Equine Flash Notes - Equine Colic Exam & Key Colics Flashcards
what is the basic mechanism of colic pain in horses?
- distension of gut with fluid, gas, or ingesta
- something is pulling on the root of the mesentery
- something causing ischemia/infarction
what are the 2 manifestations of colic pain in horses?
visceral abdominal pain - pushing on abdomen doesn’t cause pain unless you’re touching the effected organ
parietal abdominal pain - peritonitis, external palpation elicits pain
what are some examples of severe, life threatening colics?
infarctive disease - volvulus, torsion, or thromboembolism
severe visceral distension - extreme gas, impaction, or dilation
T/F: 90% of colics are uncomplicated & respond to analgesic treatment
true
what are the main clinical signs of colic?
signs of pain variable
rolling, sweating, flank watching, kicking at abdomen, anorexia, depression
severe - cold extremities, increased CRT, bright right mucus membranes from vasodilation
what are the ten p’s needed for colic diagnosis?
- physical exam
- pain
- pulse - > 60 bpm, pass NG tube, palpate digital pulses for signs of laminitis
- perfusion
- peristalsis
- percussion
- pass NG tube
- palpation per rectum
- peritoneal fluid tap - if you see plant material or RBC, indicative of rupture, euthanize
- PCV & TPR
what are the normal values of peritoneal fluid in horses?
protein < 2.5 g/dl
normal cells between 5-10,000
what are clinical signs of colic that indicate surgery is necessary?
severe abdominal pain that is poorly responsive or unresponsive to analgesics
discolored peritoneal fluid with increased protein, RBC, & WBC
on rectal - obstruction or displacement of viscera
progressive deterioration of cardiovascular status with abdominal pain & uncertain diagnosis
significant gastric reflux
recurrent abdominal pain with uncertain cause
what is the prognosis for colic in horses?
90% respond to analgesics
surgery - guarded to poor with 50% recovering from surgery, HR of 100 = 30% survival, & PCV >60 = 25% survival
what are some examples of toxic causes of colic?
blister beetle, warfarin, herbicides, lead, phenylbutazone/other nsaids, & poisonous plants
what are some examples of extra-gi causes of colic?
mesenteric abscess, ovarian tumor/abscess, parturition, acute hepatitis/hepatic lipidosis, diaphragmatic hernia, ruptured bladders in foals, urolithiasis, & uterine torsions
what are some common gi causes of colic in horses?
gas distension of intestines/cecum/colon
hypermotility & intestinal spasms
feed impaction/constipation
meconium impaction in foals
gastric ulcers in foals
what should you do before giving any drugs to a horse with colic?
check their heart rate/evaluate cardiovascular status
can mask pain
what are some common initiating factors of colic?
changes in diet, water consumption, exercise, weather
what are some signs of hypovolemia/poor perfusion in a horse with colic?
pulse higher than 52 of fair/poor quality
prolonged CRT
prolonged skin turgor
cool extremities
need for fluid therapy
if you hear a ping when doing a colic exam, where does that localize to?
large bowel or cecum
how is rectal palpation of a colic horse done? how are organs identified?
palpate backwards - sigmoid loop (long mesocolon in front of pelvic inlet), go in as far as possible & move backwards
start at left kidney & move across to spleen & nephrosplenic ligament
small colon - fecal balls & bands & sacculations
cecum - medial band
ventral large colon - bands
pelvic flexure - no bands felt, but it does have 1
where is a peritoneal tap done on a horse?
ventral midline caudal to xiphoid & to the right of midline to avoid the spleen - done at the lowest part of the abdomen
EDTA tube for cytology & sterile tube with no additives for visual inspection & culture
what are the cardinal clinical signs of colic that indicate surgery should be done?
severe abdominal pain poorly/non-responsive to analgesia
discolored peritoneal fluid containing increased protein, RBC, WBC
on rectal - obstruction and/or displacement of viscera
T/F: the earlier the decision is made for colic surgery, the better chance of recovery
true
what medical treatment is used for colic?
- analgesia - xylazine & banamine
- decompression - nasogastric tube
- fluids - oral/iv or both, oral if not refluxing at 1-2 L/hour - LRS is fluid of choice
avoid peripheral vasodilators
what percentage of horses die after R&A surgery?
75%
what are some physical parameters that indicate a poor prognosis for a horse with colic?
