Equine GI disease pt 2

Question 1

when in a colic call should we pass a nasogastric tube immediately?

Answer 1

If the horse is very painful and you suspect gastric dilatation, pass the tube immediately

Question 2

should we use a nasogastric tube for every colicky horse?

Answer 2

yes

Question 3

use of nasogastric intubation for a colic
- helps Dx what?
- allows release of what?
- can give what?

Answer 3

• Useful in diagnosing esophageal obstructions
• Allows release of gas and/or fluid from stomach
• May administer medications (mineral oil, DSS, sodium sulphate)

Question 4

diameter of tube for nasogastric intubation

Answer 4

Tube of large internal diameter (14 mm recommended)

Question 5

how do we siphon with a nasogastric tube?
- careful of what?
- measure what?
- what indicates gastric dilation?
- what is an abnormal amount of fluid? what should we do?

Answer 5

6. Reflux > administer fluid trough the tube and attempt to create siphon whilst the tube still full
7. Be careful to add too much water
8. Measure the volumes administered and retrieved
9. The return of a large volume of fluid and the immediate relief of pain is indicative of gastric dilation
10. If > 4 litres of reflux -> abnormal -> keep nasogastric tube in place
11. Measure pH

Question 6

normal pH of gastric reflux through nasogastric tube?
- what does pH 5-7 mean?

Answer 6

a. Normal pH of gastric reflux is 3.0
b. pH of 5 7 > contents of the small intestines

Question 7

Abdominal paracenthesis-abdominocenthesis
- when (is colic context) should we do this
- peritoneal fluid tells us what?

Answer 7

1. Easily performed > when severe problem exists or as a diagnostic test
2. Not recommended for every colic > associated risks
3. Peritoneal fluid reflects the changes on the peritoneal surface and in the tissues

Question 8

how to perform Abdominal paracenthesis-abdominocenthesis

Answer 8

a. Use an 18 g 1½” hypodermic needle or a teat cannula
b. Clip or shave the hair on midline or right side (ventral portion). Ultrasound may confirm the presence/absence and location of fluid
c. Surgical preparation
d. If using teat cannula:
(1) 2 ml of local anaesthetic
(2) Incise skin and linea alba with small scalpel blade (stab incision)
(3) Place teat cannula through hole, surrounded by sterile gauze sponge, that will absorb the blood and not contaminate the sample
(4) Feel pop as enters the peritoneum (or bowel)
e. Collect fluid obtained (if any) in a serum tube and one containing EDTA

Question 9

Abdominal paracenthesis-abdominocenthesis
- what do we evaluate the fluid for?

Answer 9

• colour, smell, and amount of fluid
• cytology (cell count, protein)
• lactate (N<2.0mmol/L)
  <><><><>
  (1) Colour, quantity, smell, and the presence of plant material
  (a) normal fluid is straw coloured, and serous in nature (cloudy > increased Leukocytes)
  (b) blood cells > serosanguinous (real or contamination?)
  (c) pure dark red fluid > intraperitoneal hemorrhage or from splenic puncture (if no erythrophagocytosis probably puncture)
  (d) smelly bloody brown fluid > late stage necrosis
  (e) plant material > real or contamination?
  <><>
  (2) Quantity > Usually small amount of fluid
  <><>
  (3) Protein level -> > 25 g/L total solids -> inflammatory responses
  <><>
  (4) Neutrophils
  (a) >5.0 x 109 wbc/L indicate inflammation or infection
  (b) +/- degenerate neutrophils
  <><>
  (5) Bacteria
  <><>
  (6) Lactate-biomarkers of ischemic bowel injury(N <2.0 mmol/L)

Question 10

diagnostic lab tests to run for a colic
- what do they mean?

