Acute Colic Flashcards
What are the most common signs of colic in horses?
- frequent pawing
- kicking at abdomen
- stretching out as if to urinate
- laying down
- rolling
- anorexia
- sweating
- muscle fasciculations
- Flehman response
What is the pathogenesis of strangulating lipoma? What horses are most commonly affected?
mesenteric lipoma on a stalk twists around one or more pieces of the small intestines causing strangulation
older horses, usually 20+ y/o
What is the pathogenesis of small intestinal volvulus in horses?
twist in the small intestines causes strangulation at the root of the twist
What horses are most commonly affected by small intestinal intussusception? What are 2 common causes?
younger horses
- diet changes
- parasites, especially tapeworms
Where is intussusception most common in horses?
ileocecal
What are the 3 most common places of small intestinal herniation in horses? What is the pathogenesis?
- inguinal - congenital, acquired traumatic, castration-associated
- umbilical
- incisional
small openings usually only allow SI to herniate through and become strangulated
What mesenteric defects commonly cause small intestinal strangulation in horses?
- mesenteric rent
- epiploic foramen entrapment
What does anterior/proximal enteritis mimic? How does it differ?
SI obstruction
pain is less severe, but there is significant GI reflux
What are 2 characteristic signs of small intestinal disease in horses? What else is commonly seen?
- severe pain with poor response to analgesics
- gastric reflux
elevated HR, systemic shock
What is seen on AUS in cases of small intestinal disease in horses?
dilated/non-motile loops of small intestine
What happens as small intestinal disease develops and becomes more chronic in horses?
serosanguinous abdominal fluid with elevated proteins/WBCs accumulated within the abdomen
What is seen on rectal exam in horses with small intestinal disease?
palpable distended loops of small intestines
What is the most commonly effective treatment of small intestinal strangulation in horses? What is prognosis like? What is a common complication?
surgical - resection and anastomosis if bowel has devitalized
guarded - poor with longer duration or large amounts of dead bowel (>15 ft)
post-op ileus if resection is required
What is the pathogenesis of large intestinal volvulus/torsion in horses?
portion of colon twists, rapidly becomes ischemic, and begins to necrose
What is a common risk factor that increases the development of large intestinal volvulus/torsion in horses?
older broodmares just before parturition or up to 4 months postpartum, especially larger horses (more room for colon to twist)
What are 2 classic signs of large intestinal volvulus/torsion in horses? How is it differentiated from small intestinal disease?
- severe pain poorly responsive to analgesics
- elevated HR and systemic shock
NO gastric reflux - lesion is too caudal to allow fluid back up to the stomach
What is seen on rectal exam in cases of large intestinal volvulus/torsion in horses?
palpable diffuse gas-distended large intestine
What treatment is required for large intestinal volvulus/torsion in horses? What complication is associated? What is prognosis like?
surgical - nearly impossible to resect the LI
endotoxic shock once volvulus is corrected
good/fair if early surgical correction; poor if more than a few hours
What are 2 risk factors associated with colonic impaction in horses?
- older horses or those with poor dental care, especially when fed hay or coarse feed
- decreased water intake - stress, cold weather, frozen water
In what horses is colonic impaction most common?
miniature horses - frequently impacted with hair from grooming self/other horses or feed material due to poor dentition
What clinical signs are associated with colonic impaction in horses?
mild or intermittent colic that worsens as time progresses + noticeable decrease in manure production
- may appear “normal” with analgesics
What are 3 important treatments used for colonic impaction in horses? What is prognosis like?
- analgesics
- oral fluids with laxatives via intermittent or indwelling NG tube - mineral oil, psyllium, Epsom salts
- IV fluids
(main goal is to hydrate impaction)
good - surgical correction is only necessary with severe pain or several day duration
What are 2 common causes of colonic tympany (gas colic)?
- diet change
- grain overload
(can happen anytime!)
What is a characteristic sign of colonic tympany (gas colic) in horses? What else may be seen?
often spasmodic mild to severe pain –> as gas passes, pain subsides
- increased HR
- abdominal distension
What are 3 important parts of treating colonic tympany (gas colic) in horses? What is prognosis like?
- analgesics
- sedation
- IV fluids
(often remains medical unless it becomes severe and causes circulatory issues)
good
What is the most common colon displacement in horses? What others 2 can be seen?
left dorsal displacement - nephrosplenic entrapment (colon goes into the deep space between the left kidney and spleen and becomes distended with gas
- right dorsal displacement - colon between cecum and right body wall
- pelvic flexure displacement
What is the major risk factor associated with colonic displacement in horses? Why?
large breeds (Warmbloods) –> more room for the colon to displace
How is colonic displacement diagnosed?
rectal exam –> palpable, tight bands of a gas-distended large colon
How is nephrosplenic entrapment diagnosed?
inability to identify the left kidney on transabdominal ultrasound
How is colonic displacement treated? Nephrosplenic entrapment specifically?
medical –> surgical if no improvement
IV phenylephrine to shrink spleen and decrease nephrosplenic space, then trot the horse or anesthetize and roll to encourage the colon to return to the normal space
What are 4 major risk factors for horses to develop enteroliths/sand colic? What breed is predisposed?
