Equine GI disease pt 3

Question 1

impaction with foreign body- type, place, Tx

Answer 1

bale twine, usually in transverse or small colon, require surgery

Question 2

fecolith impaction - what is it, where, who is predisposed

Answer 2

inspissated fecal material, usually in small colon, miniature horse and ponies predisposed

Question 3

impaction with sand - where, Tx

Answer 3

• large colon, sand in feces,
• treated with metamucil (psyllium hydrophobic mucilloid)
  <><><><>
  1. Common in horses grazing sandy soils
  2. Sand accumulation at multiple sites (RDC > transverse colon > LDC)
  <><>
  3. Diagnosis
  a. Detect sand in the feces (Feces + water > sand settle at bottom)
  b. Auscultation
  c. Radiographs
  d. May obtain sand on penetration of bowel during abdominocentesis
  <><>
  4. Treatment
  a. Bulk laxatives
  b. Lubricants
  c. Feeding off the ground
  d. Psyllium hydrophobic mucilloid > 300 g daily for a week followed by 300 g/week
  e. Surgery for severe cases

Question 4

enterolith impaction
- what is it?
- where
- Dx
- Tx

Answer 4

• intestinal concretion made of NH4 or Mg3(PO4)2
• usually located at the level of the right dorsal, transverse or small colon,
• radiographs may be useful,
• surgery
  <><><><>
  1. Intestinal Concretions
  2. Deposits of NH4 or Mg3 (PO4)2
  3. Round or tetrahedral
  4. If tetrahedral enteroliths pass in feces others are present
  5. Frequently cause impactions in the RDC (decrease lumen diameter at transverse colon)
  6. May produce intermittent colic (roll into and out of entrance)
  7. Older animals >12 years usually
  8. Often have a nail or other foreign body in the centre
  9. Concentric rings on section
  10. Diagnosis difficult
  a. Usually cannot palpate per rectum
  b. Can be identified by radiography
  c. Diagnosis and treatment usually by exploratory laparotomy and enterotomy

Question 5

meconium impaction
- who affected
- Dx
- Tx

Answer 5

• 1-2 day old foal
• abscence of meconium
• rectal palpation, radiographs
• Tx: enema with soapy water or mineral oil, acetylcysteine, surgery
  <><><><>
  1. Occurs in foals (24 48 hours after birth)
  2. Colts > fillies (narrower pelvis?)
  3. More common on certain farms
  <><>
  4. Clinical Signs
  a. Colic a few hours after birth
  b. Tenesmus
  c. Anorexia
  d. Increased heart and respiratory rates
  e. Absence of the meconium
  f. Gas distended abdomen
  <><>
  5. Diagnosis
  a. Usually feel meconium per rectum with finger
  b. Radiographs
  (1) Radio-opaque mass in the pelvic area or cranial to it
  (2) Gas distension of proximal intestine
  <><>
  6. Treatment
  a. Soapy water or mineral oil enemas run into the rectum by gravity
  b. Be careful! Soap solution irritates the sensitive rectal mucosa
  c. In refractory cases acetylcysteine can be used
  d. If have to repeat procedure use mineral oil or glycerine
  e. Laxatives via nasogastric tube (mineral oil)
  f. Surgery in rare occasion (massage only if possible)

Question 6

tympanic colic
- what is it?
- looks like?
- etiology

Answer 6

A. Form of enteritis characterised by excessive gas formation
B. Sometimes difficult to differentiate from volvulus or torsion
C. Etiology
1. Errors in feeding
2. Working too soon after feeding
3. Ingesting highly fermentable foods
4. Cribbing
5. Frosted feeds
6. Thrombo embolic lesions

Question 7

tympanic colic (gas colic) clinical signs

Answer 7

1. Variable
2. May commence as a mild spasmodic colic > hypermotile gut + increased borborygmi
3. Intestinal intraluminal pressure increased > hypomotility > reflex ileus
4. Colic becomes severe and continuous
5. May be passing gas per rectum
6. In tympanitic state > abdomen distended
7. Percussion of gas on both sides
8. Pulse and respiratory rate increased
9. Dyspnea (severe distension > pressure on diaphragm + decreased venous return > death)