HR > 80
PCV > 60%
uncontrollable pain
what should be done before colic surgery?
stabilization!!! pre-op fluids, abx, banamine
what anesthesia is used for colic surgery?
xylazine/ketamine combined with glycerol glycolate
isoflurane - intubate in sternal
after open the abdomen in a colic surgery, what should you immediately assess?
apex of cecum on midline
ventral colon surrounds apex of cecum
abdominal cavity - look for ingesta, distended loops of intestines ballooning out the incision (need to decompress with needle/tubing to continue exploration)
what is included in the preliminary explore of a colic surgery?
gently explore abdomen by gently sweeping viscera with hand - cause may be immediately apparent
look for: turgid loops of bowel, hard masses, tight mesenteric bands, roughened peritoneal surfaces of fibrin adhesions, & root of mesentery & connection of cecum & colon for volvulus
what is included in the deeper explore of a colic surgery?
cecum is reference point - if cause isn’t apparent, systemically explore abdomen
apex of cecum on ventral midline
ventral colon surrounds apex of cecum - right ventral, sternal flexure, & left ventral
4 bands & sacculations of ventral colon & cecum - locate cecocolic ligament between lateral band of cecum & right ventral colon
what structures can be exteriorized during colic surgery?
apex of cecum
pelvic flexure
dorsal colon - left dorsal (small with 1 band in mesentery) , diaphragmatic flexure, & right dorsal part (3 bands but no sacculations)
mesocolon - connects ventral & dorsal colon & contains blood supply (colic branch to ventral colon & right colic artery to dorsal colon) & connects to dorsal abdomen at root of mesentery
jejunum
small colon/descending colon - located to left of the base of cecum heading into pelvic cavity (2 bands, sacculations, & fecal balls) part of it can be exteriorized
transverse colon - connects right dorsal colon with small colon that transverses abdomen from right to left in front of cranial mesenteric artery
after finding the small intestines, how do you work your way through the organs of a horse during a colic surgery?
ileocecal ligament - pull apex of cecum up & locate the ligament connected to the dorsal band
ileum - follow ileocecal fold from cecum to ileum or reach down the left side of the base of the cecum to blindly find it
jejunum - trace small intestines forward (pull out & replace going along entire length, point thumb in direction you’re going to keep track) ascending duodenum becomes jejunum at duodenojejunal flexure
ascending duodenum - located by its connection to small colon, duodenocolic ligament on left side of cecum (can’t be exteriorized)
duodenocolic ligament - connects ascending duodenum to the small colon
descending duodenum - reach between the base of the cecum & the right body wall dorsally (only tubular structure located here but can’t be exteriorized)
pylorus - found by following the descending duodenum cranially but can’t be exteriorized
liver - located along right body wall & touching base of cecum
right kidney - nestled in the renal impression of the caudate lobe of the liver dorsally
epiploic foramen - pass hand between descending duodenum & right body wall to the liver & right kidney, so if no bowel is present in this region, no need to check epiploic foramen
how do you enter the epiploic foramen during a colic surgery?
pass a finger under the caudate lobe of the liver forward into epiploic foramen between the portal vein ventrally & caudal vena cava dorsally
after finding the large intestines, how do you work your way through the organs of a horse during a colic surgery?
find them by returning to the cecum
cecum - palpate up body to base in right paralumbar fossa
body of cecum - along the right abdominal wall from base to apex (can be partially exteriorized)
base of cecum - right paralumbar fossa anchored to dorsal abdomen (can’t be exteriorized)
ventral colon - around apex & body of cecum with 4 bands
cecocolic ligament - pull up on cecum & see connection between lateral band & right ventral colon
pelvic flexure - found on left side near pelvic inlet, junction between ventral & dorsal colon
what is a decompression surgery?
colic surgery - distended bowel (jejunum, cecum, or large colon)
punctured with needle through purse string suture & tie as you remove the needle
when are pelvic enterotomies used for colic surgery?
opened to empty out large colons (dirty, special table used)
incision made toward ventral or dorsal colon not in pelvic flexure
empty colon - garden hose up enterotomy!!!
wash gi & put back into correct positions
what are some examples of end to end anastomosis used in colic surgeries?
jejunum to jejunum
jejunum to small colon
large ventral colon
when are side to side anastomosis surgeries used for colics?
used to unite unequal sizes of bowel
jejunocecal anastomosis if ileum must be resected
anastomose end to end jejunum to dorsal band of cecum as far towards the base as possible
what is probably the most common cause of colic in horses? what is the suggested pathophysiology?
spastic colic - spasm/hypermotility of intestinal tract
pain caused by spasms of gut - hyperexcitable horses predisposed
causes unknown, but implicated: ANS imbalances, irritation of gut by parasites, enteritis, & moldy feed, & s. vulgaris
what is the classic case presentation of spastic colic in horses?
