Large colon Flashcards
What are the causes of large colon impactions?
Coarse feeds, poor dentition, inadequate mastication
Alterations in colonic motility, reduced water intake, sand and amitraz (a2agonist)
2 sites of large colon impactions
Pelvic flexure and transverse colon
Motor centers to induce retention of food
CS of ingesta impactions
Intermittent mild pain that worsens
Pulse 40-60 dpm
Mild dehydration
Pelvic flexure or ventral colon mass
Shock (devitalizedDx colon)
Dx ingesta impactions
CS
Rectal exam (right side pelvic mass, gas distention of colon, normal exam)
Medical tx of ingesta impactions
Mineral oil, oral fluids, IV fluids, analgesics (fluxenin meglumine), restricted oral intake
Sx tx of ingesta impactions
Perform when deterioration of vital signs and changes in peritoneal fluid
Pelvic flexure enterotomy
CS of sand impactions
Intermittent colic that responds to initial therapy
Recurs in a few days to weeks
Similar to ingesta signs
How to dx sand impactions
Rectal exam: hard mass or sand (central midline and pelvic flexure)
Medical tx for sand impactions
IV fluids
Mineral oil (lubricates intestinal tract, ↓ tympany)
Psyllium (propels the impaction)
When is sx for sand impactions performed?
There’s unrelenting pain, palpable mass on rectum and changes in peritoneal fluid
What kind of sx is done with sand impactions
Pelvic flexure colotomy and lavage
(transverse colon)
Enteroliths
Common in FL, CA and midwest
Transverse, right dorsal and pelvic flexure most common sites
Made of Mg ammonium phosphate
CS of enteroliths
Moderate abdominal pain
Lack of fecal production
Don’t pass mineral oil
Tympany in extreme cases
Sx tx for enteroliths
Pelvic flexure colotomy- retrograde manipulation of stone and empty large colon
Second colotmy in dorsal colon
Large colon displacements are due to…
Extensive movement of abdominal cavity
↑ abdominal content of weight
Excess gas production in the colon
Most common forms of large colon displacements
Left dorsal displacement (nephrosplenic)
Right dorsal displacement
Retroflexion of the pelvic flexure
CS of large colon displacements
Intermittent pain that worsens
Mild dehydration
Shock with devitalized colon
Rectal exam of left colon displacement
Nephrosplenic entrapment
Spleen not against body wall
Can’t sweep kidney to spleen
Could have flexure (needs sx!)
Rectal exam of right dorsal displacement
Left abdomen empty
Left colon lateral to cecum
Retroflexion of pelvic flexure rectal exam
Left abdomen empty
Thick blind pouch
Medical tx for left dorsal displacement (without flexure)
Short acting anesthetic
Rompun- ketamine
Right roll, hoist and hand, right roll
What tx is best for mild to moderate colon distention (left colon dispacement)
Phenylephrine
Excitement evident during infusion then jog/ lunge for 30 minutes
Sx tx for left dorsal displacements
If conservative methods fail and deteriorating condition
Large entrapment
Volvulus of the large colon
Most devastating forms of colic
Bloodmares most commonly affected
Involve cecocolic ligament or cecal base
Ventral colon dives medially
CS of volvulus of the large colon
Severe continuous abdominal pain
HR >80 bpm
Shock: delayed CRT, cyanotic mm, cold sweat, ↓ skin turgor
Dx of Volvulus of the large colon
CS
Rectal exam: severe distended large colon
Tx of Volvulus of the large colon
Sx: early intervention → replace colon in normal position with colotomy (↓ transmural absorption)
Transabdominal drain
How to evaluate the colon for sx
Serosal color
Presence of arterial pulsation
Bowel wall thickness
Hemorrhage from colotomy site
Mucosal color
Resection of the large colon (Volvulus of the large colon)
Damage extends beyond resection area
81% survival in horses with less than 50% resected
53% survival in horses with more than 50% resected
Adaptive changes of a resected large colon
Prone to poor protein absorption
↑ fecal water losses
Colopexy (Volvulus of the large colon)
Developed for recurrence of volvulus
Left ventral colon to midline closure and 6 cm to the left of midline
Done if WL and rupture of colon occurs
Prognosis of Volvulus of the large colon
Early intervention: good
Delayed: laminitis and shock
