Exam 3 - Equine Colic Evaluation Flashcards by Madeleine Swindell

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?

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what factors should be considered when making decisions about proceeding with treatment of colic?

economic value, emotional value, insurance status, & prognosis

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what is the most common cause of colic?

gas colic
pelvic flexure impaction

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why is the cecum likely to rupture in cases of impaction causing colic?

the cecum works against gravity to propulse out the stuff

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why is the jejunum involved with internal hernias?

it has a large mesentery

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where are enteroliths commonly found & why?

dorsal colon - it has the largest diameter

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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

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what horses are predisposed to impaction colic?

miniature horses & Arabians on hay

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what horse breed is predisposed to developing impaction colic from alfalfa hay?

arabians

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why do show horses commonly get gas colic?

they are on a high concentrate diet, variable schedule, & stressed

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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

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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

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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

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what are the differentials for large colon distension?

gas colic
aboral obstruction: small colon/transverse colon obstruction
large colon volvulus
large colon displacement

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what is the diagnostic test used to differentiate a simple obstruction from a strangulating obstruction?

abdominocentesis

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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

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the gold standard diagnostic for diagnosing what condition is rectal palpation?

nephrosplenic entrapment

ultrasound may make you suspicious but it can be missed

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how is sand colic diagnosed?

radiographs

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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

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what are some causes of colic in older horses?

small intestine - lipoma & epiploic foramen entrapment

poor dentition - impactions

weight loss - neoplasia

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what kind of colic do large strongyles cause?

thromboembolic colic

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why does concentrate feed predispose to gas colic?

it decreases H2O content in the large colon

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what animals are typically affected by sand colic?

horses that live in dry areas

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in strangulating colics, how long until death occurs?

12-16 hours left untreated

when approaching a colic horse, what 3 steps should you take?

1. control pain - xylazine is good, short 1/2 life & lower CV effects 2. CV status - get the HR before any sedation is given, if HR is high, pass an NG tube & get fluids started 3. 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?

1. gas colic - resolve with meds 2. displacement - surgery 3. torsion/volvulus - surgery 4. 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?

1. cardiovascular status 2. location of problem 3. cause of problem 4. 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