Equine Colic Types

Torsions and entrapments (hernias)

Both the small and large intestines can twist. The large colon tends to twist more often, likely related to changes in gas levels and motility. Intestines can also slide through small holes (hernias, mesenteric rents). Often they can’t slide back out (particularly in small holes) and become distended and swollen, leading to even more severe entrapments and devitalization.

Large colon volvulus

Signalment
  • Deep chested breeds
  • Broodmares, especially late gestation and postpartum
Clinical signs
  • Rapidly increasing severe pain
  • Abdominal distension (bloat)
  • Shock
  • Occasionally bradycardia (vagal tone?)
  • Toxic signs
Diagnosis
  • Rectal palpation – severe gas distension
  • Ultrasound -thickened colon wall >9mm and edema around vessels
  • Differential- uterine artery rupture
Complications
  • Endotoxemia
  • Hypoproteinemia
  • Diarrhea (mucosa sloughs)
  • Salmonellosis
  • DIC
  • laminitis
  • fatal hemorrhage
Treatment
  • Surgery
  • To stabilize -give hypertonic saline; trocarize if needed to decompress; wean foal
Risk factors
  • Changes in space (parturition)
Prognosis
  • Fair to grave, depending upon amount of damage
  • Can recur- up to 15% in broodmares; 80% if had two episodes
Prevention
  • Don’t let the mare carry another pregnancy (can do embryo flush)
  • Colon removal or colopexy

These horses do require surgery and intense medical therapy. The colon may be viable enough to just be untwisted and left in the horse. Much of the colon can be removed if needed. This isn’t always possible due to the location of the twist.

Small intestinal volvulus

Signalment
  • especially 2-4mo; < 3 years
Clinical signs
  • Moderate to severe colic
  • Depression in foals
Diagnosis
  • Distended SI on rectal exam or ultrasound
  • Marked abdominal distension in foals
  • Abdominocentesis
Complications
  • Peritonitis
  • Adhesions
  • Intestinal rupture
  • Hypovolemic shock
Treatment
  • Surgery
Risk factors
  • Inguinal hernia
  • Mesodiverticular band
  • Meckel’s diverticulum
  • Mesenteric rents
  • Fixation by umbilical remnants
Prognosis
  • Fair; foal are more prone to adhesions
Prevention
  • none

 

Up to 50% of the small intestine can removed if needed due to damage. These horses are more prone to postoperative ileus and adhesions.

Hernias

Inguinal hernias

Signalment
  • foals, stallions; especially Standardbreds, Tennessee Walking Horses and Saddlebreds
Clinical signs
  • foals – no pain; scrotal swelling with palpable loops SI
  • stallions – colic; enlarged scrotal neck, testicle cold and firm
Diagnosis
  • Scrotal changes
  • Ultrasound of scrotum
  • Rectal examination of inguinal rings
Complications
  • rare in foals; resolves on own 3-6mo
  • older foals: secondary volvulus
  • stallions – intestinal strangulation, testicular damage, adhesions
Treatment
  • foals – daily reduction and monitoring
  • stallions – generally need surgery with unilateral castration to close ring
Risk factors
  • breeds
  • breeding
Prognosis
  • Fair to good
Prevention
  • none

Epiploic foramen entrapments

Related to cribbing. Often have a normal belly tap despite dead bowel.

License

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Large Animal Surgery - Supplemental Notes by Erin Malone, DVM, PhD; Elaine Norton, DVM PhD; Erica Dobbs, DVM; and Ashley Ezzo, DVM is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.