Equine Board Review

8/17/2019 Equine Board Review

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EQUINE BOARD REVIEW

Colic highlights:• ⇑ Temp – anterior enteritis, Colitis• ⇑ Pulse – Ischemia, obstruction, displacement• ⇑ reflux – anterior enteritis• Rectal palpation

NSAIDS• Most commonly used:

a. Banamine

b. Phenylbuta onec. !ipyroned. "etoprofen

• Inhibit cyclooxy#enase en yme$mediated production of eicosanoids form arachidonic acid in the cell membrane• "etoprofen may also reduce inflammation by inhibitn# lipoxy#enase en yme mediated synthesis of leu%otrienes• Toxicity:

Phenylbuta one & Banamine & "etoprofen• Toxicity thou#ht to be result of reduced local sythesis of P'( causin# decreased 'I and renal blood flo) and 'I cytoprotection• (xacerbated by dehydration• *ide effects:

a. 'I ulceration b. Protein lossc. +bdominal paind. (ndotoxemiae. lceration of the ri#ht dorsal colon – phenylbuta onef. Paplillary necrosis – renal toxicity from phenylbuta one

• - anta#onists and sucralfateAnti-ulcer meds • - anta#onists /Cimetindine – Ta#amet0• Proton pump inhibitors /1mepra ole – Prolosec0• P'( /Misoprostol0• Cytoprotecti2e a#ents $ *ucrafalate

! "loc#ers $ Anti-ulcer medic%tions• -ydrophobic histamine analo# /contains an imidi ole rin#0• + Re2ersible competiti2e anta#onist to - receptor, It has 31 -4 bloc%in# acti2ity, so acts solely on #astric secretion /no effect on aller#ic rxns0• Bloc%s histamine stimulated #astric acid secretion by 56$4778 /usually around 5680• -as no effect on #astric motility, bilary or pancreatic secretion• sed chronically in human medicine, but should be used for a 4 )ee% period only. lcers )ill come bac% after medication is stopped b9c -. pyloric bacteria. *o

Ta#amet antibiotic are ulcer tx.

• Clinical uses include #astric ulcer tx, chronic #astritis, reflux exopho#itis, prophylactically prior to mast cell remo2al• (xamplesRanitidine /;antac0


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• Can cause I? hemolysis, so no #reater than a 47 percent solution should be administered at a relati2ely slo) rate

Dent%l disordersCri""ing• (xcessi2e )ear on rostral mar#in of upper central incisors

Su(ernumer%r' teeth• !ental bud is split durin# de2elopment, usually )ith incisors

&%rrot mouth $ brachy#nathia, the upper @a) is lon#er than the lo)er @a)So/ mouth0mon#e' mouth $ pro#nathia, the lo)er @a) is lon#er than the upper @a)

She%r mouth• Maxilla is )ider than the mandible• *harp ed#es on buccal of upper and lin#ual of lo)er

Other disorders• Aolf tooth extraction –


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E1uine Anesthesi% %nd reco2er'&re%nesthesi%

a. )ithold food for 4 hours /not )ater0 b. Mineral oil D hours before sxc. +tropine or Isoproterenol only )hen anesthesia used )ill induce bradycardia /atropine )ill cause ileus0d. *edate )ith Eyla ine or !etomidine

Anesthesi%a. Induction a#ents – '', Thiopental, "etamine, Tela ol, Profofol

b. Inhalation – -alothane /more potent and more lipid soluble, but more myocardial depression0, Isoflurane /peripheral 2asodilation0, *e2oflurane

Blood (ressure during %nesthesi% $ ide%l A& is 34-54a. !obutamine $ β a#onist

b. !opamine $ ⇑ renal fusionc. Phenylephrine – only if 2ery lo) BP, short actin#d. (phedrine – 2asopressin

Ventil%tion during %nesthesi%a. 3ormal 2entilation is PaC1 is F6$G6

b. -o)e2er, moderate hypercapnia of &%CO! 6 77-37 )ill actually impro2e muscle perfusion and pre2ent neuropathy post sxc. *e2ere hypercapnia of & H7 mm-# shifts dissociatio cur2e to the ri#ht causin# arrhythmias and abnormal breathin# patterns

Anesthesi% com(lic%tionsA(ne% caused by:• (arly induction period of anesthetic b9c hi#h plasma protein concentration• Too deep anesthesia• !oxapram can be used as a respiratory stimulant that also initiates relase of endo#enous epinephrine and causes and ⇑ in -R and BP

'(o8emi%• Is )hen Pa1 is less than D7 /should be & 70• Caused by hypo2entilation or 2entilation –perfusion mismatch• Tx by:

a. !obutamie infusion – increases oxy#en deli2ery to tissue b. Clenbuterol $ β a#onistc. minimi in# time in dorsal recumbency

Neurom'o(%th'• *)ollen and painful muscle, )ea%ness, profuse s)eatin#, myo#lobinuria /port )ine urine0, ⇑ C", *'1T, non$)ei#ht bearin#• Caused by:

a. improper positionin# durin# anesthesia b. mali#nant hyperthermiac. prolon#ed sxd. excessi2e anesthetic depthe. lo) Pa1 , ⇓ BP or acidosis

