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richardson
medsurg2
10.13.98

in large animals we do less 
urologic surgery
there are other limitations as well

start out by 
saying...common things you do in any patient with any illness, that are 
very important with reference to urologic disease --

history, PE 
(rectal!), UA/culture, cystoscopy
[i think maybe this lecture is on 
equine urinary problems?]

one thing about large animals - in cows, 
horses, you can always do a rectal and get a lot of information. 
otherwise, PE similar to small animals. U/A a bit more problematic in 
large animals - esp in small ruminants, it can be very hard to get urine, 
as the males are impossible to catheterize. 

another thing in large 
animals is we can pass a flexible fiberoptic scope directly into the 
bladder, and examine it that way. 

diagnosis:

CBC/fibrinogen/serum 
creat/electrolytes/ultrasound/exploratory sx

the fibrinogen is an acute 
phase reactant in large animals that will rise in response to 
inflammation (not really in small animals)

[note: those donuts from 
rounds this morning are obviously being eaten in here, the smell is 
making me crazy!]

anatomy - kidney problems in the horse are really hard 
to deal with surgery because they are tucked up behind the caudal ribs - 
usually behind the 17th and 18th ribs. remember right kidney is cranial 
to left kidney - in cattle and ruminants this is a really pronounced 
difference in location. in horse, you generally have to to do rib 
resection to get to the kidneys. 

in this VD view of the cow, left 
kidney is near midline, right kidney is tucked up into liver on the right 
side of the abdomen. remember left kidney is always further caudal and 
easier to find. on rectal exam in horse and cow, you can feel left 
kidney. if you feel the right one, either your arm is really really long, 
or the kidney is enlarged. in catte, the left kidney is very readily 
palpated, easier than in horse.

in horse - nephrectomy - you have to go 
through 17th and 18th (for right) or just 18th rib; then put in 
transfixation ligatures of artery, vein, ureter - check for accessory 
vessels. generally all you do here in horses and cows is nephrectomy - it 
would be very rare to do nephrotomy, pylonephrotomy, etc. they don't do 
renal transplants, either.  secure ligation of this large, vascular organ 
is very important - at least double ligatures, please. and always look 
for accessory vessels - ureter, renal a & v, and then CHECK to make sure 
there isn't another vessel in there!!

surgical diseases of the kidney in 
large animals: why are you removing a kidney? the foremost consideration 
when doing nephrectomy is - make sure disease isn't bilateral! you have 
to have one functional kidney left. so, you'd do nephrectomy to treat:

(none of thesse are common)
unlateral pyelonephritis (usually this is 
bilateral)
unilateral urolithiasis/hydronephrosis (also usually 
bilateral)
unilateral congenital defects (usually bilateral)
unilateral 
neoplasia (very very rare)

slide: kidney with white stuff on it. (looks 
like elmer's glue) - this is an abscessed cow kidney. contralateral 
kidney was also affected but less so.

slide: heifer looking at us. it's 
been noted she has been straining to urinate. during rectal exam, vet 
found a large structure in the caudal abdomen, felt fluid filled. right 
paralumbar fossa celiotomy revealed that the left kidney (remember, on 
the midline normally) bulging out of incision - polycystic, huge, 
unilateral, so removed.

slide: renal neoplasm - he's never seen a 
unilateral renal tumor. 

slide: renal mass from horse - hydronephrotic 
kidney, distended ureter - had bilateral stones.

slide: cross section of 
equine kidney - stones in ureter are generally multiple in the horse - 
here it is cut open and all this gravel is poured out.

So renal disease 
isn't that often a surgical disease in thesse animals. just remember the 
specific entities that dictate removal. 

surgical dz of the ureter: 
again, in large animals very rare
ureteral ectopia (signs same as in 
small animals, tx same - move them)
urolithiasis/hydroureter - tends to 
have too many stones to just remove, dx tends to be deferred until kidney 
is shot anyway, so repair rarely done.
ureteral dysplasia/rupture - more 
common in foals, but still rare, signs - urine leaking into 
retroperitoneal space which then ruptures into peritoneal space causing 
urine to be in abdomen, and signs associated with that (like with 
ruptured bladder).

one horse was treated with laser surgery to fix 
ectopic ureter...we may see video later.

