Medical treatment of colic

Question 1

What % of horses with colic signs will need surgical intervention / euthanasia?

Answer 1

around 9%

Question 2

What are risk factors for critical cases of colic?

Answer 2

• Pain score
• Heart rate
• CRT
• Weak pulse
• Absence of gut sounds in 1 or more quadrants

Question 3

What would your initial approach to colic be?

Answer 3

1. HISTORY TAKING
2. OBSERVATION - colic?
3. CLINICAL EXAMINATION - further tests?
4. ASSESSMENT - medical / surgical
5. PLAN - analgesia / Tx?

Question 4

What are indications for medical tx of colic?

Answer 4

• Mild – moderate pain
• Good response to analgesia
• HR <50 bpm
• GI motility continuing / improving
• No net reflux
• Resolving / no abdominal distension
• Normal peritoneal fluid
• Normal PCV / TP & systemic lactate

Question 5

What are principles of medical tx?

Answer 5

• Analgesia
• +/- oral fluids
• Other specific therapies - IV fluid, phenylephrine, psyllium

Question 6

What analgesia would you give horses with colic?

Answer 6

• NSAIDs
• Alpha 2 agonists
• Opiates

Question 7

What NSAIDS can be used for analgesia and why?

Answer 7

• Phenylbutazone - 12hr duration, moderate potency - good first line
• Flunixin Meglumine - 12hr duration, potent analgesia, masks increase in HR with SIRS - use with CAUTION

others =
* Metimazole (Buscopan)
* Ketoprofen
* Meloxicam

Question 8

What A2 agonists can be used for analgesia + why?

Answer 8

• Xylazine - good analgesia, short acting (30mins) - good in assessing pain of colic
• Romifidine - 2-4hr duration, IM, Useful if moderate - severe pain (combined with butorphanol)
• Detomidine - potent analgesia for 2-4hrs, (combined with butorphanol)

Question 9

What Opiates can be used for analgesia + why?

Answer 9

• Butorphanol - combined with A2, used in moderate-severe painful cases
• Pethidine - uncommonly used
• Morphine - potent but not appropriate for colic

Question 10

What is Butylscpolamine / Hyoscine?

Answer 10

• Smooth muscle relaxant
• 2 forms =
• Buscopan
• Buscopan compositum - combined with NSAID (metimazole)
• Indicated in spasmodic colic
• Useful when performing rectal exam

Question 11

When would you give flunixin?

Answer 11

– When referral is not an option & horse is exhibiting moderate / severe pain (if no response seen euthanasia is appropriate)
– When an exact diagnosis is known & medical treatment is appropriate (e.g. pelvic flexure impaction)
– When the decision to refer has already been made

Question 12

When would you be cautious of giving flunixin?

Answer 12

– Mild / moderate pain of unknown cause & where referral is an option

Question 13

What are benefits of oral fluids?

Answer 13

• Easy and inexpensive
• 4-6 litres water (500kg horse) / electrolyes administered q.4h by nasogastric intubation
  – Stimulates gastrocolic reflex
• Can place an indwelling stomach tube for continuous administration of fluids
• Provides hydration provided the horse is not refluxing
• Hydrates ingesta assisting resolution of large colon impactions

Question 14

When would you administer IV fluids?

Answer 14

– Reflux obtained on nasogastric intubation (is there a surgical lesion?)
– Severe systemic compromise & immediate systemic support needed

Question 15

What are the downsides of IV fluids?

Answer 15

• Expensive - £350
• Does not directly hydrate ingesta – excess fluids lost by urination
• Difficult to administer and monitor safely outside clinic facilities

Question 16

How would you treat spasmodic colic?

Answer 16

• Butylscopolamine +/- NSAID usually effective
• Mild pain + normal CV parameters

Question 17

What would you see with large colon impactions? Tx?

Answer 17

• Mild / moderate signs of pain
• Rectal exam findings = Doughy, firm structure on LHS of caudal abdomen
• Often in stabled animals

Tx =
* Oral fluid therapy every 4 hrs
* can add magnesium sulphate as laxative - ONCE
* Analgesia - IV flunixin meglumine
* Surgery if no response to therapy

Question 18

What would you get with 2ndary large colon impaction?