• Pre2ented by:a. maintainin# li#ht anesthesia and c92 fxns

b. a2oid excessed preanesthetic especially phenothia inesc. +de uate paddin#d. *upport of upper front and hind le#se. Balanced electrolytes and Ca #luconate /maintain muscle

contraction0

f. !obutamine, dopamine or ephedrine to maintain ade uate BP#. !onJt put horse under until sur#eon is readyh. !antrolene – muscle relaxationi. !ia epam – muscle relaxation

@. 3a bicarb – correct metabolic acidosis


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St%nding sed%tion• +ce /Eyla ine >9or Butorphanol, Meperidine, Penta ocine >9or xyla ine0• Eyla ine /Butorphanol, Penta ocine0• !etomidine Butorphanol

Intercocc'ge%l E(idur%l• =idocaine /6$47 m=0 –fast > short• Eyla ine in saline – slo) > lon#• =idocaine Eyla ine )9 saline – fast and lon#

9um"os%cr%l or su%r%chnoid e(idur%l• !etomidine in saline >9or morphine• Butorphanol lidocaine

In ect%"le %nesthetics• Thiopental – lon#, rou#h reco2ery• ''9Thiopental – better muscle relaxation, poor anal#esia• Eyla ine9"etamine – /xyla ine 6 min before %etamine0, smooth induction and reco2ery, inade uate muscle relaxation• Eyla ine9"etamine9Butorphanol – #i2e )9 xyla ine, impro2ed anal#esia• Eyla ine9"etamine9!ia epam – impro2ed muscle relaxation• **0;'l% %n%lgesi% ? muscle rel%8%tion> smooth reco2er'> re2erse /0 'ohim"ine> tol% %ti(%me may re uire more than one attempt• !etomidine9Tela ol – same as abo2e• Propofol – short term, rapid redistribution and hepatic metabolism• Profofol9'' – lasts lon#er


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Vir%l Res(ir%tor' D


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f. +borted fetus and membranes should be placed in lea%proof containersIt is not necessary to 2accinate nonpre#nant adult horses except horses %ept in close proximity to brood mares – 2accinate

E1uine Vir%l Arteritis• In same family as PRR* in pi#s• Most pre2alent in *tandardbreds• Transmitted 2ia respiratory secretions and 2enearlly /2a#ina, urine, feces, aborted tissues0• *tallions can remain carriers for a lon# time• Clinical si#ns – #enerali ed 2iremia causin# dama#e to 2asculature causes:

a. fe2er, +!R

b. limb edema and stiffnessc. edema of palpebra and 2entral body )alld. rhinitis, con@uncti2itise. nasal and lacrimal dischar#esf. urticaria in 2arious locations on the face, nec% and body#. Cou #hin #, ⇑ RR h. papular eruptions of MM of lips may also occur i. +bortion in pre#nant mares

@. =eu%openia%. Rarely causes mortality except in youn# foals

• !x – R91 :a. Resp causes – influen a, (-?

b. (dema causes – purpura hemorrha#ica, (I+, hoary alyssum intoxicationc. Confirm )9 2irus isolation on s)abs or heparini ed blood or paired serolo#y 2ia serum neutrali ation

• Tx – symptomatic or pre2ent ° bacterial infection as )ith influen a• +ll cases reco2er une2entfully )9 solid, lon#$lastin# immunity• Pre2ention 2ia se#re#ation and 2accination

E1uine erd e%lth

4. 4$ 2isits9year

. BC*a . I f too fa t then- =ipidosis- =aminitis- +rthritis

b. If too s%inny, then:- 3ot enou#h feed- Aorms- Teeth

F.


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G. ?accinations and )ormin# schedule

Month !e)orm ?accinate 1ther *eptember Pyrantel pamoate – double dose for tape)orms to

pre2ent ilial hypertrophyTetanus(((9A(( – do here if only onceInfluen a – I3Rhinopneumonitis – (-?$GRabies

1thers:

*tran#les – if tra2elin#Potomac -orse months #estation(-?$ – no problems(-?$F Coital exanthema(-?$G Respiratory

&roud lesh• (xuberant #ranulation tissue• !ue to poor )ound mana#ement• 'ranulation tissue that proliferates abo2e the s%in le2el and fa ils to epitheliali e• Tx under )ound mana#ement


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9%minitis

Descri(tion ? Etiolog'+n inflammatory resonse in2ol2in# the dorsal lamina of the hoof

Causes:• (ndotoxemia is caused by

- C-1 o2erload – lush pasture or excessi2e #rain- Retained placenta – metritis )9 endotoxemia- Causes ! , sepsis, > shoc%

• *ystemic corticosteroids- Tramcinolone & 4D m# IM- !examethasone – 2ariable doses- Causes adrenal suppression- Causes constriction of arterioles in foot

• (xcessi2e )or% or stress- Causes endo#enous corticosteroid release- road founder - !ifficult colic- !

