Equine GI Sx II Flashcards
Cecal lesions
Impaction Intussusception (cecocecal, cecocolic) Volvulus or torsion Infarction Neoplasia Cecal rupture secondary to cecal impaction is not uncommon
Cecal impaction etiology and Dx
Most common cecal disease
- 40-55% of cecal diseases, 5% of all impactions
Multifactorial etiology
- Poor dentition
- Poor quality hay
- Decreased water intake
- Tapeworms
- Hospitalization or prior Sx, particularly orthopedic
. NSAIDs, anesthesia, immobilization
Dx: Rectal palpation (firm mass on midline)
Cecal impaction complications and Tx
High risk of rupture: dehydrated intestinal contents and progressive distension leads to stasis and fluid accumulation -> mural compromise and severe cecal distension
- Can also have primary motility dysfunction
Rupture can occur without any warning signs
Can be treated medically or Sx - controversial
Medical therapy: IV and oral fluids, oral laxatives, psyllium, walking, controlled grazing to stimulate motility, flunixin meglumine
- No xylazine and butorphanol if possible - decreases cecal motility
- Promotility agents controversial; neostigmine NOT recommended
Sx intervention probably best for horses with moderate to severe impactions
Large colon lesions
Large colon tympany (gas colic, spasmotic colic) Impaction Enterolith Nephrosplenic entrapment Right dorsal displacement Strangulating large colon volvulus Right dorsal colitis Mural infarction
Large colon tympany basics and risk factors
Gas colic dt excessive fermentation Most common diseases of the large colon and most common cause of colic in the horse Bowel distension and pain Risk factors: - Cribbing - Recent change in exercise program - Ineffective deworming regimen - Hx of travel - High carb diet
Large colon tympany Dx and Tx
Dx: rectal exam
- Gas distension without tight bands
- Need to rule out other differentials
Typically respond rapidly to conservative therapy: analgesics and temporary withholding of food
Large colon impaction basics and risk factors
Second most common disease of the large colon
Impaction can be caused by feed, sand, and gravel
Tends to occur in places where the diameter of the GIT changes dramatically
- Pelvic flexure
- Junction of the right dorsal colon and transverse colon
Risk factors:
- Decreased water intake
- Poor dental care
- Recent change in exercise regimen
- Insufficient deworming regimen
- Recent travel
- High carbohydrate diet
Large colon impaction Dx and Tx
Most frequently Dx on rectal exam
Medical management: oral, IV fluids, analgesics, oral laxatives, temporarily withholding feed
Early/mid impactions typically respond to medical management within 24-48h
Large impactions often require Sx
- Uncontrollable pain, deteriorating cardiovascular status, lack of progress with medical management, bowel compromise
Large colon sand impaction
Major risk factor is feeding on the ground in regions with sandy soil
Insufficient roughage diet
Build-up is typically slow, may show few clinical signs other than transient diarrhea
Dx via rads or fluoroscopy
May be able to auscultate sand rubbing along the ventral abdomen
Rupture a major concern
Enterolithiasis
Primarily struvite crystals and magnesium ammonium phosphate
- Primary enteroliths more common in California and Florida
Ingested FB can act as nuclei for formation of enteroliths
Come in different shapes and sizes
- Single enteroliths tend to be spherical
- Flattened surfaces are highly suggestive of multiple enteroliths
Can cause acute, persistent colic OR intermittent low grade colic (ball valve effect) dt intermittent obstruction
Most commonly located in the right dorsal colon, transverse colon, and small colon
Sometimes diagnosed on rads
Treatment is always surgical***
Large colon displacement/volvulus
Volvulus (colonic torsion) may be non-strangulating (<270) or strangulating (>360)
- If 360, may also be described as right dorsal displacement or left dorsal displacement/ nephrosplenic entrapment
- Torsion most commonly occurs at or proximal to the cecocolic ligament (must be palpated to determine direction for correction)
- NSE can cause strangulation
Nephrosplenic entrapment
Large colon is displaced dorsally and to the left and becomes stuck in the nephrosplenic space
Diagnosed by rectal exam and/or abd US
- Spleen and left kidney cannot be imaged adjacent to each other
Often, impaction is also present
Medical management:
- Phenylephrine (10-20mg) to shrink spleen and jogging
- Rolling (requires general anesthesia and lots of help)
Assess correction via rectal palpation and/or US
Right Dorsal Displacement
Initiated by retropulsive movement of impacted pelvic flexure and migration of the large colon to the right
Large colon located between the cecum and the body wall
Abd pain may be acute and moderate, or mild and intermittent
Cannot palpate pelvic flexure on rectal exam, may feel bands going up and to the right
May be able to resolve medically (IV fluids, analgesia) or may require Sx correction
Level of pain/response to pain meds determining factor
Large Colon Volvulus
Most painful and devastating GI dz Exact pathophysiology unknown Risk factors: - Broodmares - Recent parturition - Diet changes - Recent access to lush pasture Usually clockwise direction as viewed from behind the horse - Palpation intra-op to confirm
Large colon volvulus sequence
Pathology linked to colonic wall devitalization via ischemia and/or congestion
Fluid sequestration in the lumen
Bacterial translocation and massive endotoxin release into systemic lymphatics and vasculature
Septic/endotoxic shock
Early referral and prompt Sx significantly improves prognosis
