Colic in the horse - decision making

Question 1

What can be the actual cause of pain in colic?

Answer 1

Distension, inflammation/ischeamia of intestine, irritiation of peritoneum

Question 2

How must obstructions be differentiated?

Answer 2

Mechanical versus functional

Question 3

Distinguish torsion and volvulus

Answer 3

TORSION = twisting along long axis
VOLVULUS = twisting along short axis

Question 4

Reasons for non-strangulating mechanical obstruction? 2

Answer 4

Blood supply not affected - impaction or displacement

Question 5

Reasons for strangulating mechanical obstruction?3

Answer 5

Blood supply compromised - volvulus, torsion, incarceration

Question 6

Examples of functional obstruction/motility dysfunction

Answer 6

enteritis, grass sickness, post-surgical ileus

Question 7

Causes of non-strangulating inflammation 4

Answer 7

enteritis, colitis, typhlitis, peritonitis

Question 8

Examples of ischaemia-induced colic 4

Answer 8

volvulus, torsion, incarcaration, parasitic (s. vulgarus)

Question 9

Define spasmodic colic

Answer 9

brief episode of pain of unknown origin that resolves with no/minimal treatment

Question 10

How does impaction resolve in most cases?

Answer 10

Enteral/IV fluid therapy. only worst cases require surgery (aim is to soften the impaction to allow it to pass out)

Question 11

How do displacements resolve?

Answer 11

Can resolve spontaneously but may require surgery at some point

Question 12

What does infection/inflammation of the SI cause? Treatment?

Answer 12

Hypomotility or amotility, large amounts of nasogastric reflux. Tx = medical treatment (IV fluids)

Question 13

Define typhlocolitis. treatment?

Answer 13

infection/inflammation of large intestine. variable amounts of diarrhoea. intensive medical treatment required

Question 14

Clinical signs of peritonitis. Treatment?

Answer 14

Variable, often fever, depression, mild to moderate colic. Intensive medical treatment or surgery

Question 15

How long does it take for a strangulating lesion to kill off a bit of intestine?

Answer 15

6-8 hours (absorption of toxins into blood at this point)

Question 16

Describe a compromised intestine

Answer 16

leakage of blood and protein into abdomen, loss of fluid into intestine.

Question 17

Examples of strangulating lesions in the SI 7

Answer 17

• volvulus (around root of mesentery),
• strangulating lipoma
• epiploic foramen impaction
• inguinal/scrotal hernia
• intussusceptions
• diaphragmatic hernia
• mesenteric rent

Question 18

Examples of LI strangulating lesions - 2

Answer 18

Colon torsion

Intussusception (caeco-colic, ileo-caecal, caeco-caecal)

Question 19

Clinical signs of a SI lesion 2

Answer 19

• reflux (may be absent)

- distended SI (palpable on rectal exam, visible on ultrasound)

Question 20

Clinical signs - LI lesion - 4

Answer 20

+/- abdominal distension

• impaction or gas accumulation palpable in the LI
• displacement of LI palpable
• usually no reflux

Question 21

Indications for medical treatment of SI lesions 2

Answer 21

Enteritis/ileus

grass sickness - diagnoses surgically by biopsy

Question 22

Indications for SURGICAL treatment of SI lesions 8

Answer 22

• Volvulus
• strangulating lipoma
• epiploic foramen entrapment
• inguinal/scrotal hernia
• intussusceptions
• diaphragmatic hernia
• mesenteric root
• (grass sickness)

Question 23

Indications for MEDICAL treatment of SI lesions 6

Answer 23

• spasmodic colic
• impaction
• left dorsal displacement
• right dorsal displacement
• colitis
• typhlocolitis

Question 24

Indications for SURGICAL treatment of SI lesions 2

Answer 24

• colon torsion

- non-resolving displacements and impactions

Question 25

When should you refer a colic case? 11

Answer 25

- slightest suscpicion of a strangulating lesion (abdominocentesis, cardiovascular compromise) - SI lesions - reflux, palpable, visible on rectal/ultrasound - (high likelihood for surgery, medical diseases need intensive therapy) - conditions requiring intensive medical treatment (enteritis/colitis) - non resolving impactions (may require IV fluids or surgery = impaction+displacement) - recurring colic/chronic colic for further work up - if you're not sure and the owner is willing - moderate to severe pain - recurrent pain - pain poorly responsive to analgesia - signs of CVS compromise - severe abdominal distension