- (xcessi2e )ei#ht on le# from fx on contralateral le#

Clinic%l signsAcute clinic%l signs


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- Bute – ponies #et half dose

3ursin# care- (xtremely important- Peat moss beddin# – reduces pressure sores > client has easy access to- se stalls to allo) dryin#- 3o pine sha2in#s- Maalox on )ounds

*hoein#- Re2erse shoe- !i#ital support system shoe for heel, fro# > toe support- -eart bar shoe

*ur#ical- Dors%l hoo) /%ll resection – raspin# to remo2e toe and reshape hoof parallel to dorsal

PF, ne) hoof continues to #ro) same

- ull thic#ness hoo) /%ll resection a . for se2ere cases

b. allo)s draina#e for necrotic debrisc. allo)s for completely ne) hoof #ro)thd . Contro2ersia l

- Dee( digit%l )le8or tenotom'a.


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Su"sol%r%"scess

• Rule this out in (?(R lameness• Most common cause of lameness• +bscess under the sole of the foot• Caused by puncture )ounds at the fro#

a. !rains at the heel bet)een thesensiti2e and insensiti2e fro#

• Puncture )ounds at the )hite line from#ra2ela. !rains at the coronary band

'et a mar%ed 'rade I to ?lameness

• Physical exam=amenessIncreased rxn to hoof testers/may e2en %ic%N0*ensiti2e to hammer Inflammation in foot / ↑

pulse )armth0• !iscolored sole – trim to further

idendify• Rads to r9o PF fx and isolate #as

densities• *cinti#raphy

• *ur#ical:

• (stablish 2entral draina#e- +de uate debridement- 'ra2el- Remo2e affected fro# to speed

healin#

• Maintain draina#e- (pson salt banda#e- Ichthammol banda#e

• +ntibiotics- Rarely needed in adults- *u##ested in foals- 1steomyelitis- Loint sepsis

• Tetanus shot


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%re@s re(roducti2e %n%tomic%l "%rriers4. ?ul2ar lips

. ?estibular sphincter – 2ul2o2estibular @unction or sealF. Cer2ix

%re0St%llion in)ertilit'•


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• *erum a##lutination is most accurate• Tx – thorou#h scrubbin# of entire clotral area /includin# the sinuses0 )9 chlorhexidine scrub, then pac% )9 nitrofua one or chlorhexidien ointment

Cer2i8 loc%tion• !iestrus – closed and lies in the middle of the cranial face of the 2a#ina )ith a round rosette appearance• (strus – softens and opens, droppin# to)ard the 2a#inal floor as it relaxes

Pre#nancy losses are #reatest early in #estation, before F6 days /before the embryo enters the uterus0

Ecto(%r%sites

&ediculosis $ 9ice in)est%tion• Haematopinus asini – suc%in# louse, mane, tail and distal le#s• amalinia equi – bitin# louse, dorsolateral trun% • Ainter • Pruritis• +cetate tape, ?(R small

&soro(tic m%nge• Psorpties equi – body man#e• Psoptes caniculi or !ippotis – otitis externa• (xtreme pruritis or pruritic ears• *u##ested uarantine for H$4 )ee%s• I2ermectin is tx• +mitra should 31T be used in the horse /causes depression, ataxia and pro#ressi2e lar#e intestinal impaction

S%rco(tic %nge• Rare in horses – has officially been eradicated in horses• R(P1RT+B=(• I2ermectin is tx

Chorio(tic m%nge $ leg m%nge• C!orioptes equie• Common, surface d)eller • Ouarantine of 47 )ee%s• Pruritis, erythema, alopecia and crust formation alon# extremities• !raft breeds most commonly affected – KfeathersJ in fetloc% area• Readily found in s%in scrapin#s

Demodectic m%nge• emode" caballi and equi• Rare, usually associated )ith immunosuppressi2e conditon or therapies• +symptomatic alopecia and scalin# may be seen• !emonstrated on s%in scrapin#s

ro"iculosis $ chiggers•


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• Incidence in normal horses is 6$4778• !e2elopment of clinical si#ns is hypersensiti2ity of microfillria )hich are most numberous alon# the 2entr%l midline , face and nec% • +lopecia, erythema, depi#mentation, ulceration and crusts alon# the 2entr%l %"domen , face and nec% • 1cular lesion – %eratitis, u2eiets, peripapular choroidal sclerosis and depid#mentation of bulbar con@uncti2a• Presence of 1nchocerca does not confirm clinical d b9c many normal horses ha2e it in tissues• !x confirmed by micro exam of s%in biopsy )9 an eosinophilic #ranulomatous reaction to the parasite around the microfilaria is seen

O8'uri%sis $ &in/orms• Common, but occasionally causes clinical d• +dult female cra)ls out of horseJs anus to lay her e##s• Pruritis of tail – rubbin#• !!x – food aller#y, culicoides hypersensiti2ity, lice, or a stable 2ice

