Rectal tear and Prolapse HORSE Flashcards
Where do rectal tears in horses most commonly appear? WHY?
- Dorsal aspect of the rectum and longitudinally
- right at the peritoneal reflection
*that is where the circular muscle layer becomes thinner
If related to dystocia, where are rectal tears most commonly seen in horses?
-Ventrally
1-30 cm long
What are the predisposing factors for rectal tears in horses?
- Arabian and Miniature horses
- Mares
- older >9yo
- other: Fractious horses and previous tears
What is the most common cause for rectal tears in horses?
Transrectal palpation
For:
- colic
- reproductive purposes
Tears as wall contrast around hand
T/F: the increasing use of US has decreased the incidence of rectal tears
TRUE
How can you prevent rectal tears?
- Copious lubrication
- cleaning out rectum of all feces
- relax arm when horse strains/peristalsis
- sedation and antispasmodic
What can be used to chemical and physically restrain a horses for a rectal exam?
- xylazine
- butorphanol
What drug can be used to decrease rectal pressure in a horse?
BUSCOPAN
(N-butylscopolammonium bromide)
- 0.3mg/kg IV
- decreases rectal pressure by 70%
T/F: lidocaine enemas can decrease rectal pressure
False they cannot
Why should a parasympatholytic drug not be given before doing a PE?
-example
It can increase HR
BUSCOPAN
-decreases rectal pressure
How are Rectal tears classified?
Grade 1 (mucosa and sub mucosa torn)
Grade 2. (Muscle layer torn)
- mucosa and sub mucosa intact
- rare/incidental finding/impaction
Grade 3 (Mucosa, submucosa, muscularis torn) -serosa intact
Grade 4 (complete tear)
How do you distinguish between grade 3A and grade 3B rectal tears?
3A - only serosa intact
3B - mesorectum invovled, more dorsal (12oclock),
What are the clinical signs or a horse with a rectal tear?
1) On palpation:
- sudden release of resistance
- FRESH blood (except grade 2)
- direct palpation of viscera (grade 4)
2) Straining to deficate
3) Peritonitis
-grade 3 and 4
-abdominocentesis
——-WBC >50 000 within 30 min
-Retroperitoneal abscess if caudal to reflection
Why do you not see blood on palpation of a grade 2 rectal tear?
Because MUCOSA and SUBMUCSA are still intact
Only the muscularis is torn!!!!
Why would you get peritonitis with grade 3 rectal tear?
You only have the serosa
What is the normal value for WBC within the peritoneal cavity?
between 5 and 10 000 WBC
Why do some horses get depressed with rectal tears?
Endotoxemia (within 2 hours)
-Horses are extremely sensitive to LPS in the blood stream
What are the clinical signs of endotoxemia?
- lucopenia
- increased HR
- toxic line
T/F: Endotoxemia will happen with all rectal tears except grade 2
True
- all rectal tears that bleed
- grade 2 doesn’t bleed because only the muscularis is torn
Why do you not get endotoxemia with grade 2 rectal tears?
Because grade 2 have an INTACT mucosal barrier
T/F: wait and see may be deemed as negligence?
TRUE
What can be used to STOP straining in a horse rectal tear case?
- assess severity (1,3,4 grade)
- Xylazine (0.17mg/kg) + lidocaine (0.2mg/kg)
- Onset 5’ duration 5 hrs
- epidural (between c1 and c2)
- Hanging drop technique
What can diagnostic tools can be done to assess the Severeity of a rectal tear in a horse?
- speculum
- endoscopy
- ABDOMINOCENTESIS (for presence of peritonitis)
- CBC (ET)
- CHEM (ET)
What first aid measures should be taken for a horse with a rectal tear?
- sedation and severity examination
- Braod spectrum Abx + NSAIDs
- Fluid therapy (ET)
- Rectal tampon
- Prompt referral**
How far oral should a rectal tampon be placed?
At least 10cm oral to the lesion
-insert partially filled and then fill the rest once inside
*refer with purse string or towel clamp
how would you treat a rectal tear in a horse CONSERVATIVELY?
1) Antibiotics + NSAIDs
2) Fluid replacement (PO,IV) as needed
3) Laxatives + low bulk Diet (pellets/ mash etc..)
—-Oral fluids + MgSO4 (1g/kg)
—-Mineral oil
4) Daily removal of feces from rectum
—Q1-2hrs for 5 days
—Q6 then until healed (9-21 days)
PREVENT impaction of feces onto the tear!!!!
What broad spectrum antibiotics would you consider for treating a rectal tear conservatively?
