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medsurg
4/23
p.orsini

there's a chapter in the handout 
that has lots of info. exam questions will come from lecture.

we're 
going to talk about horse heads, dental dz, etc.

start with anatomy- see 
how it relates to signs of dental dz, and how to treat it. hopefully if 
you know anatomy you can figure out signs and how to do the surgery.


slide: standardbreds racing.
slide: signs of dental dz - anything. not 
eating well, losing wt, colicing, not drinking cold water, dropping food, 
smelling bad around mouth, fighting bit, bleeding, not racing fast 
enough, whatever.

think of incisors - females don't have canines. 
premolars and molars - cheek teeth - 6 upper and lower on both sides, 
closely packed. because they are so close there is no room b/w them so 
extraction is different. if anything, it's more like extraction from 
people. you don't have to section the teeth b/c roots are parallel. 
similar to humans. but they are very close to each other, with little 
space for your instruments in there.

another thing - people forget this 
but it's a fact that molars do not have deciduous predecessors. premolars 
do have baby teeth first. so for premolars there are two sets, first ones 
fall out, new ones come in. in horse, there are 6 upper and lower cheek 
teeth. 3 molars, 3 premolars. easy. you may recall or not that about 20% 
of horses have an extra premolar called a wolf tooth, and that's the 1st 
premolar. the first tooth that is always there is the 2nd premolar. 
remember that. you go P2, P3, P4, M1, M2, M3. the first molar M1 comes 
out very early - a 1 yr old horse has the first molar - that's the oldest 
permanent tooth in the horse. so, it is the most commonly diseased tooth 
in the horse - M1. REMEMBER. Dean Richardson will ask you about this and 
humiliate you if you do not know. it's also on the national boards a lot. 
the most commonly diseased horse tooth is the 4th cheeck tooth - first 
molar. M1. it's been around the longest.

another tooth often having 
problems is the third cheek tooth - P4. that's the last baby tooth that 
erupts, sometimes the permanent tooth gets impacted b/c baby P4 tooth is 
stuck b/w the permanent P3 and M1. so the P4 is most commonly impacted 
tooth - permanent tooth may abcess. but really remember the oldest tooth, 
M1, most commonly involved in dental disease. 

think about anatomy. if 
cheek teeth in back - roots come up into maxillary bone region. there is 
a sinus there - the maxillary sinus which has two parts, rostral and 
caudal. big airfilled space. maxillary sinus is within maxillary bone. 
tooth roots project up into the sinus. there is a big hole into the 
frontal sinus, too. but the roots of teeth project into the floor of 
these sinuses. 
P4 and M1 project into the rostral maxillary sinus
M2 and 
M3 project into caudal maxillary sinus
so that's the last four teeth that 
project in there.

P2 and P3, the first two cheek teeth, aren't involved 
in the sinuses. so if they get infected, they drain out the side of the 
face. if the others do, they drain into the sinuses. then, from sinus, it 
drains into nose and you see nasal d/c. so if you see nasal d/c in a 
horse with tooth problems, you probably can focus on these teeth 
(assuming you ruled out another cause of nasal d/c). this makes your oral 
exam a little easier. 

when you take rads, also hone in on a certain 
area, instead of taking 15 films.
so remember that the last four upper 
cheek teeth are involved with the sinuses.

slide: horse that died of 
anesthetic complications. P4 was removed. there was a sinus infection. 
the roots of teeth are very long. we see a small crown - tip of the 
iceberg. typically the root is very long depending on age. remember they 
grow a lot - in old horse, root is shorter, in young horse, root is 
really long. this 5 yr old has long roots. the maxillary sinus region is 
seen and the thin bony floor of that sinus is all that covers the tooth 
root. if tooth is infected, it breaks through into sinus adn fills sinus 
with pus. you don't see swelling and drainage out the side of the face.


skull: standard rads
DV view - usually take but less important with 
dental dz
lateral - usually - more important with dental dz
obliques - 
usually

slides: 

young horse - straight lateral mandible - confusing 
looking. you see both L and R mandibles on top of each other and both 
lower arcades of teeth superimposed on each other. hard to see detail. 
also in young horse, you see baby teeth with permanent teeth beneath 
them. so it is very difficult to see what's going on with a plain 
lateral. the permanent molars are seen. the deciduous premolars are seen 
above their permanent ones. there is a space b/w P3 and M1 - why? P4 
erupts last - so it isn't well developed yet. the baby tooth is there, 
but permanent tooth isn't fully developed. nothing like this will be on 
exam :)

most radiologists do not like horse skull rads. they are 
confusing. 