Dise%ses o) neon%tes $ see re(ro sectionPremature9dysmature $ neutropenia*epticemia – any sic% foal

3eonatal malad@ustment syndrome /hypoxoid ischmic, KBar%er foalJ 3eonatal isoerythrolysisCombined immunodeficiency – lymphopenia, ⇓ I#M, lymphoid hypoplasia

CO&DK-ea2esJAllergic Air/%' D<+ller#y /I or III0 to spores ofhay molds /indoor0 or pollensin pastures /outdoor0

Pre2ious 2iral infection thatdama#es epithelium – C1P!si#ns after flu 2accination

(xpiratory dyspnea due to bronchitis-ea2e line /hypertrophy ofexternal abdominal obli ue0

-ealthy neutrophils and lar#eamounts of mucus on TTA/CurschmannJs spirals0

-istoryClinical si#nsResponse to tx

TTA – healthy se#s > lar#eamt of mucus

Response to controlleden2ironment

Response to +tropine or#lycopyrrolate

(n2ironmental control/outdoors, feed cubed9pelletedhay0 – donJt expect immediateresults

Corticosteroids /!ex,Triamcinolone, Beclamethason

– inhaled0

Bronchodilator dru#s+nticholiner#ic /atropine – 4dose only, #lycopyrrolate0Beta sympathomimetic –Brethine, Clenbuteral, +lbutera

=asix

-yposensiti2ity testin# / 0

hrush• Infectious de#enerati2e d of fro#• Blac% necrotic material in fro#• ?ery odoriferous• 3o specific or#anism in2ol2ed• +ssociated )9

a.


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• 3utrition is deri2ed from syno2ial fluid• Type II colla#en fibers are arran#ed 2ertically in the deepest layer of cartila#e, randomly in the middle layer and hori ontally in the surface• P's are speciali ed #lycoproteins )9 C-1 and protein core that contain chondroitin

Su"chondr%l "one• *hoc% absorber bet)een cartila#e and cortical bone

Arthritis•


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Bo/ed tendons

Common condition associated )9 se2erestrainin# or tearin# of flexor tendons

Caused by:4. -yperextension of the fetloc% – most

common cause. Trauma )9 exercise

F. Muscle fati ue )9 exhaustionG. (xternal trauma6. Improper banda#in#

F types:4. -i#h bo) – )9in carpal sheath

. Mid bo) – bet)een carpal and di#italsheaths

F. =o) bo) – caudal to P4

s)ellin#(xtreme s)ellin# in mar%edcases

R91Cellulitis and suspensorydesmitis

Immedi%te t84.


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h. R. e ui foals may sho) nonseptic syno2itis, ! and u2eitis

Rhodococcus e1ui• 5$47 )ee%s old, )hen passi2e immunity declines• 3ormal flora in horse intestine• Copropha#ic youn# foals should produce a self limitin# d• -o)e2er, infection is 2ia inhaltion, so that foals )ith compromised immunity and poor 2entilation• T)o clinical forms:

a. *ubacute – diffuse miliary pyo#ranulomatous pneumonia, usually die )9in days b. Chronic – pneumonia, compromised resp fxn and untrhiftiness

&leuritis0(leuro(neumoni%• Inflammation of the pleural surface )9 exudation into the pleural space• -orses /and not other spp0 are more prone to pleural fluid accumulation b9c arterial supply to pleura is from sytemic circulation /not pulmonary circulation0• In the horse /not other spp0, it is secondary to pneumonia or pulmonary abscesses• *tressed horses are predisposed b9c the resp tract is compromised• *econdary to:

a. Streptococcus – most common b. E colic. Klebisiellad. Pseudomonase. Pasteurellaf. Bacteroides +naerobic infection most common in horses recently transported#. Clostridal h. *ycoplasma felisi. Coccidiodomycosis

@. 3ocardiosis%. (I+l. =*+m. Pulmonary #ranulomasn. Thoracic )ounds

• Clinical si#nsa. Ranitidine0- antacids /+luminum hydroxide0- *ucralfate- proton pump inhibitor 1mepra ole- Prosta#landin ( analo# Misoprostel- Metoclopromide – stimulate 'I motility and enhance #astric empytin#


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- Bethanechol – choliner#ic a#onist

Se(ticemi%• +ny sic% foal is assumed to be septicemic until other )ise pro2en• Caused by bacteria throu#h the blood stream from resp, 'I, umbilicus, placenta or locatli ed infection /@t ill, na2el ill, pneumonia, encephalitis0• Bacteria casuin# septicemia are usually en2ironmental flora:

a. E coli – most commonb. Klebsiella' (ctinobaccilus' Salmonella' Strept' Stap!' Clostrdidum

