk of water absorption in the small intestine occur, and what are the routes for transepithelial movement of ions and water?
A
The bulk of water absorption in the small intestine occurs in its distal third region, but Na+ and water absorption in the small intestine is important for nutrient absorption. The routes for transepithelial movement of ions and water are through the cells (transcellular) and through the paracellular space (extracellular).
19
Q
Which hormone stimulates the release of bicarbonate and water from the pancreas and liver?
A
Secretin.
20
Q
Which transporter is responsible for D-glucose and D-galactose uptake in the enterocytes?
A
SGLT1 (sodium-glucose cotransporter type 1).
21
Q
How does fructose move into the enterocyte?
A
Through facilitated diffusion via the GLUT5 transporter.
22
What effect does a dietary increase in soluble carbohydrates have on glucose transport in horses?
It increases glucose transport rates and SGLT1 expression.
23
What is responsible for the solubilization of lipids in the small intestine?
formation of water-soluble mixed micelles with bile acids.
24
What are the two basic components of myoelectrical activity in gastrointestinal smooth muscle?
Slow waves and action potentials.
25
What is the role of the migrating motor complex (MMC) in the small intestine?
Reducing bacterial colonization during the interdigestive state.
26
Which peptide regulates the interdigestive migrating motor complex?
Motilin.
27
How is iron stored in the body when combined with an intracellular protein?
As ferritin.
28
What can decrease calcium absorption in the small intestine?
**High concentration** of **dietary magnesium** competing for the calcium transport site.
29
What are the end products of starch digestion by amylase?
A. D-glucose, D-fructose, and D-galactose
B. Maltose and lactose
C. Sucrose and maltase
D. Amylose and amylopectin
D-glucose, D-fructose, and D-galactose
29
In horses on a grass-based diet, where is sucrase activity comparable to other nonruminants?
Jejunum
30
What is the major site of D-glucose uptake by the SGLT1 transporter in grass-fed horses?
Duodenum
31
How does fructose move from the lumen into the cell in horses?
Facilitated diffusion through GLUT5
32
What is the primary transporter for D-glucose and D-galactose across the enterocyte membrane?
SGLT1
33
How does the dietary increase in soluble carbohydrates affect glucose transport along the equine small intestine?
Increases throughout the small intestine
34
What is the effect of a gradual switch in hydrolyzable carbohydrate in the diet from low to high?
Increases SGLT1 expression
35
How are small neutral peptides further broken down in the enterocyte?
By brush border oligopeptidases
35
How do dipeptides and tripeptides enter the portal circulation from the enterocyte?
By facilitated diffusion
36
What facilitates the movement of lipids through the unstirred water layer to the brush border?
Mixed micelles
37
What is the primary site for fat digestion in horses?
Jejunum
38
How is fat digestion in horses affected by the composition of the diet?
Highest for added triglycerides
39
How is iron transported out of the cell if no binding protein is available?
Through transferrin receptors
40
What regulates the protein that complexes with absorbed calcium in the enterocyte?
Vitamin D
41
What percentage of magnesium absorption is approximately observed in growing foals and mature ponies?
40-70%
42
What cells secrete an almost pure extracellular fluid over the mucosal surface of the small intestine?
Crypts of Lieberkühn
43
What is the primary determinant of intestinal water and electrolyte secretion?
Chloride secretion
44
What plays an important role in reducing bacterial colonization in the small intestine during an interdigestive state?
MMC (Migrating Motor Complex
45
Which receptors mediate sympathetic relaxation of ileal smooth muscle in horses?
α1-adrenergic receptors
46
What are the non-strangulating lesions in the SI?
Ileal impaction
Proximal enteritis
Ileal muscular hypertrophy
47
What are the strangulating lesions in the SI?
Pedunculated lipoma
Epiploic foramen entrapment
Volvulus
Volvulus (foals)
Inguinal/scrotal hernia
Intussusception (all types)
Intussusception (ileocecal)
Mesenteric rent
Gastrosplenic ligament entrapment
Umbilical hernia
48
What is the prevalence range of small intestinal diseases among colic cases treated at veterinary hospitals?
A. 25% to 34%
B. 34% to 58%
C. 58% to 85%
D. 85% to 100%
C. 58% to 85%
48
What is the most common cause of nonstrangulating obstruction of the equine small intestine?