Cystic calculi: in all large 
animals, this is an important disease (urolithiasis). whitlock covered 
metabolic aspects; richardson will discuss surgical aspects. 

in horse - 
middle aged to older horses - far more commonly recognized in males, 
probably b/c females can pass them more easily through their large 
urethras. classic signs: stranguria, pollakiuria, hematuria (could just 
be at end of stream, or whatever; owner more likely to see this if horse 
bedding is shavings instead of peat moss or on pasture...), although some 
of these may not be terribly obvious. also some horses do not get 
monitored that closely - may be out in a field and no one notices if/when 
it urinates; also possibly urine scalding, anorexia, depression, wt loss 
- just "not doing right". 
don't miss this diagnosis - it's not that hard 
to make, as long as you remember it exists. so just keep this in mind. dx 
is easy in an adult horse - stick your arm in the butt,and feel for it!

sometimes, this is suspected and the diagnosis is still missed. why? 
what's the most important thing? anatomy. what do you know about the 
urinary bladder in the horse/? it is very caudal, esp if horse is 
straining! you can probably feel it when you are in up to your wrist. you 
could pass it. the bladder is not - unlike the ovaries, uterus, which 
most people are used to feeling - bladder isn't usually palpated so much. 
so keep it in mind, remember it is usually fairly far caudal, and most of 
these horses aren't totally obstructed so they do not have a humongous 
bladder anyway. they have small, contracted bladders. now, if bladder IS 
full, either stimulate to urinate, or pass a urinary catheter. then you 
should be able to feel stones in the bladder, once it is empty. usually 
pretty big before it causes signs. like, a little smaller than a golf 
ball, up to the size of your fist or even the size of your head.


diagnosis: rectal, ultrasound per rectum (also will find urethral 
stones), cystoscopy - pass scope up the penis or into urethra of mare.


slide: picture of urolith against bladder wall seen via cystoscopy

tx 
options for cystic calculi - different from small animals:

-laparotomy/cystotomy: allows for complete, accurate removal, but 
requires general anesthesia and difficult incision b/c it is so far 
caudal. not an easy surgery in a big horse. but it's doable. "gold 
standard" procedure. 
-perineal urethrotomy: standing procedure, done 
under epidural anesthesia, with short convalescence, but possibly 
incomplete calculus removal. potential problems - the urethra is only 
going to distend to 2 cm or so and stones may be bigger than that. at 
some point, you probably have to smush up the stones and pull out the 
pieces - using ultrasonic means, lasers, or mechanical forces to break 
the stones. then sometimes you have to flush, drain, flush, drain, etc. 
the big advantage is the small incision and rapid recovery. or, in adult 
mare - just reaach in there. if you wear size 5 gloves you just stick 
your hand in the bladder and  pull out the stones. or, if your hands are 
bigger, you can cut the urethral sphincter and that will dilate the 
opening so you can get a bigger instrument or bigger hand in there to 
grab and remove the stone. again, these aren't that common in mares, 
though - too bad, b/c procedure is much easier. mare will regain 
continence after sphincterotomy - no problem.
-incision alongside the 
rectum, pulling bladder over, incising, pulling out stone, and closing it 
up - another technique that has been described but Dr R hasn't done.

do 
not use chromic gut or silk or any braided, nonabsorbable suture in the 
bladder. 
[note: cats get perineal urethrostomy, not urethrotomy -- note 
the difference between widening the urethra and making a neostoma, vs 
just making an incision and repairing it.]

cystotomy:
caudal ventral 
midline inc for female, or caudal ventral paramedian skin incision with 
deep midline incision in male.
elevate bladder with babcock forceps or 
stay suture,  to the level of incision. 
close with 2 layers of 
synthetic, absorbable sutures - uually simple continuous oversewn with 
cushing. remember bladder heals really really fast.
linea closed with 
interrupted synthetic absorbable sutures. the caudal ventral incision in 
the horse has an increased risk of problems compared to incisions cranial 
to the umbilicus. remember that.

note: in dogs - simple appositional 
closure of bladder; in horses and cows we oversew that with inverting 
pattern.