•


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Ocul%r in)ectious dise%ses• &!odococcus equi – can produce bilateral panophthalmitis in foals )9 pneumonia• Cryptococcus neoformans – exophthalmos and blindness from frontal sinus and retrobulbar inflammation• Steptococcus equi – retrobulbar abscess and orbital cellulits and exophthalmos• 1rbital cellulitis – caused by infectou of ad@acent paranasal and nasal sinus ca2ities or #uttoral pouch inflammation• Mar#inal blepharitis – -abronemiasis or onchocerciasis• Pin%eye – *ora"ella acute con@uncti2its )9 ocular dishar#e and superficial %eratitis• (-?$ – e uine herpes 2irus outbrea%s of %eratocon@uncti2its• T!elazia lacrymalis – transmitted to con@uncti2al sac by Musca fly

In)ectious #er%titis• *i#ns:

a. rapidly de2elopin# %eratitis in a pre2ious normal eye b. =oss of corneal epithelium accompanied by stromal cellular infilatrates and stromal edemac. Mucopurulent stomal necrosisd. *econdary anterior u2eitis )9 possible hypopyon formation

• Pseudomonas infections are most de2astatin#• =oss of cranial epithelium are sub@ect to possible infection )9 fun#al or#anisms includin# (spergillus' ,usarium and (lternaria

U2eitis• 'roup of diseases in2ol2in# the inner coats of the eye• Most fre uent eye problem of the horse• (xo#enous infection:

a. Perforatin# )ound, corneal or scleral ulcer b. Post op

• (ndo#enous infectiona. -emato#enous

b. Classic cause is Coliform or mycoplasma$associated omphalophlebitis, septicemia and infectious arthritis• Immune mediated inflammatory reaction or +utoimmunity /phacolytic u2eitis0• Recurrent 2eitis is the hyperreacti2ity to any excitin# stimulus 2ia prosta#landins• *i#ns of recurrent u2eitis:

a. -yperemia b. + ueous flare, %eratic ppts, and synechiac. Chan#es in the pupil

• Possible causes:a. -eptospirab. $cular onc!ocerciasis

Clostridi%l m'ositis• Clostridial c!au%oei' septicum and perfringens• !irect inoculation or sporulation in muscle necrosis and anaerobic en2ironment /se2ere )ounds0

• Clinical si#ns:a. =ife threatenin# situation b. )ound draina#e to induce an aerobic en2ironment

'o(%thies•


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Com(%rtment s'ndrome• Increased tissue pressure )9in an osteofascial compartment – compromisin# local circulation and function• Most commonly caused by hypotension and poor positionin# durin# anesthesia

Other m'o(%thies• - PP• Postexhaustion syndrome• ?iral and parasitic myopathies• Purpura hemorrha#ica• 3utritionaly myopathies

Ret%ined (l%cent%• +l)ays chec% placenta /chorioallantois0 after a birth to ensure it is intact /can fill )ith )ater to chec%0• Clinical si#ns of RP:

a. Toxic metritis b. *epticemiac. Toxemiad. =aminitise. !eath

• Tx of RPa. 1xytocin – most common and best tx

b.


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De2elo(ment%l ortho(edic d P 0- Radius to P4 >

P- *uperior chec%

li#ament

Conser2%ti2e t84. Correct lameness by:

- Correct the cause- Pain m#mt- *hoein# > beddin# chan#e

. Correct nutritional imbalance by:- Restrict ener#y and balance mineral

inta%e- Increase exercise

F. *hoein# tx:- Club foot

a. *horten heel and extend toe b. Re2erse )ed#e shoe padc. Increase tension on deep

flexor tendon-


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Angul%r lim"de)ormities

Medial or lateral de2iation of the limbMost common in distal radial physis/metaphysis > epiphysis, not diaphysis0Carpal 2al#us


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• Common – may be confused )9 o2arian tumors• 1ccurs )9 excessi2e amount of hemorrha#e after o2ulation• Can ha2e normal o2arian cyclic acti2ity• Aill shrin% o2er time

O2%ri%n %"scesses• *e uela of l%r'n8> tr%che% %nd (h%r'gitis $ see under e1uine res(ir%tor' d


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Sus(ensor' desmitis

Inflammation disruption of suspensoryli#ament esp in TB > *B

Most common sites:4. Proximal to sesamoids

. +ttachment to MCIII

Caused by:4. Trauma associated )9 exercise

. Callous from enlar#ed splints

Mild pain on palpationMar%ed enlar#mentof li#ament

sually a lameness prior to in@ury

Palpation ofli#ament )hile not

bearin# )ei#htClinical si#ns

9*Rads

Conser2ati2e Tx same asabo2e )9 Bo)ed tendonsexcept lon#er healin# time

*x tx is li#ament splittin#

=on#er healin# time /D months0

Better pro#nosis than *!<

Most *B return to racin# 3ot as #ood for TB

9%cer%tion o) )le8or tendons

Caused by trauma or %ic%in# a sharpob@ectMore critical than extensor laceration+thletic career is o2er )ithN

!!< tendon- toe up- fetloc% sli#htly dropped- )hen toe is held do)n,

fetloc% is lose to normal

*!< tendon- fetloc% dropped in )ei#ht

bearin#- toe is normal on #round

!!< > *!< tendon- toe is raised- fetloc% on or close to #round- )hen toe is held do)n,

fetloc% is close to the #round

*uspensory, !!