- geographic areas with sandy soil (CA, FL, AZ)
- horses fed on dirt ground
- horses fed insufficient roughage / malnourished
- alfalfa hay due to mineral composition
Arabians
What is the most common make up of an enterolith in horses? Where are they most commonly found?
precipitation of struvite salts (magnesium ammonium phosphate) around a foreign body nidus
small colon or transverse colon due to small size
What is the pathogenesis of sand colic?
chronic, low-grade ingestion of sand or dirt, which does not pass in manure well and settles on the ventral aspects of the colon
What are the most common signs associated with enteroliths and sand colic?
- mild/moderate intermittent pain
- auscultable fluid wave on sand in central abdomen
- gas distention on rectal exam (large enteroliths can block gas from passing)
How is sand colic and enteroliths diagnosed?
SAND COLIC - positive fecal sand float
ENTEROLITHS - radiopaque sand or stone visible on abdominal radiographs
How are enteroliths and sand colic treated?
ENTEROLITH - enterotomy
SAND COLIC - frequent nasogastric tubing with water, mineral oil, psyllium, and laxatives; enterotomy if medical treatment is unsuccessful
What are 3 major risk factors for horses to develop gastric ulcers?
- highly stressed or nervous horses (showing, racing, traveling)
- prolonged time with an empty stomach (no turnout, decreased roughage)
- NSAID usage
Where are gastric ulcers most commonly found in horses?
squamous region (non-glandular, dorsal stomach)
What are the most common clinical signs associated with gastric ulcers in horses?
- mild/moderate pain
- mild anorexia
- cranky/irritable behavior
- NO bleeding into GI
- often responds well to initial dose of analgesics (Banamine), but repeated use worsens the ulcers
often no abnormalities on PE, rectals, or U/S
How are gastric ulcers in horses diagnosed? What are 3 important parts to treatment?
fasted gastroscopy
- Omeprazole (gastric hydrogen potassium ATPase inhibitor) - several weeks to months
- Ranitidine (H2 blocker)
- Sucralfate
What are 3 ways of preventing gastric ulcers in horses?
- feed alfalfa hay to reduce stomach acid
- maximize roughage and turnout time
- reduce stress
What are the 2 most common causes of parasite-associated colic in horses? What horses are most commonly affected?
- Parascaris equorum (roundworm) - ascarid impaction
- Strongylus vulgaris - verminous arteritis, thromboembolic colic
horses <1 y/o that haven’t been dewormed and recently given a large dose of anthelmintics –> massive numbers of parasite die-off
What is the pathogenesis of verminous arteritis in horses?
- S. vulgaris migrates to the cranial mesenteric artery
- damage and immune response forms a thrombus that cuts off blood supply to the bowel, resulting in an infarction (most common in cecum)
What treatment is required for parasite-associated colic in horses?
surgical intervention
What are the 5 most common causes of infectious colitis in horses?
- Salmonella
- Clostridium perfringens
- Clostridium difficile
- Potomac Horse Fever - Neorickettsia risticii
- Equine Coronavirus
What are the 3 most common causes of noninfectious colitis in horses?
- diet change
- right dorsal colitis - NSAID use
- intestinal neoplasia
What is colitis X?
undiagnosed causes of peracute, fatal enterocolitis in horses, characterized by sudden onset of profuse, watery diarrhea and development of hypovolemic shock
What clinical signs are suggestive of colitis in horses?
- mild to moderate pain, frequently intermittent or spasmodic
- systemic shock
What treatments are recommended for colitis in horses?
- analgesics
- IV fluids
- probiotics
- Biosponge - horse digestive supplement
When are antibiotics used for colitis in horses?
Tetracyclines used for treating Potomac Horse Fever caused by Neorickettsia risticii
What are 2 common non-gastrointestinal causes of colic signs in horses?
- urolithiasis - stallions, geldings (mares rarely become obstructed)
- uterine torsion - pregnant mares in late gestation
What are the 2 major risk factors associated with urolithiasis in horses? What is the most common composition?
- stallions and geldings
- horses fed alfalfa or high-protein diets
calcium carbonate
What clinical signs are associated with urolithiasis in horses?
- acute severe pain
- stretching out as if to urinate
- straining without producing significant quantities of urine
What are 2 ways of diagnosing urolithiasis in horses?
- distended bladder on rectal exam
- palpable calculi on rectal or with U/S
How is urolithiasis treated in horses? What is prognosis like?
emergency surgical removal
recurrence common, especially if diet is not addressed
What is a major risk factor for the development of uterine torsion in horses?
mares in last trimester of gestation (7 months+)
What clinical signs are indicative of uterine torsion in horses? What is characteristically felt on rectal exam?
- mild to moderate colic signs
- anorexia
- recumbency
- signs persist despite appropriate treatment for GI colic
broad ligament pulled tight over uterus
How is uterine torsion in mares treated? What is prognosis like?
- place mare under general anesthesia
- roll her with a plank over the abdomen to stabilize the fetus in the direction of the torsion
good for fetus and mare especially if treated early