A. Ileal impaction
B. Muscular hypertrophy
C. Ascarid impactions
D. Duodenitis–proximal jejunitis
Ileal impaction
49
In which region of the United States is ileal impaction more prevalent, and what may be related to its high prevalence in that area?
Ileal impaction is more prevalent in the Southeast region of the United States, and its high prevalence may be related to feeding coastal Bermuda grass hay.
50
What is the primary medical treatment for ileal impaction, and what are the key components of this treatment?
The primary medical treatment for ileal impaction includes a balanced electrolyte solution administered intravenously and flunixin meglumine, along with mineral oil if gastric reflux has ceased.
51
How is ileal impaction diagnosed, and what can be palpated per rectum in cases of ileal impaction?
Ileal impaction is diagnosed through rectal palpation and ultrasonographic examination. The impacted ileum can be palpated per rectum as a smooth, tubular obstruction.
52
What complications may arise if the diagnosis of ileal impaction is delayed, and what is the prognosis for horses treated surgically versus medically?
Complications include ileus, gastric rupture, mucosal necrosis, perforation of the ileum, and laminitis. The prognosis is favorable, with a higher success rate for medical treatment compared to surgery.
53
What is the cause of muscular hypertrophy of the ileum, and how is it different from muscular hypertrophy proximal to a chronic obstruction?
Muscular hypertrophy of the ileum is considered idiopathic. It causes marked luminal constriction and is different from muscular hypertrophy proximal to a chronic obstruction.
53
What are the clinical signs and diagnostic methods for detecting muscular hypertrophy of the ileum?
Clinical signs include **recurrent colic.**
**Diagnostic methods** include **rectal palpation** and **abdominal ultrasonography,** which can show severe annular thickening in the muscle wall
54
How do Parascaris equorum infections contribute to small intestinal obstructions in foals, and what are the recommended treatments?
**P. equorum infections** can cause **impactions, intussusception, abscessation, and rupture in foals**.
Recommended treatments include **enterotomy or resection if the bowel is devitalized.**
54
# SI
Figure 35-5. Removal of impacted ascarids through an enterotomy
in the jejunum. Note that small intestine on the left is dimpled at sites where ascarids remain attached as they are drawn through the incision.
55
What is the prevalence of duodenitis–proximal jejunitis (DPJ) among small intestinal colics, and how does it manifest clinically?
The prevalence of DPJ is 3% to 22% among small intestinal colics. Clinically, it manifests as nasogastric reflux of a large volume of fluid, signs of pain, and subsequent depression.
56
Describe the diagnostic hallmarks of DPJ, including clinical signs, rectal examination findings, and laboratory parameters.
Diagnostic hallmarks include:
**nasogastric reflux**,
**tachycardia**,
**prerenal azotemia**,
**dehydration,
hypotension,
electrolyte abnormalities,
fever,
leukocytosis,
and higher liver enzyme activities.**
57
How does medical treatment differ from surgical treatment for DPJ?
Medical treatment involves frequent gastric decompression, correction of water and electrolyte disturbances.
58
DPJ is considered sx in how % of cases? Prognosis factors?
Surgery is considered in **6%** of cases. Prognosis is influenced by factors like **anion gap, abdominal fluid total protein, and gastric reflux volume.**
59
What are the complications and risks associated with surgery in DPJ cases, and how do survival rates compare between medical and surgical treatments?
Surgical complications include l**ower survival rate**s and a **higher likelihood of diarrhea**.
Survival rates are similar between medical and surgical treatments.
59
What are the potential causes of liver damage in horses with DPJ, and how is this damage manifested?
Liver damage causes may include r**eflux of duodenal contents, ascending infection, endotoxin absorption, or hepatic hypoxia.**
Manifestations include congestion, vacuolization, periportal fibrosis, and necrotizing hepatitis
60
What preventive measures are recommended for avoiding ascarid impactions in foals, and what is the significance of anthelmintic resistance?
Prevention involves a sound deworming program using effective anthelmintics and monitoring with fecal egg counts. Anthelmintic resistance is significant, emphasizing the importance of proper deworming practices.
61
How can ultrasonographic examination be useful in diagnosing ascarid impactions, and what are the possible postoperative complications?