Answer 10

Bloodwork:
- PCV, TP
> TP < 50 g/ L Severe inflammation
> PCV> 70% Poor prognosis
- CBC
- Blood gasses

<><><><>
1. Packed Cell Volume (PCV)
a. 35% > Normal
b. >45% > Mild dehydration (horses in training have a higher PCV)
c. >50% > Needs fluids
d. >60% > Very serious
e. >70% > Poor prognosis
<><>
2. Total Solid
a. 60 - 80 g/L > normal
b. >80 g/L > shock, hemoconcentration
c. <50 g/L > leakage of protein, possibly into devitalised bowel
<><>
3. Other blood parameters
a. CBC > helpful in early diagnosis of colic related to infectious diseases (salmonella, Potomac horse fever) or severe inflammatory disease (peritonitis)
b. Blood gases > loss of HCO3- may be indicative of an enteritis or a very shocky horse

Question 11

trocharization of the large bowel for colic
- when might we do this? is it common?
- what side?
- how?

Answer 11

1. If severe distension > possible suffocation or bowel rupture
2. Usually performed on right side
3. Rarely needed
   <><>
4. How?
   a. locate the distended viscus by percussion in the paralumbar region
   b. clip and surgically prepare the area
   c. inject a bleb of local anaesthetic into the skin and muscle layers
   d. insert a 15 cm 16 g spinal needle or IV catheter obliquely
   e. remove the needle once the catheter is positioned in the viscus
   f. may create leakage of intestinal contents or laceration of viscus

Question 12

imaging techniques used to investigate colic
- which are used?
- what can they find?

Answer 12

1. Ultrasonography
   a. most commonly used
   b. used externally or through the rectum
   c. detection of intussusception, distended loops of small intestine or thickened intestinal wall, adhesions …
   <><>
2. Endoscopy > gastric ulceration
   <><>
3. Radiology
   a. to detect intestinal obstruction in young foals
   b. enterolith in adults

Question 13

criteria used when deciding the need for an exploratory laparotomy

Answer 13

A. Intractable pain - not relieved by analgesics
B. Moderate to severe abdominal distension / Tympanitis if unable to relieve it medically
C. Abnormal rectal findings, e.g. displacement or tight bands
D. Gastric reflux
E. Abnormal abdominocentesis findings
F. Worsening blood picture - acidosis elevated PCV, elevated protein
G. Greatly elevated heart that remains elevated
H. Impactions that cannot be relieved medically

Question 14

Important things to do when referring a case
- when to refer
- tube
- pain
- supportive care / medications
- contacts

Answer 14

• OFF FEED
  A. If suspect a potential surgical problem, refer the case sooner than later
  B. Tape / sew a nasogastric tube in place for shipping especially if you have gastric reflux
  C. Administer sedation and analgesics if necessary (Flunixin)
  D. Administer fluids if the animal dehydrated
  E. +/- Broad spectrum antibiotics?
  F. Contact the owner if possible
  G. Warn of the cost
  H. Contact the referral centre with history and estimated time of arrival
  I. If the animal is insured > owner’s responsibility to telephone the insurance company

Question 15

which sedatives and tranquilizers are used for colic?

Answer 15

Tranquilizers:
- acepromazine

Sedatives
- xylazine (rompun)
- Detomidine
- Romifidine

Question 16

properties of acepromazine:
- what are its effects

Answer 16

• no analgesic effects, no sedation
• depresses CNS response, causes peripheral vasodilatation due to alpha-2 blockage effect
  > hypotension
• be careful in stalllion

<><><>
1. No direct analgesic properties
2. Relieves anxiety and alters the CNS response to pain by depressing the brainstem
3. Depresses spontaneous motor activity; however, co ordinated motor responses not affected and arousal is easy
4. alpha-adrenergic blocker > vasodilation > hypotension
5. Prolapse of the penis in males

Question 17

xylazine use as an analgesic in horses
- properties
- type of drug
- duration
- effects
- side effects

Answer 17

** (Rompun or Anased)
- sedative, alpha-2 agonist
- short duration
- good sedative and analgesic
- decreases intestinal motility
- produces bradycardia and 2nd degree heart block
<><><><>
1. Strength 100 mg/ml
2. 0.3 to 0.5 mg/kg I.V. or I.M.
3. Duration of action 20 50 minutes
4. Slows intestinal motility and may decrease intestinal blood flow
5. alpha2 agonist (inhibits both cholinergic and adrenergic neurons)
6. Sedative, analgesic and muscle relaxant
7. Produces bradycardia and 2nd degree heart block
8. Effects are increased by combining with an opiate (butorphanol)
9. Increase in urine output
10. May produce sweating
11. Oxytocic effect in cattle, not apparent in pregnant mares