Question 26

What to do BEFORE referral? 5

Answer 26

Discuss: - circumstances (horse age, emotional/financial value, owner situation) - finances (medical £1000-3000, surgical £4000-70000, colitis/enteritis £2000-5000) - insurance (type of cover) - expectations - willingness to agree to abdominal surgery

Question 27

Reasons for surgery in colics 4

Answer 27

Therapeutic and diagnostic reasons: - suspiscion of strangulating lesion - non-resolving displacement - non-resolving impaction - non-responsive or recurrent pain

Question 28

Signs suggestive of medical lesion 5

Answer 28

- low grade pain - still interested in feed - no worsening over time - lying down more than usual - no rolling, thrashing or kicking at abdomen

Question 29

Signs suggestive of SURGICAL lesion 5

Answer 29

- acute onset severe pain - owner has already given one/multiple analgesic doses - sweating, rolling, kicking at abdomen - progressive deterioration

Question 30

CVS findings - differentiate surgical and medical lesions

Answer 30

``` MEDICAL = no signs of CVS compromise SURGICAL = cardiovascular compromise (HR>48bpm, abnormal membrane colourm CRT>2sec, prolonged skin tent, delayed/no jugular filling, cold extremities and ears, poor pulse quality) ```

Question 31

GIT findings - differentiate surgical and medical lesions

Answer 31

MEDICAL - no change in abdominal shape, good borborygmi, passage of normal manure, no/reduced manure for some time (impaction) SURGICAL = distended abdomen (ask owner), no borborygmi

Question 32

Other organ systems - differentiate medical and surgical lesions

Answer 32

``` MEDICAL = no other abnormalities, fever (enteritis/colitis), icteric mucous membranes (liver disease) SURGICAL = increased respiratory rate (pain, shock), abrasions or other signs of trauma from rolling, profuse sweating (pain, shock) ```

Question 33

NGT intubation and transrectal palpation - differentiate medical and surgical lesions

Answer 33

MEDICAL = no reflux (2L), little haemorrhagic/black reflux (gastric rupture possible), distended SI on rectal palpation, tight gaseous distension of LI

Question 34

Response to treatment - differentiate medical and surgical lesions

Answer 34

MEDICAL - signs of pain controlled with small dose of sedative or one dose of flunixin meglumine/buscopan, no recurrence of colic signs after initial dose, horse remains comfortable for 12-24h SURGICAL - large dose of sedative required to examine horse, little response to flunixin meglumine, response short lived (<1-3h)

Question 35

Additional diagnostics - differentiate medical and surgical lesions

Answer 35

MEDICAL - normal abdominocentesis (straw coloured, clear), abdominocentesis with high nucleated cell count (>100*10^9/L) and protein (>4.5-6g/L): peritonitis, normal transabdominal ultrasonographic exam SURGICAL - abnormal abdominocentesis (haemorrhaic, orange, red, nucleated cell count >525g/L), abnormal transabominal ultrasonographic exam (distended SI, increased abdominal fluid)

Question 36

List short term complications (<2-4 weeks) after colic surgery 7

Answer 36

- Anaesthetic complications - post-operative colic - post-operative ileus (reflux) - incisional complications (infection, breakdown) - thrombosis - peritonitis - laminitis

Question 37

Long term complications (>2-4 weeks) after colic surgery - 2

Answer 37

- Recurrent/chronic colic (adhesions) | - incisional hernia

Question 38

Suggest some rough prognostic guidelines - 4 types (simple medical, non-strangulating surgical, strangulating SI surgical, strangulating LI surgical)

Answer 38

- Simple medical colic - good (around 90%) - Non-strangulating surgical colic - good (70-90%) - Strangulating SI lesion - guarded (without resection 60-80%; with resection 50-70%) - Strangulating LI lesion - guarded to poor (without resection 36-83%, resection (difficult/rarely possible) 50-80%)