Ultrasonography can show ascarids in the small intestine.
Postoperative complications include focal necrotizing enteritis, peritonitis, abscess formation, and adhesions.
62
In the context of ileal impaction, what medical treatment is recommended, and what criteria indicate the need for surgery?
Medical treatment involves balanced electrolyte solution, flunixin meglumine, and mineral oil. Surgery is indicated if there's persistent pain, gastric reflux, or peritoneal fluid abnormalities.
63
what feeding practices are associated with an increased risk of DPJ?
eeding practices associated with an increased risk include more concentrate and grazing on pasture.
64
IIn the case of DPJ, what factors are associated with death, and what complications may necessitate euthanasia in protracted cases?
Factors associated with death include anion gap, abdominal fluid total protein, and gastric reflux volume.
Complications leading to euthanasia include laminitis and the considerable cost of prolonged medical treatment.
65
What is the most common type of neoplasm causing intestinal obstruction in horses?
Alimentary lymphoma
66
Which breed of horses is reported to be 4.5 times more likely to have a diagnosis of intestinal neoplasia?
Arabians
67
What is the most common segment of the intestine affected by neoplasms?
Small intestine
68
What are the most consistent clinical signs in horses with intestinal neoplasia?
Poor body condition and diarrhea
69
How is an antemortem diagnosis of intestinal neoplasia typically made?
Rectal biopsy and ultrasonographic examination
70
What neoplasm can be curatively treated by resection, but is generally a multiorgan disease with a grave prognosis?
Alimentary lymphoma
71
What disease, characterized by inflammation in the small intestinal wall, is caused by Lawsonia intracellularis infection?
Equine proliferative enteropathy from Lawsonia intracellularis infection
71
What transmissible disease causes weight loss, colic, fever, and diarrhea in weanling foals?
Lawsonia intracellularis infection
72
What idiopathic disease is characterized by one or several circumferential mural bands causing obstruction in the small intestine?
Idiopathic Focal Eosinophilic Enteritis (IFEE)
73
In what age group are horses at the greatest risk for IFEE?
0-5 years
74
What disease is most relevant to the diagnosis of colic due to acute manifestations resembling small intestinal obstruction?
Intestinal neoplasia
75
What is the primary relevance of grass sickness (EGS) to colic surgery?
The acute form resembles some forms of small intestinal obstruction
76
What is one of the common causes of impactions in the jejunum?
Trichophytobezoar
77
What causes jejunal obstruction by forming a solid phytobezoar when exposed to gastric acid?
Persimmon fruit
77
What is a common complication of wire ingestion in horses?
Mucosal necrosis
78
Which benign tumor is one of the most common causes of colic in older horses?
Pedunculated lipoma
78
What type of lesions are formed in idiopathic focal eosinophilic enteritis (IFEE) that cause jejunal obstruction?
Circumferential mural bands
78
Where does the pedunculated lipoma cause strangulating obstruction when the pedicle wraps around the intestine and its mesentery?
Small intestine
79
What was once proposed as a predisposition to epipolic foramen entrapment (EFE) in old horses?
A. Atrophy of the left liver lobe
B. Enlargement of the epiploic foramen with age
C. Colon-related colic
D. Gastric reflux
B.Enlargement of epiploic forman with age, but not confirmed in studies
80
what has been reported as a predisposing factor for epiploic foramen entrapment (EFE)?
Cribbing behaviour
81
What is mentioned as a potential role of stabling in causing EFE?
Increased intraabdominal pressure
82
According to the text, what is the first indication of injury to the portal vein during surgery for EFE?
Presence of dark venous blood
82
In a prospective case-control study, which factor is NOT mentioned as increasing the risk of EFE?
Easily frightened behavior
83
What is reported as a complication of EFE correction?
Rupture of the portal vein
hepatic artery and caudal vena cava also present
84
Wanstrath VS 2023 published surgical enlargment of epiploic foramen in horses What is the direction of most epiploic foramen entrapments (EFE) in horses?
A. Right to left
B. Left to right
C. Ventral to dorsal
D. Cranial to caudal
B. Left to right
EpipLoic foRamen
85
Wanstrath VS 2023 What is one risk associated with prolonged surgeries to correct EFE in horses?