Urethrotomy: generally done under epidural, after which you 
evacuate rectum, pass urinary catheter, palpate the urethra/catheter on 
midline just above ischial brim. make an incision over the cath, 
separating the bulbospongiosus muscle and corpus cavernosum - if you miss 
this there will be a moderate amount of hemorrhage that you then have to 
deal with while muttering under your breath cursing (as opposed to 
running screaming out of the room), then you can incise the urethra. 
manipulate the calculus, per rectum, while stone is fragmented and 
removed through the urethral incision. so, your left arm is in horse's 
butt, and right arm is doing surgery - not really a completely sterile 
procedure but do your best. lavage/suction bladder completely - this will 
have to be copious lavage and siphoning out. close the urethra over the 
catheter with SMALL 3-0 or 4-0 simple continuous synthetic absorbable 
suture; appose fascia and skin. 

what is the structure called where 
there is a fusion, a seam? a raphe. under the anus is the median raphe of 
the perineum. remember - hernia repair is called herniorraphy? ok. 
anyway. 

slides of procedure...
lithotripe (?) is what is used to crush 
stone
also use rongeurs, sponge forceps to pull out stones

when you get 
the stones out they look like piles of sand/gravel. very gritty, stick to 
the bladder mucosa readily. that's a typical type of procedure and those 
are the  primary options for removal of cystic calculi

can you dissolve 
the calculi? one recent report of lavaging bladder with some stuff to do 
that - probably not useful in general, rarely indicated, this is a 
straightforward surgical problem. not like in dog where you can try 
special diet or whatever.

also there is another syndrome involveing 
mineral material in the bladder that is not the same thing. do not 
confuse this - sometimes, there is a neurogenic problem with emptying the 
bladder. when this occurs, horse may get huge accumulation of stuff in 
there - a gigantic blob of claylike gunk. what this is, is calcium 
carbonate, mucus, cellular debris all glommed together b/c horse hasn't 
voided normally for months to years. this particular syndrome carries a 
terrible, terrible terrible horrible awful no good very bad prognosis. 
usually recurs within a month or two, even if bladder lavage is done 
regularly. we believe it is primarily due to a neurogenic problem. 


remember the horse is one of the few spp with mucus glands in urinary 
tract, and makes a lot of mucus- horse owners new to horses sometimes 
worry about goopy thick stringy urine that is common in horses. but 
that's normal. also normal in rabbit. 

Urolithiasis in cattle: thiss is 
typically seen in feedlot or range cattle. it is not common in dairy 
cattle. it is geographically restricted pretty much to plains areas with 
lots of silicates and animals on high concentrate diets with abnormal 
Ca:PO4 ratios. usually results in stones in the sigmoid flexure urethra.


unlike the horse - horse usually has cystic calculi. cattle more often 
have calculus lodged in sigmoid flexure of urethra. not very common at 
all in heifer or cow. 

signs: restlessness/colic early on; 
anorexia/depression later. in cattle this is an obstructive disease, 
unlike in horse. much later, ruptured urethra may occur - cool, edematous 
(pitting) preputial swelling; ruptured bladder - ballotable symmetrical, 
bilateral ventral abdominal swelling/distension. 

clearly, all other 
comments about diagnosis apply here - ultrasound works, etc - but PE 
often in beef situation is what you are relying on. not that hard. 

slide: steer with ruptured urethra - this is called waterbelly by the 
producer, as is ruptured bladder. 

treatment: 
if no rupture: remove 
stone, or kill animal, or do perineal urethrostomy to fix temporarily so 
animal can recover and be slaughtered later
if urethra is ruptured: drain 
sq tissue, do perineal urethrostomy
if bladder is ruptured: drain 
abdomen, do perineal urethrostomy

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video interlude...

ok, 
moving back into cattle urolithiasis treatment. see above.
remember, the 
perineal urethrostomy here isn't a permanent fix, it's just something you 
do to help these beef animals prior to slaughter. 

this is typical tx. 
for individual valuable animals, treat similar to horse- although in cow, 
you can use flank incisions. but rarely do you get to do this.

slide: 
cow with ruptured urethra and subsequent drain placement. skin is purple.

best to use appropriate feeding techniques to avoid urolith formation in 
beef animals. 

