Large Animal Surgery

Evaluation of colic in foals

Rectal Tears/ Rectal Prolapse

What important factors in the history can help to diagnose colic in foals

• Breed• Sex• Birth circumstances (immune status, weak down

foals)• Deworming• Vaccination • Other illnesses• Pregnancy problems• Health of other mares and foals

What is the normal temp for a foal

• 99-101.5 degrees

What is the normal HR for a foal

• 70-100 bpm

What do you need to evaluate in a foal with colic

• Pain

• CV status

• GI tract

How do you evaluate for possible sepsis

• Look for hypoglycemia

• Depressed immune function

• Decreased intake

How to you evaluate the GI tract of foals

• Observe for distention and feces

• Auscultation

• NG reflux

• Abdominal palpation

• Ancillary procedures

What types of ancillary procedures might be done in a foal with colic

• US

• Rads

• Contrast rads

• Abdominocentesis

• CBC

What is the TP in foals compared to adults

• Lower in foals

What are the main differentials in a foal with colic in the neonatal period

• Meconium impaction

• Enteritis

• Ulcers

• Hernia w ruptured tunic

What are the main differentials in a foal w colic from 2-5 days of age

• Ruptured bladder

• Atresia coli

• Enteritis

• Ulcers

What are the main differentials in older foals w colic

• Ulcers

• Enteritis

• Gastric outflow obstruction

• Small intestinal volvulus

• Intussusception

• Hernias

What are the general principles when treating colic in foals

• Evaluate immunity and correct w IV plasma

• Minimal use of analgesics

• Rehydrate

• Resume feeding ASAP or use TPN

• Preventative therapy for ulcers

Meconium impaction commonly occurs in foals of what age

• <36 hours

Which foals have an increased risk for meconium impaction

• Males

• FPT foals

• Weak foals

What are the CS of meconium impaction

• Straining

• Absence of feces

• Abdominal distention

What is the main ddx for meconium impaction

• Atresia

How do you rule out atresia

• Digital palpation

• Rads

• Barium enema

How is meconium impaction treated

• Acetylcysteine enema

What are some causes of enteritis in foals

• C perfringens

• C difficile

• E coli

• Rotavirus

How do you diagnose enteritis in foals

• Fever, leukopenia

• Diarrhea

• Response to fasting

How do you treat enteritis in foals

• Check for systemic illness and give ATBS if necessary

• Decrease or discontinue milk if bloat

• NPO w TPN for a few days

How do you diagnose ulcers in foals

• Bruxism

• Colic after nursing

• Excessive salivation in older foals

How do you treat ulcers in foals

• Ensure hydration

• Address other problems

• Sucralfate

• If d/t NSAIDS give H2 blockers or omeprazole

What are the CS of ruptured bladder

• Depression, decreased nursing

• Progresive abdominal distention

What lab data is associated w a ruptured bladder

• Hyponatremia, hypochloremia, hyperkalemia

How do you diagnose a ruptured baldder

• US, rads, contrast rads

Is a ruptured bladder a surgical emergency

• No but it is a medical emergency

How do you treat a ruptured bladder

• Decrease serum potassium

• Abdominal drainage

• Sx when stabilized

What is the prognosis for uroabdomen

• Good-excellent for urachal or bladder tear

• Guarded for ureteral tear

What are the CS of atresia coli

• Initial signs of meconium impaction

• Progressive abdominal distention

• No feces

How do you dx atresia coli

• Confirm w barium enema

What is the cause of gastric outflow obstruction

• Duodenal ulcers

What are the CS of gastric outflow obstruction

• May be no hx of illness

• Bruxism

• Spontaneous reflux

• Colic after nursing

What is the tx for gastric outflow obstruction

• Gastrojejunostomy (w or wo jejunojejunostomy)