A. Portal vein thickening
B. Increased likelihood of intestinal strangulation
C. Decreased prognosis for survival and increased complications
D. Failure to visualize the hepatoduodenal ligament
C. Decreased prognosis for survival and increased complications
86
Wanstrath What percentage of all surgical colic cases in horses is caused by epiploic foramen entrapment (EFE)?
A. 3%
B. 5%
C. 12%
D. 14%
B. 5%
87
FIGURE 2 Start of digital dissection at the caudal edge of the
foramen. a = Caudate lobe, b = right dorsal colon, and
c = approximate location of the portal vein
FIGURE
87
FIGURE 3 Completed dissection to enlarge the epiploic
foramen (EF) at necropsy of a healthy horse, not included in the
study. a = pancreas, b = caudate lobe, and c = right dorsal colon.
The right arrow indicates the approximate location of the portal
vein and the cranial end of the EF. The white dot represents the
caudal end of the EF initially and the point from which the
dissection starts in a caudal direction (to the left). The two short
arrows indicate the extent to which the EF can be opened by fascial
separation, exaggerated beyond clinical relevance to demonstrate
what is possible
87
FIGURE 1 Anatomy of epiploic foramen (EF) relevant to
enlargement. a = right kidney, b = caudate lobe, c = duodenum
and d = the right dorsal colon. The broken line is the line of
dissection to separate the caudate lobe from its attachments. The
arrow indicates the approximate location of the portal vein, remote
to the line of dissection. Cranial is to the right, dorsal to the top
88
Describe the digital dissection according to Wanstrath 2023
The caudate lobe of the liver was identified and traced to the **thin fascia **connecting it to the **gastropancreatic
fold, pancreas, and right dorsal colon** in the EF (Figure 1). This fold was digitally penetrated at its attachment
to the **caudate lobe to open the fascia** and underlying
fat and to separate caudate lobe from right kidney, pancreas, and right dorsal colon (Figure 2). Continued digital dissection towards the right kidney along the perirenal
space and close to the caudate lobe enlarged the EF (Figure 1 and Figure 3)
89
FIGURE 4 Necropsy image from a clinical case, horse
1, showing partial spontaneous closure of the EF at the caudal edge
(arrow) at 30 days after surgery but leaving an opening sufficient to
accommodate a finger. a = right kidney, b = caudate lobe,
c = duodenum, and d = right dorsal colon beneath the
mesoduodenum. Cranial is to the right, dorsal to the top
90
what are the delimitations of EFE space??
4 cm wide
**craniodorsal** boundary is the visceral surface of the base of the **caudate process of the liver**
**portal vein **and the** gastropancreatic fold** form the caudoventral border of the foramen
91
What is the mesodiverticular band?
A **mesodiverticular band** develops from a **vitelline artery** and associated mesentery that fail to atrophy during early embryonic development.
92
What is Meckel diverticulum, and where is it usually located in the small intestine?
Meckel diverticulum is a remnant of the omphalomesenteric (vitelline) duct and forms a conical blind extension from the antimesenteric surface of the distal jejunum or ileum, 40 to 120 cm from the ileocecal junction.
92
mesodiverticulum band where is it typically found in the small intestine?
It is usually found in the **distal jejunum,** approximately **1.5 m from the ileocecal junction.**
92
How does a mesodiverticular band lead to small intestine volvulus?
The band can cause small intestine volvulus by shortening the mesentery at the point of attachment, leading to strangulation and secondary volvulus
93
Describe the potential complications associated with Meckel diverticulum, including its impact on small intestine.
Meckel diverticulum can lead to:
- intestinal obstruction,
- strangulation,
- impaction,
- necrosis,
- and formation of an axis for volvulus nodosus.
93
What is the potential consequence of a vitelloumbilical band associated with Meckel diverticulum?
The vitelloumbilical band is a fibrous band that can persist from the apex of Meckel diverticulum to the umbilicus, creating an axis for volvulus of the jejunum and ileum.
94
Are mesodiverticular bands more likely to be incidental findings during colic surgery or necropsy?
Mesodiverticular bands are more likely to be incidental findings at colic surgery or necropsy.