urolithiasis in small ruminants (and pet pigs)
even in 
pet practice, there is a high likelihood you will be presented with one 
of these if you're in a suburban area where there aren't many large 
animal practicioners, b/c these are emergencies and there are lots of pet 
goats and pet pigs that get treated similarly to dogs and cats, not sent 
to slaughter! 
this is an important and common problem
almost exclusively 
affects males
the number one suggestion to make to any potential pet pig, 
goat, or sheep owner is to have them get a female!
usually we see this in 
adults, but sometimes as young as 3 mos.
signs as expected - straining, 
urinary obstruction, pain, colic, depression, anorexia, etc.
slide: goat 
looking worried
these animals aren't always presented that early- goat 
owners - at the risk of offending, he says they have not always been that 
astute in our experience, in that animals are often brought in nearly 
moribund rather than at the first sign of standing around straining a 
bit. as with cats - may have been out hiding for a few days prior...goat 
might be standing with tail elevated, kind of hunched, maybe dribbling 
urine, may have worried expression as this goat  does...basic, subtle 
signs. 
slide; sheep with ears back, sort of depressed, fully 
obstructed...he looks very sad and is very flat out sick.

how to treat?

early on can try antiinflammatories, NSAIDs, steroids, antispasmodics, 
muscle relaxants...there is no magic bullet, though. valium, 
methocarbamol...none work consistently, but sometimes something does, in 
an early case.
but generally, we see the totally obstructed ones and they 
need immediate relief. 
surgical tx:
urethral stone removal is difficult 
- stone basket sometime used, special surgical instrument. generally not 
really possible b/c stones are usually multiple and require cystotomy

laparotomy/cystotomy - most commonly done. clean out bladder, pass cath - 
normograde insertion of catheter is used to try to flush urethra, using 
lube, fluids to try to flush out stones. remember - there's that 
vermiform appendage at the end of the penis in sheep/goats which can also 
be the point of obstruction. often you snip that off first to see if that 
fixes the problem. unlike a cat, in these animals, you can't use a 
catheter plus retrograde lavage to fix the problem. it's nearly 
impossible to pass urinary caths in these animals, and most practicioners 
do not waste time trying. in goats, you can't do it (pigs too) b/c of 
urethral diverticulum near the ischium; in all these animals the urethra 
is tight, it's hard to exteriorize the penis, etc. so usually proceed 
directly to more aggressive approach.

a lot of times you can't dislodge 
stone with above procedure b/c urethra is spasming. so you have to do a 
tube cystostomy - put a catheter with large diameter, and balloon or 
ridge on end, and put it in the lumen of bladder and pass it out through 
abdominal wall, so urine drips out onto the floor. not idea tx for 
housepet, but it's required in most cases. then, over time after surgery, 
keep animal on antiinflammatories and abx, wait for urethra to calm down, 
usually stone passes on its own over time as urethra relaxes, then try 
occluding catheter gradually so bladder and urethra work normally again, 
then remove catheter - usually just pull it - no repeat surgery.
in cat, 
you do urethrostomy - also possible in small ruminants/pigs, but totally 
different and more difficult. in cat, urethra is widest in that perineal 
area. in these animals, it isn't, and it tends to restricture after this 
procedure. so the other place to do it is subischial

also there are 
permanent cystotomy techniques where you open the bladder to the outside 
through the body wall - this results in permanent urine dripping and 
possible ascending infection.

slide: huge, distended goat bladder with 
surface hemorrhage. 
slide: very inflamed goat bladder. difficult, thick 
tissue to work with.
slide: postmortem specimen - bladder full of stones, 
hemorrhagic urethra and rupture present

urolithiasis in small ruminants: 

surgical followed by medical
increase water intake, force increase in 
NaCl consumption, always have water around. give grass or grass hay - not 
alfalfa which is high in mineral content; and don't give them grain! 
specifically do not feed whatever grain is lying around. don't give goats 
horse feed, for example.

dx: again, u/s is good, or contrast rads 
although not as good as in small animals. obviously bladder also can be 
imaged with u/s.
slide: permanent urethrostomy in - uh, goat? not a great 
longterm option, but if distal urethra is severely damaged, it's this or 
permanent cystotomy so maybe worth a try then.

slide: vermiform 
appendage - snip this off if obstructed.
slide: cystostomy tube in place 
in goat - allowing constant drip of urine while urethra is healing and 
recovering. intermittently occluded until animal resumes voiding through 
urethra. 

surgical disease of the bladder:
ruptured bladder
cystic 
calculi
neoplasia

Ruptured bladder - the big  disease we see in horses, 
almost exclusively foals, generally colts more often than fillies, 
usually in first few days of life but other times sometimes, too. any 
breed, TB may be overrepresented. most commonly ruptured at time of birth 
or prior to birth.
signs: important to remember! sometimes very vague and 
a real problem in foals since so many other things cause this in foals:

anorexia
depression
dysuria, oliguria, anuria -- not always seen!