loud gassy intestinal sounds, intermittent abdominal pain, patchy sweating on neck, & no systemic deterioration
frequent passage of feces
how is spastic colic diagnosed?
auscultation - loud rumbling borborygmi, elevated pulse, & normal rectal
how is spastic colic treated?
may spontaneously recover in 10-60 minutes
if not - dipyrone, rompun, & mineral oil
no atropine as an antispasmodic because it may cause adynamic ileus
what is the cause of primary intestinal tympany colic in horses?
microbial fermentation of lush grass, grains, or pelleted feeds
what is the cause of secondary intestinal tympany colic in horses?
obstruction of colon/cecum
mechanical - fecoliths/enteroliths in small colon, large colon displacement
functional - adynamic ileus
what is the cause of flatulent colic in horses?
tympanic horse that passes large amount of gas - no obstruction
synonymous with primary tympany
what is the classic case presentation of primary intestinal tympany?
moderate to severe abdominal pain that is usually intermittent
bloat, flatulence, & little systemic deterioration early
what is the classic case presentation of secondary intestinal tympany?
severe distension of cecum & large colon, dyspnea due to pressure on the diaphragm, severe bloat, & systemic deterioration
how do you differentiate between primary & secondary intestinal tympany causing colic in horses?
primary - flatulence, gas sounds & loud borborygmi, distended colon/cecum on rectal, & little systemic deterioration
secondary - no feces passed & systemic deterioration
how is primary intestinal tympany treated?
analgesics, mineral oil through NG tube, walking to promote passing gas - no need to trocar if flatulent
how is secondary intestinal tympany treated?
usually requires surgery
what is the pathophysiology of strangulating/obstructing colic?
venous return stops - area swells as arterial still pumps, arterial supply then shut off
ischemia & necrosis - leads to loss of mucosal barrier (bacteria/endotoxin absorption, proximal distension, loss of fluids & electrolytes
dehydration & hemoconcentration occurs -> metabolic acidosis & severe cardiopulmonary dysfunction
decreases peripheral perfusion markedly decreased
increase in lactate formation
if rupture, leads to peritonitis
what are examples of different causes of strangulating colic?
volvulus, strangulating lipomas, external hernias, internal hernias, intussusception, & meckel’s diverticulum
what is the classic case presentation of strangulating colic?
acute/rapid/severe unrelenting pain, increased HR > 60, sweating, increased RR, & dehydration
> 5L of gastric reflux after passing a tube, silent abdomen, metabolic acidosis, distended small intestinal loops
how is strangulating colic treated?
stabilize before surgery!!!!
decompress intestine, correct problems, R&A of nonviable sections
what are some examples of causes of intussusception in horses?
changes in motility
enteritis, intestinal polyps, diet changes, heavy ascarid load, tapeworms, parasite migration, anthelmintic treatment, intestinal surgery, or foreign body
what is the classic case presentation of intussusception in horses?
frequent in < 3 year olds
if ileal ileal - chronic abdominal pain
jejunal or ileocecal - acute colic signs, depression, anorexia, gradually shocky/dehydrated
what is the difference between intussusceptum & intussuscipiens?
intussusceptum - orad gut, propelled by peristalsis into the intussuscipiens
intussuscipiens - enveloping portion
what is the prognosis of intussusceptions in horses?
ileal-ileal is better than jejunal or ileocecal
how is an intussusception diagnosed in a horse?
history, clinical signs
peritoneal tap - maybe normal because damaged intestinal isolation, or may see increased RBC, WBC, & protein or bacteria if ruptured
rectal - 50% of intussusceptions have distended loops, may palpate it (painful & firm)
ileocecal - may feel firm, turgid intestine within cecum
exploratory surgery
how is a horse with an intussusception treated?
stabilize before surgery with intense fluid therapy
surgery - decompress intestine, surgical R&A
what is an internal hernia in a horse causing colic?
displacement of intestine through a normal or pathologic foramen within the abdominal cavity without the presence of a hernial sac
what are types of mesenteric defects causing internal hernias in horses?
acquired or congenital - gastrosplenic, cecocolic, broad ligament
congenital fibrous bands/adhesions
epiploic foramen
what is a major difference between internal & external hernias causing colic in horses?
internal hernias often cause strangulation/intestinal obstruction
external often doesn’t cause strangulation
what is incarceration in relation to internal hernias?
intestine goes through a hole & gets trapped
what is the classic case presentation of internal hernias causing colic?