94
Figure 35-10. Small intestinal volvulus. (A) Diagram. (B) Intraoperative presentation. Note the typical appearance of numerous coils of distended and ischemic small intestine stacked one on another.
94
What is a Littre hernia, and how is it related to Meckel diverticulum in one horse?
Littre hernia was formed when an impacted Meckel diverticulum was found within and adhered to an umbilical hernia in one horse.
95
Figure 35-12. Dissected vaginal tunic in a foal with a congenital scrotal hernia, demonstrating the jejunum and the testicle above it and to the left. The cremaster muscle is evident on the left side.
95
Explain the possible variant of a mesodiverticular band mentioned in the text.
A possible variant of a mesodiverticular band originated at the mesenteric root, blended with the ileocecal fold at the distal ileum, and formed a free edge around which small intestine became entrapped.
95
# si16
Figure 35-11. Direct inguinal hernia in a foal, with massive preputial and scrotal swelling from loops of small intestine beneath the skin. The tunic ruptured, allowing bowel to escape into a subcutaneous position.
96
Figure 35-19. The mesodiverticular band is evident as a thin fold extending to the antimesenteric surface of the jejunum. The jejunum was strangulated in a mesenteric rent at the point of attachment of the band and mesentery.
96
# SI17
Figure 35-20. Meckel diverticulum that was knotted around the jejunum in a 5-month-old Clydesdale foal. The diverticulum was resected and the linear defect in the jejunum was oversewn.
96
What is a vitelloumbilical band, and how can it form in relation to Meckel diverticulum?
In one horse, the right vitelline artery persisted and attached to the ileal mesentery and umbilicus to form a vitelloumbilical band.
97
How does strangulation of a loop of small intestine in an umbilical hernia differ from a parietal hernia?
Strangulation of a loop of small intestine in an umbilical hernia is rare, and the involved intestine can rupture through the hernial sac and dissect subcutaneously.
97
In Ritchers hernia which portion is incarcerated?
only portion of antimesenteric wall of ileum incarcerated
97
What are the common signs of a parietal hernia in horses with an umbilical hernia?
Signs of a parietal hernia include nonreducibility, enlargement, firmness, edema, and pain on palpation.
98
What are the potential causes of diaphragmatic hernias in foals and adult horses?
Causes in foals include congenital defects or tears from rib fractures, while causes in adult horses include trauma, parturition, and strenuous activity.
98
How is ultrasonography used in the evaluation of umbilical hernias in horses?
Ultrasonography may be used to evaluate the hernia and its contents.
99
100
How can large diaphragmatic defects affect horses compared to small defects?
Large defects may cause dyspnea from pulmonary compression but do not incarcerate bowel, while small defects are more likely to strangulate small intestine, causing severe colic.
100
What diagnostic methods can be used for preoperative diagnosis of diaphragmatic hernias in horses?
Both radiography and ultrasonography allow preoperative diagnosis, with ultrasonography potentially being superior in certain cases.
101
What considerations should be taken into account during surgery for diaphragmatic hernias in horses?
Defects in the **ventral aspect **can be accessible from a **ventral midline approach**, while more **dorsal defects **may require** standing laparoscopic surgery.**
102
Describe the surgical techniques for repairing diaphragmatic hernias in horses.
Repair involves closing the defect with **sutures** or** mesh**, with considerations for preoperative diagnosis, anatomical aspects, and controlled ventilation in certain cases.
103
Describe the surgical techniques for repairing diaphragmatic hernias in horses.
Small defect absorbable or non-absorbable sutures and large is prosthetic mesh
1) Ventral hernias (retrosternal hernia) ventral celiotomy extending incision to xyphoid and 30degree Trendelenburg position
2) Dorsal hernias ventral midline celiotomy with thorocatomy of the last ribs
3) Thoracoscopy through 10th intercostal space
104
105
What do you do if the intestine cannot be drawn back through the EF with careful traction or milking of fluid=
When the intestine cannot be drawn back through the EF by these methods, jejunum approximately 1 m proximal to the obstruction must be emptied through an enterotomy or by transection. The lumen of the empty segment of jejunum is closed and that segment can then be drawn through the foramen. After reduction, abnormal bowel is resected to include the transection or the enterotomy sites.