Question 18

detomidine use as an analgesic in horses
- type of drug
- duration
- potency
- effects
- side effects

Answer 18

(Dormosedan)
- sedative, alpha-2 agonist
- long duration
- very potent anagesic, can mask colic signs
- bradycardia and 2nd degree heart block
<><><><>
1. Strength 10 mg/ml
2. Dose .01 to .02 mg/kg
3. An alpha2 agonist with similar effects to xylazine
4. Longer duration (60-150 min) and greater potency
5. Slows intestinal motility and may decrease intestinal blood flow
6. Effects are increased by combining with an opiate (butorphanol)
7. Excellent visceral analgesia
8. Careful evaluation of an animal before administration

Question 19

romifidine use as an analgesic in horses
- type of drug

Answer 19

(Sedivet®)
- sedative - alpha-2 agonist
- similar to detomidine
<><><><>
1. Strength 10 mg/ml
2. Dose 0.02-0.05 mg/kg I.V
3. Similar analgesia (not as potent) and duration of effect as detomidine
4. Less ataxia

Question 20

general properties of NSAIDs
- how do they work
- what do they do
- adverse effects

Answer 20

1. Peripherally acting analgesics that inhibit prostaglandin production
2. Prostaglandin involved in the production of pain and fever
3. Prostaglandin are important for normal gastrointestinal mucosal blood flow and cytoprotection
4. NSAID > analgesic, anti-inflammatory and antipyretic properties
5. Prolonged therapy may produce gastrointestinal ulceration and protein loss
6. May produce renal papillary necrosis, particularly if the horse is dehydrated

Question 21

Flunixin meglumine use in horses
- what type of drug?
- how common is use
- duration
- effects

Answer 21

**(Banamine)
- NSAID
- most commonly used
- 30min - 8h duration
- anti-endotoxic effect
<><><><>
1. Strength 50 mg/ml
2. Dose 1.1 mg/kg I.V. or I.M
3. Most effective NSAID for relief of visceral pain
4. Does not appear to alter motility and intestinal blood flow
5. Analgesic effect may last up to 8 hours
6. Anti-endotoxic dose at .25 mg/kg QID > prevents the generation of the vasoconstrictive arachidonate metabolite, thromboxane A2
7. Re-evaluate horse before repeatedly giving this drug

Question 22

phenylbutazone use in horses
- type of drug
- effects

Answer 22

• NSAID
• minor effect on visceral pain
• anti-endotoxic property
  <><><><>
  1. Strength 200 mg/ml
  2. Dosage up to 4.4 mg/kg
  3. Effective analgesic for musculoskeletal pain but minor visceral effects

Question 23

ketoprofen use in horses
- type of drug
- uses
- properties

Answer 23

• NSAID
• clinically less efficacy than flunixin megalumine
• also inhibits lipoxygenase

Question 24

Dipyrone use in horses
- type of drug, effect

Answer 24

• NSAID
• weak analgesic

Question 25

butorphanol use in horses
- type of drug
- how common
- combined with?
- effects
- duration

Answer 25

(Torbugesic)
- narcotic analgesic
- most commonly used
- often in combination with an alpha-2 agonist > synergism
- decrease intestinal motility
- duration 2-4h
<><><><>
1. Strength 10 mg/ml
2. Dose recommended is 0.1 mg/kg I.V. (on bottle) > usually use 0.02-0.05 mg/kg
3. Centrally active narcotic agonist antagonist
4. Minimal cardiovascular effects in the horse
5. Duration of action of 2-4 hours
6. May be used in combination with xylazine (synergistic effect)

Question 26

narcotic analgesic general properties
- mechanism
- effects
- CV effects in horses
- effects of larger doses

Answer 26

1. Bind to specific opiate receptors within the CNS
2. Increase the pain threshold and cause euphoria and drowsiness
3. Depress progressive motility specially combined with alpha2 agonist
4. No significant cardiovascular depression in horses
5. Larger doses may result in excitation, muscle fasciculation and locomotor stimulation