straight lateral projection - rami of mandibles are visible. 
the skull is a lot of air. blackness everywhere. this is the maxillary 
sinus region. the left teeth are superimposed on right teeth - not much 
detail is seen. notice that M1 has shorter roots - is older tooth. there 
is air density above the roots. if there is anything else in there, 
that's not normal - sinusitis. 

how do you see detail of tooth roots? 
use obliques to get rid of superimposition. now we see apices of the 
roots. here P4 has a fluffy white thing above it. there is a lot of 
variance in how roots look, depends on age of the tooth. notice air above 
roots.

slide: simple rooted tooth. prototype tooth. crown, root, sitting 
in alveolar bone, surrounded by periodontal ligament attaching root to 
bone. you can usually see alveolar bone, then a space, then a root. look 
for loss of the space in presence of dz. 

here the lamina dura and root 
are widely separated. sure they are, dr orsini, sure they are. 

here, P3 
root looks a bit rounded, and there is a big increased space over the 
root. this is ongoing dental dz. there is a sclerotic bone area trying to 
cap off this problem. 

here we see ethmoid turbinates, the frontal bone, 
the roots up next to sinuses - and there is a fluid line, horizontally 
across the film - indicates interface of air and fluid - this sinus is 
full of pus, so it has sinusitis, which usually is secondary to a tooth 
problem. 

he just made a joke about arabians and brain size, i don't 
understand it.
this horse has a fluid line too, probably signifying tooth 
problem. 
one of the roots has increased bony sclerotic lesion near it. 
this tooth had a pathologic fracture, it was so sick. the root was kinda 
dissolved. a piece of it had fallen off. you can see the fragment on the 
rad if you look closely - sure you can...

fluid in the sinuses can be 
pus, could also be blood if it ran into the wall or something. but fluid 
line probably indicates pus, which probably indicates dental dz.

again, 
looking at teeth here....no fluid line, but there is increased density. 
sometimes there is thick pus that isn't liquid, and that creates this 
increased density in the sinus. 

this horse has a swelling on the left 
side of his face, just rostral to the facial crest. it's the upper area, 
rostral to sinuses, swelling out to the side of the face, no nasal d/c - 
probably a problem with first two cheeck teeth. 

rads: P3 has an area 
around it where tooth is dissolving, there is some air density near the 
root and then bony density behind that - this is an apical abcess.

how 
do you treat this? when thre is soft tissue swelling and changes in the 
root, antibiotics will not work. typically with dental dz, you tx with 
abx, they get better right away, you tx 3 wks, it's doing great, then you 
stop the meds, and it comes back a week to ten days later. this will keep 
happening. typical of dental dz. also typical of foreign body, sequestra, 
dead bone. you can't get rid of infxn until you get rid of the dead 
tissue. so, you see this problem, you're going to have to clear the 
infection somehow or remove the tooth.

easiest way to remove the tooth 
is to go in and pull it out.

tooth root abcess types: 
different types 
have different prognosis - 

without fistula or sinusitis: best scenario, 
best px. to treat this, you can probably pull the tooth out of the awake 
maybe sedated horse, using a big extractor, and pull the tooth and it 
will come right out. or, it could be really hard and require anesthesia. 
you could also refer this out. so first you try to extract this out 
through the mouth. this is best thing to try. if it won't come out b/c 
horse is young, root is long - you have to do a trephination (make a hole 
above the root) and repel the tooth - hit it with a hammer/instrument 
thing and push it into the mouth, then pull it out. also could do 
buccotomy with extraction but we won't discuss that yet.

the extractor 
is long, like giant pliers with 2 foot handles. grab tooth, pull, rock 
bck and forth - takes 5 min to an hour...if horse is nuts, anesthetize 
it. so you try this. the horse's mouth doesn't open that much b/c face is 
so long. sometimes, you can't get it out b/c it hits the lower tooth - so 
you pull out as far as you can, cut off a piece, then pull out more, etc. 
that can take a while. but this is the preferred method - avoids making 
an extra hole in the head.  sometimes this requires anesthesia


trephination - use mallets and long chisel type things. 
the trephine is 
a big drill that removes a nice bone core, making a window for your 
chisel thing to go in to push on the root. this is called repulsion.

now 
you have a hole in the head. plug with gauze, wax, other. dental acrylic, 
whatever. you have to seal the socket so there isn't a chronic oral/sinus 
fistula. in small animals you do not have to close it. also in people. in 
the horse, the hole is so big, and they eat hay and stuff and it gets in 
there. so you plug it. 