abdominal distention -- later in process, urine fills abdomen
tachycardia


a couple of things owners are sometimes unclear on. if foal urinates 
normally - hind legs behind it, tail behind it, stretched out posture. if 
it assumes that posture but no urine comes out, that's bad. or, may put 
feet underneath it and get sort of kyphotic - that is straining to 
defecate. need to tell that apart. 

slide: foal with ruptured bladder - 
hangdog (hangfoal?) expression, mom's udder is full, foal abdomen 
full/distended/round in this 2 day old - full of free fluid

dx: PE, 
history, abdominocentesis, transabdominal u/s, clinical labwork


peritoneal fluid will have creatinine 2-3x blood levels
bloodwork will 
show hyponatremia, hypochloremia, hyperkalemia, and azotemia
these are 
important things to remember!! the hyponatremia and hyperkalemia are most 
consistent. low sodium most consistent

you know from years of this now 
that the kidney wants to retain some things anad excrete others - retains 
sodium, excretes potassium and creatinine. so urine generally low in 
sodium and chloride, high in potassium and creatinine. when urine is in 
abdomen, peritoneal dialysis occurs - but instead of dialyzing with 
dialysate fluid, you're doing it with urine- so blood picks up potassium 
and creat, and drops off sodium. creatinine remains greater in peritoneal 
fluid since, as a large molecule, it won't passively diffuse along the 
gradient.

localization: urine in abdomen had to come from bladder (most 
likely), urachus, or ureter. fourth most likely possibility is kidney, 
but foals do not generally have leaking kidneys. definitive means of 
localization is u/s - see bladder tear. or inject dye through urinary 
catheter - methylene blue - then do abdominocentesis in 5 min, and if 
blue, obviously ruptured bladder or urachus.
IVP not useful - clunky, not 
sensitive in large animals. 

treatment: drain abdomen if distension is 
severe - slowly to avoid acute cardiovascular problems. correct 
electrolyte imbalance. give hypertonic or normal saline; possibly also 
give dextrose and insulin. do not give LRS b/c it contains potassium. so, 
then, you have to do surgical correction of the defect. 

ruptured 
bladder repair - caudal ventral midline incision - elevate bladder (easy 
in foal compared to adult horse) - debride edges minimally, then close in 
2 layers. simple, satisfying, generally they do really well with no 
postop complications...unless, there are anesthetic complications, b/c of 
metabolic disorder present, and the most common problem seen is asystole 
or 3rd degree AV block. they can die from that. 

sometimes the bladder 
looks ruptured, other times looks like never was in one piece. we presume 
ruptures occur when bladder is full at birth and gets squeezed coming 
through pelvis of mare. in foals, bladder is repaired with inverting 
pattern to avoid adhesions - foals have a marked tendency to form 
adhesions so always minimize suture exposed on serosal surface.

ruptured 
ureter - usually in foal under 2 weeks. less frequent than ruptured 
bladder. signs similar to ruptured bladder but dye placed in urethra 
won't show up in abdomen. often these foals have multiple congenital 
defects. dx u/s or exploratory celiotomy - infuse dye into ureters and 
find leak. if unilateral problem, can do nephrectomy/ureterectomy; but if 
bilateraal you have to fix at least one!

ruptured urachus: may be 
associated with umbilical structure infections. remember urachus is where 
urine goes into allantois prior to birth. once umbilicus is separated 
this should spontaneously close, retract, and separate so bladder isn't 
stuck to umbilicus. this sometimes fails to occur. if problem is 
intraabdominal, signs as above. if in skin level, leak is into subcu 
space; if to world, leaking to outside occurs. usually in older foal.


surgical dz of urachus - may be infected, or patent. 
slide: umbilical 
stump of this foal is moist, red, dripping - b/c urine is dripping there 
constantly
slide: calf with wet spot and pinpoint opening - also patent 
urachus.
these require surgical repair - or, some people cauterize 
w/silver nitrate or lugols iodine.

remember, know your anatomy of the 
urachal region b/c it is important. remember there are three important 
structures - urachus, two umbilical arteries (go up along bladder), and 
umbilical vein (toward liver) - any of these can get infected in a 
neonate and you need to tell them apart to treat them surgically or 
medically. 


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