Question 8

tympanic colic diagnosis

Answer 8

1. Per rectum examination
   a. Gas distension of large intestine (cecum and colon)
   b. May not be able to get arm into the rectum
   <><>
2. Abdominocentesis
   a. Increased volume of normal coloured fluid
   b. Easy to enter the lumen of distended bowel

Question 9

tympanic colic treatment

Answer 9

1. Aimed at preventing rupture or displacement of the bowel
2. Lubricants and antiferments (DSS)
3. If severe distension and danger of suffocation of bowel rupture > trocharization
4. Analgesics
5. Surgery in severe cases
   <><>
   - MUST DIFFERENTIATE FROM A VOLVULUS OR TORSION

Question 10

what is incarceration of bowel?
strangulation?
volvulus?
torsion?
> how are these conditions generally diagnosed?

Answer 10

1. Incarceration: section of bowel trapped, but still viable
2. Strangulation: section of bowel trapped, but there is partial or complete vascular occlusion, becomes nonviable with time
3. Volvulus: rotation about the longitudinal axis of the mesentery
4. Torsion: rotation along the long axis of the bowel
5. Majority of the conditions are diagnosed on exploratory laparotomy

Question 11

strangulations
- partial vs complete occlusion

Answer 11

partial occlusions> venous occlusion> Hemorrhagic strangulation

complete occlusion > venous and arterial occlusion > ischemic strangulation

Question 12

pathophysiology of small intestinal obstruction

Answer 12

a. Physical obstruction > lack of passage of fluid or gas into the cecum
b. 125 L of fluid produce in a 450 kg horse/day (saliva, gastric secretion, pancreatic fluid, bile and upper small intestine secretion) > reabsorbed in large colon
c. If small intestine obstructed > fluid accumulation > intraluminal pressure rises > bowel wall secretes more fluid
d. Initially increased intestinal movement to relieve obstruction > decrease of motility > ileus
e. Dehydration occurs due to decrease of reabsorption of fluid in large intestine
f. Fluid reflux into stomach > gastric distension > pain and eventual rupture
g. If strangulation > vascular compromise > necrosis of intestine (mucosa initially) > leakage of protein, rbc’s, bacteria > peritonitis (increased WBC) and endotoxic shock
h. Distal jejunum and ileum most commonly involved

Question 13

Clinical signs of small intestinal obstruction

Answer 13

a. Usually acute onset of colic
b. Very violent initially > intensity decreases when necrosis occurs
c. None to moderate abdominal distension
d. Increased heart and respiratory rates
e. May have gastric reflux at the nostril (not commonly)

Question 14

what do we find on physical exam for small intestinal obstruction

Answer 14

a. Severity of signs depends on state of intestine
b. Increased heart and respiratory rates
c. Mucous membrane pink to cyanotic
d. CRT normal to very prolonged
e. May be in shock (dehydration, metabolic acidosis)

Question 15

what do we find on per rectum exam for small intestinal obstruction

Answer 15

a. Usually cannot feel small intestine
b. +/- small intestine distension
c. Loop of 5-8 cm diameter gas filled

Question 16

what do we see with nasogastric intubation for small intestinal obstruction

Answer 16

a. May have spontaneous or provoked reflux
b. Alkaline pH

Question 17

what might we see on bloodwork and ultrasound for small intestinal obstruction?

Answer 17

a. +/- blood work change
b. Ultrasound
(1) Small intestine distension
(2) Edema of intestinal wall

Question 18

small intestinal obstruction treatment

Answer 18

a. Requires surgery
(1) If intestine compromise > resection necessary
(2) Cannot resect more than 50% of small intestine > chronic weight loss
b. Refer sooner than later > prognosis better because can avoid resection

Question 19

causes of small intestinal obstruction

Answer 19

a. Volvulus**
b. Lipomas**
c. Holes in the mesentery, broad ligament of the uterus or gastrosplenic ligament
d. Umbilical hernia
e. Inguinal hernias**
f. post castration evisceration
<><><>
- diaphragmatic hermia
- herniation through epiploic foramen
- adhesions
- Meckels diverticulum and mesodiverticular bands
- verminous arteritis
- intussusception
> jejunal, ileocecal

Question 20

small intestinal conditions treatment
- watch for what with intestine removal?