acute/rapid/severe unrelenting pain, increased HR, prolonged CRT, increased RR, & dehydration
abdominocentesis - cloudy to serosanguinous/turbid, TP > 3, increased cell count
what horses are at risk of epiploic entrapment?
older horses more susceptible - hepatic atrophy leads to an increased size of the epiploic foramen
where is the gastrosplenic ligament located in the abdomen? what often gets stuck there?
between the left greater curvature of the stomach & spleen
distal jejunum & ileum most commonly incarcerated
what is the problem that mesodiverticular bands potentially cause in horses?
connective tissue that forms between mesentery & antimesenteric border of small intestine which forms a passage for a possible internal hernia
where is the location where epiploic entrapment occurs in horses?
right dorsal abdomen - beneath the caudate lobe of the liver, between caudal vena cava & portal vein
epiploic entrapment is an example of what type of colic in horses?
internal hernias
what is the number one cause of colic in horses? what type is more common?
large colon impaction
simple obstruction much more common than strangulating
feed impaction - in large intestines due to decrease in diameter size at pelvic flexure & transverse colon
ileocolic impaction - hypertrophy of ileum or ileocecal intussusception
no reflux
what are some predisposing factors for large colon impaction?
coarse feed, poor dentition, dehydration, cold weather, & decreased water intake
what are the 3 most common impaction sites in large colon impaction colic?
- pelvic flexure, most common
- transverse colon - junction with large right dorsal colon
- ileocecal opening - hypertrophy & intussusception
what is the classic case presentation of large colon impaction?
mild to moderate pain
decreased fecal output
progressive anorexia
dehydration
how is large colon impaction diagnosed?
firm ingesta filled colon on rectal at pelvic flexure
what are some indications for surgery in large colon impaction?
unrelenting pain, increased peritoneal nucleated cells/protein, & colonic displacement
what is the prognosis of large colon impaction?
if caught early - can shift quickly
if late - pelvic flexure can rot
how is large colon impaction treated?
aggressive fluids, galloon of mineral oil, DSS, saline cathartics
surgery - often burst when trying surgery
what is lethal white? what is the pathopysiology? what is the treatment?
completely white foal with blue eyes - overo paint sire & dam (autosomal recessive trait) born dead or weak with colic
appears normal at birth, develops colic & dies on 2nd day
absence of submucosal & myenteric ganglia in terminal ileum, cecum, & colon
no treatment - euthanize
what is the number one cause of law suits in horses?
rectal tears that occur iatrogenically
what are the different grades for rectal tears?
grade 1 - only mucosa/submucosa
grade 2 - muscle layers only, mucosa intact
grade 3 - mucosa, submucosa, & muscle layers into space between layers of mesorectum where the serosa is the only thing separating it from the peritoneal cavity MOST COMMON
grade 4 - full thickness into peritoneal cavity
what can you give a horse to stop it from straining resulting in a rectal tear?
acepromazine, xylazine, or detomide
propantheline bromide
lidocaine lubricant enema
epidural with xylazine
what horses often get rectal tears?
males > females
arabians
how are different rectal tears treated?
grade 1 - heal by 2nd intention
grade 4 - can’t treat
grade 3 - emergency, tell owner immediately, & prepare to ship to a surgical facility
what is DPJ colic? what happens if left untreated?
duodenitis-proximal jejunitis colic - mimics obstruction colic
proximal small intestines slow down, fluid & gas builds up, refluxes into stomach
shock or gastric rupture
what are the clinical signs of DPJ?
acute onset moderate to severe colic - gastric reflux, colic abates after decompression
what are major complications of DPJ?
laminitis, renal dysfunction, fibrous adhesions, multifocal abscessation, aspiration pneumonia from tubing, diarrhea in resolution stage, peritonitis, & shock/gastric rupture
how is a post mortem diagnosis of DPJ made?
duodenum > jejunum - transmural hemorrhage, thickened intestinal wall
how is DPJ diagnosed?
decompression relieves colic
decrease gut sounds
small intestines filled but not distended
metabolic acidosis
T/F: medical treatment of DPJ carries a better prognosis that surgical treatment
true
how is DPJ treated medically?
empirical
continuous gastric decompression (indwelling NG tube), iv fluids, don’t feed, NSAIDS, abx, laminitis prophylaxis
what horses end up with sand colic?
sandy regions - florida, california
what is the pathophysiology of sand colic?