1) Penicillin for:
—Gram +
—Anaerobes
2) Gentamycin:
—GRAM -
3)Metronidozole:
—anaerobes (betalactamase producing/resistant)
-apparently not good for Cali horses (raging colitis)
How would you treat a Grade 1 rectal tear in a HORSe?
CONSERVATIVE management
- rarely require Sx
- heals from remaining SM (~10days)
- Good prognosis with CM 90% survival
How would you treat a grade 2 rectal tear in a horse?
CONSERVATIVE management
- incidental finding
- dietary changes aimed to soften feces
Unless there is chronic impaction in diverticulum, these horses need to be euthanized
How would you treat a grade 3 rectal tear in a horse?
1) Conservative management (40-70% survival rate)
- labor intensive (epidural catheter, regular manual evacuation, abdominal lavage)
PREVENT progression to grade 4
When do you consider surgical management for rectal tears in horses?
GRADE 3/4
-combine with abdominal lavage and drain (standing, ventral and midline celiotomy)
- Different techniques depending on:
1) tear location
2) settings and finances
3) Case-based
What is the survival rate of a horse with peritonitis?
50%
What surgical technique would you use for a rectal tear that is close to the anus ?
Direct suture repair
-epidural—>Pneumorectum—>+ room
-clean lumen and tear with moistened gauze
-debride
-Externl anal sphincter can be incised @ dorsal comminuted
-retraction with stay sutures
—@12,3,6,9 o’clock
Not reachable through midline
-EASY and INEXPENSIVE
- close in direction of less tension (TRANSVERSLY)
- bites <1.5cm
- sutures placed subserosally
How would you close a direct suture repair of a rectal tear (close to anus)?
Close in direction of LESS tension -usually TRANSVERSLY -suture bites <1.5cm (To avoid lumen reduction -Subserosal suture placement
What are the 3 ways to repair a rectal tear close to the anus?
1) speculum + long handle instrubments
2) Non-visual direct suturing
3) Prolapse tear through anus
Any of these can be combined with bypass procedure
T/F: in a direct suture repair of a rectal tear near the anus, you want to use gloves
FaLSE
-want to have bear hand for better feeling
What surgical repair would you recommend for a post foaling mare with a rectal tear?
PRolapse tear through the anus
-due to laxity of perirectal tissues
When should you use a Prolapse tear through the anus repair for a rectal tear in horses?
1) Post partuirent mares
2) Grade 4 tears
- pneumoperitoneum
What stapler can be used to prolapse a rectal tear through the anus?
TA 90 or SI
-overseen
What surgical approach would you use for a rectal tear that is not accessible through the anus?
1) Laparoscopy
- hand assisted per rectum
2) Ventral midline celiotomy
- more commonly done if grade 4 with eviservation (to assess blood supply)
You have a grade 4 rectal tear with evisceration what surgical approach is best?
Why?
VENTRAL midline celiotomy
*We need to assess the viability of the intestine
T/F: most rectal tears occur 15-20cm cranial to the anus
TRUE
How many bypass rectal tear procedures are there and what are they?
1) Temporary indwelling rectal liner (TIRIL)
2) Colostomy
How do bypass rectal tear procedures work?
Divert feces away from tear
- with/without direct repair of tear
- prevent progression of 3 to 4 grade
- protect suture line
- prevents impaction of feces in tear
- decreases fecal contamination
For the TIRIL (temporary indwelling rectal liner) repair, what surgical approach should be taken?
-describe the positioning of the TIRIL
CAUDAL midline celiotomy + assistant per rectum
TIRIL is positioned:
10cm cranial from tear
10cm protruding from rectum
T/F: Loop colostomy is preferred over End colostomy?
TRUE
-easier to perform and to revert
T/F: Colostomy should be performed in lateral recumbancy
FALSE
It should be done standing
-shifting of muscle layers —>inaccurate placement
-risk of traumatizing stoma upon recovery
What are the advantages of colostomy over TIRIL?
- Better control of feces diversion for longer time
- better for large tears or those too far cranial
*TIRIL only lasts 9-12 days
Why are 2 incisions required for the loop colostomy?
High flank incision
-to find and prepare colon loop
Low flank incision (~10cm)
-Stoma placement
What are the land marks for stoma placement (low flank incision) of a loop colostomy?
1) midway betweeen flank fold and last rib
2) @ level of flank fold
3) parallel to last rib
T/F: Ventral edema develops and resolves spontaneously with loop colostomy
TRUE
How long do you have to wait to reverse colostomy?
6 weeks or more usually
What does the colostomy reversal involve?
1) lateral recumbency
2) “en bloc” resection of stoma
- flank laparotomy
3) small colon anastomoses
- SC + Lemberg
T/F: Initial management of rectal tears affects survival and liability
TRUE
