Rectal Tears

Question 1

What is the aetiology of rectal tears in horses?

Answer 1

• Iatrogenic following rectal examination particularly in fractious, poorly controlled horses- although spontaneous and trauammtic rectal tears can occur, the majority follow rectal examination that is resented.
• Enema administration especially in foals
• At mating, At foaling
• Spontaneous possible associated with abnormal rectal contractility.

Question 2

Where is the most common site of rectal tears?

Answer 2

The most common site of rectal tears is 25-30 cm in from the anus, where the rectum tends to tear dorsally as the rectum changes course.

Question 3

What is the sex predisposition to rectal tears?

Answer 3

Sex predisposition: most common in males (70% of cases seen are in males) although whether they are inherently more susceptible or just more likely to resent rectal examination is unknown

Question 4

What is the breed/species predisposition to rectal tears?

Answer 4

Breed/species predisposition: less likely to be seen in ponies that are too small to examine rectally, possibly more likely to occur in ponies that are just big enough to examine rectally. Increased incidence in arabs.

Question 5

What are some specific predisposing factors of rectal tears?

Answer 5

Insufficient lubricant during rectal examination, rough rectal examination, failure to keep hands still/ remove it during peristaltic waves, inadequate restraining of the horse during rectal examination, inadequare lubrication during rectal examination, prior weakness of the rectal wall.

Question 6

What are the different grades of rectal tears?

Answer 6

• Grade 1: tears involving the mucosa only and submucosa.
• Grade two: tears involving only the muscularis layers (mucosa intact)- grade 1&2 tears can be relatively easy to treat.
• Grade three: tears involving the mucosa, submucosa and muscularis layers: 3a= only serosa left intact, grade 3b: tears that occur dorsally into the mesorectum
• Grade four: tears involving all layers so that there is direct communication with the peritoneum and retroperoneum.

Question 7

Which grades of rectal tears are most easy to fix?

Answer 7

1 and 2

Question 8

Which grades of rectal tear are most serious?

Answer 8

3 and 4

Grade three and four tears are more serious and can result in peritonitis or retroperitoneal abscessation.

Question 9

What can leakage of bacteria lead to?

Answer 9

retroperitoneal cellulitis if allowed to enter the peritoneum, result in peritonitis.

Question 10

If a tear is located at the most caudal part of the rectum, where can it be localised to?

What if its more cranial?

Answer 10

A tear occurring in the most caudal part of the rectum may remain localized in the retroperitoneal area. Leakage of bacteria can → retroperitoneal cellulitis if allowed to enter the peritoneum, result in peritonitis.

A tear occurring more cranially in the peritoneal part of the rectum or small colon may result in bacterial contamination of the paritoneal cavity and peritonitis.

Question 11

What are presenting signs of a rectal tear?

Answer 11

Presenting signs: blood on the rectal glove post examination, sensation of spasm followed by free feeling in the rectum on examination; identification of rectal diverticulum at rectal examination indicates previous grade 2 tear.

Question 12

What do you see on clinical exam in a horse with a rectal tear?

Answer 12

Passage of blood stained faeces following a rectal examination; depression, anorexia, straining, colic, tachycardia, tachyopnoea, patchy or generalised sweating, toxaemia, septicaemia, pyrexia, straining, tenesmus, abdominal pain, rectal examination reveals rectal bleeding, increase in space in the rectum and easily palpable viscera.

Question 13

What are some DD for a rectal tear?

Answer 13

colic, colitis, peritonitis

Question 14

How can we diagnose a rectal tear?

Answer 14

• Endoscopy: colonoscopy can be used to visualise and assess the extend of a rectal injury
• Haematology: assess whether toxaemia and septicaemia have resulted
• Cytopathology: fluid/ aspirate analysis: peritoneal fluid aspiration allows the examination of the peritonteal fluid. Assessment of the presence and degree of peritonitis can then be carried out.
• Rectal examination: should be undertaken with bare, well lubricated arm. Reveals bleeding and rectal damage – all faeces should be removed. A speculum may be similarly used to visualise rectal damage.
• Definitively diagnose with rectal endoscopic examination confirming presence of rectal tear, site, depth and length of injury.
• Gross autopsy findings: depending on depth of injury signs from bruising and slight tearing of rectal mucosa to full thickness ‘hole’ with consequent presence of faecal material in peritoneum and secondary changes of peritonitis.

Question 15

What is the treatment for a grade one or two tear?

Answer 15

• Grade one and two tears: can be managed conservatively with continued management of straining and tenesmus, antibiotics and analgesic/anti-endotoxic mediciation.
• Antibiotics should be continued for a minimum of two weeks
• Feeding of soft food and reduced bulk with added laxatives allow the production of soft faeces of reduced volume. A complete pelleted ration lush grass and alfalfa can achieve this. Added mineral oil can be used to keep droppings to a soft cow pat consistency.

