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donawick

medsurg3
11/12

yesterday we were talking about 
rumen gas caps being flat on the bottom, and that crooked bottom lines 
were usually LDA. just make sure to auscult and percuss in multiple 
sites. the sound of a rumen being percussed mimics that abomasal ping 
sometimes. as you do your PE, always do both sodes, listening for 
abomasal displacement on the left, which is most common in the US - >85% 
on the left in the US. the others are on the right - some call those 
right dilatations instead of displacements, because usually it is already 
slightly right of midline. both cause partial obstruction, though. and 
the abomasum can wander from left to right, too. 

success of treatment 
of abomasal displacements depends on early, accurate diagnosis, prompt, 
effective correction. does the farmer get his money back from doing the 
surgery? population medicine people will tell you you can't get enough 
milk to pay for the surgery; but this is still a common procedure.


correction of LDA: 
in order of success:
abomasopexy - paramedian: most 
secure, successful way - 90% success
omentopexy - right paralumbar fossa: 
fixing omentum to the body wall. usually done on cows with RDA, you take 
omentum near abomasum, and fix it to body wall.
left paralumbar fossa: 
make celiotomy there, in standing cow as if you were going to do a 
rumenotomy, then fix abomasum to ventral body wall via abomasopexy.
blind 
stitch: without knowing what you are doing, trying to do an abomasopexy

nonsurgical correction: this means doing something to try to move 
abomasum into relatively normal position, lose gas, and deflate. how do 
you do this? it's not uncommon for vets to cast a cow, turn her upside 
down, and shake her. this lets rumen move toward the back, gas in 
abomasum makes it rise to ventral surface which is now up, you shake cow, 
and abomasum escapes from under rumen. the problem is that these recur - 
but only about 50%. so you have minimal expense and 50% success. another 
way to handle is to put cow on truck, and to drive around over rough 
roads or fields. this is another way of shaking her. lets gas move past 
obstruction, deflating abomasum. 50-50 chance of temporary fix. 


abomasopexy - right paramedian incision - median is midline, right means 
just off to the right. landmarks are two inches to the right of midline, 
parallel to midline, and 2 inches caudal to xiphoid. cow is in dorsal 
recumbency. cast cow by putting rope behind front legs with half hitch 
and again in front of hind legs - pulling on that rope makes a cow lie 
down. use local anesthetic at proposed incision site, then make your 
incision big enough to get hand in there, find abomasum, put it in right 
place, and suture to peritoneum. ventral peritoneum is very strong, and 
will hold abomasum in place. include the muscular wall of abomasum in 
incision when you close. usually try to get 6-8 sutures into the wall of 
abomasum as you close peritoneum. fix down the fundic/front part of the 
abomasum. don't hook down back near the pylorus. 
slide: abomasum being 
held out of the incision. greater curvature is ventral - is what you see. 
this is where omentum hooks on. here, we see omentum being extended. we 
aren't sutureing omentum in this procedure. so as you suture closed the 
peritoneum, let your needle go through abomasal wall. that's it. the 
problem is you have to cast the cow, hold the cow in dorsal recumbency.


right paralumbar fossa - omentopexy. make incision in that area, reach in 
- if you have LDA, take needle over behind rumen and stick needle into 
abomasum to deflate abomasum. it will deflate and move down ventrally. 
grab it and pull it to the right. once it is in place, grasp omentum 
caudal to and up from the pylorus - so the proximal duodenal omentum - 
fix that to body wall near the incision by either including it in 
peritoneal closure, or putting in separate mattress sutures. you're sort 
of pulling this to make it more like a tube. with right dilatations, it 
prevents the kinking that allows gas to accumulate. 

slide: pylorus with 
a fold of omentum attached. 

it's just about strong enough to hang on. 
what kind of suture? people usually use nonabsorbable suture. as far as % 
goes - 85-90% so at least 8/10 cows are fixed this way. again, when you 
grab the omentum, you take a big fold of it. in Germany they put a button 
on the deep side of the stay sutures to disperse force a little. 

you 
can also go through the left paralumbar fossa. you go in this way to do 
rumenotomies and c-sections. again, cow is standing. you can't do this 
unless abomasum is displaced at the time. you go in, reach in and feel 
greater curvature of the abomasum which is what you will first feel as it 
has come across from underneath. put suture into the wall of the abomasum 
- fix a long length of suture into the greater curvature. then, deflate 
abomasum. make sure to leave long tails on that suture though. after 
deflated, tails of suture are hanging out incision. put needles on each 
end, and then reach in and push needles through ventral body wall. then 
have someone reach down under there and pull on those ends of the suture. 
this is usually done with no local anesth but it is just sort of like a 
quick piercing. then you just tie the ends together. so now you have 
direct connection b/w outside and abomasal wall. there usually is a small 
local peritonitis which will adhere abomasal serosa to the peritoneum. 
then in a few weeks you can cut the suture out if you remember. usually 
you just leave the suture in. the problem with this procedure is you 
don't really know what part of the abomasum you're tying down, and it is 
often close to the pylorus, so there is still more movement then you'd 
like, so you're down to about a 70% success rate - some cows will have 
recurrence. 

