Exam 3 - Equine Colic Evaluation Flashcards
when naming the nature of the problem in colic, what are you trying to determine?
- is it a simple obstruction?
- is it a strangulating obstruction?
- is it a functional obstruction?
what factors should be considered when making decisions about proceeding with treatment of colic?
economic value, emotional value, insurance status, & prognosis
what is the most common cause of colic?
- gas colic
- pelvic flexure impaction
why is the cecum likely to rupture in cases of impaction causing colic?
the cecum works against gravity to propulse out the stuff
why is the jejunum involved with internal hernias?
it has a large mesentery
where are enteroliths commonly found & why?
dorsal colon - it has the largest diameter
where in the gi tract are there pacemaker cells that regulates peristalsis that changes in direction, gets smaller, & is sensitive to electrolyte abnormalities?
small dorsal colon
what horses are predisposed to impaction colic?
miniature horses & Arabians on hay
what horse breed is predisposed to developing impaction colic from alfalfa hay?
arabians
why do show horses commonly get gas colic?
they are on a high concentrate diet, variable schedule, & stressed
you have successfully resolved an esophageal obstruction that had been going on for 8 hours in a horse. on physical examination, you auscultate abnormal lung sounds particularly in the right ventral thorax. what can you conclude?
a. cardiac disease with pulmonary edema
b. diaphragmatic hernia
c. strangles
d. aspiration pneumonia
d. aspiration pneumonia
a horse presents to you cough, and has feed material coming out of its nose. you suspect an esophageal obstruction. to confirm your diagnosis, you:
a. take a radiograph of the possible sites of obstruction ie. the cervical area, the thoracic inlet, & the caudal thorax
b. perform an ultrasound of the esophagus
c. perform a cytologic exam of the nasal discharge to confirm the presence of feed material
d. pass the nasogastric tube
d. pass the nasogastric tube
you can utilize oral fluids in a colic horse except when:
when there is reflux or small intestinal distension, no oral fluids, need to do IV
what are the differentials for large colon distension?
- gas colic
- aboral obstruction: small colon/transverse colon obstruction
- large colon volvulus
- large colon displacement
what is the diagnostic test used to differentiate a simple obstruction from a strangulating obstruction?
abdominocentesis
if you suspect a strangulating colic, what are you looking for on fluid analysis from the abdominocentesis?
increased lactate - double the periphery
increased protein
increased white cells - if it has been going on long enough
the gold standard diagnostic for diagnosing what condition is rectal palpation?
nephrosplenic entrapment
ultrasound may make you suspicious but it can be missed
how is sand colic diagnosed?
radiographs
in the neonatal period, what causes colic in foals? 2-5 days? older?
neonate - meconium impaction
2-5 days: ruptured bladder
older - ulcers, enteritis, gastric outflow obstruction, small intestinal volvulus, intussusception, hernias
what are some causes of colic in older horses?
small intestine - lipoma & epiploic foramen entrapment
poor dentition - impactions
weight loss - neoplasia
what kind of colic do large strongyles cause?
thromboembolic colic
why does concentrate feed predispose to gas colic?
it decreases H2O content in the large colon
what animals are typically affected by sand colic?
horses that live in dry areas
in strangulating colics, how long until death occurs?
12-16 hours left untreated
when approaching a colic horse, what 3 steps should you take?
- control pain - xylazine is good, short 1/2 life & lower CV effects
- CV status - get the HR before any sedation is given, if HR is high, pass an NG tube & get fluids started
- evaluate gi tract - buscopan helps relax smooth muscle for rectal palpation but can increase HR as a side effect
if you have a colic horse with clinical signs that are recurrent & intermittent, what are you suspecting?
enteroliths
what components of pain management make up decompression?
nasogastric intubation & trocharization
why use trocharization in a colic horse?
ensure the distension is in the large colon - place a 14G needle in the cecum on the right side of the paralumbar fossa
of the alpha-2 agonists, which has a shorter duration of effect?
xylazine
detomidine lasts longer
if a colic horse has pale mucus membranes, what do you suspect?