Question 16

What is the treatment for a grade 3 tear?

Answer 16

Grade three: may be treated the same as grade 1&2, however the additional use of more intensive treatment carries a better prognosis. Evacuation of faeces every 1-2hrs for 72hrs may be necessary until tear has healed. Use of rectal liner can improve prognosis. Thic can be achieved by surgical placement of a rectal wall, to the anal sphincter. The distal end is anchored with a modified plastic rectal ring. Surgical primary repair of tears can be attempted via athe rectum or using midline laparptomy- rarely results in successful healing. Non visual direct suturing may eliminate the need for colostromy or rectal liners. Useful for tears involving 50% or less of the circumference of the rectal lumen and tears that have very small reformation of the serosa. A diverting end or loop colostomy can b eused as a temporary measure which can be reconnected after the tear has healed.

Question 17

What is the treatment for a grade 4 tear?

Answer 17

poor prognosis- euthanasia is indicated.

Question 18

How can we prevent rectal tears?

Answer 18

Control: during rectal examination ensure the horses are restrained effectively. They should not be able to move around the examining area. Where manual restraint in insufficient a nose twitch or sedation can be used. Alpha two agonists provide suitable sedation in some cases this is rendered more effective with the addition of butorphonal. Use sufficient lubricant, remove all faecal material before the examination commences. Palpate with the hand moving caudally wherever possible. Do not palpate during peristaltic contractions or straining, even remove your hand temporarily if necessary. Should you suspect rectal damage has occurred, re-examine with a well- lubricated hand (it can be possible to feel more if a glove is not used) to assess the situation and institute prompt therapy where necessary.

Question 19

What is the prognosis for rectal tears?

Answer 19

• Grade one and two: good although the resulting scar tissue may predispose to future tearing
• Grade three and four: guarded. Peritonitis or retroperitoneal cellulitis is the likely outcome. This can be fatal. 60-75% survival rate.
• Grade four: very poor euthanasia is indicated.

Question 20

What are some reasons for treatment failure of a rectal tear?

Answer 20

Reasons for treatment failure: lack of prompt recognition of situation and first aid treatment, lack of sufficiently intensive treatment, very extensive tearing with massive contamination of the peritoneum.

Question 21

What 3 things do you do if a rectal tear is suspected? (3)

Answer 21

–Must assess severity of lesion

–Must inform owner

–Must take appropriate action

Question 22

What are the clinical signs of a rectal tear? (4)

Answer 22

• Blood on rectal glove (usually large amounts)
• Sudden release of pressure on rectal examination
• Ability to feel abdominal organs directly
• After few hours - peritonitis and endotoxic shock

Question 23

How do we grade rectal tears? (4)

Answer 23

• Grade 1: mucosa and submucosa torn
• Grade 2: muscular layer only torn (mucosa and submucosa prolapse through)
• Grade 3: all layers except serosa (IIIa), or mesorectum and retroperitoneal tissue (IIIb)
• Grade 4: all layers

Question 24

How do we assess a rectal tear? (7)

Answer 24

• Stop the horse from straining
• epidural anaesthesia
• sedation (alpha-2 agonist +/- butorphanol)
• hysocine (spasmolytic)
• lidocaine enema
• Peritoneal tap
• Assess with ungloved, well lubricated hand

Question 25

what 5 first aid techniques can we do for a rectal tear? (5)

Answer 25

• Stop horse straining
• Gentle removal of faeces from rectum and tear
• Treatment of septic shock and peritonitis
• Epidural anaesthesia and packing of rectum with clean swabs
• Referral to surgical centre

Question 26

How do you treat rectal tears grade 3 and4?

Answer 26

•Surgery indicated for Grades 3 and 4

–Some success with frequent manual evaluation for grade 3

Question 27

How do you treat grade 1 and 2 rectal tears?

Answer 27

•Grades 1 and 2 may be managed by careful monitoring, administering laxatives and reducing feed intake

Question 28

What are the surgery options for a rectal tear? (5)

Answer 28

• Surgical closure (per rectum or at celiotomy - depends on location of tear)
• Temporary indwelling rectal liner
• Loop colostomy
• End colostomy
• Details in Auer’s Equine Surgery

Question 29

What are the treatment options for a grade 3 and 4 rectal tear?

Answer 29

Question 30

What is the prognosis for a rectal tear?

Answer 30

• Grade 1: 80-93% survival
• Grade 2: rare
• Grade 3: 60% long term survival
• Grade 4: faecal peritonitis -> death