Question 27

butylscopolamine use in horses
- what does it do
- uses
- what is its effect?
<><>
- should not be used in what horses
- transient effects

Answer 27

• is a peripherally acting antimuscarinic, anticholinergic agent
• used to treat pain and discomfort caused by spasmodic activity in the digestive system.
• It is not a pain medication in the normal sense, since it does not directly affect pain, but rather works to prevent painful cramps and spasms from occurring.
  <><><><>
  A. N-butylscopolammonium bromide (Buscopan)
  1. Strength 20 mg/ml
  2. 0.3 mg/kg body weight slowly IV
  3. Should not be used in impaction colics associated with ileus, or in horses with glaucoma.
  4. The spasmolytic action is based on anticholinergic effects resulting from competitive inhibition of parasympathetic activation (via muscarinic receptors) of smooth muscle cells.
  5. Causes transient tachycardia and decreased borborygmal sounds. Transient pupillary dilation may also be observed

Question 28

laxatives used in horses

Answer 28

A. Mineral Oil
- 2-4 L by nasogastric tube
- Should be through the horse in 12 hours
- Seen on the walls and hind quarters of the horse
- Tendency to track around firm impactions / does not penetrate severe impaction
- good transit marker
<><>
B. Dioctyl Sodium Sulphosuccinate(Dioctol, Tympanex)
- Lowers the surface tension, decreases the volume of gas
- Penetrate into fecal masses > good for breaking up impaction
- May be used in combination with mineral oil
- do not give excessive amount
<><>
C. Osmotic Cathartics
- Na or Mg sulfate
- Rate of 0.5 kg/450 kg BWt dissolved in 4 litres of warm water
- Draw water into the intestinal lumen by osmotic effect
- Use with care, if complete bowel obstruction may result in rapid dehydration and rupture
<><>
D. Bran - Bulk Cathartic

Question 29

TYPES OF COLIC

Answer 29

I. Spasmodic
II. Impactions
III. Tympanitic Colic
IV. Strangulations and Incarcerations
V. Enteritis: duodenitis proximal jejunitis and colitis
VI. Acute Gastric Dilation
VII. Grass Sickness

Question 30

spasmodic colic
- how common
- predisposing factors
- pathogenesis

Answer 30

• Most common colic
• Predisposing factors: weather change, cold water, poor management, fatigue, poor dentition, medication, parasites
• Sudden irritation or fermentation > spasm of smooth muscle> distension of adjacent segment > autonomic nerve receptors > PAIN
  <><><><>
  A. Most common form of colic
  B. Acute intestinal catarrh
  C. Characterised by pain, usually intermittent
  <><><>
  D. Predisposing factors:
  1. Rapid weather changes, e.g. thunderstorms
  2. Poor management
  a. Irregular feedings
  b. Sudden changes in diet
  c. Overfeeding
  d. Eating damaged food frozen foods
  e. Eating rapidly fermentable foods, e.g. apples, grass clippings
  3. Poor teeth
  4. Irritating materials, e.g. worming medication
  5. Cold water
  6. Parasites
  7. Possibly allergy to food, or maybe allergy to the exsheathing fluid of strongylus vulgaris larvae
  8. Some animals have recurrent attacks with no apparent cause
  9. Cribbers use cribbing strap
  <><><>
  E. Pathogenesis
  1. Sudden irritation and/or excessive fermentation > acute intestinal catarrh
  2. Spasm of the smooth muscle of the bowel wall > segmentation contraction of the bowel > distension of adjacent segment > pain
  3. Verminous arteritis (strongylus vulgaris) emboli may induce an ischemic state in the mesenteric tree > acidosis at the nerve endings > pain or irregular peristalsis or ischemic necrosis

Question 31

spasmotic colic symptoms

Answer 31

• intermittent pain
• normal to hypermotile peristalsis
• HR, RR normal or mild elevation
• feces: normal to loose
• MM normal
• nothing on per-rectum examination
• no reflux
  <><><><>
  1. Sudden abdominal pain of 5-15 minutes duration
  2. Intermittent
  3. Mild colic usually
  4. Peristalsis present > often hypermotile
  5. Pulse and respiration usually normal to slightly elevated
  6. Feces normal to loose
  7. Mucous membranes normal colour
  8. No abnormal findings on per rectum palpation
  9. No gastric reflux
  10. Duration of 5-6 hours
  11. May develop volvulus from rolling or uneven peristalsis