blind stitch technique - the idea is, you cast the cow, 
turn her up into dorsal recumbency, then you auscult and percuss and hear 
the ping of abomasum. you locate this and then you take a big curved 
needle witha  big heavy nonabsorbable suture on it, drive it through body 
wall, hopefully snagging abomasal wall, and come back out. the problem 
is, you do not know what part of the abomasum you are fixing to the wall, 
and you perforate into the lumen of the abomasum - now you have gravity 
pulling abomasal contents out along the suture path into the peritoneal 
cavity and into the body wall. this isn't so good. it's cheap, quick, but 
fraught with danger. still, it is done b/c cows are really cheap and 
people want cheap fixes. after this procedure cows often develop 
cellulitis, wound infections, and peritonitis. a variation of the 
technique is to put a toggle bolt in. this is like a bolt you put through 
drywall, with a little flipper on the back, so you put it in and then it 
opens up on the back and you screw the front down. you take this thing, 
and a trochar, and drive it through the  ventral body wall, put toggle 
in, take tube off, tighten, and now you have a hole about a half an inch 
with a toggle inside the abomasum, and you tighten the skin side. same 
problems with other procedure. causes skin necrosis if too tight, leaks 
if too loose. 

slide: common result of doing blind stitch technique - 
this is us, opening a cow who came in deathly ill with diffuse, fibrinous 
peritonintis due to leakage of abomasal contents into peritoneal cavity. 
basically she's dead but doesn't know it yet. you can't save this cow. 
she has gallons of pus in there.

signs of abomasal torsion in cows::

acute illness - depressed, off feed, in grave condition w/in 2-3 days

dehydration - often severe
pulse - 100 or more/min
on simultaneous 
percussion and auscultation - ping right abdomen
we think dilatation on 
right side precedes volvulus, so if cow has RDA we do surgery that day.

on rectal exam - palpate abomasum in right abdomen. on dilatations, you 
don't feel that.  
difference b/w dilatation and volvulus is with 
volvulus, you've obstructed inflow and outflow. 

40-60 beats per minute 
is normal heart rate of cow. 100 is about double. that is very bad. 


remember - always do rectal exam on each cow when you do a PE. 

ddx of 
torsion of the abomasum:
-RDA
-torsion and displacement of the cecum: on 
rectal you would feel cecum right away, whereas abomasum is really far in 
there.cecum is more caudal.
-torsion of the intestines about the cranial 
mesenteric artery: on rectal, when intestines are involved, you feel 
distended intestine everywhere.
-gas distention of the colon: spiral 
colon is felt.

slide: rectal exam being performed on a cow

what do you 
do when you dx torsion of the abomasum? this cow is deathly sick b/c of 
the torsion and obstruction and accumulation of fluid in abomasum, and 
also is sick b/c she gets hypochloremia, hypokalemia, and paradoxic 
aciduria and metabolic alkalosis. think about this. this cow 
metabolically becomes deathly ill b/c serum chloride falls, b/c is 
accumulating in abomasum. cow is constant HCl secretor. so H+ and Cl- go 
into abomasum and stay there. serum Cl then falls. she gets hypokalemic. 
K+ is also going into the abomasum and she's not taking any in. normally 
cows eat a lot of potassium. kidney normally thorws a lot of potassium 
away and it keeps doing it so she gets hypokalemic. 

