7.1.2: Primary assessment of colic

Question 1

What term describes intestine that telescope into themselves?

Answer 1

Intussusception

Question 2

The epiploic foramen, which intestines can herniate through, is open in a) young horses or b) older horses.

Answer 2

b) older horses

Question 3

What are the most common (and often perceived milder) signs of colic?

Answer 3

• Reduced appetite/anorexia
• Depression
• Change in droppings

Owners may not call the vet when they see these signs.

Question 4

Clinical signs associated with severe cases of colic

Answer 4

• Severe unrelenting pain (including signs of self trauma)
• Dullness and depression
• Abdominal distension
• Heart rate >60bpm
• Discoloured mucus membranes or delayed CRT
• Absence of gut sounds in one or more quadrants
• Swelling over top of eyes/abrasions over top of eyes and/or hips -> shows it has had an episode of severe pain

These signs relate to obstruction or strangulation ± cardiovascular compromise. There is the potential for huge volumes of fluid to become trapped.

Question 5

When investigating a case of colic, what questions could you ask about the current episode?

Answer 5

• When was the horse last seen behaving normally?
• When did the horse last pass faeces and what did these look like?
• What signs has the horse been exhibiting and have they changed over time?
• (If the horse has had colic previously), how does this time compare to previous episodes?
• How has the horse been managed since the vet was contacted?
• What treatment/analgesia has been given?

Question 6

What are the main 5 parameters to assess on clinical exam of a horse with colic and how will you remember these?

Answer 6

Painful Horses Must Get Treatment.
* Pain
* Heart rate
* Mucous membranes
* Gut sounds
* Temperature

Question 7

True/false: changes to mucous membranes are common in both mild and critical cases of colic.

Answer 7

False
Changes to mm are a red flag for critical cases

Question 8

When investigating a case of colic, what questions could you ask regarding management/yard environment?

Answer 8

• Any recent changes in stabling/pasture turnout/forage feed/exercise regime/hard feed/access to water?
• Any previous episodes of colic on the yard?
• Has the horse has access to sand?

Question 9

When investigating a case of colic, what questions could you ask about the horse’s previous medical history?

Answer 9

• Previous medical history -> frequency and nature of colic episodes? (This will provide some idea of where they are with insurance and possible willingness to refer/hospitalise).
• Any previous abdominal surgery?
• On any current medication?
• Any other medical issues?
• Any recent history of sedation or anaesthesia?

Question 10

When investigating a case of colic, what questions could you ask about the horse as an individual generally?

Answer 10

• Age
• Sex and reproductive status
• History of cribbing or wind sucking
• Recent changes in weight/condition
• Attitude to pain (stoic or expressive)

Question 11

When investigating a case of colic, what questions could you ask about preventative healthcare, and owner factors?

Answer 11

Owner factors
* Is surgical treatment/referral is an option? Are they likely to want to use this option?

Preventative healthcare
* Is any parasite control/treatment used?
* Is any strategic parasite control (e.g. faecal egg counts and strategic worming) used?
* On what date did the horse last receive wormer?

Question 12

What should you do before administering Alpha-2 agonists for sedation in a painful colicking horse?

Answer 12

• Take a HR (and ideally RR, and gut sounds)
• Alpha-2 agonists will drop all the above parameters
• If it not safe for you to listen, crack on with your sedation

Question 13

What is considered a critical case of colic?

Answer 13

Cases in which the horse requires:
* Euthanasia on welfare grounds
* Hospitalisation for intensive medical or surgical treatment

Question 14

If you give analgesia and the horse does not respond at all, what does this tell you about the colic?

Answer 14

This is likely to be a critical case of colic

Question 15

If a horse shows signs of extreme pain, such as abrasions from rolling/thrashing, unresponsiveness, continuous rolling, continuous box walking, and then suddenly experiences alleviation of these signs, what might this suggest?

Answer 15

This might suggest that gastric or intestinal rupture has occurred

Question 16

What is the toxic ring (a.k.a. toxic line) and what does it indicate?

Answer 16

Toxic ring: red or purple line on gums above teeth. Indicates cardiovascular compromise.

Question 17

What level of nasogastric reflux is considered abnormal when you place an NG tube?

Answer 17

• Spontaneous NG reflux and/or foul mouth odour (i.e. before you place the tube) is abnormal
• If you pass the tube and get more than 4L of fluid back (500kg horse) this is abnormal

Question 18

What level of lactate is considered abnormal in peritoneal fluid?

Answer 18

• Peritoneal lactate >2mmol/L is abnormal

Question 19

What findings might you be able to detect on rectal exam of a horse with colic?

Answer 19

• Distended SI loops
• Severe LI distension
• LI displacement

Rectal examination allows palpation of the caudal third of the abdomen.

Question 20

What are the most frequently used diagnostic tests for colic in field situations?

Answer 20

• Response to analgesia
• Rectal exam
• Nasogastric intubation

Question 21

What are the indications for performing nasogastric intubation in a colicking horse?

Answer 21

Nasogastric intubation is both diagnostic and therapeutic.
* If there is an obstruction in the small intestine/stomach, fluid will back up. This can eventually lead to gastric rupture (fatal)

Perform NG intubation if:
* There is spontaneous NG reflux
* There is distended small intestine on rectal/ultrasound
* It is a suspected critical case of colic
* The horse is in severe pain
* There is a requirement for enteral fluids
* High HR (>60bpm) or high RR (>20 breaths per min) where the latter is associated with abdo pain or distension
* There is a primary impaction

Question 22

What are the potential complications of nasogastric intubation?

Answer 22

• Epistaxis
• Inadvertent administration of treatment into the lungs

Question 23

What are the potential complications of a rectal exam?

Answer 23

• Rectal tear
• (Injury to vet/handler)

Question 24

What grades of rectal tears are there?

Answer 24

• Grade I - mucosa and submucosa torn
• Grade II - muscular layer only torn
• Grade IIIa and IIIb - all layers torn except serosa or mesorectum
• Grade IV - all layers torn and you can directly palpate abdominal organs

Question 25

Grade the rectal tear pictured here:

Answer 25

Grade IV

Question 26

Grade the rectal tear pictured here:

Answer 26

Grade IIIa

Question 27

Grade the rectal tear pictured here:

Answer 27

Grade I

Question 28

What should you do in the event of a rectal tear due to palpation?

Answer 28

1. Identify it, acknowledge it, and tell the owner
2. Perform essential first aid
3. Phone for help (senior partner, referral hospital, VDS)

First aid
* Sedate horse and administer spasmolytic if not done already
* Repalpate carefully to identify the extent of the injury
* Gently remove faeces from the tear and rectum
* Treat for septic shock and peritonitis (NSAIDs + broad spec antibiotics e.g. penicillin + aminoglycosides)
* If able to, administer epidural and pack the rectum
* Refer

Question 29

Which grade of rectal tears will require surgery?

Answer 29

• Most Grade III tears
• Grave IV tears require surgery but many horses are euthanised, and if not will almost certainly die of peritonitis

Question 30

True/false: in the event of epistaxis after nasogastric intubation, you should pack the site of the bleed as this will resolve the problem.

Answer 30

False
You can pack cotton wool into the nostril but blood will just back up behind this. Bleeding is coming from the ethmoturbinates and pharynx so packing just doesn’t reach the site of origin.