fine sand accumulates in ventral colon, coarse sand in dorsal colon/transverse colon/pelvic flexure
fills right dorsal colon - fluid/gas can flow through present with soft feces
how is sand colic diagnosed?
put feces in glove & fill with water - sand will settle out in fingers
how is sand colic treated?
metamusil - NG tube
how is sand colic prevented?
monitor feeding & don’t feed off the ground
what are surgical indications for sand colic?
unrelenting pain, increased peritoneal nucleated cells/protein, & colonic displacement
how does metamusil work when treating sand colic?
lubricates & binds sand to move it out
forms gel when mixed with water so have tube in place before mixing
after initial dose, mix dry with feed for prolonged use
what horses are predisposed to enteroliths/fecoliths?
california (hay high in may), arabians more than others, 5-10 years old
what are enteroliths?
magnesium ammonium that starts as a nidus
what are fecoliths?
concentration of fecal material that can be as big as a soccer ball
how do horses with enteroliths/fecoliths present?
decreased feces, scant/liquid feces if partial obstruction
variable pain - depending on extent of distension
how are enteroliths/fecoliths diagnosed?
distension of colon on rectal exam
what is the conservative treatment for enteroliths/fecoliths? what is another option for treatment?
apple cider vinegar
surgical removal
where are enteroliths/fecoliths commonly found in the abdomen?
obstruction at the junction of right dorsal colon & transverse colon where there is a diameter change
why is it common to see displacement of the ascending/large colon causing colic in horses?
double U shaped but only proximal & distal ends attached, so the rest of the U (pelvic flexure at its center) is free to move around
other organs usually keep it in place - alterations in motility or digestive mechanisms can flip/kink the large colon resulting in obstruction because colon/cecum fill with gas, but ileocecal junction is efficient so no back up into the small intestines
what clinical signs are seen with displacement of the ascending large colon?
colic, increased HR/RR, sweating, decreased fecal output, gas distension of colon & cecum
how is displaced ascending colon diagnosed?
rectal - colon out of place, normally sacculations on the bottom & smooth on top, but if reversed, obstructed
pings due to gas distension
how is a displaced large colon treated?
conservative attempt done first in right & left displacement
surgery indicated for volvulus or obstruction
what is a right dorsal displacement colic in horses?
twist of 180-260° of large colon at the mesentery
large colon displaces between the cecum & right body wall
pelvic flexure pointed cranially with 2 possible ways to twist
clockwise around cecum (most common) or counter clockwise around cecum
what clinical signs are seen with a colic horse with a right dorsal displacement?
colic, increased HR/RR, decreased fecal output, gas distension of cecum/colon, no gastric reflux
how is right dorsal large colon displacement diagnosed?
rectal - large gas distended colon & can’t find pelvic flexure
cecum located medial to colon
pings heard
what is another name for left dorsal colon displacement?
nephrosplenic entrapment
what is the pathophysiology of nephrosplenic entrapment?
large colon is caught in nephrosplenic space (left side between dorsal spleen, nephrosplenic ligament, left kidney, & left abdominal wall)
what horses are predisposed to nephrosplenic entrapment?
warmbloods & thoroughbreds
what is the main difference between left displacement of the colon & nephrosplenic entrapment?
increased pain & systemic shock because more colon is entrapped which increases the pull on mesentery
how is nephrosplenic entrapment diagnosed?
rectal - distended large colon & spleen displaced away from body wall
what conservative treatment is used for nephrosplenic entrapment? what is used if that doesn’t work?
conservative - deny food & allow to spontaneously return
rolling - put in right lateral recumbency to have the spleen up, hoist by legs held for 1 minute & shaken, return to dorsal recumbency, & slowly turn to left lateral recumbency
surgical correction - ventral celiotomy for better room & visualization
what is the pathophysiology of colonic volvulus?
vascular occlusion & severe colonic devitalization at > 270° twist - twists 360° causing lots of strangulation, endotoxemia, & no venous return to thorax
- base of colon
- sternal & diaphragmatic flexures
what predisposes horses to colonic volvulus?
adult horses, brood mares 1 week postpartum due to extra room, summer
what clinical signs are seen with colonic volvulus?
severe colic, marked distension/bloat, shock, dehydration, cold extremities, weak pulses, increased CRT, increased HR/RR, pings
rectal - large gas distension & edematous colonic wall
how is colonic volvulus treated?
stabilize before surgery with large volume fluids!!!!!
analgesics for pain
surgically untwist
what is the prognosis of colonic volvulus?
poor
if caught within 2 hours, can surgically correct
if later than 4 hours, poor
prognosis depends on amount of devitalization