Answer 20

surgery
- resection: cannot remove more than 50% of length

Question 21

pathophysiology of large intestine obstruction

Answer 21

a. Similar process as small intestinal lesion
b. Difference > much larger volume of blood trapped in the colon and cecum
c. The submucosal space is large so if edema > weight of colon 3 times that of normal colon (can sequestered up to 22 L of body fluids)
d. Large migration of bacteria through surface area of the bowel > endotoxemic shock
e. Fermentation and haemorrhage within the bowel > abdominal distension, respiratory distress, and impaired venous return
f. If complete strangulation > rapid irreversible damage to bowel (2 hours)

Question 22

large colon obstruction clinical signs

Answer 22

a. Depends of duration of lesion and severity of obstruction
b. Acute or progressive onset of colic
c. None to severe abdominal distension
d. Mild to severe signs of colic

Question 23

diagnostics for large colon obstructoin

Answer 23

• physical exam
• per rectum exam
• nasogastric intubation
  <><>
  Physical exam:
  a. Depends on severity of strangulation and gut compromise
  b. Usually no gastric reflux
  c. Per rectum examination

Question 24

large colon torsion
- who gets this
- signs
- CV issues
- anatomic location
- per rectum feeling
- when for surgery?

Answer 24

• Often seen in mares around parturition
• moderate to severe levels of pain
• rapid cardiovascular deterioration
• most common at the base of cecum
• distension of large intestine on per rectum exam
• > 180 degree torsions require surgery
  <><><><><>
  (1) One of the most common lesions requiring surgery
  (2) Often seen in mares around parturition
  (3) Torsion occurs along the long axis of the LDC, LVC, and the free portion of the RDC and RVC
  (4) Most commonly includes the entire colon (torsion at the base of the cecum)
  (5) May also include the cecum
  (6) If venous and arterial blood supply totally obstructed death can be rapid
  (7) Some horses are predisposed to reoccurrence
  (8) Per rectum examination
  (a) Usually severe distension of large colon
  (b) Tight tenial band
  (9) Analgesics, fluid therapy
  (10) Surgery required so refer rapidly

Question 25

large colon torsion treatment
- what do we do?
- limitations?

Answer 25

• requires surgery
• correction of volvulus +/- evacuation
• Resection: impossible to remove entire colon

Question 26

left dorsal displacement of the large colon
- what is it? what occurs anatomically?

Answer 26

(Nephrosplenic Entrapment)**
(1) Very common form of colic in the Northern areas of N. America and Europe
(2) Nephrosplenic space: space dorsal to the ligament running between the left kidney and the base of the spleen (suspensory ligament of the spleen or nephrosplenic ligament)
(3) LVC and LDC entrapped over the nephrosplenic ligament
(4) Bowel caudal to the entrapment frequently rotated 180 degrees

Question 26

left dorsal displacement of the large colon
- clinical signs

Answer 26

(a) Typified by mild pain and slow progression of signs
(b) Usually degree of pain exhibited related to the degree of gaseous distension in bowel or the weight of food material
(c) HR, RR and T mildly increased
(d) Minimal signs of circulatory disturbance
(e) Occasional severe pain with an unusually low HR (28-60 beats/minute)
(f) May have abdominal distension
(g) May have some gastric reflux
(h) May still pass feces

Question 27

left dorsal displacement of the large colon
- diagnosis
- what do we observe?

Answer 27

Rectal palpation
(a) LVC and LDC usually medial to the spleen
(b) Tight tenial band on left side of abdomen aiming towards the nephrosplenic space (LVC)
(c) Gas +/- food distension of the colon
(d) Pelvic flexure may be displaced cranially
(e) If partial resolution > large colon palpated between body wall and spleen
<><><>
- ultrasound can also be useful

Question 28

left dorsal displacement of the large colon
- treatment
- prognosis

Answer 28

(a) Depends on amount of distension
(b) Spontaneous correction (after transport)
(c) Combination of exercise and phenylephrine (3 ug/kg in 500 ml saline)
(d) Rolling under general anaesthesia (may create other lesions)
(e) Surgical correction via ventral midline exploratory celiotomy
(f) Good prognosis more than 90% survival

Question 29

how does right displacement of the large colon occur?