she gets paradoxic 
aciduria. so in the face of metabolic alkalosis, where her pH is rising, 
you'd think the kidney would throw away bicarb but it does not, it 
reabsorbs it and throws away acid. urine pH is acidic. why is this 
happening, because of the low Cl-. low Cl- causes kidney to malfunction 
this way. the metabolic correction for this is to give her chloride.  
don't use balanced electrolyte solution. not enough Cl-. also there are 
bicarb precursors in there. so you have to be really stupid to say that 
you would use a balanced electrolyte solution, which is what I just 
suggested, so I guess I'm totally lame. use sodium chloride because 
saline which is 0.9% salt, contains 154 mEq/L of chloride. so now, for 
every liter of saline we give her we're adding lots of chloride ions to 
her serum and ECF. that is how you combat the metabolic alkalosis - raise 
chloride level. she'll probably need 40-50 L of this. she also needs the 
fluid. she's dehydrated. before we understood this, we did surgery but 
cows died anyway. you have to treat with saline while doing surgery. how 
do you do the surgery? make an incision, a right paralumbar fossa 
celiotomy, and abomasum is right there. it's filled with fluid and gas. 
if we can untwist without draining it, do that, or else drain it first. 
use stomach tube passed through purse-string opening into abomasal wall. 
you'd like to untwist so she can reabsorb all that ion rich fluid but 
often you have to drain. when done, some people do omentopexy to prevent 
recurrence. we do not know if that works.

you know it is untwisted when 
the duodenum is to the right of the abomasum. 

compensated metabolic 
alkalosis is what develops in these cows. 

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having treated a 
cow with abomasal volvulus, we managed to raise her Cl- from 73 to 99, 
her arterial pH was changed from 7.53 to 7.38 and pCO2 from 47.7 to 42.6 
torr. now, that should be 40. normal concentration of bicarb is 24 mEq/L.

this cow had no fluid removed from her abomasum, and 16L saline given IV. 


regarding potassium - when it drops below 2.0 mEq/L in the serum, usually 
they can't stand up b/c they are too weak. they have total body weakness.


other things that can happen to the abomasum - one is an ulcer - much 
like in people and pigs, due to stress. we do not see it a lot here in 
eastern US dairy cattle, but is more common in cattle in fattening pens 
in the midwest, where there is a lot of competition, animals grouped in 
confined space, and stuff. they can ulcerate, get peritonitis, bleeding 
out, etc. you can operate on them, and stop bleeding, maybe. major rule 
out - lymphosarcoma of abomasum. that also can make her bleed out. look 
at age of cow and BLV status. 

slide: perforated ulcer - these do not 
have to break into peritoneal cavity - this one broke into omental bursa, 
which then got full of fluid, pus. so she had a bursitis. she was 
pregnant. you could feel the full uterus, the rumen, and this other giant 
thing. the question was what was the third one. 

slide: abomasotomy - 
this cow was bleeding b/c an ulcer eroded through an artery and there it 
was, spurting blood. they just tied off this bleeder and she got better. 


usually cows that are suspected of having abomasal ulcers get shipped for 
slaughter. 

remember - the cow has a short thick mesentery; the colon is 
in the same mesentery as the small intestine, so if you were going to do 
an anastomosis and you took a wedge out you could accidentally cut 
through the spiral colon. btw,  the outside loop of the spiral colon is 
the one that continues to the colon. 

disease that cows do not get - 
ileal-cecal intussusceptoin - b/c she has an antimesenteric attachment of 
ileum to cecum. it's firm, thick, and prevents ileum from going into 
cecum. she gets intestinal intussesceptons - jejuno-ileal 
intussuscepitons.

slide: intussusception in a cow...jejunum into ileum. 
you see that just where the ligament ends. not common, but you should 
check for it during rectal exam. feel for a sausage like mass. to fix, do 
right paralumbar fossa incision. then manually reduce it. usually you 
just pull it out and leave. blood supply to intestine is good so probably 
is ok. no resections required. 

slide: bull that died from strangulating 
inguinal hernia. a loop of small intestine fell through internal inguinal 
ring and got trapped.not uncommon in beef cattle. can dx by doing rectal 
exam - feel inguinal ring - also palpate or auscult scrotum. sometimes 
from in rectum you can grab and remove bowel loop. otherwise, incise 
paralumbar fossa of affected side. sometimes this requires intestinal 
resection and anastomosis. 

torsion of the mesenteric root. can occur 
spontaneously or after cow has been cast.
remember this is one of those 
things that can also cause pinging.
signs: colic after completion of 
surgery, recumbent animal, abdominal distention, elevated heart rate and 
labored respiration, pale mms, poor crt, hemoconcentration and metabolic 
acidosis. this occurs very quickly. cows have had abomasopexy, returned 
to barn, and been in terrible shape 10 minutes later. their whole gut 
turns black even after less than an hour. 