106
What is the short term surivaval for EFE?
short term EFE 95%
lipoma 84%
other miscellaneous strangulating disease 91%
107
Inguinal hernia is in 96% of the cases in stallions, mares, geldings?
stallions (96%), geldings (8%) and mares (2%) can also develop an inguinal hernia.
108
what is the most common type of inguinal hernia? direct or indirect?
involves small intestine passing through the vaginal ring into the vaginal tunic
109
Direct inguinal hernias are common in which type of horses and what portion of intestine?
foals
jejunum into the rent of peritoneum
110
mention the difference btw foals and adults in indirect inguinal hernias
adult are acquired and difficult to reduce and small portion of SI (15cm -ileum
foals are congenital and easy to reduce with large quantity of SI - jejunum
110
size of the external inguinal ring is relevant to development of an inguinal hernia?
NO, size of the external inguinal ring is irrelevant to development of an inguinal hernia because it is the last structure for the bowel to traverse and is always sufficiently large for the intestine to negotiate easily.
111
what are the breeds predisposed to higher prevalence of inguinal/scrotal hernia?
Standardbreds, Tennessee Walking Horses, and American Saddlebreds
112
Congenital indirect scrotal hernias are noted shortly after birth, are easily reduced when the foals are rolled onto their backs, and usually resolve...
usually resolve spontaneously within 3 to 6 months
112
eventration after castration is higher in which breed?
Standardbreds also appear to be at a higher risk for intestinal eventration after an open castration
113
Direct inguinal hernias in foals appears how long after birth?
4 to 48 hours
113
acquired inguinal hernia can be diagnosed how in horses with mild to severe colic?
As it becomes strangulated, the intestine compresses the testicular v**essels and causes the testicle to become swollen, firm, and cold.**
Although the strangulated intestine may not be evident on external examination, **rectal examination** reveals small intestine entering the vaginal ring and distention of the small intestine. **Ultrasonography** can facilitate early diagnosis
114
what are the clinical signs of foals with direct ruptured inguinal hernia (4*48h post foaling)?
intermittent colic, depression, severe scrotal and preputial swelling (see Figure 35-11), and edema, with skin excoriation and splitting caused by abrasion against the inside of the thigh --> surgical emergencies
114
Congenital hernia in foals describe the surgical approach and how to solve the hernia
inguinal approach with exposure of the tunic and its contents (see Figure 35-12), removal of the cremaster muscle, twisting of the testicle and tunic to force the bowel into the abdomen, and then closed castration combined with a transfixation ligature of 0 polydioxanone through the tunic (see Chapter 40). Closure of external inguinal ring optional
114
describe the surgical techniques for congenital hernia repair (names)
1. inguinal approach
2. laparoscopic repair
3. midline celiotomy with closure of vaginal ring
115
acquired hernias can be solved how?
1. **manual reduction** under GA
2. **inguinal incision** directly over external inguinal ring + 3. v**entral midline celiotomy** if needed to tract the bowel
Final closure of the vaginal ring with barbed suture or laparoscopy 1 week later (mesh onlay, cyanoacrylate glue)
116
What are the laparoscopic surgical options for closure of vaginal ring?
1 week after reduction of hernia
1. mesh onlay graft
2. cylindrical mesh plug
3. transposition of peritoneal flap over vaginal ring
117
how can you expose better the tunic edges if you do a inguinal approach?
Medial and cranial retraction on the edge of the internal abdominal oblique muscle with a Deaver retractor will improve exposure to the tunic edges, and a finger is used to direct bowel away from the suture line.
118
why castration is recommend in acquired inguinal hernias?
A unilateral castration is recommended to allow more complete closure of the vaginal tunic and abolish the risk of recurrence.
In addition, the involved testicle can become cystic or nonfunctional in time, and postoperative swelling and inflammation could induce transient degeneration of the other testicle.
119
if vaginal ring is closed during castration and correction of the hernia is the external ring required?
If the vaginal ring can be closed after castration, closure of the external inguinal ring is not essential and does not ensure against evisceratio
120
what is the short term survival for acquired inguinal hernias?
A short-term survival rate of 56% to 85.1%
92% in those treated by closed manual reduction
121
What are the two components of an intussusception?
Intussusceptum and intussuscipiens.
122
Which type of intussusception is most common in horses?