Answer 29

Retropulsive movement of the pelvic flexure-
> Migration of the left colon cranially
> Migration to the right abdominal quadrant
> Between the cecum and the body wall
> May rotate

Question 30

Right displacement of the large colon
- clinical signs
- what we feel per rectum
- Tx

Answer 30

• Mild to moderate abdominal pain
• Rectal: absence of pelvic flexure
• Large colon lateral to cecum
• Medical therapy
• Surgical for severe cases

Question 31

types of intussusception that cause large intestine obstruction
- commonly associated with?
- what they look like/ signs
- Dx
- Tx

Answer 31

(1) cecal inversion (cecocecal)
(2) ceco colic
(3) Both frequently associated with heavy infestation of the tapeworm Anophlocephala perfoliata
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(4) Cecal inversion
(a) generally does not obstruct the flow of ingesta
(b) Produces a mild continuous colic that may persist for several days
(c) Per rectum palpation: a mass may be palpated in the area of the cecum
(d) None or minor changes on abdominocentesis
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(5) Ceco colic intussusception
(a) Per rectum palpation
i. the ventral band of cecum might be absent
ii. mass may be palpated on the right side of the abdomen
(b) Total obstruction to the flow of ingesta
(c) Animal deteriorates rapidly
<><><>
(6) Surgery required

Question 32

proximal enteritis clinical signs

Answer 32

1. Mild to severe colic
2. Depression usually replaces colic signs after 12 to 14 hours
3. Intermittent pain may appear when stomach becomes distended
4. May have fever (40C), increased HR and RR
5. Gastric reflux always present
   a. Amount varies
   b. Reflux may become chronic (up to 7 days)
   c. pH of the fluid is alkaline
   d. reflux orange yellow in colour
6. Mucous membranes vary from pink to cyanotic
7. Usually no intestinal borborygmi
   - slight distension of SI

Question 33

proximal enteritis rectal, paracentesis, and blood findings

Answer 33

8. Per rectum palpation
   a. S.I. slightly distended from 2.5 to 5.0 cm diameter
   b. Fluid-filled usually
   <><><>
9. Abdominal paracentesis
   a. Total protein may be elevated from 3 to 6 gr/dl
   b. Normal numbers of white cells, some red cells
   <><><>
10. Peripheral blood – leucocytosis usually. May have leucopenia initially.

Question 34

proximal enteritis Tx

Answer 34

a. Difficult to differentiate from other obstructive conditions of the small intestine (sometime end-up in surgery)
b. Symptomatic treatment
(1) Fluid therapy intravenously and electrolytes (K, Ca)
(2) Relief of the gastric dilation by nasogastric tube every 2 hours
(3) Pain relief if necessary
(4) Withhold food until gastric reflux ceases

Question 35

ACUTE GASTRIC DILATION
- etiology, pathogenesis

Answer 35

• Etiology: ingestion of large amount of food, fermentable food, cold water, pylorus obstruction, cribbers, idiopathic, rapid eating
  <><><><>
  1. Ingestion of large amounts of feed
  a. Grain overload ground grains worse
  b. Legumes
  c. Rapidly fermentable foods
  2. Excessive consumption of cold water > the pylorus goes into spasms
  3. Obstruction of the pylorus (bots, stricture secondary to ulcers)
  4. Cribbers and wind suckers that suck air into the stomach.
  5. Fatigue - rapid eating following hard work (following a race) > food stays in the stomach and rapidly ferments
  6. Idiopathic
  <><><><>
  1. Emesis not possible in the horse > dilation occurs > increased osmotic pressure > dehydration + further dilation + pain > shock
  2. Violent pressure and muscle contractions may cause rupture

Question 36

ACUTE GASTRIC DILATION
- clinical signs

Answer 36

• acute, severe pain
• increased HR
• possible ingesta at nares
• shock if rupture

Question 37

acute gastric dilation tx

Answer 37

Treatment: passage of nasogastric tube, Gastric lavage, DSS
<><><><>
1. Pass a nasogastric tube to relieve the gas and froth immediately
2. Leave it in position for several hours
3. Gastric lavage with a small amount of DSS and warm water may help (be careful)