large colon volvulus - painful, vasoconstriction
in a mare with large colon volvulus, what would you expect the vaginal mucosa to look like? why?
congested - the cranial mesenteric artery is blocked, so everything caudal to it is congested
if you have increased gut sounds, what type of process do you suspect is causing the colic signs? what about decreased sounds?
increased - inflammatory
decreased - obstruction
how much reflux is considered significant?
greater than 2 L
if you have 10L of reflux, where do you expect to have your localization of the colic? what about delayed reflux 12-14 hours later?
more than 10L = proximal impaction
delayed = distal lesions, ileum
if the reflux you get has bile & feed stuff, what kind of colic do you expect? what about if it smells and is bloody?
bile & feed stuff - obstruction
smells & bloody - inflammatory
if you palpate a horse that has a HR of 50, with mild-to-moderate colic signs, and you feel gas distended intestines but no thickening, what kind of colic do you suspect is occurring?
simple colic
if you palpate a horse that has a HR of 90, with mild-to-moderate colic signs, and you feel gas distended intestines with thickening of the intestinal walls, what kind of colic do you suspect is occurring?
vascular colic - strangulation or volvulus/displacement, anything causing compromise of blood flow
what are some differentials for small intestinal distension?
ileus, simple obstruction, & strangulating obstruction
what are some differentials for cecal distension?
gas - cecal tympany, primary, or secondary to displacement of large colon (most common)
cecal impaction - risk of rupture
what are your 4 differentials for large colon distension?
- gas colic - resolve with meds
- displacement - surgery
- torsion/volvulus - surgery
- aboral obstruction - small colon/enterolith
what are your differentials for large colon impaction?
simple impaction (pelvic flexure)
displacement with secondary impaction
when should you not do an abdominocentesis?
if decision for referral or surgery has already been made, severe distension, & be careful in foals!!!
what is normal on abdominal fluid analysis?
TP: <2.5 g/dl, WBC < 5,000 cells/uL
if you have an increased ratio of your plasma lactate to abdominal lactate, what are you thinking?
devitalization of bowel or peritonitis
lactate should be the same across plasma & abdominal fluid
how can you differentiate between a bloody tap & hemoabdomen on fluid analysis?
hemoabdomen - doesn’t clot, absent platelets, & hemolysed supernatant
what would you expect to see on fluid analysis of peritonitis?
degenerate neutrophils, no plant material, & one or several different bacteria types
what would you expect to see on fluid analysis of enterocentesis?
no cells, plant material, & protozoa
what would you expect to see on fluid analysis of rupture colic?
degenerate neutrophils, plant material, & several different types of bacteria
when doing a post-op tap on a colic horse, what are you wanting to see on the cytologic evaluation?
no degenerate neutrophils - increased TP for up to 3 weeks, increased WBC for 7-10 days
if you have >9mm thickening of the large colon seen on ultrasound, what is this supportive of?
large colon torsion
what are the factors that can be used to predict survival/outcome of colic in horses?
- cardiovascular status
- location of problem
- cause of problem
- age of horse
what is the prognosis of a colic horse with a HR of >80 & lactate of > 4 mmol/l, with CV status indicating perfusion problems?
may be guarded
what signs are consistent with small intestinal obstruction?
reflux, small intestinal distension on palpation, & small intestinal distension on ultrasound
what signs are consistent with large colon obstruction?
no reflux unless distension is severe, abdominal distension, large colon distension on rectal palpation, radiographs (sand or enteroliths)
what patient histories may be suggestive for the need of referral?
acute onset colic that is unresponsive to medication, chronic recurrent problem, ingestion of sand, recent deworming in foals, excess bute, scrotal/umbilical hernia, & post-castration evisceration
what condition of colic is most likely to spontaneously rupture?
cecal distension
what is a major consequence of delayed referral?
large colon torsion, small intestinal obstruction, colitis, cecal impaction
when referring a horse, what should be done en route?
place nasogastric tube, withhold feed/water, tie horse loosely or not at all with a breakaway halter, make sure there isn’t a partition the horse could get stuck under if it goes down, & make stops every hour to check on the horse