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Buc#ed shins

Caused by:4. Too much )or% too yound

. Common in@ury in trainin# horses /TB,O-0

F. Metacarpus conditionin# for racin#

BilateralInside le# morese2erely affected – leftle# in TB*hrotened anterior

phase of stride=ocal heat=ocal pain

Rads*ho) doral thic%enin# of MCIII!eep palpation of anterior MCIII)ill exhibit pain

R91 stress fxs of dorsal lateral aspeci anddorsal cortical MCIII.

Medical tx4. Rest for D7 days

. PoulticeF. 3*+I!sG. Pin firin# > blisterin#

*x Tx4.


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Eso(h%ge%l o"struction ,cho#e.+natomy of horse esopha#us iscranial 9F s%eletal muscle

G layer of esopha#us – ad2entitiamuscularissubmucosamucosa

+nxiety*tretchin# of head > nec% Repeated s)allo)in#


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'(er#%lemi%• Tall spi%ed T )a2e• !imishished P )a2e and atrial standstill• +? bloc% • *urpra2entricular tachcardia

Sinus Arrh'thmi%• *peedin# and slo)in# of heart )9 respiration• -i#h 2a#al tone and increased -R should abolish this arrhythmia•• *+ bloc%

• !iastolic pauses Q P$P inter2als•• *inus arrest• *+ acti2ity ceases for & inter2als• Parasympathetically mediated• +bolished )9 exercise or excitement• +bolished )9 2a#olytic or sympathomimetic dru#s

+ AV "loc# • Conductio delay causin# a prolon#ed P$R inter2al• -i#h 2a#al tone in the restin# horses and not )9 cardiac patholo#y

! AV Bloc# • (lectrical acti2ity is inermittently completely bloc%ed at the +? node• Common in horses• 31RM+= – homeostatic mechanism to control blood pressure• +tropine or #lycopyrollate can be used to R91 patholo#y in these horses b9c it )ill #o a)ay )9 parasympatholytic a#ents• Moblit type I – most common, )9 pro#ress2ely len#thenin# P$R inter2al in the beats precedin# the bloc% • Moblit type II )9 a fixed P$R inter2al is less common but also normal

&%thlogic%l %rrh'thmi%s:

Atri%l )i"rill%tion• Most common clinically si#nificant arrhythmia in the horse• Characteri ed by )a2y baseline %no)n as K


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• 3o conduction throu#h +? node atrium and 2entricles are completely dissociated• Aill see promenent @u#ular pulses

%ch'%rrh'thmi%s• (ither supra2entricular or 2entricular • Can be primary or secondary• Causes of Primary myocardial d :• ?iral and bacterial infection• ?ascular and parasitic lesions• Toxins – ionophore +bs• Immune$mediated• Causes of secondary:• -ypoxia• -ypercarbia• +cid base and electrolyte imbalance• (ndotoxemia• 3eed continuous G hour (C' and exercisin# (C' )9 radiotelemetry to dx•• +trial premature depolari ations /+P!s0• Re#ular beat that is prematurely interrupted• P )a2es occur earlier than normal• 1n restin# (C', loo%s similar to a sinus arrhythmia, so must incrase 2a#al tone or sympathetic tone to differentiate• +trial tachycardia is & G +P!s in succession• Most fre uent in horses )9 uinidine treatment•• Rectal tears•Most commonly iatro#enic+lso from breedin# accident!ystocia

In females, HH8 occurred )hile palpatin# uro#enital tractH8 o2erall )hile palpatin# 'I tract

Most tear occur dorsally, apporx. 4 inches cranial to anus in pertoneal ca2ity

G #rades'rade 4: mucosa and submucosa'rade : muscular layer, intact mucosa'rade F: +ll tissue except serosa /Fa0 ormesorectum /Fb0'rade G: all layers

Blood on rectal slee2e*udden feelin# of no resistance on rectal

palpation

Immediate tx:*edate(pidural+tropineTampona#eBroad +bs, 3*+I!sRefer immediately

Tx of 'rade F:ColostomyRectal liner *uturin# tear intrarectum(mpytin# of colon 2ia enterotomy and dailyla2a#e of tear

Pro#nosis:Rectal liner – HG8 sur2i2al )9 Fa, GG8 )9 FbColostomy – H94F sur2i2ed

Complications:Peritonitis, =aminitis, +dhesions, +bscess,-ernia, Prolapse

•• 'uttural pouch d s•• (mpyema > Mycosis+ccumulationof pus )ithinthe pouchca2ity

Chronic se uella to RT infections,esp *tran#les / Strep .0


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+bnormal resp noise=aryn#eal hemiple#ia /R sided – rare0 (n#land

sually unilateral(pisode can be fatal

*pontaneous reco2ery has beenreported

• Chronic ! 9#ranulomatous enteritisReported in youn# horses /*tandardbred and TA-0Cause un%no)n – Mycobacteria paratuberculosis1ften compared to CrohnJs d in people