Answer 18

• Due to grass sickness
  – Corrugated feel – not smooth and large ‘vacuum packed’
  – usually a primary small intestinal lesion
  – results of initial +/- repeat assessments indicative of need for surgical management

Question 19

What are problems with caecal impactions?

Answer 19

• Can rupture quickly = death
• Medical / surgical management dependent on findings on clinical exam

Question 20

How would you treat gastric impaction?

Answer 20

• Medical Tx if mild signs
• Surgery often unsuccessful
• IV fluid therapy
• Repeated gastric lavage
• +/- use of carbonated drinks - diet coke

Question 21

When would you treat large intestine displacement / distention medically / surgically?

Answer 21

• Medical management:
  – Horses CV parameters normal
  – Degree of pain not severe
  – Marked gaseous distention of the large colon is absent
• Surgical management indicated if:
  – Severe pain / marked or increasing gas distention of colon
  – Deteriorating CV parameters
  – Non-response to treatment

Question 22

How would you treat large intestine displacement / distention medically?

Answer 22

• Analgesia – careful monitoring if using potent analgesia
• Light walking / trotting exercise
• Oral fluid therapy – bolus fluids as for primary large
  colon impaction
• Withhold feed until faeces start to be passed

Question 23

How would you diagnose / treat nephrosplenic entrapment?

Answer 23

• Diagnosis:
  – Rectal examination
  – Ultrasonography = Failure to image left kidney and spleen – gas distended large colon visualised
• Medical vs. surgical management depends on initial evaluation
  – Medical therapy indicated if systemic status good, pain can be controlled and mild degree of gaseous distention
• Phenylephrine infusion
  – 3𝜇g/kg/min as infusion in 500ml / 1L sterile saline administered IV over 15 minutes
  – Horse lunged for 15 mins
  – Repeat rectal examination to assess if LC has repositioned itself
  – *increased risk of haemorrhage in older horses (>15 y.o 64 x the risk) – owners should be made aware of this

Question 24

How would you diagnose sand colic?

Answer 24

– Sand in the faeces
– Classic ‘seashore’ sound on auscultation
– Sand retrieved on abdominocentesis
– Ultrasonography
– Abdominal radiography

Question 25

How would you treat sand colic?

Answer 25

• Medical / surgical management will depend on presenting signs of colic.
  – Intensive medical treatment with Magnesium sulphate (1g/kg) and psyllium sulphate (1g/kg) once daily for 4 days more effective than either treatment alone
  – Monitoring of clearance using radiography
• Treatment mild cases / preventive management in at risk horses:
  – Remove source of sand
  – Provide plenty forage
  – +/- psyllium added to feed intermittently

Question 26

What are causes of colic in neonatal foals?

Answer 26

• Degree of pain is less useful to assess need for potential surgery
  – Enteritis can present as severe abdominal pain
• Ultrasound particularly valuable (+/- radiography occasionally indicated)
• More likely causes of colic:
  – Meconium impaction
  – (Ruptured bladder)
  – Enteritis
  – SI volvulus
  – Congenital anomalies

Question 27

What is seen with colic in donkeys?

Answer 27

• Usually present with signs of dullness – uncommon to show marked signs of colic
  – Degree of pain less useful
• Colonic impactions are common
  – Always check for dental abnormalities
  – May be due to ingestion of foreign materials in working equid populations
• Rectal examination can be performed safely

Question 28

What are risk factors for recurrence of colic?

Answer 28

– Known dental problem
– Crib-biting / windsucking behaviour
– Weaving
– Time at pasture

Question 29

When would you consider euthanasia?

Answer 29

• Uncontrollable pain despite potent analgesia
• Severe CV compromise
  – HR >90bpm
  – PCV >60%
  – Purple mucous membranes
• Gastrointestinal rupture
  – Brown / red ingesta contaminated peritoneal fluid
  – Profuse sweating, sudden reduction in pain