What are the CS of small intestinal obstruction

• Pain

• Abdominal distention

• reflux

What types of small intestinal obstruction occur

• Congenital or acquired hernia

• Intussusception

• Volvulus

• Meckels diverticulum

Which Cs should make you suspect intussusception or volvulus

• Pain following onset of diarrhea

What is your diagnosis

• Meckels diverticulum

What is a meckels diverticulum

• Embryologic remnant of the omphalomesenteric duct– Band that connects antimesenteric surface of

the ileum to the umbilicus

What is your diagnosis

• Umbilical hernia

What is your diagnosis

• Intestinal adhesions

What is the prognosis for foals <14 days old w SI obstruction

• 10% survival

What is the prognosis for foals 15-150 days old w SI obstruction

• 46% survival

Why is the prognosis so bad for SI obstructions

• Increased risk of adhesions

• Delayed indentification

• Sepsis

What are some examples of LC and SC obstructions

• Fecalith, bedding ingestion, hairball

What is the main cause of rectal tears

• Iatrogenic d/t rectal palpation

How will you first know that there is a rectal tear

• Blood on the rectal sleeve

• Feel rectum suddenly relax

Where are most rectal tears

• Dorsally between 10 and 2 oclock

What is a grade 1 rectal tear

• Mucosa and submucosa

What is a grade 2 rectal tear

• Disruption of the muscular layer (mucosa and serosa still intact)

What is a grade 3 rectal tear

• Disruption of the mucosa, submucosa and muscularis

What is the difference between a 3a and 3b tear

• 3a the serosa remains intact

• 3b is extension into the mesocolon

What is a grade 4 rectal tear

• Disruption of all layers of the rectal wall

What is your dx

• Grade 4 rectal tear

What is your dx

• Grade 1 rectal tear

What is your dx

• Grade 2 rectal tear

What is your dx

• Grade 3a rectal tear

Which grades of rectal tear should be referred

• Grade 3 or 4

What should be done prior to referring a grade 3 or 4 rectal tear

• Pack rectum cranial to tear

• Banamine

• ATBs

• Atropine (to slow intestinal motility)

What is the tx for grade 1 or 2 rectal tear

• No palpation for a few weeks

• Banamine

• ATBs

• Diet that will cause soft feces

What are the options for surgical repair of a grade 3 or 4 rectal tear

• Rectal liner

• Colostomy

What surgical approach is needed to place a rectal liner

• Caudal ventral midline incision

What is the principle behind placing a rectal liner

• Liner is placed using a PVC pipe and long plastic bag so that feces will pass through the bag and not interrupt the rectal tear

• The tear heals by second intention

How is the rectal liner removed

• Chromic gut is used to suture it in place…breaks down in 2 weeks and the PVC pipe and plastic bag are passed in feces

What is a complication of placing a rectal liner

• Retraction of the liner into the rectum when the horse lies down

What can be done to prevent retraction of the liner into the rectum

• Patient should be kept standing until the ring has been passed

What is a colostomy

• Fecal diversion to the left paralumbar fossa

How long are colostomys left in place

• 6-7 weeks

What is the prognosis for for a grade 1 or 2 tear

• Good

What is the prognosis for for a grade 3 or 4 tear

• Fair-poor

What is the etiology of rectal prolapse

• Straining to defecate

• Chronic pneumonia

• Short tail

What is the tx for rectal prolapse

• Epidural anesthesia

• Manual reduction or sx resection

• Topical agents/astringents

• +/- purse string

What can be done to create inflammation and adhesions around the

rectum in ruminants• Inject iodine perirectally

What can be done to create inflammation and adhesions around the

rectum in foals or mares• Nothing you cant inject iodine in equines

What is your diagnosis

• Grade 4 rectal prolapse; full thickness tear w omentum coming out

What is your diagnosis

• Rectal and vaginal prolapse

How would you treat the previous case

• Amputate the devitalized tissue

What is the prognosis with a grade 1 or 2 rectal prolapse with reduction

• Good

What is the prognosis with a grade 1 or 2 rectal prolapse with resection

• Guarded

What is the prognosis with a grade 3 or 4 rectal prolapse

• Guarded-poor