Dr D has never successfully 
saved one of these cows even when making the dx and being there within 
minutes. it gets all twisted and you can't get it untwisted. he tries, 
though.

dx: history of casting, rolling, acute onset, rapid 
deterioration and shock, and feeling multiple distended loops of bowel 
and edematous mesentery palpable on rectal exam. 

tx: theoretically you 
can do a number of things but they are not going to work. emergency 
laparotomy, but probably won't save cow.

torsion or displacement of the 
cecum: signs: 
sudden loss of appetite
failure to defecate
restlessness 
and abdominal distress
ruminal movements reduced or absent
distended 
right flank
on simultaneous auscultation and percussion, high pitched 
resonance sound, and you can feel the cecum well back on the right side 
on rectal exam. 
drop in milk production
sort of sick but not deathly 
sick. 
slower onset over a few days.
you can almost always fix this cow - 
do a celiotomy on the right, you find the cecum, so deliver the apex out 
through incision, cut hole, drain it, close it, untwist it, return it 
into the cow. these cows do slowly get metabolic alkalosis, but you don't 
usually have to treat it b/c it is slow and the next day the cow is 
usually fine. 

slides: apex of cecum outside of cow. 

if cow is 
severely dehydrated can give IV but usually just give water per os.


slide: cecum of cow who will not get better - twist was so tight that it 
cut off blood supply. cecum is black. would have to cut it off, 
anastomose ileum to outer loop of spiral colon.

rectum and colon:


slide: Bernie the llama's abdominal radiograph. he came in at about 3 
days of age. his problem is that developmentally he has no intact GI 
tract. this isn't uncommon in large animals. we see distended loops of 
intestine in there, and there is no distal part of the GI tract 
connecting to the proximal part. they put barium in the rectum and sent 
it forward - it eventually stops somewhere. it isn't connected. he had 
surgery to put his guts together. he was very cute and healthy after 
surgery. he became a zoo llama. sometimes, the digestive tract hooks up 
with the wrong part. here, a calf has no anus. nature has hooked the 
descending colon to the vagina. so now, the ingesta is coming out through 
the vulva. 

we also saw one with no anus that was a male goat, and he 
had feces coming out through the penis. that's a bummer. 

when you see a 
newborn who isn't eating well and feels bad, always check and make sure 
there is an anus and that feces can come out of it. 

for that calf with 
feces coming out the vulva, they took some rads. 
one thing you can do in 
these animals is make a pullthrough type procedure to create an anus by 
sewing rectum to body. that assumes the animal has a rectum. 
slides: 
made circular incision, and pulled blunt end of rectum to it. also had to 
find the communication to the vagina and close that. then they cut the 
blind end off and sutured to skin. 

rectal tears in horses - they occur. 
in cattle, they only very very rarely occur. in horses, they are not 
uncommon and are usually life threatening, and usually almost always 
iatrogenic. the breed that has a great predisposition to rectal tears is 
the arabian horse. no one knows why, but many of these occur in those 
horses. be careful doing rectal exams on these horses. you never know 
when it is going to happen to you. it is like flying a plane with 
retractable gear, you never know which day you'll land with your wheels 
up. if it takes a lot of power to taxi...

one thing to do to try to 
prevent rectal tears is sedate the horse. another is put a twitch on it 
to distract it. restrain it in stocks or confined area so you have 
control wear sleeve and use a lot of lubricant. pray as you begin your 
exam. try to find a responsible person and make sure they know there is a 
risk of tear but that the procedure is medically necessary. always get 
permission. insurance companies have to pay off on this more than 
anything else in large animal medicine. 

do you ask permission before 
doing every rectal? well, if you get a new farm client, you have to talk 
to the farmer on your first visit and make sure he knows risks and stuff, 
and then you do not have to ask each time. 

don't fight the contractions 
- do not be there when a wave of contraction comes by. get your arm out 
of the way. 

slide; fatal peritonitis is most common sequela of rectal 
tear.
there is a rectal tear grading system - 
grade 1 involves mucosa 
and sometimes submucosa (finding blood on your sleeve can indicate this)

grade 2 involves only muscular layers, with mucosa and serosa intact

grade 3: involves mucosa, submucosa, and muscular layers - includes tears 
extending into dorsal mesentery. only serosa intact.
grade 4: perforates 
all layers and extends into the peritoneal cavity

grade 4 almost always 
fatal. they happen in the field and then by the time they get to hospital 
there is feces in the peritoneal cavity.

if this occurs and it will if 
you do enough rectals, you have to say something. you have to say - I 
think this rectum just ruptured. you can't just leave. leaving would be 
very bad. that's why you have insurance. you don't say "oh god, i'm 
sorry, i just ruptured the rectum." You say "i think this rectum has just 
ruptured" and then pack the rectum and send to referral facility, then 
call your insurance company and say "i have a problem." this is a 
defensible situation. it just happens sometimes, it doesn't mean you did 
something horrible. but you have to follow correct procedures, and get 
permission. 
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