=esions in2ol2e the small intestine+ffected bo)el is thic%ened )9mononuclear cells?illus atrophy common /malabsorption0P=(

!x:*uspect if P=( is seen in youn# horse )9 chronic ! 9colic!x made on histopath durin# exploratory celiotomy

Tx:1nly remo2al of diseased bo)el /one reported case of sur2i2alof a horse )9 #ranulomatous enteritis had diseased intestineremo2ed0*teroid tx may cause temporary remission

•• ( uine Cushin#s !• =oss of dopamine ne#ati2e feedbac% causes Pars intermedia pituitary adenoma, causin# excess cortisol production by adrenal cortex 2ia ⇑ P1MC, a precursor to

+CT- and β$endorphin.1lder horses

=aminitis – ⇑ cortisol, ⇑ catecholamine 2asoacti2ity andinsulin anta#onism, coritsol ties up insulin receptors neededfor 2asodilation, causin# chronic 2asoconstriction

At loss $ !M from insulin anta#onism of excess cortisol

Polypha#ia

P 9P!!I $ +!- anta#onism from excess cortisol or ⇓ +!-

secretion from posterior pituitary due to expansionof intermediate lube into posterior pituitary

!M – initiatin# insulin insensiti2ity /see belo)0

-yperhidrosis

Bul#in# orbital fat

Beha2ioral chan#es $ β endorphin in C*<

Chronic infection /often respiratory0 – immunosupression ofcortisol

-irsutism $ nnaturally lon# hair coat in 78 of affectedhorses. Could be thermo dysfxn by tumor pressure onhypothalamus, or ⇑ andro#ens by adrenal cortex

3o one test )ill 2erify C!

*i#nalment > clinical si#ns for dx

1ther:+CT- – fe) labs, special tubes

There is no endocrine or biochemical testthat al)ays 2erifies C!

4. R stim – test of choice, C! ha2e⇑ cortisol )9 TR-

. Serum glucose – C! esp if & 467F. Urine glucose – suspect if & 457G. Cortisol – no 2alue b9c pulsatile6. !ex suppression – can #et false ,

should remain hi#h in C!D. +CT- – expect hi#h le2els, but

adrenal is maxmially stimulated sois )orthless

H. Insulin – b9c insensiti2e to insulin,

almost al)ays ele2ated in horses )9C!, =ab should ha2e o)n normals,multiple sampes, a2oid samplin#soon after feedin# b9c secret moreinsulin

5. CBC – many thin#s seen

Tx is often not appropriate b9c oldlaminitic horse that canJt #et into foal.

4. Serotonin %nt%gonist /Cyproheptadine, Pericactin 0 –listed as anti$histamine, effecti2e inabout 49F of cases, stops stimulationof serotonin on pituitary

. Do(%mine %gonist /Per#olidemedylate0 more effecti2e thanPeriactin ⇑ dopamine )hichinhibits pituitary – expensi2e butdru# of choice

F. Do(%mine %gonist /Bromocriptinemesylate0 – does not )or% )ell, butnot too expensi2e can be used for

persistent lactation

G. Insulin – #ood for hyper#lycemic

C!

6. 9%minitis t8 $ correcti2e trimmin#or shoein# and anal#esics

D. AB tx – secondary infections

H. ito%in /=yso#ren 0 – not used inhorses, adrenocrticolytic dru# usedin do#s – causes se2ere ulceration of esopha#us in horses

•E1uine CIDs ,SCIDs.

autosomal recessi2e microdeletion of 6 basepairs of !3+$P"cs in +rabian foalsCell receptors on T cells and I# on B cells donJt mature*i#ns are pneumonia and profound lymphopenia

⇓ I#' e2en )ith colostrum inta%e at 477 days old-ypoplasia of all lymphoid tissue••• +nterior (nteritis•*outhern

*+dulthorses*almonella

Clostridium


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&otom%c horse )e2er• ( uine monocytic ehrlishiosis• E!rlic!ia risticii• e8(losi2e D• ?accination protocol:

a. T)o 2accinations F$G )ee%s apart in sprin# follo)ed by a booster in the fall in hi#h ris% areas

9'm(hos%rcom%• Most common form of thoracic tumor

• Can present in mediastinal, alimentary, multicentric, cutaneous and #enerali ed forms• Combinations can be found• Clinical si#ns are inappetance, )t loss, 2etral edema, dyspnea, pleural effusion and distension of @u#ular 2eins• Cou#hin# )hen mediastinal mass )as compressin# the ma@or bronchi and trachea

&eritonitisWh%t signs /ill the horse sho/ /0 (eritonitisGColicBric% red MM

Wh%t is the "lood/or# li#e o) % horse /0 (eritonitisG+cidotic – accumulation of lactic acidIncreased melanoma- (2aluate urethral di2erticula for sme#ma bean- *tallion rin# scar – pre2ents erection- +ccessory sex #lands rarely cause a problem

- Prostate is lar#er, 2esicular #lands are smaller

- Can ha2e impaction of ampulla, but causes 2ery subtle or no chan#es on rectal but )ill ha2e history of little e@aculate or loose heads. Tx is to mil% ampullato)ard urethra, strip and repeat e@aculate

*ame as bullTesticles lay differently than the bull, lays hori ontally rather than 2ertically$ (pididymis is on dorsomedial side of testicle*easonal breeder so sperm, testosterone, semen 2olume, beha2ior > T*( ⇑ in +pril.