Question 32

spasmodic colic treatment

Answer 32

• OFF FEED
• control of pain
• laxative
  <>
• If persist: re-evaluate the horse prior to giving more drugs
  <><><><>
  1. Off feed until pain has resolved
  2. Control the pain if excessive
  3. Usually a laxative and analgesic
  a. Mineral oil via nasogastric tube
  b. Flunixin meglumine, xylazine, Detomidine

Question 33

impaction colic sites and causes

Answer 33

1. Usual sites of impactions are where sudden changes of direction and diameter occur, i.e. Pelvic Flexure **, RDC, Transverse Colon, Small colon
2. May be secondary to intraluminal mass
3. Other site includes: Cecum*, ileum, jejunum

Question 34

impactions predisposing factors

Answer 34

1. More in fall and winter
2. Dry feed and decreased water intake
3. Exposure to unfamiliar surroundings and water bowls
4. Long distance transportation
5. Poor quality feed
6. Abnormal eating habit, e.g. eating wood shavings, fencing, lead shanks
7. Chronic intake of sand in diet
8. Older animals - lack of bowel tone
9. Poor teeth - dental pain
10. Lack of exercise
11. Use of astringents following diarrhea
12. Damage to gut wall from strongyles
13. Severe ascarid burden (if suspect heavy infection half worming dose first)
14. Bots obstructing the pylorus

Question 35

impaction colic pathogenesis

Answer 35

irritation by dry food > spasm> reabsorption of fluid > pain > can result in necrosis with time
<><><><>
1. Coarse dry feed irritating to the mucosa of bowel > irritation produces a spasm > fluid resorbed and bowel distension > pain
2. If total obstruction of the bowel > gaseous distension > acute signs
3. Eventually muscle necrosis, inflammation and necrosis of the serosa

Question 36

impactions clinical signs

Answer 36

1. Usually mild and develop slowly
2. Pain increases with time
3. Animal becomes restless
4. Abdomen becomes distended > no distension initially
5. Feces scant and dry usually

Question 37

impactions Dx (and hints of prognosis)

Answer 37

Per rectum examination:
1. Diagnostic made on palpation
2. Feels like firm bread dough
3. Easily indented by digital pressure > impressions remain
<><>
Abdominocenthesis:
1. Peritoneal fluid remains normal usually
2. If more distension > excretion of protein from the intestinal wall
3. If severe distension > protein + white blood cells but no rbc’s
4. If necrosis > leakage of bacteria, rbc’s, endotoxin release > peritonitis
5. If bowel rupture > bacteria, rbc’s, plant material…> death

Question 38

treatment for food impaction

Answer 38

• OFF FEED
• analgesics
• mineral oil, DSS, cathartics
• parenteral or per nasogastric tube fluid
• small colon impaction > enema?
• surgery
• when resolved > gradual reintroduction of food

Question 39

cecal impaction pathogenesis

Answer 39

a. Primary cecal motility dysfunction
b. Risk to have reoccurrence of the problem
c. Subsequent to a routine surgery (orthopedics often)

Question 40

cecal impaction signs, rectal exam

Answer 40

Signs:
a. Subtle
b. May be eating and defecating (+/- diarrhea)
c. Dull and lethargic
d. May present as chronic, repeated mild attacks of colic
e. Unless detected and treated early death may occur due to rupture
<><><>
a. Firm viscus with a distinct band coursing dorsally to ventrally (ventral cecal band) on the right side of the abdomen

Question 41

cecal impaction treatment

Answer 41

a. Medical
(1) considered if organ is moderate in size and ingesta easily indented
(2) withhold food
(3) I-V fluid
(4) oral laxatif (DSS) until cecum normal
- analgesic
<><><><>
b. Surgery
(1) empty cecum through enterotomy / typhlotomy
(2) possible bypass of the cecum (recurrent cases)