123
What percentage of small intestinal intussusceptions are ileocecal?
Ileocecal intussusception.
124
What parasitic infection is commonly associated with ileocecal intussusception?
Tapeworm (Anoplocephala perfoliata).
125
What is a common cause of chronic, intermittent colic in horses?
Chronic ileocecal intussusception.
126
What type of intussusception often involves long segments of bowel?
Jejunojejunal intussusception.
127
What type of lesion is formed by ileoileal intussusceptions?
A short, doughnut-like lesion.
128
What compensatory changes occur in the jejunum proximal to chronic intussusceptions?
Jejunal dilation, thickened muscular coat, and areas of ecchymosis.
129
Which sex was overrepresented in intussusception cases in one study?
Females (86%).
130
Which breed or type of horse was reported to have a higher risk of intussusception?
Thoroughbred horses and ponies.
131
At what age are intussusceptions most commonly reported as a cause of surgical colic in horses?
3 to 12 months of age.
132
What ultrasonographic feature is characteristic of jejunojejunal or ileocecal intussusceptions?
Concentric rings with a bull’s-eye appearance.
133
What peritoneal fluid finding is associated with acute ileocecal intussusception?
Serosanguineous abdominal fluid.
134
What is a common symptom of short intussusceptions?
Mild, intermittent colic.
135
What diagnostic finding is often palpated per rectum in horses with chronic intussusception?
Large-diameter, moderately distended loops with thick walls.
136
Mesenteric rents there is 2 types: acute and chronic say the difference
In one form, jejunum becomes strangulated in a **very constrictive mesenteric rent** that develops **acutely** in any part of the small intestine, whereas the other form is a more **chronic rent** that develops in the **duodenojejunal mesentery,** typically in **broodmares**
137
Postpartum mares are prone to tears in the mesentery due to
vigorous movements of the foal, as has been implicated in tears of the small colon mesentery.309–312 Such tears in postparturient mares can cause segmental ischemic necrosis of the related segment of jejunum or predispose to later strangulation of a more distant portion of small intestine
JEJUNUM +++
138
Prognosis of mesenteric tears (47%) what are the reasons?
inability to reduce the strangulation,
the long segments of bowel involved,
hemorrhage from the affected mesentery,
failure to close the entire mesenteric defect
139
Strangulation in chronic tears in the duodenojejunal mesentery appears to have an_________prognosis for survival
excellent prognosis
140
mares affected by mesenteric tears get affect and have less foals?
no, affected mares can also have a high rate of successful foalings in the spring following surgery
141
closure of mesenteric tears in mares can be a challange, why?
Complete repair of these rents during a ventral midline approach for the first surgery is difficult because they can extend to the root of the mesentery, where they are inaccessible for closure
Closure can be especially difficult in mid- to late-gestation pregnant mares because of the size of the fetus,
and cesarean section should not be performed
142
Entrapment of small intestine by the gastrosplenic ligament (ESIGL) prevalence
4-11%
143
which horses are more prone to entrapment of SI by gastrosplenic ligament?
geldings middle age and causes larger volume of reflux than other situations
144
what is the origin of gastrosplenic ligament?
a broad but thin attachment between the left part of the greater curvature of the stomach and hilus of the spleen.
145
gastrosplenic ligament vasculature?
major source of blood supply is through the gastroepiploic artery, which originates from the celiac artery and splits into left and right branches.
146
Si passes in the gastrosplenic ligament from R to L or L to R
R to L gastRo Ligament that the strangulated loop is lateral to the stomach and craniolateral to the spleen (Figure 35-18).
147
gratosplenic ligament should be suspect if SI is visible where in the US
distended small intestine detected in the left cranial abdomen between the stomach and sp
jejunum is the segment most likely involved
148
how do you surgically correct gastrosplenic ligament entrapment?
the strangulation is usually easily corrected by traction, and enlarging the rent does not cause problems or predispose to recurrence. The edges of the mesenteric defect are not readily identified at surgery, and so no attempt is made to repair it.
149
gratosplenic ligament prognosis
favorable
150
mention the possible causes of miscellaneous strangulating
uterine torsion
colon mesentery
lateral ligament of urinary bladder
cecocolic fold
mesentery of the large colon
omental adhesions