buccotomy:
slide: M1 here looks abnormal. kinda 
rounder, less density in some areas, more in others, no sinusitis seen. 
this horse is a root canal candidate, or you can put horse under anesth 
and try to remove through oral extraction. or, you can cut into side of 
the face to get into mouth - buccotomy - so you can open mouth, get in 
there, and section the tooth as in dog/cat, and remove. 
this is a rare 
technique, but...
your incision is going to have to avoid the facial 
nerve, the parotid duct, etc. so you incise into oral cavity, remove some 
alveolar bone, cut tooth longitudinally and pull out the pieces. this 
avoids going into the sinus. now you pack the cavity, close it, close 
incision, you're all set. 


ok, next. now you have some swelling along 
the ventral jawline. there is some drainage coming out. on rads there is 
sclerotic bone and a draining tract associated with a tooth root. you can 
put a metal probe into the fistula and take rads -it will point to the 
tooth.

tooth root abcess with draining fistula: still try to take out 
through mouth, but now you hae to curette out the infected area. same as 
above but with curettage, also leave open to drain. same as above but 
requires tx of soft tissue infection. similar to first type of problem. 
prognosis still good. the lower teeth are good b/c they do not involve 
sinuses. 

prognosis - lower teeth better than upper - they drain well. 
upper teeth - rostral two have better prognosis b/c no sinus involvement. 
when the sinus is involved, prognosis isn't quite as good. sinus 
involvement isn't a good thing.

horse with nasal d/c - 
horse with 
draining tract dorso/caudal to eye - due to sinusitis which drained out 
through head as well as through nose. 

tooth root abscess with sinusitis 
- bad., worse px. may take $3-5,000 to get horse back to shape!! 
sometimes never works. 
you will make maxillary or frontal sinusotomy, as 
required - usually maxillary. also can do buccotomy to remove tooth, and 
then do sinusotomy. that is rare. that's a long surgery. 

maxillary 
sinusotomy - make window into maxillary sinus region - know this - you're 
going over facial crest - b/w medial canthus and infraorbital foramen. 
surgical landmarks for approach to max sinus - facial crest ventrally, 
and line b/w medial canthus and infraorbital foramen are your dorsal 
border. this gives you a rectangle within which you should stay. so 
connect the dots. if you stay in there you will not cut anything bad. 


ok, you can leave now.

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Ross - guttural pouch disease


slides are in handout.
the guttural pouch is one of those things you 
learn in anatomy and then forget about. that's ok except sometimes you 
are faced with a problem in there and then you might wish you knew more 
about it. however, you can look in the books to find stuff out. you could 
be in equine practice all your life and not be faced with a true guttural 
pouch problem, unless you work with foals a lot or if you work at a track 
where you have to flush guttural pouches. 

pouches are peculiar to the 
horse
disease of the pouch is rare and usually dramatic.
pouches are 
lined by respiratory epithelium so any infxn/inflammation of upper 
respiratory tract can spread here.
anatomical considerations are 
important!

however, it's rare to have to intervene in guttural pouch 
problems. this is good b/c the pouch is borded by nerves, vessels, and 
approach to the pouch is harrowing. 

anatomy: outpouching of auditory 
tube with no known function - may be involved in equilibrium. you can go 
in there with the endoscope and look around. there are openings into the 
nasopharynx - paired, dorsolateral openings, with cartilage flaps. dorsal 
position makes drainage difficult. but you can look in there and see all 
kinds of stuff going on. 

dorsal border - base of cranium, atlas 
caudally. medially, ventral straight muscles of the head. ventrally the 
pharynx and trachea, laterally the mandible, SM muscle, parotid, 
retropharyngeal LNs. the stylohyoid bone divides into medial and lateral 
pouch compartments. 
on rads - generally the ventral border seems 
thickened. sometimes you see enlarged LNs, or fluid line. 

lateral 
compartment smaller than medial
normal lining: thin, transparent 
epithelium. can see muscles and nerves really well through it. it's a 
window to nearby structures. 

a horse came in with presumed dx guttural 
pouch mycosis. it didn't have that - they went in and saw a big black 
mass on lateral aspect of pouch, and through the thin membrane another 
mass in the LN was seen. the horse had unilateral hemorrhage from that 
side, too - but blood was coming from the sinus. this was a grey horse. 
he had melanoma. 

important nearby structures:
medial (bigger) 
compartment: more commonly gets mycosis. in here are internal carotid and 
vein, CN 9-12, cranial cervical ganglion. all can be involved with 
mycosis.
lateral compartment - external carotid artery, branches to form 
maxillary artery.