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Brin# to 2et after a )ee% of normal use or sexual rest. Collect on phantom or @ump mare. Collect t)ice, one hour apart. (2aluate nd e@aculate.

- Rxn time – time to mount, time to #et erection, > time to e@aculation

- Temperature of +? should be F5$G7 °C /a little )armer than body temp0.


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*lin#s or deep beddin#Penicillin to tx ori#inatin# )ound infection+ntitoxin at hi#h dosesParenteral nutrition and I? electrolytes

&rognosis'ood if:4. -orse can drin%

. Remain standin#F. *ur2i2e more than one )ee%

&re2ention

?accine a#ainst T1EI3 /not or#anism0Probably lasts lon#er than a year, e2en thou#h #i2en at yearly shots'i2e tetanus shot to any horse )9 a )ound )9 un%no)n history or hasnJt been 2accinated )9in a year P= * #i2e 4677 units of antitoxin

Antito8in+r#ued dan#erous in lactatin# broodmare causin# hi#hly fatal li2er d called TheilerJs d*afe in foals+2oid antitoxin if 2accinated or if older than years old

Cer2ic%l Verte"r%l stenosis0m%l)orm%tion0m%l%rticul%tionA=A HWo""lers@

Etiolog'0(%thogenesisBone malformation causes either a fxnl /dynamic0 or absolute /static0 stenosisi in the spinal canal4. C?I – cer2ical 2ertebral instability /dynamic0 at CF$G in )eanlin#s

. C** – cer2ical static stenosis at C6$D in older horses?ertebral instability leads to soft tissue /muscle and li#ament0 hypertrophy causin# spinal cord compression

Caused bya. o2erfeedin#

b. diet imbalances esp of Ca Ph, Co > ;nc. osteochondrosis in2ol2in# the epiphyseal plate or articular processd. heredity – but osteochondrosisi is an inherited condition, and )obblers is a form of osteochondrosis0

Sign%lmentoun# TB or TA- males )hen trainin# be#ins

&E4. +bnormal #ait, most ob2iously in hind limbs but forelimbs are also affected

a. +taxia b. +bnormal turin# of small circles, )hen )al%ed do)n hill, at sudden stops > )hen led o2er obstacles

. Aea%nessF. !ysmetria

G. *pasticity6. +bnormal slap test on both sides /contralateral arytenoid )ill flutter )hen slapped on )ither0

D8=ocali e to cer2ical re#ionRad I! fxl or absolute stenosisMost common is dynamic compression atCF$G or CG$6 durin# flexion of a )eanlin# or yearlin#*tatic compression esions of C6$H occur in older horses

'elogr%m s area. usually too expensi2e

b. re uire #eneral anesthesiac. !onJt al)ays dx b9c can ha2e false ne#ati2esd. *ide effects – prolon#ed reco2ery, con2ulsions, anaphylactic shoc%

84. sually euthanasia

. 3*+I!s, !M*1 /I?0 > corticosteroids #i2e only short term impro2ementF. *tar2ation diets – prior to clinical si#ns #i2e lo) ener#y diet that is balanced for 2itamins and mineralsG. *x tx of laminectomy has a hi#h death rate6. ?erebral body fusion tx both static and dynamic compression at 1* – the lo)er the lesion, the hi#her the death rate but has 2ery #ood statistics

E1uine Vir%l Ence(h%lom'elitis in the Americ%s ,EEE> WEE> VEE.Aestern – 68 mortalitymost common e uine arbo2irus and most mild?ene uelan – Texas D78 mortality((( – 4778 mortality reportable

r%nsmissionReser2oir – birds and small mammals /?((0?ector – 2ery specific spp. 1f mos uitos

Clinic%l signsVV-i#hts incidence in +u#ust and *eptember – important for 2accination schedule


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altered consciousnessC3 dysfxn+taxia


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Sei


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&re2ention?accinate pre#nant mares durin# last part of pre#nancy to pre2ent sha%er foals

S(in%l Cord r%um%

istor'Peracute onset > nonpro#ressi2e*i#ns depend on le2el of in@ury /T $* in2ol2e hind limbs only0

D84. -x

. Rads – fx 2ertebrae, C4$C bro%en dens most commonF. C*< analysis – see erythroid pleocytosis be sure not iatro#enic hemorrha#e from needle, let set for a )hile

84. Corticosteroids or 3*+I!s – *olu$delta cortef is 2ery helpful in tx of human spinal trauma 2ictims

. ?ery hi#h !M*1F. Mannitol – expensi2e – may cause brain edema 2ia hypertonicityG. Bute6. *x tx – initial decompression or later decompression after callus formationD. (uthanasia – if paralysis

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Equine Board Review