Question 38

Grass sickness
- forms, signs, Tx

Answer 38

Peracute / acute form:
- similarity to small intestinal obstruction
- supportive treatment
<><><>
Subacute/chronic form:
- intermittent colic, weight loss, muscle atrophy
- regurgitation down the nose when eat
- no treatment

Question 39

rectal tears pathophysiology

Answer 39

1. Usually iatrogenic
2. Most commonly as a complication of manual palpation per rectum
3. May occur as complication of enema administration (foals,dystocia,breeding accidents)
4. Most tears involve the dorsal aspect of the rectum and are located 15 to 55 cm from the anus

Question 40

grades of rectal tears, and treatment type

Answer 40

5. Four grades:
   a) Grade 1—Tearing of the rectal mucosa and submucosa.
   - Medical Tx
   <><><><>
   b) Grade 2—The muscular layer of the rectum is torn, and the mucosa and submucosa prolapse through the defect to create a diverticulum, which may act as a pocket for fecal impaction.
   - Medical Tx
   <><><><>
   c) Grade 3(a)—Disruption of the rectal mucosa, submucosa, and muscularis layers, resulting in a palpable void in the rectal wall that exposes the serosa.
   - Surgical Tx
   <><>
   d) Grade 3(b)—Disruption of the rectal mucosa, submucosa, and muscularis layers, without involvement of the mesorectum. This tear is palpable as a defect in the rectal wall that exposes the fat-filled mesorectum. Grade 3 tears can cause formation of a retroperitoneal space within the
   pelvic cavity that can become impacted, then rupture and convert to a grade 4 tear. The presence of intact serosa or mesorectum prevents contamination of the abdominal cavity with fecal material; however, movement of bacteria through these tissues may induce local peritonitis.
   - Surgical Tx
   <><><><>
   e) Grade 4—Tearing of all layers of the rectum; as a result, direct communication exists between the rectum and the abdominal cavity, resulting in septic peritonitis, which may result in development of endotoxemia and circulatory shock.

Question 41

rectal tears clinical signs, sequelae

Answer 41

1. Gastrointestinal
2. Local and diffuse peritonitis may develop within 2 hr of occurrence a rectal tear. Ileus secondary to diffusion of bacteria and toxins may follow.
3. Abdominal discomfort and straining
4. Depression and endotoxic shock
5. Horses with grades 1 or 2 rectal tears rarely demonstrate signs relative to the tear until signs of rectal impaction develop

Question 42

rectal exam complications - tears
- Tx for Grade 1 and 2

Answer 42

Grade 1 & 2: Medical Treatment
* Sedation/Epidural anesthesia
* Evacuate rectal contents
* Off Feed
* Laxative
* Broad spectrum antibiotics
* NSAIDs

Question 43

rectal exam complications - tears
- Tx for grade 3 and 4

Answer 43

medical treatment and:
- referral
- repair the tear
- rectal liner or…
- loop colostomy
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1. Grade 3 or 4 rectal tear may require placement of a rectal liner, may be sutured directly or under laparoscopic guidance, or require a loop colostomy.
<><><><>
Medical compenent:
1. Sedation, epidural anesthesia, and/or parasympatholytic drugs.
2. Lidocaine enema (12–25 mL of 2% lidocaine in 50 mL water) or lidocaine jelly may be used
3. Fecal softeners and a laxative diet
<><>
AND:
a. should be considered emergencies that require referral to a surgical facility
b. *Rectal tear may be packed with 3-inch (7.5-cm) stockinette filled with moistened roll cotton. This should be sprayed with povidone–iodine and lubricated with surgical gel and inserted to a point 10 cm proximal to the tear. The tear should not be packed. The packing may be secured by closing the anus with towel clamps or a purse-string suture. If too difficult avoid as it can enlarge the tear!
c. Epidural anesthesia should be maintained to prevent straining during transport.
d. Parenteral anti-inflammatory and broad-spectrum antibiotic therapy
e. Intravenous fluids should be administered to horses in shock
f. Off Feed

Question 44

rectal tear diet

Answer 44

1. All horses with rectal tears should be fed a low-bulk laxative diet, such as green grass, a complete pelleted ration, or alfalfa pellets soaked in water.