the larger medial pouch extends ventrally. when there 
is mycosis of the guttural pouch, it can affect external maxillary 
artery.

surical approaches:
classically, Viborg's triangle - ventral 
border is linguofacial vein; dorsal _ sternomandibularis m.; cranial - 
ramus of mandible. another approach is the white house approach - just 
under linguofacial vein - slide up into pouch. so there are two 
approaches. but don't go whacking around in there b/c of important 
structures.

how to examine it: palpate behind mandible, feel for masses, 
enlargments, fluid or gas in there. horses with infections may have 
change in TPR, nasal d/c. can examine specifically with endoscope (most 
important) or rads.

endoscopic exam: 
not only includes the pouch but 
also nasopharynx, pharynx, pouch openings. it takes skill to get into the 
pouch. can thread biopsy instrument in first, then push endoscope over 
with it as a guide. or can use a catheter or something. it's not that 
easy to get in there. you can, once in, look for exudate, mycotic 
lesions, changes in the lining (thickening, inflammation), masses, 
swellings, etc. 

slide: round pink area seen through endoscope. he says 
you can see the larynx and that the white flaps represent guttural pouch 
openings which open every time the horse swallows. I don't see any flaps, 
but ok. the other thing that is confusing is when you do your exam often 
mucus is hanging around the g-pouch opening, and mucus can go into the 
pouch when horse swallows. so if you see mucus in there, it's not always 
from there, maybe it went in there, and you might accidentally dx a 
problem with the gpouch when there isn't one, there is a problem 
elsewhere. 

he's describing an episode where he tried to relieve 
epiglottic entrapment using that through the nose method that we were 
warned about before. he hooked the hook into the tissue and then the 
horse swallowed, causing the hook to flip up and lodge into the guttural 
pouch opening. so he tried to gently get the hook out. the other guy 
working with him pulled the hook really hard. it came out but the end of 
the hook stayed in there. it took about 4 surgeries to remove the hook. 
the horse was fine and raced for a few years after that. 
another time 
someone slipped and cut the soft palate with the hook - so now we do that 
procedure through the mouth using short acting general anesth (that case 
went to court; Penn won)

fungal mats may look white, fluffy - here is 
one on the medial side of the pouch. this is aspergillus. can also be 
black. most melanomas are in lateral compartment, mycoses usually in 
medial, but not always. 

other - can see retropharyngeal LNs, can see 
hemorrhge/swelling in ventral muscles of skull, can see petrous temporal 
bone swelling to dx internal ear infxn.

rads can be useful. rads and 
endoscopy together are the only specific techniques to dx gpouch dz. 


dzs of guttural pouch:

catarrh - inflammation of lining, mucus 
accumulation in pouch. may be overdxed, more common in racehorses.

empyema - pus in pouch - one step beyond catarrh. usually secondary to 
abcess LN, often strangles, strep equi  infects LN then spreads
mycosis - 
most dramatic
tympany - occurs when congenital or other problem with 
gpouch opening doesn't allow air out of pouch, air comes in, is trapped, 
pouch swells. tx=sx
chondroids - firm concretions in ventral aspect of 
gpouch - inspissated pus, gets firm, called chondroid.

these are all 
rare. the most dramatic of them is the mycosis - most life threatening. 


clinical perspective -as a group these are all rare. signs are similar to 
more common conditions - nasal d/c: URI, sinusitis, LRI; epistaxis: 
trauma, ethmoid hematoma.

we get 5-6 calls a year out of which 1-2 have 
g-pouch mycosis. s0 you might not ever see this. if you have signs 
associated with gpouch dz they are more likely to be due to something 
else. hemorrhage from a single nostril should make you think of gpouch 
mycosis, but also more commonly trauma, etc. 

Guttural pouch mycosis:


-fungal infection of the GP - aspergillus most common
-insidious 
localized infection - no nasal d/c. 
-signs are secondary to process: 
hemorrhage due to injury to vessels, cranial nerve injury if fungus 
invades nerve, all secondary to invasion of fungus - it goes into wall of 
pouch near big blood vessels. if you occlude the vessel, the fungus goes 
away. that's the treatment.
-most common in TB, rare in STB (never in 
stb?), sometimes in large warmbloods. seen in foals and adults. 

when 
you have one of these, you do not wait to deal with it. it's a surgical 
case. the fungus can erode the carotid and cause severe hemorrhage. it's 
a very dramatic disease. never let the sun set on a guttural pouch 
mycosis. if you find this disease, and it isn't actively bleeding, get it 
in, on the table, do surgery to occlude the vessel. maybe not that night, 
but ASAP.

the more cranial nerve injury, the worse the prognosis. you 
don't dx this until either the horse bleeds or shows cranial nerve signs. 


epistaxis is most common sign - can be life threatening, not related to 
exercise, is intermittent, profuse. 
dysphagia, horner's syndrome may 
occur when fungus affects pharyngeal nerves, cranial cervical ganglion, 
symp trunk.

also may see (rare) corneal ulceration, respiratory noise 
due to DDSP, laryngeal hemiplegia, or facial nerve paralysis.

dx made on 
clinical signs and endoscopic exam - if blood is coming out of pouch 
opening, or clot is there - probably this. observation of fungal lesion 
also diagnostic. blood in pouch may obscure the lesion. the site of the 
lesion determines the tx plan. need to see if it is in medial or lateral 
compartment.

slide: left pouch opening is propped open by a blood clot - 
strongly suggests hemorrhage. 
slide: fungal lesion - grey/red plaquelike 
appearance. can also be black, white. pretty localized. 
need to see if 
it is involving lateral/maxillary a. or medial/internal carotid a. 
sometimes involves both vessels. 

emergency surgical occlusion of 
involved vessels. the good thing about arteries is that there can be 
retrograde flow. but that's also bad, because we can't just tie it off in 
one place. we have to tie it off on both sides. with simple ligation, 
fatal hemorrhage can still occur. but wait, how do you get past the 
lesion? need to use balloon cath - occludes vessel proximally and 
distally from lesion. you can't just ligate it, because sometimes fatal 
hemorrhage will still occur. balloon catheter is preferred. some horses 
will stop bleeding if you do simple ligation, but that isn't usually what 
you see. so the balloon catheter is recommended to allow occlusion of 
vessel proximal and distal to the lesion. 

so, most often it is the 
internal carotid. approach - incise cranial and ventral to wing of atlas 
"hyovertebrotomy incision" - find common carotid, identify internal 
carotid, make arteriotomy, thread up a fogarty cath, blow up balloon, tie 
off, away you go. sometimes this is done as an emergency during active 
hemorrhage, it is hard to be sure you are in the right place, or 
sometimes you go through the lesion into the guttural pouch by accident. 


once the balloon is blown up, it occludes retrograde flow. you tie off 
proximally. don't confuse occipital artery with internal carotid. leave 
catheter in 7-14 days and then you can remove it or leave it in. by then 
the fungus is gone. usually we leave cath in though.

if maxillary a. 
involved, more complex. maxillary a has a lot of collateral circulation. 
there is so much that ligation is really hard. under TMJ is transverse 
facial artery. make a small incision there, thread catheter through and 
occlude there, to prevent flow in one direction. then incise through 
mouth to expose palatine artery and thread through to occlude  - this 
will prevent flow in maxially artery. so maxillary a occlusion requires 
two catheters, indirect approach. you leave this in 7 days and take it 
out.

if both vessels involved you use three balloon caths. 
when you 
can't tell which is involved, put three in. safest.
one problem with 
occluding flow in this area - one or two horses have gone blind, but that 
is rare. but a potential complication when using three catheters is 
unilateral blindness. usually caths can be removed in 7-14 days. always 
remove ones in mouth.

local tx with topical antifungals - not really 
needed. once vessel is occluded, sometimes they do that, or try to remove 
fungus - but really it will go away on its own. 

prognosis good to 
excellent if no other signs besides hemorrhage and if there is successful 
balloon cath technique. guarded with cranial nerve injury, and poor with 
profound dysphagia. 

some universities do not teach the balloon cath 
technique -some of those horses bleed out after surgery, though.

POUCH 
CATARRH	- inflammation of the lining of the pouch. occurs in conjunction 
with any URI. probably way overdiagnosed. if the rest of pharynx is 
inflamed, pouch probably will be inflamed and not need tx. but at 
racetracks, they will ask you to flush the pouches. do not flush the 
pouches with anything irritating, though - can cause permanent injury - 
don't use anything other than dilute betadine or abx. do not use 
formalin, formaldehyde, 7% iodine or anything. be really careful whta you 
flush with.

endoscopic findings - mucous at opening of pouch, lymphoid 
pharyngitis, mucuous may be there due to retrograde flow into pouch, not 
from pouch. if pouch inflamed, lining will be thick, cloudy, inflamed.


tx - rest, tx other respiratory problem, systemic abx, 
antiinflammatories, pharyngeal sprays, etc. if you flush the pouch, avoid 
irritating solutions!!

handout has info about other diseases of pouch.


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